CN111595442A - Snapshot type polarization spectrum imaging method and device - Google Patents

Abstract

The invention relates to a snapshot type polarization spectrum imaging method and device. It aims to solve the technical problems that the spectral imaging method or device in the prior art is not suitable for the needs of dynamic target detection and real-time detection, the time-division period of polarization state measurement is long, the spectral aliasing phenomenon and the low energy utilization rate; the present invention A snapshot-type polarization spectrum imaging method, the target light is collimated and then interfered by the F-P interferometer, and the F-P interferometer is continuously fine-tuned, and then the polarization spectrum image with the continuously changing spectrum is obtained and output, Then collect the polarization spectrum image; thus realize the ability of snapshot type polarization spectrum acquisition, for this reason, the present invention also provides a snapshot type polarization spectrum imaging device for realizing the above method, the device does not have moving parts with a large stroke, and has very Good stability, non-traditional way to rotate the polarizing wheel or wave plate.

Description

A snapshot-type polarization spectrum imaging method and device

technical field

The invention relates to a spectral imaging method and device, in particular to a snapshot-type polarization spectral imaging method and device.

Background technique

The combination of spectral imaging and polarization imaging forms a new optical remote sensing technology - polarization spectral imaging technology, which is a new detection technology that can integrate the image information, spectral information and polarization state information of the target. Due to the advanced principle and technical advantages, spectral imaging equipment may have the phenomenon of "same spectrum foreign matter" and "same spectrum different spectrum", and there are certain limitations in the accuracy of target identification. The best detection and identification capabilities can be achieved by adding polarization information to the image and spectral information. Especially suitable for target detection in turbid media (smoke, fog, haze, dust, water, etc.) detection area at both ends. At the same time, the atmospheric attenuation can be accurately described and regular discovered by means of polarization, which can provide an objective basis for the new atmospheric window theory.

At present, there are mainly the following methods for polarization spectral imaging detection methods:

1. Polarized spectral imaging method based on AOTF (acousto-optic tunable) and LCTF (liquid crystal tunable): the principle of this method is to use the principle of acousto-optic diffraction and the principle of liquid crystal electrical tuning to select the spectral spectrum, and at the same time, use the phase The combination of delay device LCVR and other combinations of polarization state measurement has the disadvantage that it can only be used for the measurement of static targets, which does not meet the requirements of dynamic application targets and real-time performance.

2. Computed Tomography-based polarization spectrum imaging method: The detection of polarization state and spectral information is performed by installing multiple polarizers and wave plates with different polarization directions. The disadvantage is that the polarization state measurement is time-sharing, the measurement period is long, and there are moving parts. , not applicable when there are moving objects that change rapidly.

3. Spectral polarization imaging method based on slit dispersion: This method adopts polarization-spectral intensity modulation technology, and realizes the measurement of polarization state by adding a spectral modulation module to the optical path of ordinary slit dispersion spectrometer. The disadvantage of this method is the acquisition of spectrum. The system uses a slit, so the energy utilization rate is relatively low, and the acquired raw data has spectral aliasing.

4. Polarization spectral imaging system based on polarization grating: The system adopts a new type of transmissive anisotropic polarization-sensitive grating, which can realize the separation of polarization dimension and spectral dimension, but the system has aliasing phenomenon in spectral acquisition. , the measurement of the polarization state needs to be calculated by combination. At the same time, the system has slits, the energy utilization rate is not high, and the processing and preparation of the transmission grating is difficult.

Based on the above typical shortcomings, there is an urgent need for a spectral imaging technology with non-push-broom, snapshot type, synchronous acquisition of polarization information, and programmable output of spectral bands.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problems that the spectral imaging method or device in the prior art is not suitable for the needs of dynamic target detection and real-time detection, the time-division period of the polarization state measurement is long, the spectral aliasing phenomenon and the low energy utilization rate, To provide a snapshot-type polarization spectrum imaging method and device.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A snapshot-type polarization spectrum imaging method is special in that it includes the following steps:

Step 1) collimating the target light;

Step 2) Interfering with the collimated target light by the F-P interferometer, and constantly fine-tuning the F-P interferometer, so that the wavelength of the light wave output by it is constantly changed, thereby generating a continuous spectrum with constantly changing spectral segments;

Step 3) obtain the polarized spectrum image that the spectrum segment is constantly changing and output;

Step 4) Collect polarization spectrum images.

Further, in the step 2), the fine-tuning of the F-P interferometer is to continuously change the displacement of the micro-displacement motor in the F-P interferometer.

Based on the above-mentioned snapshot-type polarization spectrum imaging method, the present invention also provides a snapshot-type polarization spectrum imaging device, which is special in that:

It includes a front optical telephoto unit, an F-P interferometer, a detection unit and an acquisition control unit arranged in sequence along the optical path;

The front optical telephoto unit collimates and emits the target light;

The F-P interferometer is used to change the optical path difference of the target light;

The detection unit acquires a polarized spectral image of the target light;

The acquisition control unit acquires polarization spectrum images, and outputs different voltage signals to the F-P interferometer.

Further, the detection unit includes an imaging lens group and a polarization detector;

The imaging lens group images the target light on the polarization detector;

The polarization detector is used to acquire polarization spectrum images.

Further, the F-P interferometer includes a micro-displacement motor;

The acquisition control unit is provided with a data set corresponding to the displacement of the micro-displacement motor and the wavelength of the output light wave.

Further, the polarization detector includes a first polarization unit;

The first polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a non-polarized direction.

Further, the polarization detector includes a second polarization unit;

The second polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a circular polarization direction.

Further, the polarization detector includes a third polarization unit;

The third polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 90-degree linear deflection direction, and a 135-degree linear deflection direction.

Further, the polarization detector is configured by any combination of at least one of the first polarization unit, the second polarization unit and the third polarization unit in the form of an N*N matrix;

The first polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a non-polarized direction;

The second polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction and a circular polarization direction;

The third polarizing unit is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 90-degree linear deflection direction, and a 135-degree linear deflection direction.

Further, the front optical telephoto unit includes a front mirror group, a field diaphragm and a collimating mirror group arranged in sequence along the optical path;

The front lens group realizes the front collection of the target light, and the target light is incident on the field diaphragm, and the field diaphragm selects and adjusts the field of view of the target light, and then is collimated by the collimating lens group and exits to the field of view. F-P interferometer.

The beneficial effects of the present invention are:

1. Compared with the traditional polarization spectrum imaging method, the spectral imaging method of the present invention has the ability to realize snapshot-type polarization spectrum acquisition, and has the ability to detect moving targets.

2. The polarization state acquisition of the present invention is synchronous acquisition, which has very good real-time performance, and non-traditional time-sharing and asynchronous measurement.

3. The spectral imaging device of the present invention has no moving parts with a large stroke, and has very good stability, and the non-traditional method needs to rotate the polarization wheel or the wave plate.

4. The spectral acquisition of the spectral imaging device of the present invention does not use slits, so the energy utilization rate is high, and there is no spectral aliasing phenomenon.

5. The polarization spectrum imaging device of the present invention has the ability to select spectrum bands under different polarization state information acquisition conditions.

Description of drawings

1 is a schematic structural diagram of a snapshot-type polarization spectrum imaging device of the present invention;

Fig. 2 is the configuration diagram of the first polarizing unit in the present invention;

Fig. 3 is the configuration diagram of the second polarizing unit in the present invention;

Fig. 4 is the configuration diagram of the third polarizing unit in the present invention;

FIG. 5 is a configuration diagram in which four first polarizing units are combined in a 2*2 matrix form in the present invention.

In the figure, 1-front optical telephoto unit, 11-front mirror group, 12-field diaphragm, 13-collimation mirror group, 2-F-P interferometer, 3-detection unit, 31-imaging mirror group, 32-polarization detector, 321-first polarization unit, 322-second polarization unit, 323-third polarization unit, 4-collection control unit.

Detailed ways

In order to make the purpose, advantages and features of the present invention clearer, a snapshot-type polarization spectrum imaging method and device proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following detailed description. It should be noted that: the accompanying drawings are all in a very simplified form and use inaccurate scales, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention; secondly, the structures shown in the accompanying drawings are often actual structures. part.

A snapshot-type polarization spectrum imaging device of the present invention, as shown in FIG. 1 , includes a front mirror group 11 , a field diaphragm 12 , a collimating mirror group 13 , an F-P interferometer 2 , and an imaging mirror group 31 arranged in sequence along the optical path. , a polarization detector 32 and an acquisition control unit 4;

The front mirror group 11, the field diaphragm 12 and the collimating mirror group 13 constitute the front optical telephoto unit 1 that collimates and emits the target light; the F-P interferometer 2 is used to change the optical path difference of the target light; the imaging mirror The group 31 and the polarization detector 32 constitute the detection unit 3 for acquiring the beam polarization image; the acquisition control unit 4 realizes the acquisition of polarization spectrum data, and the control and adjustment of the detector and the micro-displacement motor.

The F-P interferometer 2 includes a micro-displacement motor, and changing the displacement of the micro-displacement motor can change the wavelength of the light wave output by the F-P interferometer, thereby generating a continuous spectrum with continuously changing spectral bands.

The target light enters the front mirror group 11 to realize the front collection, and the target light is incident on the field diaphragm 12. The field diaphragm 12 selects and adjusts the field of view of the target light, and then is collimated by the collimating lens group 13 and exits to the field of view. F-P interferometer 2; the displacement of the micro-displacement motor in the F-P interferometer 2 is controlled by the acquisition control unit 4, so as to continuously modulate and transform the spectral band, and then image the polarization detector 32 through the imaging lens group 31 to realize the polarization image of the continuous spectrum acquisition, the polarization state adjustment of different spectral bands can be achieved through the change of the polarization detector to achieve the acquisition of different polarization states.

The displacement generated by the micro-displacement motor is proportional to the optical path difference of the two interference beams, and the optical path difference corresponds to the wavelength generated by the interference. Therefore, in the present invention, the displacement of the micro-displacement motor and the beam wavelength are provided in the acquisition control unit 4. the corresponding data set. In use, it can be directly added to the required wavelength position as needed, without gradually scanning from the starting point, and the detection wavelength can be selected as needed, that is, by programming the driving voltage signal applied to the micro-displacement motor, the micro-displacement amount can be realized. Therefore, the selection and output of wavelength can be realized, which has great advantages in application. For example, the detection purpose can be achieved without generating a large amount of data (data cube), and the work efficiency can be greatly improved.

The present invention provides four configurations of polarization detectors:

The first type, as shown in FIG. 2 , the polarization detector 32 includes a first polarization unit 321; *2 It is configured in matrix form, which can avoid weak incident light energy and limited target detection.

The second type, as shown in FIG. 3 , the polarization detector 32 includes a second polarization unit 322; *2 It is configured in matrix form; this configuration adopts the memory effect of circular polarization information to obtain full polarization information;

The third type, as shown in FIG. 4 , the polarization detector 32 includes a third polarization unit 323; It is configured in the form of a 2*2 matrix. This configuration method can obtain two orthogonal linear polarization information, respectively corresponding to different application scenarios.

In the fourth type, the polarization detector 32 is composed of at least one of the first polarization unit 321 in the first type, the second polarization unit 322 in the second type, and the third polarization unit 323 in the third type with N* It is configured in any combination in the form of an N matrix; that is, all of them can be one of the above three, or any two of them, or all of the three, and the configuration methods are various. As shown in FIG. 5 , four first polarizing units 321 are arranged in a 2*2 matrix. With this configuration, the polarization information of the target can be acquired at any position in the field of view.

A snapshot-type polarization spectrum imaging method of the present invention includes the following steps:

Step 1) Pre-collecting, selecting and adjusting the field of view and collimating the target light in sequence through the front optical telephoto unit, and then incident on the F-P interferometer;

Step 2) continuously modulate the F-P interferometer by the acquisition control unit, thereby continuously adjusting the wavelength of the light wave output by the F-P interferometer, to generate a continuous spectrum with constantly changing spectral bands;

Step 3) imaging the continuous spectrum of the continuously changing spectrum segment to the polarization detector by the imaging mirror group in the detection unit, and obtaining and outputting the polarization spectrum image of the constant changing spectrum segment through the polarization detector;

Step 4) Collect the polarization spectrum image through the acquisition control unit.

Claims (10)

1. a snapshot type polarization spectrum imaging method, is characterized in that, comprises the following steps: Step 1) collimating the target light; Step 2) Interfering with the collimated target light by the F-P interferometer, and constantly fine-tuning the F-P interferometer, so that the wavelength of the light wave output by it is constantly changed, thereby generating a continuous spectrum with constantly changing spectral segments; Step 3) obtain the polarized spectrum image that the spectrum segment is constantly changing and output; Step 4) Collect polarization spectrum images. 2. a kind of snapshot type polarization spectrum imaging method according to claim 1, is characterized in that: In the step 2), the fine-tuning of the F-P interferometer is to continuously change the displacement of the micro-displacement motor in the F-P interferometer. 3. A snapshot type polarization spectrum imaging device for realizing a kind of snapshot type polarization spectrum imaging method according to claim 1, is characterized in that: comprise the front optical telephoto unit (1), F-P interferometer (1) that are arranged in turn along the optical path. 2), a detection unit (3) and an acquisition control unit (4); The front optical telephoto unit (1) collimates and emits the target light; The F-P interferometer (2) is used to change the optical path difference of the target light; The detection unit (3) acquires a polarization spectrum image of the target light; The acquisition control unit (4) acquires polarization spectrum images, and outputs different voltage signals to the F-P interferometer (2). 4. A snapshot type polarization spectrum imaging device according to claim 3, characterized in that: the detection unit (3) comprises an imaging mirror group (31) and a polarization detector (32); The imaging lens group (31) images the target light on the polarization detector (32); The polarization detector (32) is used for acquiring polarization spectrum images. 5. A snapshot-type polarization spectrum imaging device according to claim 3 or 4, characterized in that: the F-P interferometer (2) comprises a micro-displacement motor; The acquisition control unit (4) is provided with a data set corresponding to the displacement of the micro-displacement motor and the wavelength of the output light wave. 6. The snapshot-type polarization spectrum imaging device according to claim 3, wherein the polarization detector (32) comprises a first polarization unit (321); The first polarizing unit (321) is configured by a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction and a non-polarizing direction in a 2*2 matrix. 7. The snapshot-type polarization spectrum imaging device according to claim 3, wherein the polarization detector (32) comprises a second polarization unit (322); The second polarizing unit (322) is configured by a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a circular polarization direction in the form of a 2*2 matrix. 8. The snapshot-type polarization spectrum imaging device according to claim 3, wherein the polarization detector (32) comprises a third polarization unit (323); The third polarizing unit (323) is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 90-degree linear deflection direction, and a 135-degree linear deflection direction. 9 . The snapshot-type polarization spectrum imaging device according to claim 3 , wherein the polarization detector ( 32 ) is composed of a first polarization unit ( 321 ), a second polarization unit ( 322 ) and a third polarization unit ( 321 ). 10 . At least one of the polarization units (323) is configured in any combination in the form of an N*N matrix; The first polarizing unit (321) is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a non-polarized direction; The second polarizing unit (322) is configured in a 2*2 matrix form by a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 135-degree linear deflection direction, and a circular polarization direction; The third polarizing unit (323) is configured in a 2*2 matrix form with a 0-degree linear deflection direction, a 45-degree linear deflection direction, a 90-degree linear deflection direction, and a 135-degree linear deflection direction. 10. A snapshot-type polarization spectrum imaging device according to claim 5, characterized in that: the front optical telephoto unit (1) comprises a front mirror group (11) arranged in sequence along the optical path, a field of view light A diaphragm (12) and a collimating lens group (13); The front lens group (11) realizes the front collection of the target light, and the target light is incident on the field of view diaphragm (12), and the field of view diaphragm (12) selects and adjusts the field of view of the target light, and then calibrates the target light. The collimating lens group (13) is collimated and output to the F-P interferometer (2).

Images