Strong laser interference suppression control method based on DMD spatial light control camera

Abstract

The invention discloses an intense laser interference suppression control method based on a DMD spatial light control camera. The intense laser interference suppression control method comprises the following steps: initializing a DMD mask; detecting whether the original image output by the detector is interfered by laser; if it is detected that the original image output by the detector is interfered by the laser, setting a DMD mask to be all 1, and adjusting the overall exposure time of the DMD spatial light control camera to be minimum; obtaining a to-be-processed image under the condition that the overall exposure time is minimum, detecting laser interference in the to-be-processed image, and determining laser interference parameters; according to the determined laser interference parameters, generating a DMD mask with a laser suppression function in real time; and loading the DMD mask with the laser suppression function to a DMD device of the DMD space light regulation and control camera, regulating and controlling light in an imaging view field, and generating a laser interference suppression image. The method provided by the invention has the capability of inhibiting strong laser, and can also detect surrounding interested targets at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of target detection and recognition, and in particular relates to a strong laser interference suppression control method based on a DMD spatial light control camera. Background Art

[0002] When a traditional imaging device is exposed to a strong laser light source, the image quality will be seriously degraded, temporary blindness will occur, and the imaging device will be unable to image the target. When the laser power is high to a certain level or the exposure is long-term, the detector in the imaging device may be permanently damaged.

[0003] In the case of dealing with this kind of blinding interference, traditional imaging devices use methods such as filtering and reducing exposure time. This method not only suppresses the laser but also filters out the scene information, which can provide a certain degree of protection, but cannot effectively detect surrounding targets of interest in the case of strong laser interference. Summary of the invention

[0004] The technology of the present invention solves the problem: overcomes the shortcomings of the prior art and provides a strong laser interference suppression control method based on a DMD spatial light control camera, which has the ability to suppress strong lasers and can also detect surrounding targets of interest.

[0005] In order to solve the above technical problems, the present invention discloses a strong laser interference suppression control method based on a DMD spatial light control camera, comprising:

[0006] Step 1, initialize the DMD mask;

[0007] Step 2, detecting whether the original image output by the detector is interfered by the laser;

[0008] Step 3: If it is detected that the original image output by the detector is interfered by the laser, the DMD mask is set to all 1s, and the overall exposure time of the DMD spatial light control camera is adjusted to the minimum;

[0009] Step 4, obtaining an image to be processed under the condition of minimum overall exposure time, detecting laser interference in the image to be processed, and determining laser interference parameters; wherein the laser interference parameters include: interference intensity, interference source location, and interference quantity;

[0010] Step 5, generating a DMD mask with a laser suppression function in real time according to the determined laser interference parameters;

[0011] Step 6, loading the DMD mask with laser suppression function into the DMD device of the DMD spatial light control camera, controlling the light in the imaging field of view, and generating a laser interference suppression image.

[0012] In the above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera, detecting whether the original image output by the detector is interfered by the laser includes:

[0013] Get the original image output by the detector;

[0014] Calculate the mean u of the original image:

[0015]

[0016] Among them, M (0) and N (0) Represent the width and height of the original image, I(x (0) ,y (0) ) represents the gray value of the original image, (x (0) ,y (0) ) represents the pixel coordinates in the original image;

[0017] According to the mean value u, it is determined whether the original image output by the detector is interfered by the laser; if u≥T1, it is determined that the original image is interfered by the laser; if u<T1, it is determined that the original image is not interfered by the laser; T1 represents the laser interference threshold.

[0018] In the above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera, the image to be processed is obtained under the condition that the overall exposure time is minimum, the laser interference in the image to be processed is detected, and the laser interference parameters are determined, including:

[0019] Obtain the image to be processed under the condition that the overall exposure time is minimum;

[0020] Use the saturation region detection method to determine the saturation region of the image to be processed:

[0021]

[0022] Among them, Thesheld(x (1) ,y (1) ) is the saturation region mark; Thesheld(x (1) ,y (1) )=1, it means the current pixel is in the saturated area; Thesheld(x (1) ,y (1) )=0, it means that the current pixel is an unsaturated area; T2 represents the image saturation threshold;

[0023] Based on the connected region analysis method, the connectivity analysis of the determined saturated area is performed to find the saturated area marker Thesheld(x (1) ,y (1)) is 1, and marked with different labels, to obtain the saturated and connected region ConReg(x (1) ,y (1) ):

[0024] ConReg(x (1) ,y (1) )=bwlable(Thesheld(x (1) ,y (1) ))

[0025] Among them, bwlable() represents the labeling of connected areas marked as 1 for different saturated areas;

[0026] Determine the saturated and connected region ConReg(x (1) ,y (1) ) is the number of pixels n occupied by the image, i.e., the number of interferences;

[0027] The saturated and connected region ConReg(x (1) ,y (1) )’s center point (x c ,y c ), i.e. the location of the interference source:

[0028]

[0029] Among them, M (1) and N (1) Respectively represent the width and height of the image to be processed;

[0030] The saturated and connected region ConReg(x (1) ,y (1) )’s area A:

[0031]

[0032] According to A, the interference intensity I is calculated:

[0033] I=f(A)

[0034] Among them, f() represents the functional relationship between A and I.

[0035] In the above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera, a DMD mask with a laser suppression function is generated in real time according to the determined laser interference parameters, including:

[0036] According to the interference intensity I, the center point (x c ,y c ) light intensity near I jam (x (1) ,y(1) ):

[0037]

[0038] Among them, k(I) represents the intensity parameter affected by I, and σ represents the standard deviation of the controlled strong light range;

[0039] According to I jam (x (1) ,y (1) ), calculate the local DMD mask M of the corresponding point jam (x (1) ,y (1) ):

[0040]

[0041] The local DMD mask M jam (x (1) ,y (1) ) is combined with the initialized DMD mask to obtain a DMD mask M with laser suppression function. adj (x (1) ,y (1) ):

[0042]

[0043] Among them, M0(x (1) ,y (1) ) represents the initialized DMD mask.

[0044] In the above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera, a DMD mask with a laser suppression function is loaded onto the DMD device of the DMD spatial light control camera to control the light in the imaging field of view to generate a laser interference suppression image, including:

[0045] M adj (x (1) ,y (1) ) is loaded into the DMD device of the DMD spatial light control camera to control the light in the imaging field of view and generate an image I after strong light suppression adj (x (1) ,y (1) );

[0046] According to M jam (x (1) ,y (1) ), from I adj (x (1) ,y (1) ) to obtain the laser interference suppression image I2(x (1) ,y (1) ):

[0047]

[0048] In the above-mentioned strong laser interference suppression control method based on DMD spatial light control camera, it also includes: according to I2(x (1) ,y (1) ), recalculate the laser interference parameters, and based on the recalculated laser interference parameters, repeat steps 5 to 6, and update the DMD mask with laser suppression function and the laser interference suppression image in real time to achieve continuous strong laser interference suppression.

[0049] The above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera also includes: step 7, evaluating the suppression effect of the laser interference suppression image.

[0050] In the above-mentioned strong laser interference suppression control method based on the DMD spatial light control camera, the suppression effect of the laser interference suppression image is evaluated, including:

[0051] Get the currently updated DMD mask M with laser suppression function a ' dj (x (1) ,y (1) );

[0052] Confirm in M a ' dj (x (1) ,y (1) ) is the image I after strong light suppression generated under the control of a ' dj (x (1) ,y (1) );

[0053] Calculate I a ' dj (x (1) ,y (1) )’s image saturation ratio, image entropy value and image grayscale gradient;

[0054] If the calculated I a ' dj (x (1) ,y (1) ) when the image saturation ratio, image entropy value and image gray gradient all meet their corresponding preset thresholds, then the laser interference suppression image effective flag is output;

[0055] If the calculated I a ' dj (x (1) ,y (1)) when any one of the image saturation ratio, image entropy value and image grayscale gradient does not meet the corresponding preset threshold, the laser interference suppression image invalid flag is output and the process returns to step 1.

[0056] The present invention has the following advantages:

[0057] (1) The present invention discloses a strong laser interference suppression control method based on a DMD spatial light control camera, which utilizes the spatial light control capability of the DMD to reduce the exposure time and achieve accurate estimation of the laser interference position and intensity without adjusting the detector.

[0058] (2) The present invention discloses a strong laser interference suppression control method based on a DMD spatial light control camera, which generates a DMD mask with a strong light suppression function according to the strong light information, and retains the scene information outside the interference area as much as possible while suppressing the strong laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a flow chart of a strong laser interference suppression control method based on a DMD spatial light control camera in an embodiment of the present invention;

[0060] Figure 2 is a schematic diagram of a laser interference image in a case where a DMD mask is set to an adjustable minimum template value (all 1s) in an embodiment of the present invention;

[0061] Figure 3 is a schematic diagram of light intensity distribution of an interfering laser in an embodiment of the present invention;

[0062] Figure 4 Schematic diagram of a DMD mask with laser interference suppression function in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0064] One of the core ideas of the present invention is that: in the event of strong laser interference causing blinding of the imaging system, firstly, relatively accurate interference position and intensity information is obtained from the image by reducing the exposure time; a control mask with a strong light suppression function is generated according to the obtained interference position and intensity information, thereby obtaining a strong light suppression image that retains the target information; the strong light is continuously tracked and estimated according to the control mask and the strong light suppression image, so as to achieve continuous suppression of the strong laser by the imaging system; finally, the suppressed image is evaluated according to the demand, and effective information is output.

[0065] Reference Figure 1In this embodiment, the strong laser interference suppression control method based on the DMD spatial light control camera includes:

[0066] Step 1, initialize the DMD mask.

[0067] Step 2: Detect whether the original image output by the detector is interfered by the laser.

[0068] In this embodiment, first, the original image output by the detector is obtained; then, the mean value u of the original image is calculated:

[0069]

[0070] Among them, M (0) and N (0) Represent the width and height of the original image, I(x (0) ,y (0) ) represents the gray value of the original image, (x (0) ,y (0) ) represents the pixel coordinates in the original image.

[0071] According to the mean value u, determine whether the original image output by the detector is subject to laser interference. If u≥T1, it is determined that the original image is subject to laser interference, and step 3 is executed; if u<T1, it is determined that the original image is not subject to laser interference, the DMD mask is kept in the initial state, and the image is continuously received. T1 represents the laser interference threshold. The laser interference threshold is related to the optical system and detector performance of the DMD spatial light control camera. For the current optical system and the 8-bit pixel detector, the laser interference is mainly considered to blind the detector, and the laser interference threshold T1 is taken as a fixed value.

[0072] Step 3, set the DMD mask to all 1s, and adjust the overall exposure time of the DMD spatial light control camera to the minimum.

[0073] In this embodiment, the DMD mask is set to all 1s, that is:

[0074]

[0075] Considering a 1:1 pixel-level registration between the DMD mask and the detector image, the DMD mask size is also M. (0) and N (0) .

[0076] Step 4, obtaining the image to be processed under the condition that the overall exposure time is minimum, detecting the laser interference in the image to be processed, and determining the laser interference parameters.

[0077] In this embodiment, the laser interference parameters mainly include: interference intensity, interference source location and interference quantity. The laser interference parameters are determined as follows:

[0078] Obtain the image to be processed under the condition of minimum overall exposure time. In this case, the system exposure time is the minimum, and the laser spot on the image is the smallest, which is conducive to accurately estimating the center position of the laser interference.

[0079] The image to be processed is Figure 2 Specifically, the saturation area detection method can be used to determine the saturation area of ​​the image to be processed:

[0080]

[0081] Among them, Thesheld(x (1) ,y (1) ) is the saturation region mark; Thesheld(x (1) ,y (1) )=1, it means the current pixel is in the saturated area; Thesheld(x (1) ,y (1) )=0, it indicates that the current pixel is in an unsaturated area; T2 indicates the image saturation threshold. For an 8-bit grayscale image, T2=250 is set. Here, the image saturation threshold is related to the number of image bits. Considering the 8-bit image of the system, the threshold is set to be close to the maximum value that the pixel can represent.

[0082] Based on the connected region analysis method, the connectivity analysis of the determined saturated area is performed to find the saturated area marker Thesheld(x (1) ,y (1) ) is 1, and marked with different labels, to obtain the saturated and connected region ConReg(x (1) ,y (1) ):

[0083] ConReg(x (1) ,y (1) )=bwlable(Thesheld(x (1) ,y (1) ))

[0084] Among them, bwlable() represents the labels of connected areas marked as 1 for different saturated areas.

[0085] Determine the saturated and connected region ConReg(x (1) ,y (1) ) is the number of pixels n occupied by the image, that is, the number of interferences.

[0086] The saturated and connected region ConReg(x (1) ,y (1) )’s center point (xc ,y c ), i.e. the location of the interference source:

[0087]

[0088] Among them, M (1) and N (1) Respectively represent the width and height of the image to be processed. This method takes into account the interference of point source lasers. The interference spot is approximately circular or symmetrical about the center point. This method has a high accuracy in position estimation.

[0089] The saturated and connected region ConReg(x (1) ,y (1) )’s area A:

[0090]

[0091] According to A, the interference intensity I is calculated:

[0092] I=f(A)

[0093] Among them, f() represents the functional relationship between A and I. The connected area and the laser intensity reaching the detector are affected by factors such as the optical system and the detector response. In order to accurately obtain the functional relationship between the connected area area and the laser intensity reaching the detector, the measured data fitting method is currently used to determine it.

[0094] Step 5: generating a DMD mask with a laser suppression function in real time according to the determined laser interference parameters.

[0095] In this embodiment, the steps of generating the DMD mask with laser suppression function are as follows:

[0096] According to the interference intensity I, the center point (x c ,y c ) light intensity near I jam (x (1) ,y (1) ):

[0097]

[0098] Where k(I) represents the intensity parameter affected by I, and σ represents the standard deviation of the controlled bright light range.

[0099] Center point (x c ,y c ) light intensity near I jam (x (1) ,y (1) )like Figure 3As shown, laser is generally considered to be Gaussian light, so the laser intensity is estimated using a Gaussian distribution model.

[0100] According to I jam (x (1) ,y (1) ), calculate the local DMD mask M of the corresponding point jam (x (1) ,y (1) ):

[0101]

[0102] Among them, the local DMD mask M jam (x (1) ,y (1) )like Figure 4 shown.

[0103] The suppression mask considers retaining scene information as much as possible. For the part that exceeds the dynamic adjustment capability of the DMD, the mask is set to 0, and all of it is reflected out of the imaging light path. For the part that does not exceed the dynamic adjustment range, the dynamic adjustment method is used for intensity control.

[0104] The local DMD mask M jam (x (1) ,y (1) ) is combined with the initialized DMD mask to obtain a DMD mask M with laser suppression function. adj (x (1) ,y (1) ):

[0105]

[0106] Among them, M0(x (1) ,y (1) ) represents the initialized DMD mask. According to the imaging system design, it is required to be able to detect the target with the smallest features. At this time, the initialized DMD mask is generally set to 255, and the DMD adjusts the exposure time to the maximum to obtain the best detection performance.

[0107] Step 6, loading the DMD mask with laser suppression function into the DMD device of the DMD spatial light control camera, controlling the light in the imaging field of view, and generating a laser interference suppression image.

[0108] In this embodiment, the process of generating the laser interference suppression image is as follows:

[0109] M adj (x (1) ,y (1)) is loaded into the DMD device of the DMD spatial light control camera to control the light in the imaging field of view and generate an image I after strong light suppression adj (x (1) ,y (1) ).

[0110] According to M jam (x (1) ,y (1) ), from I adj (x (1) ,y (1) ) to obtain the laser interference suppression image I2(x (1) ,y (1) ):

[0111]

[0112] Among them, I2(x (1) ,y (1) ) only obtains the interference information and does not process other information in the scene.

[0113] Furthermore, according to I2(x (1) ,y (1) ), recalculate the laser interference parameters; then, based on the recalculated laser interference parameters, repeat steps 5 to 6, update the DMD mask with laser suppression function and the laser interference suppression image in real time, and achieve continuous strong laser interference suppression.

[0114] Step 7, evaluating the suppression effect of the laser interference suppression image.

[0115] In this embodiment, the suppression effect of the laser interference suppression image can be evaluated by the following method: obtaining the currently updated DMD mask M with the laser suppression function; a ' dj (x (1) ,y (1) );Determine in M a ' dj (x (1) ,y (1) ) is the image I after strong light suppression generated under the control of a ' dj (x (1) ,y (1) ); calculate I a ' dj (x (1) ,y (1) ) of the image saturation ratio, image entropy value and image gray gradient; if the calculated I a ' dj (x (1) ,y (1)) when the image saturation ratio, image entropy value and image gray gradient all meet their corresponding preset thresholds, the laser interference suppression image effective flag is output; if the calculated I a ' dj (x (1) ,y (1) ) when any one of the image saturation ratio, image entropy value and image grayscale gradient does not meet the corresponding preset threshold, the laser interference suppression image invalid flag is output and the process returns to step 1.

[0116] In summary, the present invention discloses a strong laser interference suppression control method based on a DMD spatial light control camera, which realizes the suppression of strong laser from the optical path system through rapid spatial light field control, effectively suppresses laser blinding and glare caused by strong light, and at the same time retains background information and target information of interest to the greatest extent possible, which helps to improve the ability of existing imaging systems to cope with strong laser interference.

[0117] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0118] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A strong laser interference suppression control method based on a DMD spatial light control camera, characterized in that: include: Step 1, initialize the DMD mask; Step 2, detecting whether the original image output by the detector is interfered by the laser; Step 3: If it is detected that the original image output by the detector is interfered by the laser, the DMD mask is set to all 1s, and the overall exposure time of the DMD spatial light control camera is adjusted to the minimum; Step 4, obtaining an image to be processed under the condition of minimum overall exposure time, detecting laser interference in the image to be processed, and determining laser interference parameters; wherein the laser interference parameters include: interference intensity, interference source location, and interference quantity; Step 5, generating a DMD mask with a laser suppression function in real time according to the determined laser interference parameters; Step 6, loading the DMD mask with laser suppression function into the DMD device of the DMD spatial light control camera, controlling the light in the imaging field of view, and generating a laser interference suppression image.

2. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 1 is characterized in that: Check whether the original image output by the detector is interfered by the laser, including: Get the original image output by the detector; Calculate the mean u of the original image: Among them, M (0) and N (0) Represent the width and height of the original image, I(x (0) ,y (0) ) represents the gray value of the original image, (x (0) ,y (0) ) represents the pixel coordinates in the original image; According to the mean value u, it is determined whether the original image output by the detector is interfered by the laser; if u≥T1, it is determined that the original image is interfered by the laser; if u<T1, it is determined that the original image is not interfered by the laser; T1 represents the laser interference threshold.

3. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 1 is characterized in that: Acquire the image to be processed under the condition of minimum overall exposure time, detect the laser interference in the image to be processed, and determine the laser interference parameters, including: Obtain the image to be processed under the condition that the overall exposure time is minimum; Use the saturation region detection method to determine the saturation region of the image to be processed: Among them, Thesheld(x (1) ,y (1) ) is the saturation region mark; Thesheld(x (1) ,y (1) )=1, it means the current pixel is in the saturated area; Thesheld(x (1) ,y (1) )=0, it means that the current pixel is an unsaturated area; T2 represents the image saturation threshold; Based on the connected region analysis method, the connectivity analysis of the determined saturated area is performed to find the saturated area marker Thesheld(x (1) ,y (1) ) is 1, and marked with different labels, to obtain the saturated and connected region ConReg(x (1) ,y (1) ): ConReg(x (1) ,y (1) )=bwlable(Thesholded(x (1) ,y (1) )) Among them, bwlable() represents the labeling of connected areas marked as 1 for different saturated areas; Determine the saturated and connected region ConReg(x (1) ,y (1) ) is the number of pixels n occupied by the image, i.e., the number of interferences; The saturated and connected region ConReg(x (1) ,y (1) )’s center point (x c ,y c ), i.e. the location of the interference source: Among them, M (1) and N (1) Respectively represent the width and height of the image to be processed; The saturated and connected region ConReg(x (1) ,y (1) )’s area A: According to A, the interference intensity I is calculated: I=f(A) Among them, f() represents the functional relationship between A and I.

4. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 3 is characterized in that: Based on the determined laser interference parameters, a DMD mask with laser suppression function is generated in real time, including: According to the interference intensity I, the center point (x c ,y c ) light intensity near I jam (x (1) ,y (1) ): Among them, k(I) represents the intensity parameter affected by I, and σ represents the standard deviation of the controlled strong light range; According to I jam (x (1) ,y (1) ), calculate the local DMD mask M of the corresponding point jam (x (1) ,y (1) ): The local DMD mask M jam (x (1) ,y (1) ) is combined with the initialized DMD mask to obtain a DMD mask M with laser suppression function. adj (x (1) ,y (1) ): Among them, M0(x (1) ,y (1) ) represents the initialized DMD mask.

5. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 4 is characterized in that: The DMD mask with laser suppression function is loaded onto the DMD device of the DMD spatial light control camera to control the light in the imaging field of view and generate a laser interference suppression image, including: M adj (x (1) ,y (1) ) is loaded into the DMD device of the DMD spatial light control camera to control the light in the imaging field of view and generate an image I after strong light suppression adj (x (1) ,y (1) ); According to M jam (x (1) ,y (1) ), from I adj (x (1) ,y (1) ) to obtain the laser interference suppression image I2(x (1) ,y (1) ):

6. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 5 is characterized in that: Also includes: According to I2(x (1) ,y (1) ), recalculate the laser interference parameters, and based on the recalculated laser interference parameters, repeat steps 5 to 6, and update the DMD mask with laser suppression function and the laser interference suppression image in real time to achieve continuous strong laser interference suppression.

7. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 6 is characterized in that: The method also includes: Step 7, evaluating the suppression effect of the laser interference suppression image.

8. The strong laser interference suppression control method based on the DMD spatial light control camera according to claim 7 is characterized in that: Evaluate the suppression effect of the laser interference suppression image, including: Get the currently updated DMD mask M with laser suppression function a ' dj (x (1) ,y (1) ); Confirm in M a ' dj (x (1) ,y (1) ) is the image I generated after strong light suppression under control a ' dj (x (1) ,y (1) ); Calculate I a ' dj (x (1) ,y (1) )’s image saturation ratio, image entropy value and image grayscale gradient; If the calculated I a ' dj (x (1) ,y (1) ) when the image saturation ratio, image entropy value and image gray gradient all meet their corresponding preset thresholds, then the laser interference suppression image effective flag is output; If the calculated I a ' dj (x (1) ,y (1) ) when any one of the image saturation ratio, image entropy value and image grayscale gradient does not meet the corresponding preset threshold, the laser interference suppression image invalid flag is output and the process returns to step 1.

Images