CN102096091A - Particle field optical holographic high-precision reproduction collecting system and method - Google Patents

Abstract

The invention relates to a particle field optical holographic high-precision reproduction acquisition system and method. A beam expansion collimation device, a particle field information carrier, an imaging lens, and a CCD are sequentially arranged on the output optical path of a laser, and the CCD is connected to a computer; the sensitive surface of the CCD is arranged on the At the rear focal plane of the imaging lens; the particle field information carrier is a holographic dry plate carrying the particle field information; the carrier positioning and moving device includes a three-dimensional translation stage; the CCD positioning and moving device includes a one-dimensional translation stage and a lens focal plane positioning device; the lens The focal plane positioning device includes a positioning component and a standard reticle; the standard reticle is installed on one end surface of the positioning component, and the other end surface of the positioning component is connected with the object plane side of the imaging lens. The invention solves the problems of low efficiency and low precision of the existing optical path adjustment and the resulting low precision of the final data of the system, quickly realizes precise adjustment of the optical path of the system according to the principle of lens imaging, and improves the final data precision of the system.

Description

Particle field optical holographic high-precision reproduction acquisition system and method

technical field

The invention relates to an imaging optical diagnosis system and method, in particular to a particle field optical holographic reproduction collection system and method.

Background technique

Particle field holographic diagnostic technology has the advantages of non-contact, high precision, and large test space. In particular, it can directly provide three-dimensional information of the particle field, and has become a standard method for particle field measurement. The reproduction acquisition of particle field is an essential link in the particle field optical holographic diagnosis technology. The holographic interferogram recording the particle field information is optically reproduced to obtain the three-dimensional reconstruction image of the original particle field, and the CCD is used to receive the reconstruction images of each layer of the particle field and input them into the computer for storage and post-processing. This process is called the reproduction acquisition of the particle field .

Since most of the particles diagnosed by the particle field are small particles in the order of microns, in order to meet the resolution requirements of the image receiving device CCD, the reproduced particle field is usually enlarged by the imaging lens and then imaged to the sensitive surface of the CCD for reception. Since the particle field diagnosis requires the parameters such as the scale and spatial position of the reproduced particles to be given quantitatively, the reference plane of the reproduced particle field and the sensitive surface of the CCD must be accurately positioned on the front focal plane and rear of the imaging lens, respectively, before image acquisition starts. focal point.

Due to the existence of external mechanical interface components between the imaging lens and the sensitive surface of the CCD, the positions of the holographic dry plate and the CCD cannot be accurately determined by directly measuring the length in the experiment. In the currently used particle field optical holographic reconstruction acquisition system, the holographic dry plate and CCD are usually roughly placed according to the given object distance and image distance of the imaging lens, and then finely adjusted. The basis for its adjustment is: when the reference plane of the reproduced particle field and the sensitive surface of the CCD are accurately positioned on the front focal plane and back focal plane of the imaging lens, the reproduced image of the standard wire on the reference plane is clear and its magnification is the same as that of the imaging lens The design uses the same magnification. Since there is no fixed reference in the adjustment process, and the definition of the image has a direct impact on the measurement accuracy of the image size, the adjustment process is blind, which not only consumes a lot of time, but also has low positioning accuracy, which affects the final data accuracy of the system.

In order to avoid blindness and improve work efficiency, another method is: estimate the distance from the sensitive surface of the CCD to its mechanical interface, combine the given value of the lens image distance, and directly determine the position of the CCD through length measurement; then use the CCD The sensitive surface is the rear focal plane of the lens. According to the principle of lens imaging, the position of the holographic dry plate is determined by judging the clarity of the reproduced image of the standard wire on the reference plane. In this method, due to the estimation error and length measurement error, the positioning of the CCD is not accurate enough, and there is often a deviation of mm order, which reduces the final data accuracy of the system.

Contents of the invention

In order to solve the problems of low efficiency and low precision of optical path adjustment in the existing particle field optical holographic reproduction acquisition technology and the resulting low accuracy of the final data of the system, the present invention provides a system and method for high-precision reproduction and acquisition of particle field optical holography , with the help of the lens focal plane positioning device, according to the principle of lens imaging, the precise adjustment of the system optical path is quickly realized, and the final data accuracy of the system is improved.

Technical solution of the present invention is:

A particle field optical holographic high-precision reproduction acquisition system, including a laser 1, a beam expanding collimation device 2, a particle field information carrier, a carrier positioning and moving device, an imaging lens 5, a CCD 7, a CCD positioning and moving device, and a computer 9; The beam expanding and collimating device 2, the particle field information carrier, the imaging lens 5, and the CCD7 are sequentially arranged on the output optical path of the laser 1, and the CCD7 is connected to the computer 9; the sensitive surface of the CCD7 is arranged on the rear focal plane of the imaging lens 5 place; the particle field information carrier is a holographic dry plate 3 carrying particle field information; the carrier positioning and moving device includes a three-dimensional translation platform 4 for particle field information carrier installation and movement control; the CCD positioning and moving The device includes a one-dimensional translation stage 8 for CCD installation and movement control, and its special features are: the CCD positioning and moving device also includes a lens focal plane positioning device; the lens focal plane positioning device includes a positioning component 6 and a standard Reticle 10; said standard reticle is installed on an end face of positioning part 6, and the other end face of said positioning part 6 is connected with the object plane side of imaging lens 5; said positioning part is used to ensure standard reticle The photoresist surface of 10 is located on the front focal plane of imaging lens 5 .

The above-mentioned standard reticle 10 is preferably fixedly connected with the positioning component 6; the above-mentioned positioning component 6 is preferably movably connected with the imaging lens 5.

The above-mentioned positioning component 6 is preferably a hollow sleeve.

A particle field optical holographic high-precision reproduction acquisition method, comprising the following steps:

1] Precise positioning of the image receiving device CCD, the specific steps are as follows:

1.1] Set the beam expander collimation device 2 and the imaging lens 5 sequentially on the optical path output by the laser 1, and fix the imaging lens 5;

1.2] lens focal plane positioning device is installed on the object plane side of imaging lens 5; Described lens focal plane positioning device comprises positioning part 6 and standard reticle 10; Described standard reticle is installed on an end face of positioning part, so The other end face of the positioning part is connected with the object plane side of the imaging lens; the positioning part is used to ensure that the lithography surface of the standard reticle 10 is positioned on the front focal plane of the imaging lens 5;

1.3] CCD7 is installed on the one-dimensional translation stage 8, and CCD is arranged near the rear focal plane of imaging lens 5 on the output optical path of laser 1, and CCD is connected with computer 9, then moves CCD7 along the optical axis direction, and at the same time Interpret the quality of the image formed by the corresponding lines on the CCD on the photoetching surface of the standard reticle 10 on the computer, fix the CCD until the image is clear, then the sensitive surface of the CCD7 is positioned at the back focal plane of the imaging lens;

2] Determine the initial axial collection position of the particle field and the reference zero point of the axial coordinates, the specific steps are as follows:

2.1] Remove the lens focal plane positioning device on the imaging lens 5;

2.2] Install the holographic dry plate 3 carrying the particle field information on the three-dimensional translation stage 4, and set the holographic dry plate 3 near the front focal plane of the imaging lens 5 on the output optical path of the laser 1, and then move the holographic plate 3 along the optical axis At the same time, interpret and reproduce the image of the standard wire on the CCD on the reference plane of the particle field on the computer until the image is clear, record the axial coordinates of the holographic dry plate as the initial axial collection position and axial coordinates of the particle field the reference zero point;

3] Collect particle field images: move the holographic dry plate 3 sequentially through the three-dimensional translation stage 4 to collect particle field images until all images are collected.

The above-mentioned three-dimensional translation platform is a three-dimensional space mobile platform with a step length of 0.1 μm; the above-mentioned one-dimensional translation platform is a one-dimensional space mobile platform with a step length of 0.1 μm.

Advantages of the present invention:

1, the core feature of the present invention is to have designed a lens focal plane positioning device (hollow sleeve), and this device marks the precise position of front focal plane of lens with the lithographic surface of standard reticle, and then according to lens according to standard reticle The imaging principle quickly completes the precise positioning of the CCD, realizes the precise adjustment of the system optical path, and ensures the final data accuracy of the system. The invention solves the problems of low efficiency and low precision of optical path adjustment and low precision of final data of the system in the prior art.

2. The fixed connection between the standard reticle 10 of the present invention and the hollow sleeve can avoid the problem of poor reset accuracy.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the particle field optical holographic high-precision reproduction acquisition method of the present invention;

Fig. 2 is the installation schematic diagram of step 1] in the realization method of the present invention;

Fig. 3 is the installation schematic diagram of step 2] in the implementation method of the present invention;

Fig. 4 is a schematic structural view of the connection between the lens focal plane positioning device and the lens in the present invention;

In the figure, 1-laser, 2-beam expander and collimator, 3-holographic dry plate, 4-three-dimensional translation stage, 5-imaging lens, 6-positioning component, 7-CCD, 8-one-dimensional translation stage, 9- Computer, 10-standard reticle.

Detailed ways

The particle field optical holographic high-precision reproduction acquisition system of the present invention includes a laser 1, a beam expanding collimation device 2, a particle field information carrier, a carrier positioning and moving device, an imaging lens 5, a CCD 7, a CCD positioning and moving device, and a computer 9; The field information carrier is a holographic dry plate 3 carrying particle field information. The carrier positioning and moving device includes a three-dimensional translation platform 4 for particle field information carrier installation and movement control. The CCD positioning and moving device includes a CCD installation and movement control device. The one-dimensional translation stage 8 and the lens focal plane positioning device, the lens focal plane positioning device includes a positioning part 6 and a standard reticle 10, and the positioning part 6 is a hollow sleeve; a beam expanding collimation device 2, a holographic dry plate 3, an imaging Lens 5 and CCD7 are sequentially arranged on the output optical path of laser 1, and CCD7 is connected with computer 9; the sensitive surface of CCD7 is arranged at the rear focal plane of imaging lens 5; The other end of the barrel is movably connected to the object plane side of the imaging lens 5 ; the hollow sleeve is used to ensure that the photoreticle surface of the standard reticle 10 is located on the front focal plane of the imaging lens 5 .

In the system optical path adjustment, first install the lens focal plane positioning device on the object side of the imaging lens, and set the sensitive surface of the CCD at the rear focal plane of the imaging lens; then remove the lens focal plane positioning device and take it away The holographic dry plate of the particle field information is placed near the front focal plane of the imaging lens, and its position is adjusted so that the standard wire on the reference plane of the reproduced particle field is clearly imaged on the CCD.

The working principle of the system of the present invention is: through the imaging lens, the reproduced particle field is imaged on the image receiving device CCD, and then the received image is input into the computer to complete image processing and storage.

The working steps of the system of the present invention are:

Step 1. First, accurately position the sensitive surface of the CCD at the back focal plane of the imaging lens.

The specific steps are: set a beam expander collimator 2 on the output optical path of the laser 1, set an imaging lens 5 on the output optical path of the beam expander collimator 2, and fix the imaging lens 5 on the optical guide rail, and position the focal plane of the lens The device includes a hollow sleeve and a standard reticle 10; the standard reticle is fixedly installed on one end face of the hollow sleeve, and the other end face of the hollow sleeve is movably connected with the imaging lens; through the predetermined axial dimension of the hollow sleeve, The photoresist plane of the standard reticle installed on the other end face of the hollow sleeve can be placed at the front focal plane of the imaging lens 5; then the CCD7 is arranged near the rear focal plane of the imaging lens 5, and the CCD7 is installed on a one-dimensional On the translation stage 8, the image received by the CCD7 is input into the computer 9, and the image quality of the sixth group of six pairs of lines on the photolithographic surface of the standard reticle is judged on the computer 9. Move the position of the CCD7 on the optical axis through the one-dimensional translation stage 8, and fix the CCD7 until the image is clear. The image quality of which line pair is judged is actually related to the pixels of the CCD used. The higher the pixel, the greater the number of line pairs that can form a clear image.

Step 2. Determine the initial axial collection position of the particle field and the reference zero point of the axial coordinates.

The specific steps are: disassemble and take away the lens focal plane positioning device in the optical path of step 1, set the holographic dry plate 3 carrying the particle field information at the front focal plane of the imaging lens 5, and install the holographic dry plate 3 On the three-dimensional translation platform 4, the reconstructed real image and the reconstructed virtual image of the measured particle field and the standard wire are formed at the front and back symmetrical positions of the holographic dry plate 3, and the reconstructed real image is imaged on the CCD7 through the imaging lens 5, and interpreted on the computer 9 For the image of the standard wire, adjust the position of the holographic dry plate 3 on the optical axis through the three-dimensional translation stage 4 until the image of the standard wire is clear, record the axial coordinates of the holographic dry plate 3 as the initial axial collection position and axis of the particle field to the reference zero point of the coordinates.

Step 3, sequentially collect the particle field, and complete the image collection of the whole field.

The specific steps are: sequentially moving the holographic dry plate 3 through the three-dimensional translation stage 4 to collect the particle field images until all the images are collected.

Among them: laser 1 is a continuous semiconductor pumped Nd:YAG laser source; beam expander collimator 2 is an optical device that can expand the output light of the Nd:YAG laser and collimate it into parallel light; There is a holographic interferogram recording particle field information on the holographic dry plate 3 of the information; the three-dimensional translation stage 4 is controlled by a computer, and can realize three-dimensional space movement with a step size of 0.1 μm; the imaging lens 5 has a small depth of field and a constant magnification; One end of the surface positioning device can be accurately installed on the object plane side of the imaging lens 5, and the other end is fixedly installed with a standard reticle, and the photolithographic surface of the standard reticle is used to mark the precise position of the front focal plane of the imaging lens 5; CCD7 It is an image receiving device with a pixel size of 7.9 μm; the one-dimensional translation stage 8 is controlled by a computer and can realize one-dimensional space movement with a step size of 0.1 μm; the computer 9 is installed with image acquisition control software.

In step 1 of the present invention, the precise position of the front focal plane of the lens is given by the lens focal plane positioning device, thereby realizing the precise positioning of the image receiving device CCD according to the principle of lens imaging; based on the precise positioning of the CCD, according to the principle of lens imaging, The reference zero point of the axial coordinates of the particle field is precisely given by step 2.

Claims (5)

1. a Particle Field optical holography high precision is reproduced acquisition system, comprises laser instrument (1), beam-expanding collimation device (2), Particle Field information carrier, carrier location and mobile device, imaging len (5), CCD (7), CCD location and mobile device, computing machine (9); Described beam-expanding collimation device (2), Particle Field information carrier, imaging len (5), CCD (7) are successively set on the output light path of laser instrument (1), and described CCD (7) links to each other with computing machine (9); The sensitive face of described CCD (7) is arranged on imaging len (5) back focal plane place; Described Particle Field information carrier is the holographic dry plate (3) that carries Particle Field information; Described carrier location and mobile device comprise that being used for the Particle Field information carrier installs and move the D translation platform of controlling (4); Described CCD location and mobile device comprise that being used for CCD installs and move the one dimension translation stage of controlling (8);

It is characterized in that:

Described CCD location and mobile device also comprise the lens focal plane locating device;

Described lens focal plane locating device comprises positioning element (6) and standard graticule (10); Described standard graticule is installed in an end face of positioning element (6), and the other end of described positioning element (6) is connected with the object plane side of imaging len (5); Described positioning element is used to guarantee that the photoetching face of standard graticule (10) is positioned at the front focal plane of imaging len (5).

2. Particle Field optical holography high precision according to claim 1 is reproduced acquisition system, and it is characterized in that: described standard graticule (10) is fixedlyed connected with positioning element (6); Described positioning element (6) flexibly connects with imaging len (5).

3. Particle Field optical holography high precision according to claim 1 and 2 is reproduced acquisition system, and it is characterized in that: described positioning element (6) is a cannulated sleeve.

4. a Particle Field optical holography high precision is reproduced acquisition method, it is characterized in that: may further comprise the steps:

1] image is accepted the accurate location of device CCD, and concrete steps are as follows:

1.1] on the light path of laser instrument (1) output, set gradually beam-expanding collimation device (2) and imaging len (5), and imaging len (5) is fixing;

1.2] in the object plane side of imaging len (5) the lens focal plane locating device is installed; Described lens focal plane locating device comprises positioning element (6) and standard graticule (10); Described standard graticule is installed in an end face of positioning element, and the other end of described positioning element is connected with the object plane side of imaging len; Described positioning element is used to guarantee that the photoetching face of standard graticule (10) is positioned at the front focal plane of imaging len (5);

1.3] CCD7 is installed on the one dimension translation stage (8), and CCD is arranged near imaging len (5) back focal plane on laser instrument (1) output light path, and CCD is connected with computing machine (9), move CCD along optical axis direction then, simultaneously on computers on the photoetching face of interpretation standard graticule (10) homologous lines on CCD, becoming the quality of image, when clear picture CCD is fixed, then the sensitive face of CCD is positioned the back focal plane place of imaging len;

2] determine the axial initial acquisition position of Particle Field and the reference zero of axial coordinate, concrete steps are as follows:

2.1] the lens focal plane locating device on the imaging len (5) pulled down take away;

2.2] holographic dry plate (3) that will be loaded with Particle Field information is installed on the D translation platform (4), and holographic dry plate (3) is arranged near imaging len (5) front focal plane on laser instrument (1) output light path, move holographic dry plate along optical axis direction then, the picture of standard silk on CCD on the Particle Field reference field reproduced in interpretation on computers simultaneously, when clear picture, the axial coordinate of recording holographic dry plate is as the axial initial acquisition position of Particle Field and the reference zero of axial coordinate;

3] gather the Particle Field image: carry out the Particle Field image acquisition by D translation platform (4) the mobile holographic dry plate of order (3), finish up to all images collection.

5. Particle Field optical holography high precision according to claim 4 is reproduced acquisition method, and it is characterized in that: described D translation platform is the three dimensions mobile platform of step-length 0.1 μ m; Described one dimension translation stage is the one-dimensional space mobile platform of step-length 0.1 μ m.

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