WO2021044670A1

WO2021044670A1 - Super-resolution measurement device and super-resolution measurement device operation method

Info

Publication number: WO2021044670A1
Application number: PCT/JP2020/018465
Authority: WO
Inventors: 岡本　淳; 聡川島; 龍介大▲崎▼; 直毅林
Original assignee: 富士フイルム株式会社; 国立大学法人北海道大学
Priority date: 2019-09-03
Filing date: 2020-05-01
Publication date: 2021-03-11
Also published as: JP7195556B2; JPWO2021044670A1

Abstract

This super-resolution measurement device comprises: a real optical system comprising a diffusion member for diffusing input light waves from an object under measurement and a partial transmission mask for partially transmitting the diffused input light waves; a sensor for measuring the intensity and phase of the input light waves that have passed through the partial transmission mask and outputting an optical complex-amplitude image; and a virtual optical system for generating an output image by using a computer to carry out computation processing that is for reproducing, from the optical complex-amplitude image, input light waves from the object under measurement that include a super resolution component, which is a component of a resolution exceeding the resolution of the sensor, and includes a phase conjugation function of the transmission function of the diffusion member.

Description

How to operate the super-resolution measuring device and the super-resolution measuring device

The technology of the present disclosure relates to a super-resolution measuring device and a method of operating the super-resolution measuring device.

A technique (hereinafter, super-resolution technology) for measuring an object to be measured with a sensor such as a CCD (Charge-Coupled Device) image sensor and obtaining an output image having a resolution exceeding the resolution of the sensor (hereinafter, super-resolution) is known. ing.

Atsushi Ideshita, 2 outsiders, "Development of super-resolution measurement algorithm by digital holography", Proceedings of the 2009 Autumn Meeting of the Japan Society for Precision Engineering, Proceedings of the Academic Lecture, Internet <URL: https://www.jstage.jst.go. jp / article / pscjspe / 2009A / 0 / 2009A_0_687 / _article / -char / ja /> describes a super-resolution technique using phase-shift digital holography, which is one of the optical complex amplitude measurement techniques. In "Development of super-resolution measurement algorithm by digital holography" by Ideshita and Gaito, in order to improve the horizontal resolution, the sensor is moved in several places in the horizontal direction at a pitch smaller than the pixel size, and the sensor is fixed. A component with a resolution exceeding the resolution of the sensor (hereinafter referred to as a super-resolution component) that cannot be obtained is acquired. Then, a super-resolution output image is obtained by synthesizing the holograms measured at each location where the sensor is moved. The optical complex amplitude represents the vibration of a light wave as a complex number.

Also, Masao Hamada, "Adaptive Filter Type Super-Resolution", Panasonic Technical Journal Vol. 56 No. 4 Jan. 2011, Internet <URL: https://www.panasonic.com/jp/corporate/technology-design/ptj/pdf/v5604/p0208.pdf> is an image obtained by measuring the object to be measured with a sensor. A super-resolution technique for estimating a super-resolution component by applying a magnifying filter process to the image is described. That is, in Hamada's "Adaptive Filter Type Super-Resolution", the super-resolution component is estimated by magnifying filter processing from an image that does not contain the super-resolution component.

In the technology described in "Development of super-resolution measurement algorithm by digital holography" by Ideshita and Gaita, it is necessary to move the sensor in the horizontal direction. In addition, in the technology described in "Adaptive Filter Type Super-Resolution" by Hamada, it is guaranteed that the super-resolution component is only estimated by magnifying filter processing and accurately reflects the actual super-resolution component. There is no. Therefore, the present inventors actually measure the super-resolution component with the sensor by diffusing the input light wave of the object to be measured and incidenting it on the sensor and measuring the optical complex amplitude of the diffused input light wave with the sensor. However, we are considering generating a super-resolution output image based on the image obtained by this.

That is, in "Development of super-resolution measurement algorithm by digital holography" by Ideshita and Gaito, the super-resolution component is acquired by moving the sensor in the horizontal direction at a pitch smaller than the pixel size. In Hamada's "Adaptive Filter Type Super-Resolution", the super-resolution component is estimated by magnifying filter processing. On the other hand, in the super-resolution technology studied by the present inventors, a super-resolution component is acquired by diffusing the input light wave of the object to be measured. Therefore, according to the super-resolution technology studied by the present inventors, it is possible to obtain a super-resolution output image without moving the sensor and without relying on estimation by magnifying filter processing. It becomes.

However, in the super-resolution technology for diffusing the input light wave of the object to be measured, which the present inventors are studying, the image quality of the super-resolution output image may be deteriorated. The present inventors have found that one of the causes of this deterioration in image quality is that the amount of information contained in the diffused input light wave is large.

An object of the present disclosure technique is to provide a super-resolution measuring device and a method of operating a super-resolution measuring device capable of reducing image quality deterioration that occurs in a super-resolution output image.

In order to achieve the above object, the super-resolution measuring apparatus of the present disclosure includes a diffuser member that diffuses the input light wave of the object to be measured, and a partial transmission mask that partially transmits the diffused input light wave. A sensor that measures the intensity and phase of the input light wave transmitted through the partial transmission mask and outputs an optical complex amplitude image, and an input light wave of the object to be measured that contains a super-resolution component that is a component with a resolution exceeding the resolution of the sensor. Is a calculation process for reproducing an optical complex amplitude image, and includes a virtual optical system that generates an output image by performing a calculation process including a phase conjugation function of a transmission function of a diffuser member on a computer.

The virtual optical system generates a first intermediate image from an optical complex amplitude image, generates a second intermediate image from a reference image of the object to be measured, and subtracts a second intermediate image from the first intermediate image based on the image. It is preferable to generate an output image.

The real optical system includes an optical complex amplitude image acquisition optical path for obtaining an optical complex amplitude image that reaches the sensor via a diffuser member, and a reference image acquisition optical path for obtaining a reference image that reaches the sensor without passing through the diffuser member. It is preferable to have.

It is preferable that the reference image acquisition optical path branches from the object to be measured side rather than the diffusion member of the optical complex amplitude image acquisition optical path. In this case, it is preferable that the reference image acquisition optical paths merge on the sensor side of the diffusion member of the optical complex amplitude image acquisition optical path. Further, in the reference image acquisition optical path, it is preferable that the input light wave is focused to a size that fits in the transmission portion of the partial transmission mask.

The optical complex amplitude image acquisition optical path and the reference image acquisition optical path are also used, and the diffusion member and the partial transmission mask are the approach position that entered the optical complex amplitude image acquisition optical path and the evacuation that was retracted from the optical complex amplitude image acquisition optical path. The optical complex amplitude image acquisition optical path, which is moved to the position, preferably functions as a reference image acquisition optical path when the diffusion member and the partial transmission mask are in the retracted position.

The diffusing member is preferably a random diffusing plate that randomly diffuses the input light wave.

The diffuser member is a spatial light modulator whose diffusion characteristics of the input light wave can be changed, and the sensor measures the intensity and phase of a plurality of types of input light waves whose diffusion characteristics are changed by the spatial light modulator, and the input light wave. The virtual optical system outputs a plurality of optical complex amplitude images having different diffusion characteristics, generates an intermediate image from each of the plurality of optical complex amplitude images, and obtains an image obtained by adding and averaging the plurality of intermediate images as an output image. Is preferable.

The actual optical system preferably includes a pair of Fourier transform lenses arranged on the object to be measured side of the diffusing member and on the sensor side of the diffusing member.

The diffusing member is a random diffusing plate that randomly diffuses the input light wave, and a random diffusing plate provided in the central portion with a light-shielding portion that cuts low spatial frequency components by a Fourier transform lens arranged on the object to be measured. Is preferable.

The diffuser member is a random diffuser plate that randomly diffuses the input light wave, and is a random diffuser plate provided in the central portion with an opening that transmits low spatial frequency components by the Fourier conversion lens arranged on the side to be measured. Therefore, it is preferable that the actual optical system is provided with a condensing lens that collects low spatial frequency components transmitted through the aperture on the transmission portion of the partial transmission mask.

The method of operating the super-resolution measuring device of the present disclosure uses a real optical system including a diffuser member that diffuses the input light wave of the object to be measured and a partially transmitted mask that partially transmits the diffused input light wave, and uses a sensor. , The intensity and phase of the input light wave transmitted through the partial transmission mask are measured to output an optical complex amplitude image, and in the virtual optical system, the object to be measured containing a super-resolution component that is a component with a resolution exceeding the resolution of the sensor. It is a calculation process for reproducing an input light wave from an optical complex amplitude image, and a calculation process including a phase conjugation function of a transmission function of a diffuser member is performed on a computer to generate an output image.

According to the technique of the present disclosure, it is possible to provide an operating method of a super-resolution measuring device and a super-resolution measuring device capable of reducing image quality deterioration that occurs in a super-resolution output image.

It is a figure which shows the super-resolution measuring apparatus. It is a figure which shows the state which uses the optical complex amplitude image acquisition optical path in the real optical system. It is a figure which shows the state which uses the reference image acquisition optical path in the real optical system. It is a figure which conceptually shows the operation of a random diffuser, FIG. 4A shows the case where there is no random diffuser, and FIG. 4B shows the case where there is a random diffuser. It is a figure which shows the partial transparency mask. Optical complex amplitude image acquisition It is a figure which shows the state of obtaining the optical complex amplitude image using an optical path. It is a figure which shows the state of obtaining the reference image using the reference image acquisition optical path. It is a block diagram of the computer which constitutes a processing apparatus. It is a block diagram which mainly shows the processing part of the CPU of the processing apparatus. It is a figure which shows the transfer function information. It is a figure which shows the process of the 1st intermediate image generation part. It is a figure which shows the 1st virtual optical system which is equivalent to the processing of the 1st intermediate image generation part. It is a figure which shows the process of the 2nd intermediate image generation part. It is a figure which shows the process of the 2nd intermediate image generation part. It is a figure which shows the 2nd virtual optical system which is equivalent to the processing of the 2nd intermediate image generation part. It is a figure which shows the processing of the subtraction part. It is a flowchart which shows the processing procedure of the super-resolution measuring apparatus. It is a figure which conceptually shows the relationship between the 1st intermediate image, the 2nd intermediate image, and an output image. It is a table which shows various parameters in Examples 1 to 3. FIG. 20A is a diagram showing an input image of the first embodiment, FIG. 20A shows an intensity image of the input image, and FIG. 20B shows a phase image of the input image. It is a figure which shows the optical complex amplitude image of Example 1, FIG. 21A shows the intensity image of the optical complex amplitude image, and FIG. 21B shows the phase image of the optical complex amplitude image. FIG. 22A is a diagram showing a first intermediate image of the first embodiment, FIG. 22A shows an intensity image of the first intermediate image, and FIG. 22B shows a phase image of the first intermediate image. FIG. 23A is a diagram showing a reference image of the first embodiment, FIG. 23A shows an intensity image of the reference image, and FIG. 23B shows a phase image of the reference image. It is a figure which shows the 2nd intermediate image of Example 1, FIG. 24A shows the intensity image of the 2nd intermediate image, and FIG. 24B shows the phase image of the 2nd intermediate image. It is a figure which shows the subtraction image of Example 1, FIG. 25A shows the intensity image of the subtraction image, and FIG. 25B shows the phase image of the subtraction image. FIG. 26A is a diagram showing an output image of the first embodiment, FIG. 26A shows an intensity image of the output image, and FIG. 26B shows a phase image of the output image. FIG. 27A is a diagram showing another example of the input image of the first embodiment, FIG. 27A shows an intensity image of the input image, and FIG. 27B shows a phase image of the input image. It is a figure which shows the reference image in the case of the input image of FIG. It is a figure which shows the optical complex amplitude image obtained by measuring the input image of FIG. 27, FIG. 29A shows the intensity image of the optical complex amplitude image, and FIG. 29B shows the phase image of the optical complex amplitude image. It is a figure which shows the output image in the case of the input image of FIG. 27, FIG. 30A shows the intensity image of the output image, and FIG. 30B shows the phase image of the output image. It is a figure which shows another example of a real optical system. It is a figure which shows another example of a real optical system. It is a figure which shows the real optical system of 2nd Embodiment. It is a figure which shows the generation part of the 2nd Embodiment. It is a figure which shows the process of 2nd Embodiment collectively. It is a figure which shows the phase image of the output image of Example 2. It is a figure which shows the real optical system of 3rd Embodiment. It is a figure which shows the random diffusion plate of 3rd Embodiment. It is a figure which shows the input image of Example 3, FIG. 39A shows the intensity image of the input image, and FIG. 39B shows the phase image of the input image. It is a figure which shows the high spatial frequency component of the input image shown in FIG. 39, FIG. 40A shows the intensity image of the high spatial frequency component, and FIG. 40B shows the phase image of the high spatial frequency component. FIG. 41A is a diagram showing an output image of the third embodiment, FIG. 41A shows an intensity image of the output image, and FIG. 41B shows a phase image of the output image. It is a figure which shows the real optical system of 4th Embodiment. It is a figure which shows the random diffusion plate of 4th Embodiment. It is a figure which shows the generation part of 4th Embodiment. It is a figure which shows another example of a partial transmission mask. It is a figure which shows another example of a partial transmission mask.

[First Embodiment]
In FIG. 1, the super-resolution measuring device 10 includes a stage 11, an actual optical system 12, a sensor 13, and a processing device 14. The object to be measured 15 is set on the stage 11. The real optical system 12 takes in the input light wave of the object to be measured 15 set on the stage 11 and guides it to the sensor 13. The sensor 13 measures the intensity and phase of the input light wave guided by the real optical system 12 and outputs an optical complex amplitude image 54 (see FIG. 6). The sensor 13 transmits the optical complex amplitude image 54 to the processing device 14. The processing device 14 is, for example, a desktop personal computer. The processing device 14 generates an output image 76 (see FIG. 9) based on the optical complex amplitude image 54 from the sensor 13.

In FIGS. 2 and 3, the real optical system 12 has an optical complex amplitude image acquisition optical path 20 and a reference image acquisition optical path 21. The optical complex amplitude image acquisition optical path 20 is an optical path for obtaining an optical complex amplitude image 54. The reference image acquisition optical path 21 is an optical path for obtaining a reference image 61 (see FIG. 7) of the object to be measured 15. A random diffusion plate 22 which is an example of the “diffusion member” according to the technique of the present disclosure is arranged in the optical complex amplitude image acquisition optical path 20. On the other hand, the random diffuser plate 22 is not arranged in the reference image acquisition optical path 21. That is, the optical complex amplitude image acquisition optical path 20 is an optical path that reaches the sensor 13 via the random diffuser plate 22. On the other hand, the reference image acquisition optical path 21 is an optical path that reaches the sensor 13 without passing through the random diffuser plate 22.

The random diffusion plate 22 has an uneven surface 23 on which random irregularities are formed on the surface. The random diffusion plate 22 is arranged with the uneven surface 23 facing the sensor 13 side. The random diffuser plate 22 diffuses the input light wave of the object to be measured 15.

In addition to the random diffuser plate 22, a beam splitter 25, a Fourier transform lens 26, a Fourier transform lens 27, a beam splitter 28, and a partial transmission mask 29 are arranged in the optical complex amplitude image acquisition optical path 20.

The beam splitter 25 transmits the input light wave of the object to be measured 15 toward the Fourier transform lens 26. Further, the beam splitter 25 reflects the input light wave of the object to be measured 15 toward the mirror 30 of the reference image acquisition optical path 21 by 90 °. The beam splitter 25 branches the reference image acquisition optical path 21 from the object to be measured 15 side of the random diffuser plate 22 of the optical complex amplitude image acquisition optical path 20.

The

Fourier transform lenses

26 and 27 are arranged at positions sandwiching the random diffuser plate 22. More specifically, the Fourier transform lens 26 is arranged closer to the object to be measured 15 than the random diffuser 22. The Fourier transform lens 27 is arranged closer to the sensor 13 than the random diffuser 22. The

Fourier transform lenses

26 and 27 are described as "a diffraction image obtained on the rear focal plane of the lens when a transmitting object is placed on the front focal plane of the lens and illuminated with a plane wave having a uniform intensity (amplitude) distribution from behind the transparent object. Is defined as a lens having the property that the intensity distribution of is represented by the Fourier transform of the intensity distribution of the object.

The beam splitter 28 transmits the input light wave of the object to be measured 15 diffused by the random diffuser plate 22 toward the partial transmission mask 29. Further, the beam splitter 28 reflects the input light wave of the object to be measured 15 from the reference image acquisition optical path 21 toward the partial transmission mask 29 by 90 °. By this beam splitter 28, the reference image acquisition optical path 21 merges on the sensor 13 side of the random diffuser plate 22 of the optical complex amplitude image acquisition optical path 20.

A mirror 30, a lens 31, a lens 32, and a mirror 33 are arranged in the reference image acquisition optical path 21. The mirror 30 reflects the input light wave of the object to be measured 15 from the beam splitter 25 toward the lens 31 by 90 °. The

lenses

31 and 32 collect the input light wave of the object to be measured 15 into a size that fits in the transmission portion 35 (see also FIG. 5) of the partial transmission mask 29. The mirror 33 reflects the input light wave of the object to be measured 15 focused by the

lenses

31 and 32 toward the beam splitter 28 of the optical complex amplitude image acquisition optical path 20 by 90 °.

A shutter 36 is provided between the Fourier transform lens 27 of the optical complex amplitude image acquisition optical path 20 and the beam splitter 28. Similarly, a shutter 37 is also provided between the mirror 33 of the reference image acquisition optical path 21 and the beam splitter 28 of the optical complex amplitude image acquisition optical path 20.

The shutter 36 is movable between an approach position that has entered the optical complex amplitude image acquisition optical path 20 and a retracted position that has been retracted from the optical complex amplitude image acquisition optical path 20. Similarly, the shutter 37 is movable between the approach position that has entered the reference image acquisition optical path 21 and the retracted position that has been retracted from the reference image acquisition optical path 21. When the

shutters

36 and 37 are in the approach position, the input light wave of the object to be measured 15 is blocked. When the

shutters

36 and 37 are in the retracted position, the input light wave of the object to be measured 15 is allowed to enter.

When the optical complex amplitude image 54 is obtained by using the optical complex amplitude image acquisition optical path 20, the shutter 36 is moved to the retracted position and the shutter 37 is moved to the approach position as shown in FIG. On the other hand, when the reference image 61 is obtained by using the reference image acquisition optical path 21, the shutter 36 is moved to the approach position and the shutter 37 is moved to the retracted position as shown in FIG. In this way, the optical complex amplitude image acquisition optical path 20 and the reference image acquisition optical path 21 are used properly. The positions where the

shutters

36 and 37 are provided are not limited to the positions exemplified above. A shutter 36 may be provided between the beam splitter 25 and the Fourier transform lens 26, or a shutter 37 may be provided between the beam splitter 25 and the mirror 30.

FIG. 4 conceptually shows the action of the random diffusion plate 22. FIG. 4A shows the case where the random diffuser plate 22 is not present, and FIG. 4B shows the case where the random diffuser plate 22 is present. As shown in FIG. 4A, in the absence of the random diffuser 22, the input light wave (indicated by the dashed arrow) from the region 41 for one pixel of the object 15 to be measured is one of the plurality of pixels 40 of the sensor 13. Incident in. That is, there is a one-to-one relationship between the area 41 for one pixel of the object to be measured 15 and the pixel 40 of the sensor 13. On the other hand, as shown in FIG. 4B, when there is a random diffuser plate 22, the input light wave from the region 41 for one pixel of the object to be measured 15 is diffused by the random diffuser plate 22 and a large number of pixels 40 of the sensor 13. Incident in. That is, the area 41 for one pixel of the object to be measured 15 and the pixel 40 of the sensor 13 have a one-to-many relationship. In this way, the input light wave from the region 41 for one pixel of the object to be measured is incident on a large number of pixels 40 of the sensor 13, so that the final output image 76 has a super-resolution that exceeds the resolution of the sensor 13. Image components will be included.

In FIG. 5, the partial transmission mask 29 has a square shape in which a transmission portion 35, which is a square hole, is formed in the central portion. The portion of the partial transmission mask 29 other than the transmission portion 35 blocks the input light wave of the object to be measured 15. Therefore, when the optical complex amplitude image acquisition optical path 20 is used, the input light wave of the measured object 15 incident on the sensor 13 is 1/2 or less of the input light wave of the measured object 15 diffused by the random diffuser plate 22. , More preferably limited to 1/4 or less. When the reference image acquisition optical path 21 is used, the input light waves of the object to be measured 15 are focused by the

lenses

31 and 32 to a size that fits in the transmitting portion 35, as described above. Therefore, the input light wave of the object to be measured 15 incident on the sensor 13 is not limited by the partial transmission mask 29. The partially transparent mask 29 is not limited to a square shape. For example, it may be circular. Similarly, the transmission portion 35 is not limited to a square shape, and may be, for example, a circular shape.

For the sensor 13, for example, a general sensor for phase shift digital holography is used. Specifically, the sensor 13 is a CCD image sensor, a CMOS (Complementary Metal Oxide Sensor) image sensor, or the like. However, the type of the sensor 13 is not particularly limited as long as it can measure the spatial distribution of the optical complex amplitude of the input light wave.

FIG. 6 shows how the optical complex amplitude image acquisition 54 is obtained by using the optical complex amplitude image acquisition optical path 20. First, when the optical complex amplitude of the input image 50 represented by the input light wave of the object 15 to be measured is a_R (x, y) and the complex Fourier transform function of the Fourier transform lens 26 is F_R {*}, after the complex Fourier transform. The optical complex amplitude of the image 51 of
F_R {a_R (x, y)} = A_R (X, Y)
Can be expressed as.

When the transmission function of the random diffuser plate 22 is Φ_R (X, Y), the optical complex amplitude of the image 52 transmitted through the random diffuser plate 22 is
A_R (X, Y) x Φ_R (X, Y)
Can be expressed as. Here, in order to acquire A_R (X, Y) × Φ_R (X, Y), the method is not necessarily limited to the method using the random diffuser plate 22, and the light whose phase is randomly modulated spatially is measured. Transmitted light or scattered light obtained by irradiating the object 15 may be used.

When the complex Fourier transform function of the Fourier transform lens 27 is F_R {*} as in the Fourier transform lens 26, the optical complex amplitude of the image 53 after the complex Fourier transform is
F_R {A_R (X, Y) x Φ_R (X, Y)}
Can be expressed as.

When the transmission function of the partial transmission mask 29 is Rect_R {*}, the optical complex amplitude of the optical complex amplitude image 54 measured by the sensor 13 through the partial transmission mask 29 is
Rec_R {F_R {A_R (X, Y) x Φ_R (X, Y)}}
Can be expressed as. Here, Rec_R {*} shows a value of * in the transmission portion 35 of the partial transmission mask 29, and shows a value of 0 in the peripheral light-shielding portion other than the transmission portion 35.

FIG. 7 shows how the reference image 61 is obtained by using the reference image acquisition optical path 21. The

Fourier transform lenses

26 and 27 and the random diffuser 22 are not arranged in the reference image acquisition optical path 21. Further, as described above, in the reference image acquisition optical path 21, the size is such that the input light wave of the object to be measured 15 fits in the transmission portion 35. Therefore, the optical complex amplitude of the reference image 61 measured by the sensor 13 can be represented by b_R (x, y), which is the same as the optical complex amplitude of the input image 60 represented by the input light wave of the object to be measured 15. At this time, even if the object to be measured 15 has fine information exceeding the resolution of the sensor 13, the resolution of the reference image 61 to be measured is limited to the resolution of the sensor 13. That is, the reference image 61 does not have a super-resolution component that exceeds the resolution of the sensor 13.

In FIG. 8, the computer constituting the processing device 14 includes a storage device 65, a memory 66, a CPU (Central Processing Unit) 67, a communication unit 68, a display 69, and an input device 70. These are interconnected via a bus line 71.

The storage device 65 is a hard disk drive built in the computer constituting the processing device 14 or connected via a cable or a network. Alternatively, the storage device 65 is a disk array in which a plurality of hard disk drives are connected in series. The storage device 65 stores control programs such as an operating system, various application programs, and various data associated with these programs. A solid state drive may be used instead of the hard disk drive.

The memory 66 is a work memory for the CPU 67 to execute a process. The CPU 67 comprehensively controls each part of the computer by loading the program stored in the storage device 65 into the memory 66 and executing the processing according to the program.

The communication unit 68 is a network interface that controls the transmission of various information via various networks. The display 69 displays various screens. The computer constituting the processing device 14 receives input of an operation instruction from the input device 70 through various screens. The input device 70 is a keyboard, a mouse, a touch panel, or the like.

In FIG. 9, the operation program 75 is stored in the storage device 65. The operation program 75 is an application program for operating the computer as the processing device 14. The storage device 65 also stores an optical complex amplitude image 54, a reference image 61, an output image 76, and transfer function information 77.

When the operation program 75 is activated, the CPU 67 of the computer constituting the processing device 14 cooperates with the memory 66 and the like to form an image acquisition unit 80 and a read / write (hereinafter abbreviated as RW (Read Write)) control unit 81. , And function as a generator 82.

The image acquisition unit 80 acquires the optical complex amplitude image 54 and the reference image 61 from the sensor. The image acquisition unit 80 outputs the acquired optical complex amplitude image 54 and the reference image 61 to the RW control unit 81.

The RW control unit 81 controls the storage of various data in the storage device 65 and the reading of various data in the storage device 65. The RW control unit 81 stores the optical complex amplitude image 54 and the reference image 61 from the image acquisition unit 80 in the storage device 65. Further, the RW control unit 81 reads out the optical complex amplitude image 54 and the reference image 61 from the storage device 65 and outputs them to the generation unit 82.

The RW control unit 81 reads the transfer function information 77 from the storage device 65 and outputs it to the generation unit 82. Further, the RW control unit 81 stores the output image 76 from the generation unit 82 in the storage device 65.

The generation unit 82 generates the output image 76 by performing calculation processing on the optical complex amplitude image 54. The calculation process is a process of reproducing the input light wave of the object to be measured 15 including a super-resolution component which is a component having a resolution exceeding the resolution of the sensor 13 from the optical complex amplitude image 54, and is a process of reproducing the input light wave of the optical complex amplitude image 54 from the computer constituting the processing device 14. This is the process performed above. This calculation process includes the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107, which is an example of the “phase conjugation function of the transmission function of the diffusion member” described later. By such calculation processing, the output image 76 is generated as an image showing the input light wave including the super-resolution component. Therefore, the generation unit 82 is an example of the “virtual optical system” according to the technique of the present disclosure.

The generation unit 82 includes a first intermediate image generation unit 85, a second intermediate image generation unit 86, and a subtraction unit 87. An optical complex amplitude image 54 is input to the first intermediate image generation unit 85. The first intermediate image generation unit 85 generates the first intermediate image 88 (see also FIG. 11) from the optical complex amplitude image 54. The first intermediate image generation unit 85 outputs the first intermediate image 88 to the subtraction unit 87.

On the other hand, the reference image 61 is input to the second intermediate image generation unit 86. The second intermediate image generation unit 86 generates a second intermediate image 89 (see also FIG. 14) from the reference image 61. The second intermediate image generation unit 86 outputs the second intermediate image 89 to the subtraction unit 87.

The subtraction unit 87 subtracts the second intermediate image 89 from the first intermediate image 88. The subtraction unit 87 generates the output image 76 based on the image obtained by subtracting the second intermediate image 89 from the first intermediate image 88.

As shown in FIG. 10, a plurality of transfer functions are registered in the transfer function information 77. These transfer functions are used when the first intermediate image generation unit 85 generates the first intermediate image 88 and when the second intermediate image generation unit 86 generates the second intermediate image 89.

F_V1 ^-1 {*} is the complex Fourier inverse transform function of the virtual Fourier transform lens 106, 108 (see FIG. 12). F_V1 ^-1 {*} is an inverse function of the complex Fourier transform function F_R of the

Fourier transform lens

26, 27 of the actual optical system 12 {*}. Φ_V1 (X, Y) is a transmission function of the virtual random diffuser plate 107 (see FIG. 12). Φ_V1 (X, Y) is a computer that returns the diffused input light wave to the input light wave before diffusion, as opposed to the action of the random diffuser plate 22 diffusing the input light wave of the object to be measured 15 in the real optical system 12. It is a function that is virtually realized above. Therefore, Φ_V1 (X, Y) has a phase conjugation relationship with the transmission function Φ_R (X, Y) of the random diffuser plate 22 of the real optical system 12. That is,
Φ_R (X, Y) x Φ_V1 (X, Y) = 1
Is. Φ_V1 (X, Y) is an example of the "phase conjugation function of the transmission function of the diffusion member" according to the technique of the present disclosure.

F_V2 {*} is a complex Fourier transform function of the virtual Fourier transform lens 131, 133 (see FIG. 15). F_V2 {*} is a function equivalent to the complex Fourier transform function F_R {*} of the

Fourier transform lenses

26 and 27 of the real optical system 12. Φ_V2 (X, Y) is a transmission function of the virtual random diffuser 132 (see FIG. 15). Φ_V2 (X, Y) is a function equivalent to the transmission function Φ_R (X, Y) of the random diffuser plate 22 of the real optical system 12. Rect_V {*} is a transparency function of the virtual partial transparency mask 134 (see FIG. 15). Rect_V {*} is a function equivalent to the transmission function Rect_R {*} of the partial transmission mask 29 of the actual optical system 12.

As shown in FIG. 11, the first intermediate image generation unit 85 includes a fast Fourier inverse transform unit 95, a calculation unit 96, and a fast Fourier inverse transform unit 97.

Inverse fast Fourier transform unit 95, using the complex Fourier inverse transform function ^F_V1 -1 virtual Fourier transform lens 106 {*} is subjected to inverse fast Fourier transform with respect to the optical complex amplitude image 54.

Here, generally, F ^-1 {F {G (X, Y)}} = G (X, Y) holds. However, since the optical complex amplitude Rect_R {F_R {A_R (X, Y) × Φ_R (X, Y)}} of the optical complex amplitude image 54 is multiplied by the transmission function Rec_R of the partial transmission mask 29, the above equation holds. do not do. However, the optical complex amplitude of the image 98 after the fast Fourier inverse transform is approximately
^{F_V1 -1 {Rect_R {F_R {A_R} (X, Y) × Φ_R (X, Y)}}} ≒ A_SR (X, Y) × Φ_R (X, Y)
Can be expressed as. A_SR (X, Y) contains a super-resolution component.

The calculation unit 96 multiplies the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107 by the optical complex amplitude A_SR (X, Y) × Φ_R (X, Y) of the image 98 after the fast Fourier inverse transform (X, Y). A_SR (X, Y) x Φ_R (X, Y) x Φ_V1 (X, Y)). As described above, Φ_V1 (X, Y) has a phase conjugation relationship with Φ_R (X, Y), and Φ_R (X, Y) × Φ_V1 (X, Y) = 1. Therefore, the calculated optical complex amplitude of the image 99 eventually becomes A_SR (X, Y). As described above, the calculation process performed by the generation unit 82 includes the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107, which is an example of the “phase conjugation function of the transmission function of the diffusion member”.

Inverse fast Fourier transform unit 97, using the complex Fourier inverse transform function ^F_V1 -1 virtual Fourier transform lens 108 {*} is subjected to inverse fast Fourier transform to calculate the image after 99. As a result, the first intermediate image 88 is generated. The optical complex amplitude of the first intermediate image 88 is
^{F_V1 -1 {A_SR (X, Y} )} = a_SR (x, y)
Can be expressed as.

FIG. 12 shows a first virtual optical system 105 equivalent to the processing of the first intermediate image generation unit 85. The first virtual optical system 105 includes a virtual Fourier transform lens 106, a virtual random diffuser plate 107, and a virtual Fourier transform lens 108. The action of the virtual Fourier transform lens 106 is equivalent to the processing of the fast Fourier inverse transform unit 95. The action of the virtual random diffuser 107 is equivalent to the processing of the calculation unit 96. The action of the virtual Fourier transform lens 108 is equivalent to the processing of the fast Fourier inverse transform unit 97.

As shown in FIGS. 13 and 14, the second intermediate image generation unit 86 includes a fast Fourier transform unit 110, a calculation unit 111, a fast Fourier transform unit 112, a calculation unit 113, a fast Fourier inverse transform unit 114, and a calculation unit 115. And has a fast Fourier transform unit 116.

As shown in FIG. 13, the fast Fourier transform unit 110 performs a fast Fourier transform on the reference image 61 using the complex Fourier transform function F_V2 {*} of the virtual Fourier transform lens 131. The optical complex amplitude of the image 117 after the fast Fourier transform is
F_V2 {b_R (x, y)} = B_R (X, Y)
Can be expressed as. Since the reference image 61 measures the input light wave of the object to be measured 15 focused so as to fit in the transmission portion 35 of the partial transmission mask 29, it is before being input to the fast Fourier transform unit 110. It has been changed to the same size as the optical complex amplitude image 54.

The calculation unit 111 multiplies the transmission function Φ_V2 (X, Y) of the virtual random diffusion plate 132 by the optical complex amplitude B_R (X, Y) of the image 117 after the fast Fourier transform. The calculated optical complex amplitude of image 118 is
B_R (X, Y) x Φ_V2 (X, Y)
Can be expressed as.

The fast Fourier transform unit 112 performs a fast Fourier transform on the calculated image 118 by using the complex Fourier transform function F_V2 {*} of the virtual Fourier transform lens 133. The optical complex amplitude of image 119 after the fast Fourier transform is
F_V2 {B_R (X, Y) x Φ_V2 (X, Y)}
Can be expressed as.

In FIG. 14, the calculation unit 113 uses the transmission function Rect_V {*} of the virtual partial transparency mask 134 to perform a calculation equivalent to that of the partial transparency mask 29 on the image 119 after the fast Fourier transform. The calculated optical complex amplitude of the image 120 is
Rec_V {F_V2 {B_R (X, Y) x Φ_V2 (X, Y)}}
Can be expressed as.

Inverse fast Fourier transform unit 114, like the fast Fourier inverse transform unit 95 of the first intermediate image generating unit 85, using the complex Fourier inverse transform function ^F_V1 -1 virtual Fourier transform lens 106 {*}, after calculation A fast Fourier transform is applied to the image 120.

As in the case of the first intermediate image generation unit 85, the optical complex amplitude of the image 121 after the fast Fourier inverse transform is approximately
^{F_V1 -1 {Rect_V {F_V2 {B_R} (X, Y) × Φ_V2 (X, Y)}}} ≒ B_NSR (X, Y) × Φ_V2 (X, Y)
Can be expressed as. B_NSR (X, Y) does not contain a super-resolution component.

The calculation unit 115 multiplies the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107 by the optical complex amplitude B_NSR (X, Y) × Φ_V2 (X, Y) of the image 121 after the fast Fourier inverse transform (X, Y). B_NSR (X, Y) x Φ_V2 (X, Y) x Φ_V1 (X, Y)). As described above, Φ_V1 (X, Y) has a phase conjugation relationship with Φ_R (X, Y), and Φ_V2 (X, Y) is equivalent to Φ_R (X, Y). Therefore, Φ_V2 (X, Y) × Φ_V1 (X, Y) = 1, and the calculated optical complex amplitude of the image 122 is B_NSR (X, Y) after all.

Inverse fast Fourier transform unit 116, using the complex Fourier inverse transform function ^F_V1 -1 virtual Fourier transform lens 108 {*} is subjected to inverse fast Fourier transform to calculate the image after 122. As a result, the second intermediate image 89 is generated. The optical complex amplitude of the second intermediate image 89 is
^{F_V1 -1 {B_NSR (X, Y} )} = b_NSR (x, y)
Can be expressed as.

FIG. 15 shows a second virtual optical system 130 equivalent to the processing of the second intermediate image generation unit 86. In the second virtual optical system 130, in addition to the virtual Fourier transform lens 106, the virtual random diffuser plate 107, and the virtual Fourier transform lens 108 of the first virtual optical system 105, the virtual Fourier transform lens 131, the virtual random diffuser plate 132, and the virtual It is composed of a Fourier transform lens 133 and a virtual partial transmission mask 134. The action of the virtual Fourier transform lens 131 is equivalent to the processing of the fast Fourier transform unit 110. The action of the virtual random diffuser 132 is equivalent to the processing of the calculation unit 111. The action of the virtual Fourier transform lens 133 is equivalent to the processing of the fast Fourier transform unit 112. The action of the virtual partial transparency mask 134 is equivalent to the processing of the calculation unit 113.

The virtual Fourier transform lens 131, the virtual random diffuser 132, the virtual Fourier transform lens 133, and the virtual partial transmission mask 134 are the Fourier transform lens 26, the random diffuser 22, the Fourier transform lens 27, and the partial transmission mask of the real optical system 12. Equivalent to 29. That is, the processing of the fast Fourier transform unit 110, the calculation unit 111, the fast Fourier transform unit 112, and the calculation unit 113 of the second intermediate image generation unit 86 virtualizes the action of the optical complex amplitude image acquisition optical path 20 of the real optical system 12. Equivalent to the transformed process.

As shown in FIG. 16, the subtraction unit 87 subtracts the optical complex amplitude b_NSR (x, y) of the second intermediate image 89 from the optical complex amplitude a_SR (x, y) of the first intermediate image 88. More specifically, the real and imaginary parts of a_SR (x, y) and b_NSR (x, y) are subtracted. As a result, the output image 76 (O (x, y)) approximates the original input image 50 by subtracting the real and imaginary parts of the optical complex amplitudes a_R (x, y) and b_R (x, y). ) Can be obtained. That is,
Re {a_R (x, y) -b_R (x, y)} ≒ Re {a_SR (x, y) -b_NSR (x, y)}
Im {a_R (x, y) -b_R (x, y)} ≒ Im {a_SR (x, y) -b_NSR (x, y)}
Is. Re {*} represents the real part and Im {*} represents the imaginary part.

More specifically, the output image 76 (O (x, y)) is
O (x, y) = C × {a_SR (x, y) -b_NSR (x, y)} + b_R (x, y)
Obtained by

C is a standardized constant. Since the standardization constant C captures a part of the input light wave diffused by the random diffuser 22 by the partial transmission mask 29 and measures it by the sensor 13, the reference image 61 is not diffused by the random diffuser 22. It is a constant for correcting the amount that the intensity is significantly different from that in the case of obtaining. The normalization constant C is how much the intensity of the optical complex amplitude a_SR (x0, y0) of the first intermediate image 88 decreases when the point light source a_R (x0, y0) is placed at the center (x0, y0). Can be obtained by examining in advance. That is,
C ² = {a_R (x0, y0)} ² / {a_SR (x0, y0)} ²
The standardization constant C is stored in the storage device 65 by the RW control unit 81. Further, the standardized constant C is read from the storage device 65 by the RW control unit 81 and output to the subtraction unit 87.

In the first embodiment, calculation processing for generating the output image 76, the first intermediate image generating unit 85, shown in FIG. 10, the complex inverse Fourier transform of the virtual Fourier transform lens 106 functions F_V1 ^-1 {*}, Processing to generate the first intermediate image 88 using the transmission function Φ_V1 (X, Y) of the virtual random diffuser 107, and all the transfer functions shown in FIG. 10 in the second intermediate image generation unit 86. The process of generating the second intermediate image 89 by using the image, and the process of generating the output image 76 based on the image obtained by subtracting the second intermediate image 89 from the first intermediate image 88 in the subtraction unit 87 correspond.

Next, the operation of the above configuration will be described with reference to the flowchart shown in FIG. First, the object to be measured 15 is set on the stage 11 (step ST100). Then, as shown in FIG. 2, the shutter 36 is set to the retracted position and the shutter 37 is set to the approach position, and the input light wave of the object to be measured 15 is guided to the optical complex amplitude image acquisition optical path 20 (step ST110).

The input light wave of the object to be measured 15 passes through the Fourier transform lens 26 and is subjected to complex Fourier transform by the Fourier transform lens 26. The input light wave after the complex Fourier transform passes through the random diffuser plate 22 and is diffused by the random diffuser plate 22. The diffused input light wave passes through the Fourier transform lens 27 and is subjected to complex Fourier transform by the Fourier transform lens 27. The input light wave after the complex Fourier transform passes through the transmission portion 35 of the partial transmission mask 29 and reaches the sensor 13. As a result, the optical complex amplitude image 54 is output from the sensor 13 (step ST120).

The optical complex amplitude image 54 is sent from the sensor 13 to the image acquisition unit 80 and acquired by the image acquisition unit 80. Then, it is stored in the storage device 65 by the RW control unit 81 (step ST130).

Subsequently, as shown in FIG. 3, the shutter 36 is set to the approach position and the shutter 37 is set to the retracted position, and the input light wave of the object to be measured 15 is guided to the reference image acquisition optical path 21 (step ST140).

The input light wave of the object to be measured 15 passes through the

lenses

31 and 32, and is focused by the

lenses

31 and 32 to a size that fits in the transmission portion 35 of the partial transmission mask 29. The collected input light wave of the object to be measured 15 passes through the transmission portion 35 of the partial transmission mask 29 and reaches the sensor 13. As a result, the reference image 61 is output from the sensor 13 (step ST150).

The reference image 61 is sent from the sensor 13 to the image acquisition unit 80 and acquired by the image acquisition unit 80. Then, it is stored in the storage device 65 by the RW control unit 81 (step ST160).

The RW control unit 81 reads out the optical complex amplitude image 54 and the reference image 61 from the storage device 65 and outputs them to the generation unit 82. In the generation unit 82, as shown in FIGS. 11 and 12, the first intermediate image generation unit 85 generates the first intermediate image 88 (step ST170). Further, as shown in FIGS. 13 to 15, the second intermediate image generation unit 86 generates the second intermediate image 89 (step ST180). The first intermediate image 88 and the second intermediate image 89 are output to the subtraction unit 87.

As shown in FIG. 16, the subtraction unit 87 subtracts the second intermediate image 89 from the first intermediate image 88, and the output image 76 is generated (step ST190). More specifically, the output image 76 is generated by multiplying the first intermediate image 88 minus the second intermediate image 89 by the normalization constant C and further adding the reference image 61. The output image 76 is sent from the subtraction unit 87 to the RW control unit 81, and is stored in the storage device 65 by the RW control unit 81 (step ST200). The output image 76 stored in the storage device 65 is transmitted to another device via the communication unit 68 or displayed on the display 69.

As described above, the super-resolution measuring device 10 includes an actual optical system 12, a sensor 13, and a generation unit 82. The real optical system 12 includes a random diffuser 22 that diffuses the input light wave of the object 15 to be measured, and a partial transmission mask 29 that partially transmits the diffused input light wave. The sensor 13 measures the intensity and phase of the input light wave transmitted through the partial transmission mask 29, and outputs an optical complex amplitude image 54. The generation unit 82 is a calculation process for reproducing the input light wave of the object to be measured 15 including the super-resolution component which is a component having a resolution exceeding the resolution of the sensor 13 from the optical complex amplitude image 54, and is a calculation process of the random diffuser plate 22. The output image 76 is generated by performing a calculation process including the phase conjugation function Φ_V1 (X, Y) of the transmission function on a computer. Since the partial transmission mask 29 limits the input light wave of the object to be measured 15 incident on the sensor 13, it is possible to reduce the image quality deterioration that occurs in the super-resolution output image 76.

According to the partial transmission mask 29, the input light wave of the object to be measured 15 diffused by the random diffuser plate 22 is limited. Then, the limited input light wave is measured by using the sensor 13 at the same resolution as when the reference image 61 is obtained. Therefore, it is possible to obtain a finer change in the wave surface of the input light wave. In other words, compared to the case where the input image 50 is photographed at the same magnification, the resolution is equivalently twice or four times higher. The super-resolution component is woven into the finer changes in the wave surface of the input light wave. Therefore, by limiting the input light wave of the object to be measured 15 by the partial transmission mask 29, it is possible to efficiently obtain the super-resolution component.

The generation unit 82 generates the first intermediate image 88 from the optical complex amplitude image 54, and generates the second intermediate image 89 from the reference image 61. Then, the output image 76 is generated based on the image obtained by subtracting the second intermediate image 89 from the first intermediate image 88.

As conceptually shown in FIG. 18, the first intermediate image 88 contains a noise component in addition to the super-resolution component. The noise component is mainly due to a measurement error due to the finite size and resolution of the sensor 13. The measurement error is noticeable because the input image 50 is diffused by the random diffuser 22. In addition to the above measurement errors, the noise component is also caused by processing errors of the fast Fourier inverse transform unit 95, the calculation unit 96, etc., and distortion applied to the input light wave transmitted through the transmission unit 35 of the partial transmission mask 29. .. On the other hand, the second intermediate image 89 does not contain a super-resolution component, but contains a noise component. Therefore, by subtracting the second intermediate image 89 from the first intermediate image 88, only the noise component can be removed from the first intermediate image 88. Therefore, the deterioration of the image quality of the output image 76 can be further reduced.

The actual optical system 12 has an optical complex amplitude image acquisition optical path 20 that reaches the sensor 13 via the random diffuser plate 22 and a reference image acquisition optical path 21 that reaches the sensor 13 without passing through the random diffuser plate 22. Therefore, the optical complex amplitude image 54 and the reference image 61 can be easily obtained in a short time.

The reference image acquisition optical path 21 is branched from the object to be measured 15 side of the random diffusion plate 22 of the optical complex amplitude image acquisition optical path 20. Further, the reference image acquisition optical path 21 merges on the sensor 13 side of the random diffuser plate 22 of the optical complex amplitude image acquisition optical path 20. Therefore, it is not necessary to prepare two sensors 13 for the optical complex amplitude image acquisition optical path 20 and the reference image acquisition optical path 21, and one sensor 13 can cover the problem.

In the reference image acquisition optical path 21, the

lenses

31 and 32 collect the input light wave of the object to be measured 15 into a size that fits in the transmission portion 35 of the partial transmission mask 29. Therefore, when the reference image 61 is obtained using the reference image acquisition optical path 21, the partial transmission mask 29 is retracted from the optical path, and when the optical complex amplitude image acquisition optical path 20 is used to obtain the optical complex amplitude image 54, the partial transmission mask 29 is retracted from the optical path. It is not necessary to provide a mechanism for returning the transmission mask 29 to the optical path. It is possible to avoid an increase in component cost for the real optical system 12 and an increase in the size of the real optical system 12.

The actual optical system 12 uses a random diffuser plate 22 that randomly diffuses an input light wave as a diffuser member. Therefore, the input light wave of the object to be measured 15 can be incident on a larger number of pixels 40 of the sensor 13, and the super-resolution component included in the output image 76 can be increased.

[Example 1]
In the following, Example 1 based on the numerical simulation of the super-resolution measuring device 10 of the first embodiment will be shown.

FIG. 19 is Table 140 showing various parameters in the first embodiment. The light wavelength used is the wavelength of light emitted from the light source of the sensor 13, and is 532 nm. The number of pixels of the input light wave is 512 × 512, and the pixel size is 20 μm. The calculated oversampling rate for the input light wave is 4, and the zero padding rate is 2. The number of pixels of the random diffuser 22 is 4096 × 4096, the pixel size is 5 μm, and the phase gradation is 256. The number of pixels of the sensor 13 is 256 × 256, and the pixel size is 5 μm. Since the number of pixels of the input light wave is 512 × 512 and the number of pixels of the sensor is 256 × 256, the input image 50 has four times the resolution of the sensor 13. It should be noted that these various parameters are also followed in the following Examples 2 and 3.

FIG. 20 shows an example of the input image 50 (a_R (x, y)) used in the first embodiment. FIG. 20A shows the intensity image 50AM of the input image 50, and FIG. 20B shows the phase image 50PH of the input image 50. The input image 50 is an image in which minute marks 145 are attached to the central portion and the left corner portion of the white background, as shown by the intensity image 50AM. The mark 145 is a black dot surrounded by a black square frame. Reference numeral 146 in FIG. 20A indicates an intensity scale, and reference numeral 147 in FIG. 20B indicates a phase scale.

FIG. 21 shows an optical complex amplitude image 54 (Rect_R {F_R {) obtained by measuring the input image 50 shown in FIG. 20 with the sensor 13 using the optical complex amplitude image acquisition optical path 20 as shown in FIG. A_R (X, Y) × Φ_R (X, Y)}}). 21A shows the intensity image 54AM of the optical complex amplitude image 54, and FIG. 21B shows the phase image 54PH of the optical complex amplitude image 54, respectively. The square-shaped region in the center indicates a portion that has passed through the transparent portion 35 of the partial transparent mask 29. The transparent portion 35 has a size of (1/8) × (1/8) of the input image 50.

FIG. 22 shows a first intermediate image 88 (a_SR (x, y)) generated by subjecting the optical complex amplitude image 54 shown in FIG. 21 to the processing shown in FIGS. 11 and 12. FIG. 22A shows the intensity image 88AM of the first intermediate image 88, and FIG. 22B shows the phase image 88PH of the first intermediate image 88. The first intermediate image 88 no longer retains the original form of the input image 50, but contains a super-resolution component. The first intermediate image 88 also includes a noise component.

FIG. 23 is a reference image 61 (b_R (x, y)) obtained by measuring with the sensor 13 using the reference image acquisition optical path 21 as shown in FIG. FIG. 23A shows the intensity image 61AM of the reference image 61, and FIG. 23B shows the phase image 61PH of the reference image 61. The reference image 61 is an image that embodies the resolution of the sensor 13 as it is, and is an image in which the super-resolution component included in the input image 50 is missing. Therefore, the reference image 61 is an image in which the outline of the mark 145 is unclear or the mark 145 itself is not reflected as compared with the input image 50 shown in FIG.

FIG. 24 is a second intermediate image 89 (b_NSR (x, y)) generated by performing the processes shown in FIGS. 13 to 15 with respect to the reference image 61 shown in FIG. 23. FIG. 24A shows the intensity image 89AM of the second intermediate image 89, and FIG. 24B shows the phase image 89PH of the second intermediate image 89. Like the first intermediate image 88, the second intermediate image 89 no longer retains the original shape of the reference image 61, but contains a noise component.

FIG. 25 is an image (hereinafter referred to as a subtracted image) 148 obtained by subtracting the second intermediate image 89 shown in FIG. 24 from the first intermediate image 88 shown in FIG. 22. FIG. 25A shows the intensity image 148AM of the subtraction image 148, and FIG. 25B shows the phase image 148PH of the subtraction image 148.

FIG. 26 is an output image 76 (O (x, y)) obtained by performing the processing shown in FIG. FIG. 26A shows the intensity image 76AM of the output image 76, and FIG. 26B shows the phase image 76PH of the output image 76. According to FIG. 26, it can be seen that the mark 145 is accurately reproduced in both intensity and phase.

FIG. 27 shows another example of the input image 50 (a_R (x, y)). 27A shows the intensity image 50AM of the input image 50, and FIG. 27B shows the phase image 50PH of the input image 50. The input image 50 is an image in which minute marks 150 are added to the central portion and the left corner portion of the black background, as shown by the intensity image 50AM. The mark 150 is a square horizontal line drawn in the center of a white frame as shown by the intensity image 50AM. The mark 150 is a phase image 50PH in which a black point is surrounded by a black square frame.

The input image 50 shown in FIG. 27 has an extremely small proportion of the signal light wave (the portion where the pixel value is not 0) in the input light wave as compared with the input image 50 shown in FIG. As the reference image 61 in the case of such an input image 50, a solid black image shown in FIG. 28 is used. The optical complex amplitude b_R (x, y) of the reference image 61 of such a solid black image is 0.

FIG. 29 shows an optical complex amplitude image 54 (Rect_R {F_R {) obtained by measuring the input image 50 shown in FIG. 27 with the sensor 13 using the optical complex amplitude image acquisition optical path 20 as shown in FIG. A_R (X, Y) × Φ_R (X, Y)}}). FIG. 29A shows the intensity image 54AM of the optical complex amplitude image 54, and FIG. 29B shows the phase image 54PH of the optical complex amplitude image 54. Similar to FIG. 21, the central square region indicates a portion that has passed through the transparent portion 35 of the partial transparent mask 29.

In this case, the optical complex amplitude b_NSR (x, y) of the second intermediate image 89 is 0 because the reference image 61 is a solid black image (b_R (x, y) = 0) shown in FIG. 28. That is mathematically self-evident. Therefore, in this case, the processing by the second intermediate image generation unit 86 shown in FIGS. 13 to 15 and the processing by the subtraction unit 87 shown in FIG. 16 are not performed.

FIG. 30 is an output image 76 (O (x, y)) in the case of the input image 50 of FIG. 27. FIG. 30A shows the intensity image 76AM of the output image 76, and FIG. 30B shows the phase image 76PH of the output image 76. According to FIG. 30, it can be seen that the mark 150 of the input image 50 is accurately reproduced in terms of both intensity and phase, as in the case of FIG. 26.

As shown above, it is possible to demonstrate that the super-resolution measuring device 10 of the first embodiment has the effect of reducing the image quality deterioration that occurs in the super-resolution output image 76. did it.

31 and 32 show other examples of real optical systems.

In the real optical system 160 shown in FIG. 31, the reference image acquisition optical path 162 is branched from the object to be measured 15 side of the random diffuser plate 22 of the optical complex amplitude image acquisition optical path 161 as in the real optical system 12. However, the reference image acquisition optical path 162 does not merge on the sensor 13 side of the random diffuser plate 22 of the optical complex amplitude image acquisition optical path 161. Two sensors 13 are provided, a sensor 13A for the optical complex amplitude image acquisition optical path 161 and a sensor 13B for the reference image acquisition optical path 162. The number of measurement pixels (resolution) of the sensor 13A is equal to the number of measurement pixels (resolution) of the sensor 13B.

The optical complex amplitude image acquisition optical path 161 has the same configuration as the optical complex amplitude image acquisition optical path 20 of the actual optical system 12 except that the beam splitter 28 and the shutter 36 are not arranged. On the other hand, the reference image acquisition optical path 162 has a configuration fundamentally different from that of the reference image acquisition optical path 21 of the actual optical system 12. More specifically, the reference image acquisition optical path 162 does not have the mirror 33 and the shutter 37 arranged. Further, the

lenses

163 and 164 collect the input light waves of the object to be measured 15, such as the

lenses

31 and 32 of the reference image acquisition optical path 21 of the actual optical system 12, into a size that fits in the transmission portion 35 of the partial transmission mask 29. It is not a lens that has the effect of

According to the real optical system 160, unlike the real optical system 12, it is not necessary to provide a mechanism for moving the

shutters

36, 37 and the

shutters

36, 37 to the approach position and the retract position. Further, it is not necessary to use

lenses

31 and 32 having a special action. Further, the optical complex amplitude image 54 and the reference image 61 can be obtained at the same time.

In the real optical system 170 shown in FIG. 32, the optical complex amplitude image acquisition optical path 171 and the reference image acquisition optical path 172 are used in combination. The random diffuser plate 22 and the partial transmission mask 29 are retracted from the optical complex amplitude image acquisition optical path 171 and the reference image acquisition optical path 172, and the approach position indicated by the solid line that has entered the optical complex amplitude image acquisition optical path 171 and the reference image acquisition optical path 172. It is moved to the retracted position indicated by the broken line. When the random diffusion plate 22 and the partial transmission mask 29 shown in FIG. 32 are in the approach position, they function as an optical complex amplitude image acquisition optical path 171. On the other hand, when the random diffuser plate 22 and the partial transmission mask 29 are in the retracted position, they function as the reference image acquisition optical path 172.

According to the real optical system 170, no optical members such as

beam splitters

25 and 28 and mirrors 30 and 33 of the real optical system 12 are required. Further, unlike the actual optical system 12, it is not necessary to provide a mechanism for moving the

shutters

36, 37 and the

shutters

36, 37 to the approach position and the retract position. Further, as with the actual optical system 12, one sensor 13 can cover the problem.

If the reference image 61 can be prepared in advance, the step of obtaining the reference image 61 using the reference image acquisition optical path 21 is unnecessary. When the reference image 61 can be prepared in advance, the solid black image shown in FIG. 28 may be used as the reference image 61. Alternatively, it is also conceivable to use the super-resolution measuring device 10 for product defect inspection for detecting minute scratches on the surface of a mirror-processed product that cannot be discriminated by the resolution of the sensor 13. In this case, since there is product design data when there are no scratches, the design data can be diverted to the reference image 61.

When the real object capable of generating the reference image 61 is the object to be measured 15, for example, the real object capable of generating the reference image 61 is covered by using the optical complex amplitude image acquisition optical path 20 of the real optical system 12. It may be measured as the measuring object 15. As a result, in the sensor 13, an image represented by Rec_R {F_R {B_R (X, Y) × Φ_R (X, Y)}} can be obtained. This image is equivalent to the image 120 represented by Rect_V {F_V2 {B_R (X, Y) × Φ_V2 (X, Y)}} output from the calculation unit 113 of the second intermediate image generation unit 86.

Even when the actual object capable of generating the reference image 61 is the object to be measured 15, the step of obtaining the reference image 61 using the reference image acquisition optical path 21 is unnecessary. Further, in this case, as described above, the sensor 13 can obtain an image represented by Rec_R {F_R {B_R (X, Y) × Φ_R (X, Y)}}, and therefore FIGS. 13 to 15 Of the processes of the second intermediate image generation unit 86 shown in the above, the processes of the fast Fourier transform unit 110, the calculation unit 111, the fast Fourier transform unit 112, and the calculation unit 113 are unnecessary.

The object to be measured 15 may be an actual image as illustrated in FIG. 20 or the like, or may be an image displayed on a display.

The random diffusion plate 22 is not limited to the one on which the uneven surface 23 is formed. A resin containing fine particles may be applied to the surface. In short, it suffices as long as it can sufficiently diffuse the input light wave of the object to be measured 15. Further, the

Fourier transform lenses

26 and 27 may be omitted.

The partial transmission mask 29 may be moved to an approach position that has entered the optical complex amplitude image acquisition optical path 20 and a retracted position that has been retracted from the optical complex amplitude image acquisition optical path 20. In this case, when the optical complex amplitude image acquisition optical path 20 is used to obtain the optical complex amplitude image 54, the partial transmission mask 29 is moved to the approach position, and when the reference image acquisition optical path 21 is used to obtain the reference image 61, the partial transmission mask 29 is partially transmitted. The mask 29 is moved to the retracted position. In this way, it is not necessary for the

lenses

31 and 32 to collect the input light wave of the object to be measured 15 into a size that fits in the transmission portion 35 of the partial transmission mask 29.

The second to fourth embodiments shown below are configured to eliminate the need for the reference image 61 itself.

[Second Embodiment]
In the second embodiment shown in FIGS. 33 to 35, a spatial light modulator 182 capable of changing the diffusion characteristics of the input light wave is used as the diffusion member.

In FIG. 33, the real optical system 180 of the second embodiment has a Fourier transform lens 26, a beam splitter 181 and a spatial light modulator 182, a Fourier transform lens 27, and a partial transmission mask 29. The beam splitter 181 transmits the input light wave of the object to be measured 15 that has passed through the Fourier transform lens 26 toward the spatial light modulator 182. Further, the beam splitter 181 reflects the input light wave phase-modulated by the phase pattern displayed on the spatial light modulator 182 toward the Fourier transform lens 27 by 90 °.

The spatial light modulator 182 is also called an SLM (Spatial Light Modulator), and is composed of, for example, an LCD (Liquid Crystal Display), an LCOS (Liquid Crystal on Silicon), a DMD (Digital Mirror Device), or the like. The spatial light modulator 182 can change the displayed phase pattern in various ways.

In FIG. 34, the generation unit 185 of the second embodiment is the same as the generation unit 82 of the first embodiment, and is an input of the object to be measured 15 including a super-resolution component which is a component having a resolution exceeding the resolution of the sensor 13. The output image 76 is generated by performing a calculation process on a computer to reproduce the light wave from the optical complex amplitude image 54. That is, the generation unit 185 is an example of the "virtual optical system" according to the technique of the present disclosure.

The generation unit 185 has an intermediate image generation unit 186 and an addition averaging unit 187. The intermediate image generation unit 186 uses the phase conjugation of the transmission function of the spatial light modulator 182 instead of the transmission function Φ_V1 (X, Y) of the virtual random diffuser 107 in the first intermediate image generation unit 85 of the first embodiment. Using the function, an intermediate image 188 (a_SR (x, y)) corresponding to the first intermediate image 88 of the first embodiment is generated from the optical complex amplitude image 54. The intermediate image generation unit 186 outputs the intermediate image 188 to the addition averaging unit 187. The addition averaging unit 187 adds and averages the intermediate image 188. The addition averaging unit 187 outputs the averaging image as an output image 76.

As shown in FIG. 35, in the second embodiment, the phase pattern displayed in the spatial light modulator 182 is changed to

phase patterns

1, 2, 3, ..., N. The sensor 13 outputs optical complex amplitude images 54_1, 54_2, 54_3, ..., 54_N each time the phase pattern displayed by the spatial light modulator 182 is changed. The intermediate image generation unit 186 generates intermediate images 188_1, 188_2, 188_3, ..., 188_N each time the phase pattern displayed in the spatial light modulator 182 is changed. As shown by reference numeral 189, the addition averaging unit 187 adds the intermediate images 188_1, 188_2, 188_3, ..., 188_N. Next, the addition averaging unit 187 divides the added image by N as shown by reference numeral 190. The optical complex amplitude of the output image 76 in this case is
O (x, y) = (1 / N) x Σ (a_SR (x, y))
Can be expressed as.

In the second embodiment, the calculation process for generating the output image 76 performed by the generation unit 185 is the process of generating the intermediate image 188 in the intermediate image generation unit 186 and the intermediate image 188 in the addition averaging unit 187. The process of calculating the added average corresponds. The calculation process performed by the generation unit 185 includes the phase conjugation function of the transmission function of the spatial light modulator 182, which is an example of the “phase conjugation function of the transmission function of the diffusion member”.

As described above, in the second embodiment, the spatial light modulator 182 capable of changing the diffusion characteristics of the input light wave is used as the diffusion member. The sensor 13 measures the optical complex amplitudes of a plurality of types of input light waves whose diffusion characteristics are changed by the spatial light modulator 182, and outputs a plurality of optical complex amplitude images 54_1 to 54_N having different diffusion characteristics of the input light waves. The generation unit 185 generates intermediate images 188_1 to 188_N from each of the plurality of optical complex amplitude images 54_1 to 54_N, and adds and averages the plurality of intermediate images 188_1 to 188_N to obtain the output image 76.

Every time the phase pattern displayed by the spatial light modulator 182 is changed, the number and / or position of the pixels 40 of the sensor 13 on which the input light wave of the object to be measured 15 is incident can be changed. As a result, the optical complex amplitude images 54_1 to 54_N, and thus the intermediate images 188_1 to 188_N, contain super-resolution components having slightly different contents. Then, the output image 76, which is the addition average of the intermediate images 188_1 to 188_N, contains a clear super-resolution component as compared with the output image 76 when one random diffusion plate 22 is used. .. Therefore, even if the reference image 61 is not used, the image quality deterioration that occurs in the output image 76 can be sufficiently reduced.

[Example 2]
FIG. 36 is an example of the phase image 76PH of the output image 76 by the numerical simulation of the second embodiment (number of changes in the phase pattern N = 200). As can be seen from the phase image 76PH, the image quality deterioration that occurs in the output image 76 can be sufficiently reduced without using the reference image 61.

[Third Embodiment]
In the third embodiment shown in FIGS. 37 and 38, a random diffusion plate 201 in which the light-shielding portion 202 is provided in the central portion is used as the diffusion member.

In FIG. 37, the real optical system 200 of the third embodiment has a Fourier transform lens 26, a random diffuser 201, a Fourier transform lens 27, and a partial transmission mask 29. As shown in FIG. 38, a light-shielding portion 202 is provided in the central portion of the random diffusion plate 201. The light-shielding portion 202 cuts the low spatial frequency component by the Fourier transform lens 26, and diffuses only the high spatial frequency component by the Fourier transform lens 26. In this case, the optical complex amplitude image 54 output from the sensor 13 lacks the low spatial frequency component of the input light wave of the object to be measured 15. Reference numeral 203 is an uneven surface.

The generation unit of the third embodiment uses the phase conjugation function of the transmission function of the random diffusion plate 201 instead of the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107. 1 It is the same as the intermediate image generation unit 85. Therefore, the illustration of the generation unit of the third embodiment is omitted. The generation unit of the third embodiment, like the generation unit 82 of the first embodiment and the generation unit 185 of the second embodiment, includes a super-resolution component which is a component having a resolution exceeding the resolution of the sensor 13. The output image 76 is generated by performing a calculation process on the computer to reproduce the input light wave of the measurement object 15 from the optical complex amplitude image 54. That is, the generation unit of the third embodiment is an example of the "virtual optical system" according to the technique of the present disclosure.

The generation unit of the third embodiment performs substantially the same processing as the first intermediate image generation unit 85 on the optical complex amplitude image 54 output from the sensor 13. Then, the image obtained by this is output as the output image 76. In the third embodiment, the calculation process for generating the output image 76 performed by the generation unit corresponds to substantially the same processing as the first intermediate image generation unit 85 performed on the optical complex amplitude image 54. The calculation process performed by the generation unit of the third embodiment includes the phase conjugation function of the transmission function of the random diffusion plate 201, which is an example of the “phase conjugation function of the transmission function of the diffusion member”.

As described above, in the third embodiment, as the diffusion member, the light-shielding portion 202 for cutting the low spatial frequency component by the Fourier transform lens 26 arranged on the object to be measured 15 side is provided in the central portion of the random diffusion plate 201. Is used.

Here, it is considered that the super-resolution component is hardly contained in the low-spatial frequency component, and most of it is contained in the high-spatial frequency component. For example, in the input image 50 shown in FIG. 20, it is considered that the white background portion without the mark 145 becomes a low spatial frequency component due to the Fourier transform lens 26, and the portion marked 145 becomes a high spatial frequency component due to the Fourier transform lens 26. .. Therefore, if the low-spatial frequency component that is considered to hardly contribute to the super-resolution component is cut by the light-shielding unit 202, most of the resolution of the sensor 13 can be allocated to the high-spatial frequency component. Therefore, even if the reference image 61 is not used, the image quality deterioration that occurs in the output image 76 can be sufficiently reduced.

[Example 3]
FIG. 39 shows an input image 50 used in the numerical simulation of the third embodiment. FIG. 39A shows the intensity image 50AM of the input image 50, and FIG. 39B shows the phase image 50PH of the input image 50. The input image 50 is an image in which the mark 210 is attached to the central portion and the left corner portion of the white background, similarly to the input image 50 shown in FIG.

FIG. 40 shows the high spatial frequency component 205 of the input image 50 shown in FIG. 39. FIG. 40A shows the intensity image 205AM of the high spatial frequency component 205, and FIG. 40B shows the phase image 205PH of the high spatial frequency component 205. The mark 210 can also be confirmed in the high spatial frequency component 205.

FIG. 41 is an output image 76 with respect to the input image 50 shown in FIG. 39. FIG. 41A shows the intensity image 76AM of the output image 76, and FIG. 41B shows the phase image 76PH of the output image 76. According to the output image 76, it can be seen that the mark 210 is accurately reproduced.

[Fourth Embodiment]
In the fourth embodiment shown in FIGS. 42 to 44, a random diffusion plate 221 having an opening 223 provided in the central portion is used as the diffusion member.

In FIG. 42, the actual optical system 220 of the fourth embodiment has a Fourier transform lens 26, a random diffuser plate 221 and a condenser lens 222, a Fourier transform lens 27, and a partial transmission mask 29. As shown in FIG. 43, an opening 223 is provided in the central portion of the random diffuser plate 221. Through this aperture 223, the low spatial frequency component by the Fourier transform lens 26 is transmitted without being diffused, and only the high spatial frequency component by the Fourier transform lens 26 is diffused. The condenser lens 222 concentrates the low spatial frequency component transmitted through the aperture 223 on the transmission portion 35 of the partial transmission mask 29. In this case, the optical complex amplitude image 54 output from the sensor 13 includes a diffused high spatial frequency component and an undiffused low spatial frequency component of the input light wave of the object to be measured 15. Reference numeral 224 is an uneven surface.

In FIG. 44, the generation unit 230 of the fourth embodiment is the same as the generation unit 82 of the first embodiment, the generation unit 185 of the second embodiment, and the generation unit of the third embodiment of the sensor 13. The output image 76 is generated by performing a calculation process on a computer to reproduce the input light wave of the object to be measured 15 including the super-resolution component which is a component having a resolution exceeding the resolution from the optical complex amplitude image 54. That is, the generation unit 230 is an example of the "virtual optical system" according to the technique of the present disclosure.

The generation unit 230 has a component separation unit 231, a first processing unit 232, a second processing unit 233, and a synthesis unit 234. The component separation unit 231 separates the high spatial frequency component 205 and the low spatial frequency component 235 of the optical complex amplitude image 54 output from the sensor 13. The component separation unit 231 outputs the high spatial frequency component 205 to the first processing unit 232 and the low spatial frequency component 235 to the second processing unit 233, respectively.

The first processing unit 232 performs substantially the same processing as the first intermediate image generation unit 85 on the high spatial frequency component 205 of the optical complex amplitude image 54. Then, the processed high spatial frequency component 205PR obtained thereby is output to the synthesis unit 234. Similarly, the second processing unit 233 performs substantially the same processing as the first intermediate image generation unit 85 on the low spatial frequency component 235 of the optical complex amplitude image 54. Then, the processed low spatial frequency component 235PR obtained thereby is output to the synthesis unit 234. The first processing unit 232 and the second processing unit 233 use the phase conjugation function of the transmission function of the random diffusion plate 221 instead of the transmission function Φ_V1 (X, Y) of the virtual random diffusion plate 107.

The synthesis unit 234 synthesizes the processed high spatial frequency component 205PR and the processed low spatial frequency component 235PR, and outputs the combined image as an output image 76.

In the fourth embodiment, the calculation process for generating the output image 76, which is carried out by the generation unit 230, is performed by the component separation unit 231 with the high spatial frequency component 205 and the low spatial frequency component 235 of the optical complex amplitude image 54. The first processing, which is performed in the first processing unit 232 for the high spatial frequency component 205, is substantially the same as that in the first intermediate image generation unit 85, and is performed in the second processing unit 233 for the low spatial frequency component 235. The processing substantially the same as that of the intermediate image generation unit 85, and the processing of synthesizing the processed high spatial frequency component 205PR and the processed low spatial frequency component 235PR in the compositing unit 234 correspond. The calculation process performed by the generation unit 230 includes the phase conjugation function of the transmission function of the random diffusion plate 221 which is an example of the "phase conjugation function of the transmission function of the diffusion member".

As described above, in the fourth embodiment, the opening 223 that transmits the low spatial frequency component by the Fourier transform lens 26 arranged on the object to be measured 15 side uses the random diffusion plate 221 provided in the central portion as the diffusion member. .. Then, a condenser lens 222 that concentrates the low spatial frequency component transmitted through the aperture 223 on the transmission portion 35 of the partial transmission mask 29 is arranged in the actual optical system 220.

Although the low spatial frequency component by the Fourier transform lens 26 contains almost no super-resolution component, it is still a part of the input light wave of the object to be measured 15. Therefore, in the fourth embodiment, the low spatial frequency component cut in the third embodiment is taken into the sensor 13 by the aperture 223 and the condenser lens 222. However, if the low spatial frequency component is diffused by the random diffuser plate 221 in the same manner as the high spatial frequency component, the resolution of the sensor 13 which is already small is wasted in the low spatial frequency component. Therefore, in the fourth embodiment, an opening 223 for transmitting the low spatial frequency component is formed in the random diffuser plate 221 and is guided to the sensor 13 without diffusing the low spatial frequency component. Therefore, even if the reference image 61 is not used, the image quality deterioration that occurs in the output image 76 can be sufficiently reduced.

The partial transmission mask 29 in which the transmission portion 35 is formed of holes, which is shown in each of the above embodiments, is an example, and is not limited thereto. As in the partial transmission mask 240 shown in FIG. 45, the peripheral portion may be coated with a light-shielding material, and the central portion may be formed as a transmission portion 241 without being coated with a light-shielding material.

Further, the transmissive portion does not necessarily have to be formed in the central portion of the partial transmissive mask. For example, as in the partial transmission mask 250 shown in FIG. 46, the transmission portion 251 may be displaced from the central portion.

The technique of the present disclosure can be appropriately combined with the various embodiments described above and / or various modifications. In addition, not limited to each of the above embodiments, it goes without saying that various configurations can be adopted as long as they do not deviate from the gist.

The description and illustration shown above are detailed explanations of the parts related to the technology of the present disclosure, and are merely an example of the technology of the present disclosure. For example, the above description of the configuration, function, action, and effect is an example of the configuration, function, action, and effect of a portion of the art of the present disclosure. Therefore, unnecessary parts may be deleted, new elements may be added, or replacements may be made to the described contents and illustrated contents shown above within a range that does not deviate from the gist of the technique of the present disclosure. Needless to say. In addition, in order to avoid complications and facilitate understanding of the parts relating to the technology of the present disclosure, the above-mentioned description and illustrations require special explanation in order to enable the implementation of the technology of the present disclosure. The explanation about common technical knowledge is omitted.

In the present specification, "A and / or B" is synonymous with "at least one of A and B". That is, "A and / or B" means that it may be A alone, B alone, or a combination of A and B. Further, in the present specification, when three or more matters are connected and expressed by "and / or", the same concept as "A and / or B" is applied.

All documents, patent applications and technical standards described herein are to the same extent as if the individual documents, patent applications and technical standards were specifically and individually stated to be incorporated by reference. Incorporated by reference in the book.

Claims

An actual optical system including a diffusing member that diffuses the input light wave of the object to be measured and a partially transmitted mask that partially transmits the diffused input light wave.
A sensor that measures the intensity and phase of the input light wave that has passed through the partial transmission mask and outputs an optical complex amplitude image.
This is a calculation process for reproducing the input light wave of the object to be measured containing the super-resolution component which is a component having a resolution exceeding the resolution of the sensor from the optical complex amplitude image, and is a phase conjugation function of the transmission function of the diffusion member. A virtual optical system that generates an output image by performing calculation processing including
Super-resolution measuring device equipped with.
The virtual optical system generates a first intermediate image from the optical complex amplitude image.
A second intermediate image is generated from the reference image of the object to be measured.
The super-resolution measuring apparatus according to claim 1, wherein the output image is generated based on an image obtained by subtracting the second intermediate image from the first intermediate image.
The actual optical system is
An optical complex amplitude image acquisition optical path for obtaining the optical complex amplitude image, which reaches the sensor via the diffusion member, and
The super-resolution measuring device according to claim 2, further comprising a reference image acquisition optical path for obtaining the reference image, which reaches the sensor without passing through the diffusion member.
The super-resolution measuring device according to claim 3, wherein the reference image acquisition optical path branches from the object to be measured side of the diffusion member of the optical complex amplitude image acquisition optical path.
The super-resolution measuring device according to claim 4, wherein the reference image acquisition optical path merges on the sensor side of the diffusion member of the optical complex amplitude image acquisition optical path.
The super-resolution measuring device according to claim 5, wherein in the reference image acquisition optical path, the input light wave is focused to a size that fits in the transmission portion of the partial transmission mask.
The optical complex amplitude image acquisition optical path and the reference image acquisition optical path are also used.
The diffusion member and the partial transmission mask are moved to an approach position that has entered the optical complex amplitude image acquisition optical path and a retracted position that is retracted from the optical complex amplitude image acquisition optical path.
The super-resolution measuring device according to claim 3, wherein the optical complex amplitude image acquisition optical path functions as the reference image acquisition optical path when the diffusion member and the partial transmission mask are in the retracted position.
The super-resolution measuring device according to any one of claims 1 to 7, wherein the diffusing member is a random diffusing plate that randomly diffuses the input light wave.
The diffusion member is a spatial light modulator capable of changing the diffusion characteristics of the input light wave.
The sensor measures the intensity and phase of a plurality of types of input light waves whose diffusion characteristics have been changed by the spatial light modulator, and outputs a plurality of optical complex amplitude images having different diffusion characteristics of the input light waves.
The super-resolution measuring device according to claim 1, wherein the virtual optical system generates an intermediate image from each of the plurality of optical complex amplitude images, and uses an image obtained by adding and averaging the plurality of the intermediate images as the output image. ..
The super-resolution measuring device according to claim 1, wherein the actual optical system includes a pair of Fourier transform lenses arranged on the object to be measured side of the diffusing member and on the sensor side of the diffusing member.
The diffusing member is a random diffusing plate that randomly diffuses the input light wave, and a light-shielding portion for cutting low spatial frequency components by the Fourier transform lens arranged on the object to be measured is provided in the central portion. The super-resolution measuring device according to claim 10, which is a random diffusion plate.
The diffusing member is a random diffusing plate that randomly diffuses the input light wave, and an opening that transmits a low spatial frequency component by the Fourier transform lens arranged on the object to be measured is provided in the central portion. It is a random diffuser and
The super-resolution measuring apparatus according to claim 10, wherein the actual optical system is provided with a condensing lens that condenses the low spatial frequency component transmitted through the aperture on a transmitting portion of the partial transmission mask.
Using a real optical system including a diffusing member that diffuses the input light wave of the object to be measured and a partially transmitted mask that partially transmits the diffused input light wave.
The sensor measures the intensity and phase of the input light wave transmitted through the partial transmission mask and outputs an optical complex amplitude image.
In the virtual optical system, it is a calculation process for reproducing the input light wave of the object to be measured including the super-resolution component which is a component having a resolution exceeding the resolution of the sensor from the optical complex amplitude image, and is the transmission of the diffusion member. Generate an output image by performing a calculation process including the phase conjugation function of the function on a computer.
How to operate the super-resolution measuring device.