CN116907647A - Strong light interference resistant polarization imaging device and imaging method for spatial light modulation - Google Patents

Abstract

A polarization imaging device and a method for resisting strong light interference of spatial light modulation relate to the field of optical detection. The problems that most of the existing imaging devices are limited by target wavelength, the light intensity reflected by a target is difficult to distinguish from the interference light intensity, and the interference of strong light cannot be resisted are solved; the problem that the image with the highest contrast and the highest definition is difficult to automatically obtain due to the lack of an adaptive aperture adjusting technology. The invention provides the following scheme: the device comprises a spatial light modulation system, an image definition evaluation system and an adaptive aperture automatic adjustment system; the spatial light modulation system is used for collecting optical signals, modulating the optical signals to generate electric signals, and sending the electric signals to the image definition evaluation system; the image definition evaluation system sends the electric signal to the self-adaptive aperture automatic adjustment system; the self-adaptive aperture automatic adjusting system is used for receiving the electric signals, adjusting the aperture value and the image definition of the electric signals and outputting the electric signals to the spatial light modulation system. The optical detection device is suitable for the optical detection working process.

Description

A polarization imaging device and imaging method for spatial light modulation and resistance to strong light interference

Technical Field

The invention belongs to the field of optical detection.

Background Art

With the advancement and development of science and technology, weak space targets under strong light background have become an important direction for future scientific research. Such targets are affected by radar scattering, weak infrared radiation, and are interfered by complex environmental backgrounds such as atmospheric transmission paths, cloud scene clutter, and surface radiation. Their radiation brightness is likely to be close to or even weaker than the background, which greatly reduces the target's detectable distance, warning time, and detection probability. Optical detection has high-precision, high-efficiency, long-range wide-area monitoring and detection capabilities, and has become an important development direction for early detection, rapid detection, tracking and identification of weak targets under strong light background.

Polarization imaging technology uses the polarization characteristics of light to obtain the polarization state, spatial profile and other characteristics of the target, thereby improving the contrast of the target in the image. At the same time, the polarization imaging detection system has high stability, strong anti-interference ability, and long detection distance, and has outstanding advantages in the field of dark target detection.

Research on polarization detection technology for dim targets in space has important application value for further promoting the development of space technologies such as autonomous rendezvous and docking of spacecraft and confrontation of space targets in my country. By obtaining the polarization parameters of space targets under strong background, the polarization characteristics of dim targets under strong background are obtained, so as to improve the stability, anti-interference ability and detection accuracy of polarization detection system.

At present, there are still some problems in detecting dim targets under strong light background: most imaging devices are limited by the target wavelength, and it is difficult to distinguish the intensity of light reflected by the target from the intensity of interfering light, and cannot resist the interference of strong light; the lack of adaptive aperture adjustment technology makes it difficult to automatically obtain images with the maximum contrast and the highest clarity. Therefore, a new technology is needed to solve the existing problems.

Summary of the invention

The present invention solves the problem that most existing imaging devices are limited by the target wavelength, making it difficult to distinguish the light intensity reflected by the target from the interference light intensity and unable to resist the interference of strong light; and lack adaptive aperture adjustment technology, making it difficult to automatically obtain images with maximum contrast and highest clarity.

The present invention provides the following technical solution: a polarization imaging device with spatial light modulation and strong light interference resistance, comprising: the polarization imaging device with strong light interference resistance comprises a spatial light modulation system, an image clarity evaluation system and an adaptive aperture automatic adjustment system;

The spatial light modulation system is used to collect light signals, modulate the light signals to generate electrical signals, and send the electrical signals to the image clarity evaluation system to suppress interference light intensity;

The image clarity evaluation system is used to process the received electrical signal to obtain the clarity of the captured image, and send the received electrical signal to the adaptive aperture automatic adjustment system;

The adaptive aperture automatic adjustment system is used to receive the electrical signal, adjust the aperture value and image clarity according to the electrical signal, and output it to the spatial light modulation system.

Further, a preferred embodiment is provided, wherein the spatial light modulation system comprises a telecentric optical system unit, a spatial light modulator unit, a semi-reflective and semi-transmissive filter unit, a first CCD polarization detector unit, a second CCD polarization detector unit, an image acquisition and feedback unit, a field editable gate array unit, and a spatial light modulation controller unit;

The telecentric optical system unit sends the optical signal to the spatial light modulator unit, and the spatial light modulator unit transmits the received optical signal to the semi-reflective and semi-transparent filter unit; the semi-reflective and semi-transparent filter unit transmits the received optical signal to the first CCD polarization detector unit and the second CCD polarization detector unit respectively, and the optical signal is mutually transmitted between the first CCD polarization detector unit and the second CCD polarization detector unit;

The second CCD polarization detector unit converts the optical signal into an electrical signal and transmits it to the image acquisition and feedback unit; the image acquisition and feedback unit transmits the received electrical signal to the field editable gate array unit and the spatial light modulation controller unit; the spatial light modulation controller unit converts the received electrical signal into an optical signal and transmits it to the spatial light modulator unit, so as to realize the estimation and optimization of the intensity of the interference light.

Furthermore, a preferred embodiment is provided, wherein the image clarity evaluation system comprises an image acquisition unit to be detected and a first computer unit; the image acquisition unit to be detected receives an optical signal from the first CCD polarization detector unit, converts the optical signal into an electrical signal, and transmits the electrical signal to the first computer unit; the first computer unit transmits the received electrical signal to an adaptive aperture automatic adjustment system for calculating and evaluating the clarity of the captured image.

Further, a preferred embodiment is provided, wherein the adaptive aperture automatic adjustment system comprises a second computer unit, a scene light intensity collector unit, a proportional integral differential controller unit, and an aperture adjustment controller unit;

The second computer unit receives the electrical signal from the first computer unit and transmits it to the aperture adjustment controller unit; the proportional integral differential controller unit converts the electrical signal into an optical signal and transmits it to the scene light intensity collector unit, and feeds the optical signal back to the second computer unit, so as to establish a functional mapping relationship between the aperture value and the image clarity, and automatically adjust the aperture parameters according to the image clarity.

Furthermore, a preferred embodiment is provided, wherein a signal conversion module is embedded in the first computer unit, and the signal conversion module converts the optical signal received by the first CCD polarization detector unit into an electrical signal.

Furthermore, a preferred embodiment is provided, wherein a signal integration module is embedded in the second computer unit, and the signal integration module receives the electrical signal of the proportional-integral-differential controller unit and the optical signal converted from the electrical signal in the scene light intensity collector unit.

Solution 2: A spatial light modulated polarization imaging method that is resistant to strong light interference, the method is implemented using any device described in Solution 1, and the method comprises the following steps:

Step 1: Through the telecentric optical system unit, the main light of the telecentric optical system unit is vertically incident on the spatial light modulator unit located at the focal plane of the imaging objective lens, the spatial light modulator unit receives the main light from the telecentric optical system unit, and reduces the transmittance of the interference light to zero, so that the transmittance of the signal light remains unchanged; the light modulated by the spatial light modulator unit is transmitted to the semi-reflective and semi-transparent filter unit;

Step 2: The semi-reflective and semi-transparent filter unit refracts and reflects the processed light signal, and the reflected light is transmitted to the second CCD polarization detector unit for use and receives the reflected light from the semi-reflective and semi-transparent filter unit, and the refracted light is transmitted to the first CCD polarization detector unit; and the received image signal is transmitted to the image acquisition and feedback unit;

Step 3: After the image acquisition and feedback unit processes the image signal, determine the interference light intensity and signal intensity and passing the information to the field editable gate array unit;

Step 4: The editable gate array unit issues adjustment instructions to the spatial light modulation controller unit in real time according to the judgment from the image acquisition and feedback unit; the transmittance of each pixel on the spatial light modulation controller unit is changed;

Step 5: The first CCD polarization detector unit receives the refracted light from the semi-reflective and semi-transmissive filter unit, and transmits the received image signal to the image clarity evaluation system, and the entire spatial light modulation system realizes closed-loop negative feedback regulation;

Step 6: The image acquisition and feedback unit to be detected receives the image signal from the first CCD polarization detector unit and transmits it to the first computer unit;

Step 7: The first computer unit processes the image to be detected with high and low thresholds, performs image segmentation, calculates the clarity of the flat area, calculates the clarity of the edge area, and performs weighted summation to obtain the clarity Y of the current image, and transmits the information to the second computer unit of the adaptive aperture automatic adjustment system;

Step 8: The scene light intensity collector unit collects the current scene light intensity in real time and transmits it to the second computer unit;

Step 9: The relationship between the image clarity and the aperture adjustment step length is established through multiple training of the proportional-integral-differential controller unit, and the signal is transmitted to the second computer unit;

Step 10: The second computer unit combines the image clarity detected by the image clarity evaluation system, the scene light intensity collected by the scene light intensity collector unit, and the relationship between the image clarity and the aperture adjustment step length established by the proportional integral differential controller unit training, to obtain an accurate functional mapping relationship between the aperture value and the image quality, and transmits the mapping relationship instruction to the aperture adjustment controller unit;

Step 11: The aperture adjustment controller unit receives the mapping relationship instruction from the second computer unit, and the entire system forms a closed-loop control to realize adaptive automatic adjustment of the aperture parameters of the first CCD polarization detector unit and the second CCD polarization detector unit until an image closest to the ideal clarity is obtained.

Further, a preferred embodiment is provided, wherein the interference light intensity is determined and signal intensity The method is:

When the second CCD polarization detector unit captures four images with polarization directions of 0°, 45°, 90°, and 135°, the intensities are recorded as I ₀ (u, v, s, t), I ₄₅ (u, v, s, t), I ₉₀ (u, v, s, t), and I ₁₃₅ (u, v, s, t), respectively. The linear Stokes vectors of the scene can be expressed as:

(1)

Where: I(u, v, s, t) is the total light intensity of the scene; Q(u, v, s, t) is the intensity difference between the horizontal and vertical directions; U(u, v, s, t) is the intensity difference between the 45° and 135° directions. The expressions of the degree of polarization P(u, v, s, t) and the polarization angle θ(u, v, s, t) obtained from the above formula are:

(2)

(3)

Obtain the polarization angle image of the central viewing angle, and select the polarization angle with the highest frequency as the interference light polarization angle θ _B; the interference light polarization degree _PB is the maximum value of the central viewing angle polarization degree P(u, v, s, t) obtained after refocusing and fusion of the polarization degree images of each viewing angle;

(4)

(5)

When the shooting directions 0° and 90° are defined as the x-axis and y-axis respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light on the x-axis and y-axis are:

(6)

Since the image intensities collected in the x-axis and y-axis directions are Ⅰ ₀ (u, v, s, t) and Ⅰ ₉₀ (u, v, s, t) respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light in the x-axis and y-axis directions are expressed as follows:

(7)

The intensity of the polarized part of the interference light is obtained as:

(8)

From the above formula, we can know that the interference light intensity value at the central viewing angle is:

(9)

The original reflected light intensity L(u, v, s, t) of the target becomes unpolarized light after scattering effect. _A∞ (u, v, s, t) is the interference light intensity at infinity, which is partial channel polarized light with polarization degree _PB . Then:

(10)

Then when the detection distance z→∞, e ^（-z） →0, the interference light intensity at infinity is:

(11)

According to the physical degradation model, the image obtained by the detector is expressed as:

(12)

Select the closest 1% pixel value of _A∞ (u,v,s,t) at infinity obtained in formula Ⅰ ₀ (u,v,s,t) and the original image intensity I(u,v,s,t) as the reflected light intensity value A'∞ at infinity _;

Then the signal light intensity of the scene target is:

(13).

Further, a preferred embodiment is provided, wherein the image clarity evaluation method in step 7 is:

The second computer unit analyzes the image to be tested and introduces high and low threshold processing. The expression of this process is: (14)

Where GH is the maximum gradient value of the entire image, GL is the average value of the entire image, Th is the high gradient threshold, and Tl is the low gradient threshold; G represents the original image gradient, and G' represents the image gradient after high and low threshold processing;

The edge is taken as the foreground and the flat area is taken as the background to achieve the segmentation of the edge and the flat area. The process expression is:

(15)

Among them, Threshold is the optimal threshold calculated by Ostu method. Although the above process realizes the segmentation of edge area and flat area, it cannot remove the pseudo edge generated by isolated noise points; E represents edge, NE represents flat area;

In order to remove the pseudo edges generated by isolated noise points, the gradient image after removing the pseudo edges is recorded as Edge; the process expression is

(16)

Among them, sum(i, j) represents the number of edge points in the eight neighborhoods of pixel point (i, j). So far, the image segmentation process is completed, and the final flat area NEdge and edge area Edge are obtained;

Flat area clarity calculation:

The point sharpness algorithm is used to calculate the clarity of the image flat area NEdge. The definition of image clarity based on the point sharpness function is as follows:

(17)

Where df is the grayscale change amplitude, dx is the distance increment between pixels, M×N is the image size; (i, j) is the image pixel point;

Edge area clarity calculation:

The normalized square gradient algorithm is used to calculate the clarity of the flat area of the image; the square gradient function is defined as follows:

(18)

Since the above formula cannot achieve the horizontal comparison of the clarity of images of different sizes, the formula is normalized to:

(19)

Among them, the image size is M×N, I (i, j) represents the pixel gray value at the image pixel point (i, j); image clarity calculation:

The clarity of the entire image is obtained by weighted summation of the clarity of the flat area and the clarity of the edge area. The calculation formula is as follows:

(20)

in, and The weights corresponding to the clarity of the flat area and the clarity of the edge area respectively.

Further, a preferred implementation manner is provided, in which the method for obtaining the accurate functional mapping relationship between the aperture value and the image quality in step 10 is:

Use the scene light intensity collector unit to obtain the current scene light intensity and set the optimal aperture position to The corresponding optimal resolution is ,in is the aperture evaluation value determined by experiment; under certain scene light intensity conditions, the image clarity is proportional to the square of the aperture position. Y represents the current image clarity value, and D represents the current aperture position. Then:

(twenty one)

Wherein, k is a parameter of scene light intensity ratio, and the second computer unit sets k according to the image definition information and the current aperture position, and optimizes the k value in real time according to the image information.

Let the clarity deviation value , aperture shift , then:

(twenty two)

At the same time, the aperture shift The linear relationship with the rotation angle α is approximately similar to:

(twenty three)

From this, we can get the angle α of the aperture rotation and The relationship is:

(twenty four)

Based on the above functional relationship, the formula obtained by simplifying the proportional integral differential controller unit (33) is:

(25).

The present invention is beneficial in that:

The present invention controls the spatial light modulator to selectively modulate the light intensity at the pixel level, thereby changing the transmittance of each pixel on the spatial light modulator, thereby reducing the transmittance of the interference light on the spatial light modulator to zero and keeping the transmittance of the signal light unchanged, thereby suppressing the interference light and achieving image output without interference light.

The present invention uses adaptive aperture adjustment technology to establish an accurate functional mapping relationship between aperture value and image quality through multiple training of a proportional-integral-differential controller. An iterative method is usually used to continuously adjust the aperture parameters so that the image brightness approaches the target value, thereby maximizing image clarity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a polarization imaging device with spatial light modulation and strong light interference resistance according to the present invention.

FIG. 2 is a flow chart of an image clarity evaluation method of a polarization imaging method with spatial light modulation and resistance to strong light interference as described in Embodiment 7.

FIG3 is a flow chart of an automatic adaptive aperture adjustment method in a polarization imaging device with spatial light modulation and strong light interference resistance as described in the first embodiment.

Among them, 1 spatial light modulation system, 11 telecentric optical system unit, 12 spatial light modulator unit, 13 semi-reflective and semi-transparent filter unit, 14 first CCD polarization detector unit, 15 second CCD polarization detector unit, 16 image acquisition and feedback unit, 17 field editable gate array unit, 18 spatial light modulation controller unit, 2 image clarity evaluation system, 21 to-be-detected image acquisition unit, 22 first computer unit, 3 adaptive aperture automatic adjustment system, 31 second computer unit, 32 scene light intensity collector unit, 33 proportional integral differential controller unit, 34 aperture adjustment controller unit.

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

Embodiment 1: This embodiment is described with reference to FIG1. This embodiment provides a polarization imaging device with spatial light modulation and strong light interference resistance, including the following parts:

The polarization imaging device resistant to strong light interference comprises a spatial light modulation system 1, an image clarity evaluation system 2 and an adaptive aperture automatic adjustment system 3;

The spatial light modulation system 1 is used to collect light signals, modulate the light signals to generate electrical signals, and send the electrical signals to the image clarity evaluation system 2 to suppress interference light intensity;

The image clarity evaluation system 2 is used to process the received electrical signal to obtain the clarity of the captured image, and send the received electrical signal to the adaptive aperture automatic adjustment system 3;

The adaptive aperture automatic adjustment system 3 is used to receive the electrical signal, adjust the aperture value and image clarity according to the electrical signal, and output the received electrical signal to the spatial light modulation system 1 .

This embodiment further defines the connection relationship between the spatial light modulation system 1, the image clarity evaluation system 2 and the adaptive aperture automatic adjustment system 3, so that the spatial light modulation system 1 can change the transmittance of each pixel according to the adjustment instruction, so that the transmittance of the interference light is reduced to zero, and the transmittance of the signal light remains unchanged, and the light without interference light is transmitted to the detector in real time.

Embodiment 2: This embodiment is a polarization imaging device for spatial light modulation and strong light interference resistance provided in embodiment 1. The spatial light modulation system 1 includes a telecentric optical system unit 11, a spatial light modulator unit 12, a semi-reflective and semi-transparent filter unit 13, a first CCD polarization detector unit 14, a second CCD polarization detector unit 15, an image acquisition and feedback unit 16, a field editable gate array unit 17, and a spatial light modulation controller unit 18.

The telecentric optical system unit 11 sends the optical signal to the spatial light modulator unit 12, and the spatial light modulator unit 12 transmits the received optical signal to the semi-reflective and semi-transparent filter unit 13; the semi-reflective and semi-transparent filter unit 13 transmits the received optical signal to the first CCD polarization detector unit 14 and the second CCD polarization detector unit 15 respectively, and the optical signal is mutually transmitted between the first CCD polarization detector unit 14 and the second CCD polarization detector unit 15;

The second CCD polarization detector unit 15 converts the optical signal into an electrical signal and transmits it to the image acquisition and feedback unit 16; the image acquisition and feedback unit 16 transmits the received electrical signal to the field editable gate array unit 17 and the spatial light modulation controller unit 18; the spatial light modulation controller unit 18 converts the received electrical signal into an optical signal and transmits it to the spatial light modulator unit 12, so as to realize the estimation and optimization of the intensity of the interference light.

The spatial light modulation system 1 described in this embodiment includes a telecentric optical system unit 11, which is a BT-F series manufactured by BTOS Vision Technology Co., Ltd.; an LCoS spatial light modulator unit 12 manufactured by Haoliang Optoelectronics Co., Ltd.; a GIAI semi-reflective and semi-transparent filter unit 13 by GIAI Optoelectronics Co., Ltd., a Symphony first CCD polarization detector unit 14 by HORIBA Jobin Yvon, France, a Symphony second CCD polarization detector unit 15 by HORIBA Jobin Yvon, France, a KV COM+ image acquisition and feedback unit 16 by Keyence Corporation, a SALEAGLE field-editable gate array unit 17 by Shanghai Anlu Technology Co., Ltd., and an E-SERIES spatial light modulation controller unit 18 by Haoliang Optoelectronics Co., Ltd.

Embodiment 3. This embodiment is a polarization imaging device with spatial light modulation and resistance to strong light interference provided in embodiment 1. The image clarity evaluation system 2 includes an image acquisition unit 21 to be detected and a first computer unit 22. The image acquisition unit 21 to be detected receives the optical signal of the first CCD polarization detector unit 14, converts it into an electrical signal and transmits it to the first computer unit 22. The first computer unit 22 transmits the received electrical signal to the adaptive aperture automatic adjustment system 3 for calculating and evaluating the clarity of the captured image.

This embodiment includes a KV COM+ image acquisition unit 21 to be detected by Keyence Corporation, and the image clarity evaluation system performs high and low threshold processing, image segmentation, flat area clarity calculation, edge area clarity calculation, weighted summation on the image to be detected, and finally obtains the clarity Y of the current image.

Embodiment 4. This embodiment is a polarization imaging device with spatial light modulation and strong light interference resistance provided in embodiment 1. The adaptive aperture automatic adjustment system 3 includes a second computer unit 31, a scene light intensity collector unit 32, a proportional integral differential controller unit 33, and an aperture adjustment controller unit 34.

The second computer unit 31 receives the electrical signal from the first computer unit 22 and transmits it to the aperture adjustment controller unit 34; the proportional integral differential controller unit 33 converts the electrical signal into an optical signal and transmits it to the scene light intensity collector unit 32, and feeds the optical signal back to the second computer unit 31, so as to establish a functional mapping relationship between the aperture value and the image clarity, and continuously and automatically adjust the aperture parameters through the image clarity.

In this embodiment, the second computer unit 31 calculates and obtains the scene light intensity ratio parameter k and the current image clarity Y according to the image information and the current scene light intensity, and optimizes them in real time. The relationship between the image clarity and the aperture adjustment step is established after multiple simulations by the proportional integral differential control unit, and an accurate functional mapping relationship between the aperture value and the image quality is obtained. The aperture parameters of the first CCD polarization detector unit and the second CCD polarization detector unit are adaptively and automatically adjusted until an image closest to the ideal clarity is obtained.

The adaptive aperture automatic adjustment system 3 in this embodiment adopts the RS485 scene light intensity collector unit 32 of Zhilian Communication Company, the SR470 proportional integral differential controller unit 33 of A-Light Technology, and the XF300 aperture adjustment controller unit 34 of Sony Corporation of Japan; thereby further limiting the connection relationship between the units in the adaptive aperture automatic adjustment system 3, using adaptive aperture adjustment technical means, and establishing an accurate functional mapping relationship between the aperture value and image quality through multiple training of the proportional integral differential controller, and usually using an iterative method to continuously adjust the aperture parameters so that the image brightness approaches the target value, thereby maximizing the image clarity.

Embodiment 5: This embodiment is a spatial light modulated polarization imaging device that is resistant to strong light interference provided in embodiment 3. A signal conversion module is embedded in the first computer unit 22, and the signal conversion module converts the optical signal received by the first CCD polarization detector unit 14 into an electrical signal.

Embodiment 6. This embodiment is a polarization imaging device with spatial light modulation and resistance to strong light interference provided in embodiment 4. The second computer unit 31 is embedded with a signal integration module, and the signal integration module receives the electrical signal of the proportional-integral-differential controller unit 33 and the optical signal converted from the electrical signal in the scene light intensity collector unit 32.

Embodiments 5 and 6 further define the internal structures of the first computer unit 22 and the second computer unit 31, so as to realize the signal conversion in the polarization imaging device with spatial light modulation and strong light interference resistance.

Embodiment 7: This embodiment provides a polarization imaging method of spatial light modulation and anti-strong light interference, the method is implemented by the device described in any one of embodiments 1 to 4, and the method includes the following steps:

Step 1: Through the telecentric optical system unit 11, the main light of the telecentric optical system unit 11 is vertically incident on the spatial light modulator unit 12 located at the focal plane of the imaging objective lens. The spatial light modulator unit 12 receives the main light from the telecentric optical system unit 11 and reduces the transmittance of the interference light to zero, so that the transmittance of the signal light remains unchanged; the light modulated by the spatial light modulator unit 12 is transmitted to the semi-reflective and semi-transparent filter unit 13;

Step 2: The semi-reflective and semi-transparent filter unit 13 refracts and reflects the processed light signal, and the reflected light is transmitted to the second CCD polarization detector unit 15 for use and receiving the reflected light from the semi-reflective and semi-transparent filter unit 13, and the refracted light is transmitted to the first CCD polarization detector unit 14; and the received image signal is transmitted to the image acquisition and feedback unit 16;

Step 3: After the image acquisition and feedback unit 16 processes the image signal, the interference light intensity is determined. and signal intensity and passing the information to the field editable gate array unit 17;

Step 4: The editable gate array unit 17 issues adjustment instructions to the spatial light modulation controller unit 18 in real time according to the judgment from the image acquisition and feedback unit 16; the transmittance of each pixel on the spatial light modulation controller unit 18 is changed;

Step 5: The first CCD polarization detector unit 14 receives the refracted light from the semi-reflective and semi-transmissive filter unit 13, and transmits the received image signal to the image clarity evaluation system 2, so that the entire spatial light modulation system 1 realizes closed-loop negative feedback regulation;

Step 6: The image acquisition and feedback unit 16 receives the image signal from the first CCD polarization detector unit 14 and transmits it to the first computer unit 22;

Step 7: The first computer unit 22 performs high and low threshold processing, image segmentation, flat area clarity calculation, edge area clarity calculation, and weighted summation on the image to be detected to obtain the clarity Y of the current image, and transmits the information to the second computer unit 31 of the adaptive aperture automatic adjustment system 3;

Step 8: The scene light intensity collector unit 32 collects the current scene light intensity in real time and transmits it to the second computer unit 31;

Step 9: The relationship between the image clarity and the aperture adjustment step length is established through multiple trainings of the proportional-integral-differential controller unit 33, and the signal is transmitted to the second computer unit 31;

Step 10: The second computer unit 31 combines the image clarity detected by the image clarity evaluation system 2, the scene light intensity collected by the scene light intensity collector unit 32, and the relationship between the image clarity and the aperture adjustment step length established by the proportional integral differential controller unit 33, to obtain an accurate functional mapping relationship between the aperture value and the image quality, and transmits the mapping relationship instruction to the aperture adjustment controller unit 34;

Step 11: The aperture adjustment controller unit 34 receives the mapping relationship instruction from the second computer unit 31, and the entire system forms a closed-loop control to realize adaptive automatic adjustment of the aperture parameters of the first CCD polarization detector unit 14 and the second CCD polarization detector unit 15 until an image with the closest ideal clarity is obtained.

The imaging method described in this embodiment is implemented using the devices described in embodiments one to four. The aperture adjustment controller unit 34 receives mapping relationship instructions from the second computer unit 31, and the entire system forms a closed-loop control to adaptively and automatically adjust the aperture parameters of the first CCD polarization detector unit 14 and the second CCD polarization detector unit 15 until an image with the closest ideal clarity is obtained.

Embodiment 8: This embodiment further defines the polarization imaging method for spatial light modulation and strong light interference resistance provided in Embodiment 7. and signal intensity The method is:

When the second CCD polarization detector unit 15 captures four images with polarization directions of 0°, 45°, 90°, and 135°, respectively, the intensities are recorded as I ₀ (u, v, s, t), I ₄₅ (u, v, s, t), I ₉₀ (u, v, s, t), and I ₁₃₅ (u, v, s, t), respectively, then the linear Stokes vectors of the scene can be expressed as:

(1)

Where: I(u, v, s, t) is the total light intensity of the scene; Q(u, v, s, t) is the intensity difference between the horizontal and vertical directions; U(u, v, s, t) is the intensity difference between the 45° and 135° directions. The expressions of the degree of polarization P(u, v, s, t) and the polarization angle θ(u, v, s, t) obtained from the above formula are:

(2)

(3)

Obtain the polarization angle image of the central viewing angle, and select the polarization angle with the highest frequency as the interference light polarization angle θ _B; the interference light polarization degree _PB is the maximum value of the central viewing angle polarization degree P(u, v, s, t) obtained after refocusing and fusion of the polarization degree images of each viewing angle;

(4)

(5)

When the shooting directions 0° and 90° are defined as the x-axis and y-axis respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light on the x-axis and y-axis are:

(6)

Since the image intensities collected in the x-axis and y-axis directions are Ⅰ ₀ (u, v, s, t) and Ⅰ ₉₀ (u, v, s, t) respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light in the x-axis and y-axis directions can be expressed as follows:

(7)

The intensity of the polarized part of the interference light is obtained as:

(8)

From the above formula, we can know that the interference light intensity value at the central viewing angle is:

(9)

The original reflected light intensity L(u, v, s, t) of the target becomes unpolarized light after scattering effect. _A∞ (u, v, s, t) is the interference light intensity at infinity, which is partial channel polarized light with polarization degree _PB . Then:

(10)

Then when the detection distance z→∞, e ^(-z) →0, the interference light intensity at infinity is obtained:

(11)

According to the physical degradation model, the image obtained by the detector is expressed as:

(12)

Select the closest 1% pixel value of _A∞ (u,v,s,t) at infinity obtained in formula Ⅰ ₀ (u,v,s,t) and the original image intensity I(u,v,s,t) as the reflected light intensity value A'∞ at infinity _;

Then the signal light intensity of the scene target is:

(13).

Embodiment 9: This embodiment further limits the polarization imaging method of spatial light modulation and strong light interference resistance provided in embodiment 7. The image clarity evaluation method in step 7 is:

The second computer unit 31 analyzes the image to be tested and introduces high and low threshold processing. The expression of this process is:

(14)

Where GH is the maximum gradient value of the entire image, GL is the average value of the entire image, Th is the high gradient threshold, and Tl is the low gradient threshold; G represents the original image gradient, and G' represents the image gradient after high and low threshold processing;

The edge is taken as the foreground and the flat area is taken as the background to achieve the segmentation of the edge and the flat area. The process expression is:

(15)

Among them, Threshold is the optimal threshold calculated by Ostu method. Although the above process realizes the segmentation of edge area and flat area, and can reduce the influence of flat area on image clarity evaluation function in subsequent processing, this process cannot remove the pseudo edge generated by isolated noise points; E represents edge, NE represents flat area;

In order to remove the pseudo edges generated by isolated noise points, the gradient image after removing the pseudo edges is recorded as Edge; the process expression is

(16)

Among them, sum(i, j) represents the number of edge points in the eight neighborhoods of pixel point (i, j). So far, the image segmentation process is completed, and the final flat area NEdge and edge area Edge are obtained;

Flat area clarity calculation:

The point sharpness algorithm is used to calculate the clarity of the image flat area NEdge. The definition of image clarity based on the point sharpness function is as follows:

(17)

Where df is the grayscale change amplitude, dx is the distance increment between pixels, M×N is the image size; (i, j) is the image pixel point;

Edge area clarity calculation:

The normalized square gradient algorithm is used to calculate the clarity of the flat area of the image; the square gradient function is defined as follows:

(18)

Since the above formula cannot achieve the horizontal comparison of the clarity of images of different sizes, the formula is normalized to:

(19)

Among them, the image size is M×N, and I (i, j) represents the pixel gray value at the image pixel point (i, j);

Image clarity calculation:

The clarity of the entire image is obtained by weighted summation of the clarity of the flat area and the clarity of the edge area. The calculation formula is as follows:

(20)

in, and The weights corresponding to the clarity of the flat area and the clarity of the edge area respectively.

Embodiment 10: This embodiment further defines a polarization imaging method for spatial light modulation and resistance to strong light interference provided in embodiment 7. The method for obtaining the precise functional mapping relationship between the aperture value and the image quality in step 10 is:

Use the scene light intensity collector unit to obtain the current scene light intensity and set the optimal aperture position to The corresponding optimal resolution is ,in is the aperture evaluation value determined by experiment; under certain scene light intensity conditions, the image clarity is proportional to the square of the aperture position. Y represents the current image clarity value, and D represents the current aperture position. Then:

(twenty one)

Wherein, k is a parameter of scene light intensity ratio, and the second computer unit sets k according to the image definition information and the current aperture position, and optimizes the k value in real time according to the image information.

Let the clarity deviation value , aperture shift , then:

(twenty two)

At the same time, the aperture shift The linear relationship with the rotation angle α is approximately similar to:

(twenty three)

From this, we can get the angle α of the aperture rotation and The relationship is:

(twenty four)

Based on the above functional relationship, the formula obtained by simplifying the proportional integral differential controller unit (33) is:

(25).

The flowchart and block diagram in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the device and method according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and/or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (10)

1. A spatial light modulation polarization imaging device that is resistant to strong light interference, characterized in that the polarization imaging device that is resistant to strong light interference comprises a spatial light modulation system (1), an image clarity evaluation system (2) and an adaptive aperture automatic adjustment system (3); The spatial light modulation system (1) is used to collect light signals, modulate the light signals to generate electrical signals, and send the electrical signals to the image clarity evaluation system (2) to suppress interference light intensity; The image clarity evaluation system (2) is used to process the received electrical signal to obtain the clarity of the captured image, and send the received electrical signal to the adaptive aperture automatic adjustment system (3); The adaptive aperture automatic adjustment system (3) is used to receive the electrical signal, adjust the aperture value and image clarity according to the electrical signal, and output the received electrical signal to the spatial light modulation system (1). 2. According to claim 1, a polarization imaging device with spatial light modulation and strong light interference resistance, characterized in that the spatial light modulation system (1) comprises a telecentric optical system unit (11), a spatial light modulator unit (12), a semi-reflective and semi-transparent filter unit (13), a first CCD polarization detector unit (14), a second CCD polarization detector unit (15), an image acquisition and feedback unit (16), a field editable gate array unit (17), and a spatial light modulation controller unit (18); The telecentric optical system unit (11) transmits the optical signal to the spatial light modulator unit (12); the spatial light modulator unit (12) transmits the received optical signal to the semi-reflective and semi-transparent filter unit (13); the semi-reflective and semi-transparent filter unit (13) transmits the received optical signal to the first CCD polarization detector unit (14) and the second CCD polarization detector unit (15), respectively; the optical signal is mutually transmitted between the first CCD polarization detector unit (14) and the second CCD polarization detector unit (15); The second CCD polarization detector unit (15) converts the optical signal into an electrical signal and transmits it to an image acquisition and feedback unit (16); the image acquisition and feedback unit (16) transmits the received electrical signal to a field editable gate array unit (17) and a spatial light modulation controller unit (18); the spatial light modulation controller unit (18) converts the received electrical signal into an optical signal and transmits it to a spatial light modulator unit (12), so as to achieve estimation optimization of the intensity of the interference light. 3. According to claim 1, a spatial light modulated polarization imaging device that is resistant to strong light interference is characterized in that the image clarity evaluation system (2) comprises an image acquisition unit (21) to be detected and a first computer unit (22); the image acquisition unit (21) to be detected receives an optical signal from the first CCD polarization detector unit (14), converts the optical signal into an electrical signal, and transmits the electrical signal to the first computer unit (22); the first computer unit (22) transmits the received electrical signal to the adaptive aperture automatic adjustment system (3) for calculating and evaluating the clarity of the captured image. 4. The spatial light modulation polarization imaging device resistant to strong light interference according to claim 1, characterized in that: The adaptive aperture automatic adjustment system (3) comprises a second computer unit (31), a scene light intensity collector unit (32), a proportional-integral-differential controller unit (33), and an aperture adjustment controller unit (34); The second computer unit (31) receives the electrical signal from the first computer unit (22) and transmits it to the aperture adjustment controller unit (34); the proportional integral differential controller unit (33) converts the electrical signal into an optical signal and transmits it to the scene light intensity collector unit (32), and feeds the optical signal back to the second computer unit (31) to establish a functional mapping relationship between the aperture value and the image clarity, and automatically adjust the aperture parameter according to the image clarity. 5. The spatial light modulated polarization imaging device resistant to strong light interference according to claim 3 is characterized in that a signal conversion module is embedded in the first computer unit (22), and the signal conversion module converts the optical signal received by the first CCD polarization detector unit (14) into an electrical signal. 6. According to claim 4, a polarization imaging device with spatial light modulation and resistance to strong light interference is characterized in that a signal integration module is embedded in the second computer unit (31), and the signal integration module receives the electrical signal of the proportional-integral-differential controller unit (33) and the optical signal converted from the electrical signal in the scene light intensity collector unit (32). 7. A polarization imaging method for spatial light modulation and strong light interference resistance, characterized in that the method is implemented by using the device described in any one of claims 1 to 6, and the method comprises the following steps: Step 1: through a telecentric optical system unit (11), the main light of the telecentric optical system unit (11) is vertically incident on a spatial light modulator unit (12) located at the focal plane of an imaging objective lens; the spatial light modulator unit (12) receives the main light from the telecentric optical system unit (11) and reduces the transmittance of the interference light to zero, thereby keeping the transmittance of the signal light unchanged; the light modulated by the spatial light modulator unit (12) is transmitted to a semi-reflective and semi-transparent filter unit (13); Step 2: The semi-reflective and semi-transparent filter unit (13) refracts and reflects the processed light signal, and the reflected light is transmitted to the second CCD polarization detector unit (15) for use and receiving the reflected light from the semi-reflective and semi-transparent filter unit (13), and the refracted light is transmitted to the first CCD polarization detector unit (14); and the received image signal is transmitted to the image acquisition and feedback unit (16); Step 3: After the image acquisition and feedback unit (16) processes the image signal, the interference light intensity is determined. and signal intensity and passing the information to the field editable gate array unit (17); Step 4: The editable gate array unit (17) issues adjustment instructions to the spatial light modulation controller unit (18) in real time based on the judgment from the image acquisition and feedback unit (16); the transmittance of each pixel on the spatial light modulation controller unit (18) is changed; Step 5: The first CCD polarization detector unit (14) receives the refracted light from the semi-reflective and semi-transmissive filter unit (13), and transmits the received image signal to the image clarity evaluation system (2), so that the entire spatial light modulation system (1) realizes closed-loop negative feedback regulation; Step 6: The image acquisition and feedback unit (16) receives the image signal from the first CCD polarization detector unit (14) and transmits it to the first computer unit (22); Step 7: The first computer unit (22) performs high and low threshold processing, image segmentation, flat area clarity calculation, edge area clarity calculation, and weighted summation on the image to be detected to obtain the clarity Y of the current image, and transmits the information to the second computer unit (31) of the adaptive aperture automatic adjustment system (3); Step 8: The scene light intensity collector unit (32) collects the current scene light intensity in real time and transmits it to the second computer unit (31); Step 9: The relationship between the image clarity and the aperture adjustment step length is established through multiple trainings by the proportional-integral-differential controller unit (33), and the signal is transmitted to the second computer unit (31); Step 10: The second computer unit (31) combines the image clarity detected by the image clarity evaluation system (2), the scene light intensity collected by the scene light intensity collector unit (32), and the relationship between the image clarity and the aperture adjustment step length established by the proportional integral differential controller unit (33) to obtain an accurate functional mapping relationship between the aperture value and the image quality, and transmits the mapping relationship instruction to the aperture adjustment controller unit (34); Step 11: The aperture adjustment controller unit (34) receives the mapping relationship instruction from the second computer unit (31), and the entire system forms a closed-loop control to realize adaptive automatic adjustment of the aperture parameters of the first CCD polarization detector unit (14) and the second CCD polarization detector unit (15) until an image with the closest clarity to the ideal is obtained. 8. The method for polarization imaging of spatial light modulation and strong light interference resistance according to claim 7, characterized in that the method for judging the interference light intensity and signal intensity The method is: When the second CCD polarization detector unit (15) captures four images with polarization directions of 0°, 45°, 90°, and 135°, respectively, the intensities are recorded as I ₀ (u, v, s, t), I ₄₅ (u, v, s, t), I ₉₀ (u, v, s, t), and I ₁₃₅ (u, v, s, t), respectively, then the linear Stokes vectors of the scene can be expressed as: (1) Where: I(u, v, s, t) is the total light intensity of the scene; Q(u, v, s, t) is the intensity difference between the horizontal and vertical directions; U(u, v, s, t) is the intensity difference between the 45° and 135° directions. The expressions of the degree of polarization P(u, v, s, t) and the polarization angle θ(u, v, s, t) obtained from the above formula are: (2) (3) Obtain the polarization angle image of the central viewing angle, and select the polarization angle with the highest frequency as the interference light polarization angle θ _B ; the interference light polarization degree _PB is the maximum value of the central viewing angle polarization degree P(u, v, s, t) obtained after refocusing and fusion of the polarization degree images of each viewing angle; (4) (5) When the shooting directions 0° and 90° are defined as the x-axis and y-axis respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light on the x-axis and y-axis are: (6) Since the image intensities collected in the x-axis and y-axis directions are Ⅰ ₀ (u, v, s, t) and Ⅰ ₉₀ (u, v, s, t) respectively, the component expressions of the polarized light intensity B _p (u, v, s, t) of the interference light in the x-axis and y-axis directions can be expressed as follows: (7) The intensity of the polarized part of the interference light is obtained as: (8) From the above formula, we can know that the interference light intensity value at the central viewing angle is: (9) The original reflected light intensity L(u, v, s, t) of the target becomes unpolarized light after scattering effect. _A∞ (u, v, s, t) is the interference light intensity at infinity, which is partial channel polarized light with polarization degree PB. Then: (10) Then when the detection distance z→∞, e ^-z →0, the interference light intensity at infinity is obtained: (11) According to the physical degradation model, the image obtained by the detector is expressed as: (12) Select the closest 1% pixel value between _A∞ (u,v,s,t) at infinity obtained in formula Ⅰ ₀ (u,v,s,t) and the original image intensity I(u,v,s,t) as the reflected light intensity value _A'∞ at infinity; Then the signal light intensity of the scene target is: (13). 9. The method for polarization imaging of spatial light modulation and strong light interference resistance according to claim 7, characterized in that the image clarity evaluation method in step 7 is: The second computer unit (31) analyzes the image to be tested and introduces high and low threshold processing. The expression of this process is: (14) Where GH is the maximum gradient value of the entire image, GL is the average value of the entire image, Th is the high gradient threshold, and Tl is the low gradient threshold; G represents the original image gradient, and G' represents the image gradient after high and low threshold processing; The edge is taken as the foreground and the flat area is taken as the background to achieve the segmentation of the edge and the flat area. The process expression is: (15) Among them, Threshold is the optimal threshold calculated by Ostu method. Although the above process realizes the segmentation of edge area and flat area, it cannot remove the pseudo edge generated by isolated noise points; E represents edge, NE represents flat area; In order to remove the pseudo edges generated by isolated noise points, the gradient image after removing the pseudo edges is recorded as Edge; the process expression is (16) Among them, sum(i, j) represents the number of edge points in the eight neighborhoods of pixel point (i, j). So far, the image segmentation process is completed, and the final flat area NEdge and edge area Edge are obtained; Flat area clarity calculation: The point sharpness algorithm is used to calculate the clarity of the image flat area NEdge. The definition of image clarity based on the point sharpness function is as follows: (17) Where df is the grayscale change amplitude, dx is the distance increment between pixels, M×N is the image size; (i, j) is the image pixel point; Edge area clarity calculation: The normalized square gradient algorithm is used to calculate the clarity of the flat area of the image; the square gradient function is defined as follows: (18) Since the above formula cannot achieve the horizontal comparison of the clarity of images of different sizes, the formula is normalized to: (19) Among them, the image size is M×N, I (i, j) represents the pixel gray value at the image pixel point (i, j); image clarity calculation: The clarity of the entire image is obtained by weighted summation of the clarity of the flat area and the clarity of the edge area. The calculation formula is as follows: (20) in, and The weights corresponding to the clarity of the flat area and the clarity of the edge area respectively. 10. The method for polarization imaging with spatial light modulation and strong light interference resistance according to claim 7, characterized in that the method for obtaining the accurate functional mapping relationship between the aperture value and the image quality in step 10 is: Use the scene light intensity collector unit (32) to obtain the current scene light intensity, and set the optimal aperture position to The corresponding optimal resolution is ,in is the aperture evaluation value determined by experiment; under certain scene light intensity conditions, the image clarity is proportional to the square of the aperture position. Y represents the current image clarity value, and D represents the current aperture position. Then: (twenty one) Wherein, k is a parameter of scene light intensity ratio, and the second computer unit sets k according to the image definition information and the current aperture position, and optimizes the k value in real time according to the image information. Let the clarity deviation value , aperture shift , then: (twenty two) At the same time, the aperture shift The linear relationship with the rotation angle α is approximately similar to: (twenty three) From this, we can get the angle α of the aperture rotation and The relationship is: (twenty four) Based on the above functional relationship, the formula obtained by simplifying the proportional integral differential controller unit (33) is: (25).