CN206038152U - Polarized interference spectral imaging system - Google Patents

Abstract

The utility model discloses a polarization interference spectrum imaging system, which comprises sequentially arranged along the direction of the optical path: a lens group for receiving light emitted by an object and collimating the incident light; a microlens array, including N microlenses; a birefringent beam splitting system for dividing each sub-image light into a parallel component and a vertical component perpendicular to the vibration direction, and forming two beams of linearly polarized light with a preset optical path difference for each component; The imaging lens used to converge the interference light formed by the two beams of linearly polarized light of each component to the photodetector; the photodetector; the N interference images formed by the parallel components and the N interference images obtained by A data processor that processes the interference image formed by the vertical component to obtain a spectrogram with polarization information. The polarization interference spectrum imaging system of the utility model has the characteristics of simple and stable structure, wide spectral bandpass, high spectral resolution, etc., and can realize real-time detection of dynamic targets.

Description

A Polarization Interference Spectral Imaging System

technical field

The utility model relates to the technical field of polarization spectrum imaging, in particular to a polarization interference spectrum imaging system.

Background technique

Polarization spectral imaging technology combines the advantages of spectral imaging technology and polarization technology. It can simultaneously obtain the spatial information, spectrum and polarization information of the target. It is an important technical means in optical remote sensing and space detection.

Differential polarization spectroscopy imaging technology is developed from differential polarization imaging technology. The differential polarization imaging technology only obtains the polarization image of the orthogonal polarization component of the target to remove the background and improve the contrast of the target. The differential polarization spectral imaging technology is a combination of spectral imaging technology and differential polarization imaging technology. At present, there are differential polarization spectral imagers based on grating spectrometers and differential polarization spectral imagers based on acousto-optic tuning filters. Low-level disadvantages, and can only detect static targets; In addition, there are differential polarization spectral imagers based on polarization spectroscopic devices. Although this type of spectral imager has a stable structure and wide spectral bandpass, it uses window scanning when collecting images, and it needs to be scanned within a time period. Multiple images of the target are collected within the target, and the polarization spectrum measurement results of the target are obtained according to the images collected multiple times, which belongs to the space-time modulation type and cannot detect dynamic targets.

Utility model content

In view of this, the utility model provides a polarization interference spectral imaging system, which has the characteristics of simple and stable structure, wide spectral bandpass and high spectral resolution, and can realize real-time detection of dynamic targets.

In order to achieve the above object, the utility model provides the following technical solutions:

A polarization interference spectrum imaging system, including sequentially arranged along the direction of the optical path:

A lens group for receiving the light emitted by the target and collimating the incident light;

A microlens array for generating N sub-images of the target, the microlens array includes N microlenses arranged in an array, and N is a positive integer greater than zero;

A birefringent beam splitting system for dividing each sub-image light into a parallel component and a vertical component perpendicular to the vibration direction, and forming two beams of linearly polarized light with a preset optical path difference for each component;

An imaging lens for converging the interference light formed by two beams of linearly polarized light of each component to the photodetector;

said photodetector;

connected to the photodetector, used to process the N interference images formed by the parallel components and the N interference images formed by the vertical components obtained by the photodetector to obtain the data of the spectral diagram with polarization information processor.

Optionally, the birefringence splitting system includes:

a birefringent polarizer for splitting each sub-image light into parallel and perpendicular components with orthogonal vibration directions;

a pair of birefringent prisms for splitting each component of each sub-image light into two linearly polarized beams whose directions of vibration are orthogonal;

A linear polarizing element for converting the polarization direction of each linearly polarized light.

Optionally, the birefringent polarizer includes a first polarizing plate with a first optical axis direction and a second polarizing plate with a second optical axis direction that are attached to each other, and the projection of the first optical axis direction on the xy plane is the same as The included angle of the projection of the second optical axis direction on the xy plane is 90 degrees;

The included angles between the optical axis and the x-axis of the pair of birefringent prisms are respectively 0 degrees and 90 degrees;

The polarization direction of the linear polarization element is parallel to any optical axis direction of the birefringent polarizer;

The direction along which the incident light propagates is the z-axis direction, the vertical direction perpendicular to the z-axis direction is the y-axis direction, and the horizontal direction perpendicular to the z-axis direction is the x-axis direction, and the x-axis, y-axis, and z-axis are right-handed Spiral rule.

Optionally, the photosensitive surface of the photodetector is located on the focal plane of the imaging lens.

Optionally, the lens group is a telephoto lens group.

Optionally, the photodetector includes a CCD detector.

Optionally, the data processor is a computer.

It can be seen from the above technical solutions that the polarization interference spectrum imaging system provided by the utility model includes a lens group, a microlens array, a birefringent spectroscopic system, an imaging lens, a photodetector and a data processor arranged in sequence along the direction of the optical path. The light emitted by the target object is converted into parallel light by the lens group, and N sub-images carrying the same information are formed through the micro-lens array; each sub-image light is divided into parallel components orthogonal to the vibration direction and vertical components, and form two beams of linearly polarized light with a preset optical path difference for each component; the interference light formed by the two beams of linearly polarized light corresponding to the parallel component of each sub-image light is converged to the photodetector through the imaging lens to form The interference image of the parallel component, the interference light formed by the two beams of linearly polarized light corresponding to the vertical component of each sub-image light is converged to the photodetector through the imaging lens to form the interference image of the vertical component; the data processor combines the N parallel components The interference image and the interference image of N vertical components are processed to obtain a spectrogram with polarization information.

The polarization interference spectrum imaging system of the utility model obtains the interference images of N parallel components and the interference images of N vertical components at the same time, and processes and obtains the band of the target object according to the interference images of N parallel components and the interference images of N vertical components. A spectrogram with polarization information. Real-time detection of dynamic targets can be realized, and the polarization interference spectral imaging system has the characteristics of simple and stable structure, wide spectral bandpass, high spectral resolution and the like.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the schematic diagram of a kind of polarization interference spectrum imaging system provided by the embodiment of the utility model;

Fig. 2 is a schematic diagram of a polarization interference spectrum imaging system provided by another embodiment of the present invention;

Fig. 3 is the structural representation of birefringent polarizer in the utility model embodiment;

Fig. 4 is a schematic structural diagram of a pair of birefringent prisms in an embodiment of the present invention.

detailed description

In order to enable those skilled in the art to better understand the technical solution in the utility model, the technical solution in the utility model embodiment will be clearly and completely described below in conjunction with the accompanying drawings in the utility model embodiment. Obviously, The described embodiments are only some of the embodiments of the present utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

Please refer to FIG. 1, which is a schematic diagram of a polarization interference spectrum imaging system provided in this embodiment of the utility model. The polarization interference spectrum imaging system of this embodiment includes sequentially arranged along the optical path direction:

A lens group 10 for receiving the light emitted by the target object and collimating the incident light;

A microlens array 11 for generating N sub-images of the target, said microlens array 11 comprising N microlenses arranged in an array, where N is a positive integer greater than zero;

A birefringent beam splitting system 12 for dividing each sub-image light into a parallel component and a vertical component perpendicular to the vibration direction, and forming two beams of linearly polarized light with a preset optical path difference for each component;

An imaging lens 13 for converging the interference light formed by two beams of linearly polarized light of each component to the photodetector 14;

The photodetector 14;

The one connected to the photodetector 14 is used to process the N interference images formed by the parallel components and the N interference images formed by the vertical components acquired by the photodetector 14 to obtain a spectral diagram with polarization information The data processor 15.

The polarization interference spectroscopy imaging system provided in this embodiment includes a lens group 10 , a microlens array 11 , a birefringent spectroscopic system 12 , an imaging lens 13 , a photodetector 14 and a data processor 15 sequentially arranged along the optical path direction. The light emitted by the target enters the imaging system through the lens group, is converted into parallel light by the lens group, and forms N sub-images carrying the same information through the micro-lens array; It is divided into parallel components and vertical components that are orthogonal to the vibration direction, and forms two beams of linearly polarized light with a preset optical path difference for each component; the parallel component of each sub-image light is formed by two beams of linearly polarized light The interference light is converged to the photodetector through the imaging lens to form an interference image of the parallel component of each sub-image, and the interference light formed by two beams of linearly polarized light corresponding to the vertical component of each sub-image light is converged to the photodetector through the imaging lens. An interference image of the vertical component of each sub-image is formed; the data processor processes the interference image of N parallel components and the interference image of N vertical components to obtain a spectrogram with polarization information.

The polarization interference spectrum imaging system of this embodiment can simultaneously obtain the interference images of N parallel components and the interference images of N vertical components, and process and obtain the image of the target object according to the interference images of N parallel components and the interference images of N vertical components. Spectrogram with polarization information. Therefore, the dynamic target can be imaged, and the real-time detection of the dynamic target can be realized, and the polarization interference spectral imaging system has the characteristics of simple and stable structure, wide spectral bandpass, high spectral resolution and the like.

The polarization interference spectroscopy imaging system of this embodiment will be described in detail below. The polarization interference spectroscopy imaging system provided in this embodiment includes a lens group 10 , a microlens array 11 , a birefringent spectroscopic system 12 , an imaging lens 13 , a photodetector 14 and a data processor 15 . In this embodiment, it is defined that the direction along which the incident light propagates is the z-axis direction, the vertical direction perpendicular to the z-axis direction is the y-axis direction, the horizontal direction perpendicular to the z-axis direction is the x-axis direction, and the x-axis, y-axis, The three on the z-axis conform to the right-hand spiral rule.

Wherein, the lens group 10 is used for receiving the light emitted by the target object and collimating the incident light, so that the light emitted by the target object is converted into parallel light through the lens group. The lens group 10 may be a telescopic lens group, and the imaging system is capable of remote sensing detection.

The microlens array 11 includes N microlenses arranged in an array. After the parallel light passes through the microlens array 11, N sub-images of the target object are formed, which carry the same information.

In this embodiment, as shown in FIG. 2 , the birefringence splitting system 12 includes:

A birefringent polarizer 120 for dividing each sub-image light into a parallel component and a vertical component perpendicular to the vibration direction;

A pair of birefringent prisms 121 for dividing each component of each sub-image light into two beams of linearly polarized light whose vibration directions are orthogonal;

A linear polarization element 122 for converting the polarization direction of each linearly polarized light.

Specifically, the birefringent polarizer 120 in this embodiment is a Savall polarizer, and the birefringent polarizer 120 includes a first polarizer with a first optical axis direction and a second polarizer with a second optical axis direction that are attached to each other. Two polarizers, the angle between the projection of the first optical axis direction on the xy plane and the projection of the second optical axis direction on the xy plane is 90 degrees, as shown in Figure 3, which is a birefringent polarizer in this embodiment Schematic diagram of the structure, the direction of the arrow in the figure is the direction of the optical axis. Each sub-image light passes through the birefringent polarizer and is divided by 120 into a parallel component and a vertical component perpendicular to the vibration direction. The parallel component refers to the component parallel to the x-axis direction, and the vertical component refers to the component perpendicular to the x-axis direction.

The pair of birefringent prisms 121 is a Wollaston prism, and the angles between the optical axis and the x-axis of the pair of birefringent prisms 121 are respectively 0 degrees and 90 degrees, as shown in Fig. The direction is the direction of the optical axis of the prism. The parallel component of each sub-image light passes through the pair of birefringent prisms 121, and is divided into two beams of linearly polarized light whose vibration directions are orthogonal; Two beams of linearly polarized light.

The optical path difference generated by the two linearly polarized lights of each component light passing through the birefringent prism pair 121 has a linear relationship with the y-coordinate value of the incident position of the component light on the birefringent prism pair, and the expression of the optical path difference is: Δ=2(n _e -n _o )ytanθ, where Δ represents the optical path difference, n _e represents the refractive index of e light in the prism, n _o represents the refractive index of o light in the prism, θ represents the wedge angle of the prism, and y represents the incident light The y coordinate of the incident location. Therefore, for N sub-image lights, the positions incident on the birefringent prism are different, and the optical path differences of the two linearly polarized lights of the same component are different, so N interference images with parallel components with different optical path differences and N interference images with different optical path differences can be produced. Interference images of the vertical components of different optical path differences.

The polarization direction of the linear polarization element 122 is parallel to any optical axis direction of the birefringent polarizer 120 .

The two beams of linearly polarized light of the parallel component of each sub-image pass through the linear polarization element 122, and are converted into linearly polarized light with the same polarization direction as the linear polarization element, and the interference light formed by the two beams of linearly polarized light is converged to the photoelectric The photosensitive surface of the detector is used to obtain the interference image of the parallel component of each sub-image. The two beams of linearly polarized light of the vertical component of each sub-image pass through the linear polarization element and are converted into linearly polarized light with the same polarization direction as the linear polarization element. The interference light formed by the two beams of linearly polarized light is converged to the photoelectric The photosensitive surface of the detector is used to obtain the interference image of the vertical component of each sub-image.

Preferably in this embodiment, the photosensitive surface of the photodetector 14 is located on the focal plane of the imaging lens 13 .

On the photosensitive surface of the photodetector 14, for each sub-image, the expressions of the electric field vectors forming the orthogonal polarization components are respectively as follows:

Among them, J _wp1 + J _wp2 e ^i2πΔλ represents the Jones matrix of the Wollaston prism, J _sp1 and J _sp2 represent the Jones matrix of the Savall polarizer, J _LA represents the Jones matrix of the linear polarization element, E _|| represents the target image The parallel component of the electric field vector, E _⊥ represents the vertical component of the electric field vector of the target image.

The expressions of the two interference images of the orthogonal polarization components received on the photosensitive surface of the photodetector 14 are respectively:

For N sub-image lights, due to the different positions incident on the birefringent prism, the optical path difference between different sub-images is different, and the optical path difference between two beams of linearly polarized light of the same component in different sub-images is different, which can produce Interference images of N parallel components with different optical path differences and N interference images of perpendicular components with different optical path differences. The data processor extracts and reconstructs the data of the interferogram sequence of the parallel component and the interferogram sequence of the vertical component respectively according to the interference image of N parallel components and the interference image of N vertical components, and obtains the three-dimensional interference of the target object image, and then use the Fourier transform to invert two spectral images, that is, the orthogonal polarization component spectral image, the difference between the two spectral images is the differential polarization spectral image of the target object, and the difference between the two spectral images and the sum of the two spectral images The ratio is the linear polarization spectrum image of the target object.

In this embodiment, the photodetector may be a CCD detector. The data processor 15 is a computer.

A polarization interference spectrum imaging system provided by the utility model has been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present utility model, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made to the utility model, and these improvements and modifications also fall into the protection of the claims of the utility model. within range.

Claims (7)

1. A polarization interference spectral imaging system, characterized in that it comprises sequentially arranged along the light path direction: A lens group for receiving the light emitted by the target and collimating the incident light; A microlens array for generating N sub-images of the target, the microlens array includes N microlenses arranged in an array, and N is a positive integer greater than zero; A birefringent beam splitting system for dividing each sub-image light into a parallel component and a vertical component perpendicular to the vibration direction, and forming two beams of linearly polarized light with a preset optical path difference for each component; An imaging lens for converging the interference light formed by two beams of linearly polarized light of each component to the photodetector; said photodetector; connected to the photodetector, used to process the N interference images formed by the parallel components and the N interference images formed by the vertical components obtained by the photodetector to obtain the data of the spectral diagram with polarization information processor. 2. The system according to claim 1, wherein the birefringence splitting system comprises: a birefringent polarizer for splitting each sub-image light into parallel and perpendicular components with orthogonal vibration directions; a pair of birefringent prisms for splitting each component of each sub-image light into two linearly polarized beams whose directions of vibration are orthogonal; A linear polarizing element for converting the polarization direction of each linearly polarized light. 3. The system of claim 2, wherein: The birefringent polarizer includes a first polarizing plate with a first optical axis direction and a second polarizing plate with a second optical axis direction that are attached to each other, and the projection of the first optical axis direction on the xy plane and the second optical axis The included angle of the projection of the direction on the xy plane is 90 degrees; The included angles between the optical axis and the x-axis of the pair of birefringent prisms are respectively 0 degrees and 90 degrees; The polarization direction of the linear polarization element is parallel to any optical axis direction of the birefringent polarizer; The direction along which the incident light propagates is the z-axis direction, the vertical direction perpendicular to the z-axis direction is the y-axis direction, and the horizontal direction perpendicular to the z-axis direction is the x-axis direction, and the x-axis, y-axis, and z-axis are right-handed Spiral rule. 4. The system according to claim 3, wherein the photosensitive surface of the photodetector is located on the focal plane of the imaging lens. 5. The system according to claim 1, wherein the lens group is a telephoto lens group. 6. The system of claim 1, wherein the photodetector comprises a CCD detector. 7. The system according to claim 6, wherein the data processor is a computer.