Non-uniform calibration method based on DMD infrared dynamic scene simulation system

Abstract

The invention discloses a non-uniform calibration method based on a DMD infrared dynamic scene simulation system, and belongs to the technical field of infrared dynamic scene simulation. Generating an infrared scene matched with the scene image; calculating a non-uniform deviation value of the image acquired by the thermal imager; non-uniform micro mirror image elements are calibrated; setting an image gray value corresponding to the position of the micro mirror image element which is calibrated to be non-uniform as 0, and calculating an average gray value of the collected image; on the basis of the average gray value of the collected image, calculating an adjustment coefficient of the micro mirror image element which is calibrated to be non-uniform; setting the adjustment coefficient of the micro mirror image element which is not calibrated to be non-uniform as 1; the dynamic scene image gray value is multiplied by the adjustment coefficient for correction, the new corrected gray value modulates the DMD micro mirror image element overturning time, an infrared scene matched with the corrected scene image is generated, and non-uniform compensation is completed. According to the invention, the uniformity of the infrared scene generated by the DMD-based infrared dynamic scene simulation system is improved, and the accuracy of system simulation is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared dynamic scene simulation and emulation, and in particular relates to a non-uniform calibration method based on a DMD infrared dynamic scene simulation system. Background Art

[0002] Infrared dynamic scene simulation technology uses infrared radiation light modulation technology to generate infrared radiation that simulates real scene targets and backgrounds in a laboratory environment. It is a key link in the full-process semi-physical simulation evaluation of infrared imaging systems. Based on the DMD infrared dynamic scene simulation system, the micro-mirror element flip time is modulated according to the grayscale value of the dynamic scene image to achieve modulation of the incident infrared radiation, and generate an infrared scene that matches the dynamic scene image. The accuracy of this simulation technology is limited by factors such as the performance differences of the micro-mirror elements of the DMD device and the stray light of the optical system. The infrared dynamic scene simulation system based on the DMD has different energy reflected by the micro-mirror after pulse width modulation of the same incident radiation intensity, and even bright spots and dark spots appear, showing obvious non-uniformity, which affects the fidelity and accuracy of the system simulation.

[0003] Therefore, the present invention proposes a non-uniform calibration method based on a DMD infrared dynamic scene simulation system. Summary of the invention

[0004] Technical issues to be solved:

[0005] In order to avoid the shortcomings of the prior art, the present invention provides a non-uniform calibration method for a DMD-based infrared dynamic scene simulation system, which calibrates the non-uniformity of the DMD-based infrared dynamic scene simulation system, adjusts the grayscale value of the dynamic scene image based on the calibration data, completes the micro-mirror element flip time adjustment, and thus realizes non-uniform compensation. The present invention improves the uniformity of the infrared scene generated by the DMD-based infrared dynamic scene simulation system and improves the accuracy of the system simulation.

[0006] The technical solution of the present invention is: a non-uniform calibration method based on a DMD infrared dynamic scene simulation system, and the specific steps are as follows:

[0007] According to the resolution and grayscale level of the infrared dynamic scene simulation system, a corresponding scene image is generated, and then an infrared scene adapted to the scene image is generated;

[0008] The infrared scene generated by the infrared dynamic scene simulation system is collected by a thermal imager, and the non-uniform deviation value of the image collected by the thermal imager is calculated;

[0009] Based on the non-uniform deviation value of the image captured by the thermal imager, a threshold for calibrating the non-uniform micro-mirror element is set, the difference between the pixel response grayscale value of the image captured by the thermal imager and the pixel response grayscale mean is calculated, and all DMD micro-mirror element positions with a difference greater than or less than the threshold are calibrated as non-uniform micro-mirror elements;

[0010] The image grayscale value corresponding to the micro-mirror element position calibrated as non-uniform is set to 0, and the average grayscale value of the collected image is calculated;

[0011] Based on the average gray value of the acquired image, calculating the adjustment coefficient of the micro-mirror element calibrated as non-uniform;

[0012] The adjustment coefficient of the micro-mirror element that is not calibrated as non-uniform is set to 1;

[0013] The grayscale value of the dynamic scene image is multiplied by the adjustment coefficient to obtain a new grayscale value. The new grayscale value is used to modulate the DMD micro-mirror element flip time, and the infrared dynamic scene simulation system generates an infrared scene that matches the corrected scene image, thereby completing non-uniform compensation.

[0014] A further technical solution of the present invention is: the method for generating an infrared scene adapted to the scene image is: according to the resolution M×N and gray level n of the infrared dynamic scene simulation system, a resolution of M×N and a gray level of 2 are generated. n-1 -1 scene image, the DMD micro-mirror element flipping time is modulated by the gray value of the generated scene image, and the infrared dynamic scene simulation system generates an infrared scene adapted to the scene image.

[0015] A further technical solution of the present invention is: the calculation formula of the non-uniform deviation value NU0 of the image collected by the thermal imager is as follows:

[0016]

[0017] In the formula, G(i,j) is the pixel response grayscale value of the image collected by the thermal imager, i is the number of rows of the pixel in the image, j is the number of columns of the pixel in the image, M is the total number of rows in the image, and N is the total number of columns in the image. Represents the mean grayscale response of the pixels in the image captured by the thermal imager.

[0018] A further technical solution of the present invention is: the pixel response grayscale mean of the image collected by the thermal imager The calculation formula is as follows:

[0019]

[0020] A further technical solution of the present invention is: the threshold is 10×NU0, when or Then the position (i, j) in the image is marked as a non-uniform micro-mirror element.

[0021] A further technical solution of the present invention is: the calculation formula for the average gray value of the collected image is:

[0022]

[0023] Where d is the number of calibrated non-uniform micro-mirror elements.

[0024] A further technical solution of the present invention is: the calculation formula of the adjustment coefficient of the micro-mirror element calibrated as non-uniform is:

[0025]

[0026] In the formula, G nu (i, j) is the image grayscale value of the non-uniform micro-mirror element.

[0027] A further technical solution of the present invention is: the new gray value is obtained by multiplying the gray value of the dynamic scene image by the micro-mirror element adjustment coefficient. If it is greater than 2 n -1, then take 2 n -1; if less than or equal to 2 n -1, then round down to get the new grayscale value.

[0028] A DMD-based infrared dynamic scene simulation system includes an infrared scene simulator, an infrared thermal imager, and a scene image source generation computer. The infrared scene simulator includes a signal processing circuit, a drive circuit, a black body, a black body illumination optical system, and a projection matching optical system. The projection matching optical system is arranged relative to the optical entrance pupil of the infrared thermal imager, and the optical axis centers are aligned and parallel.

[0029] The scene image source generating computer converts the scene image data constructed according to the infrared scene simulator into infrared radiation, and transmits it to the infrared thermal imager through the projection matching optical system to simulate the infrared scene.

[0030] Beneficial Effects

[0031] The beneficial effects of the present invention are as follows: the present invention proposes a non-uniform calibration method based on a DMD infrared dynamic scene simulation system, and obtains a threshold for judging a non-uniform micro-mirror element by calculating a non-uniform deviation value of an image captured by a thermal imager, and all non-uniform micro-mirror elements can be accurately calibrated by the threshold, and then the non-uniform micro-mirror element adjustment coefficient obtained by calculation is used to compensate for the non-uniform micro-mirror element, thereby completing the non-uniform calibration of the DMD infrared dynamic scene simulation system, and adjusting the grayscale value of the dynamic scene image based on the calibration data to complete the micro-mirror element flipping time adjustment and thus realize non-uniform compensation, and the method has strong operability and good engineering practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a non-uniform calibration method based on a DMD infrared dynamic scene simulation system.

[0033] Figure 2 This is a comparison of the projection effects of the infrared dynamic scene simulation system before and after the non-uniform calibration. (a) is the projection effect of the infrared dynamic scene simulation system before calibration. There are pixels with non-uniform responses (marked with red circles) in the figure. (b) is the projection effect of the infrared dynamic scene simulation system after calibration. The compensation for non-uniform pixels has been completed, there is no bright spot or dark spot phenomenon, and the projection effect is good. DETAILED DESCRIPTION

[0034] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0035] Based on the fact that the accuracy of existing infrared dynamic scene simulation technology is limited by factors such as the performance difference of the micro-mirror element of the DMD device and the stray light of the optical system, the infrared dynamic scene simulation system based on the DMD has differences in the energy reflected by the micro-mirror after pulse width modulation of the same incident radiation intensity, and even bright spots and dark spots appear, showing obvious non-uniformity, affecting the fidelity and accuracy of the system simulation. The present invention provides a non-uniform calibration method for the infrared dynamic scene simulation system based on the DMD, and the specific steps are as follows:

[0036] Step 1: Generate a corresponding scene image according to the resolution and grayscale of the infrared dynamic scene simulation system, and then generate an infrared scene adapted to the scene image;

[0037] Step 2: Using a thermal imager to capture the infrared scene generated by the infrared dynamic scene simulation system, and calculating the non-uniform deviation value of the image captured by the thermal imager;

[0038] Step 3: Based on the non-uniform deviation value of the image captured by the thermal imager, a threshold for calibrating the non-uniform micro-mirror element is set, and the difference between the pixel response grayscale value of the image captured by the thermal imager and the pixel response grayscale mean is calculated, and all DMD micro-mirror element positions whose difference is greater than or less than the threshold are calibrated as non-uniform micro-mirror elements;

[0039] Step 4: setting the image grayscale value corresponding to the micro-mirror element position calibrated as non-uniform to 0, and calculating the average grayscale value of the collected image;

[0040] Step 5: Based on the average gray value of the acquired image, the adjustment coefficient of the micro-mirror element calibrated as non-uniform is calculated;

[0041] The adjustment coefficient of the micro-mirror element that is not calibrated as non-uniform is set to 1;

[0042] Step 6: Multiply the grayscale value of the dynamic scene image by the adjustment coefficient to obtain a new grayscale value, and use the new grayscale value to modulate the DMD micro-mirror element flip time. The infrared dynamic scene simulation system generates an infrared scene that matches the corrected scene image, thereby completing non-uniform compensation.

[0043] The above technical solution is further described below in conjunction with the accompanying drawings:

[0044] Reference Figure 1 As shown, this embodiment is a non-uniform calibration method based on a DMD infrared dynamic scene simulation system, and the specific steps are as follows:

[0045] Step 1: Based on the resolution (M×N) and grayscale level (n) of the infrared dynamic scene simulation system, use the image computer to generate a resolution of M×N and a grayscale value of 2 n-1 -1 scene image, and use the image grayscale value to modulate the DMD micro-mirror element flipping time, and the infrared dynamic scene simulation system generates an infrared scene adapted to the scene image.

[0046] Step 2: Adjust the thermal imager to align with the infrared dynamic scene simulation system and collect infrared scenes. Calculate the non-uniform deviation value NU0 of the image collected by the thermal imager according to the following formula:

[0047]

[0048] Where G(i,j) is the grayscale value of the pixel response of the image captured by the thermal imager, i is the number of rows of the pixel in the image, j is the number of columns of the pixel in the image, M is the total number of rows in the image, and N is the total number of columns in the image.

[0049] Step 3: If G(i,j)-G m >10×NU0 or G(i,j)-G m <10×NU0, the position (i, j) in the image is calibrated as a non-uniform micro-mirror element, and the calibration of all non-uniform micro-mirror elements of the DMD is completed.

[0050] Step 4: Set the image grayscale value corresponding to the non-uniform micro-mirror element position to 0, and calculate the average grayscale value of the image:

[0051]

[0052] Where d is the number of calibrated non-uniform micro-mirror elements.

[0053] Step 5: If the micro-mirror element is calibrated as a non-uniform micro-mirror element, calculate the micro-mirror element adjustment coefficient Among them G nu(i, j) is the image grayscale value of the non-uniform micro-mirror element, otherwise the micro-mirror element adjustment coefficient is 1.

[0054] Step 6: Multiply the grayscale value of the dynamic scene image by the micro-mirror element adjustment coefficient. If the grayscale value is greater than 2 n If -1, take 2 n -1, otherwise round down to get a new grayscale value, and use the new grayscale value to modulate the DMD micro-mirror element flipping time. The infrared dynamic scene simulation system generates an infrared scene that matches the scene image and completes non-uniform compensation at the same time.

[0055] Reference Figure 2 As shown in the figure, the projection effects of the infrared dynamic scene simulation system before and after the non-uniform calibration are compared. (a) is the projection effect of the infrared dynamic scene simulation system before calibration. There are pixels with non-uniform responses (marked with red circles) in the figure. (b) is the projection effect of the infrared dynamic scene simulation system after calibration. The compensation for non-uniform pixels has been completed, there is no bright spot or dark spot phenomenon, and the projection effect is good.

[0056] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A non-uniform calibration method based on DMD infrared dynamic scene simulation system, characterized in that The specific steps are as follows: According to the resolution and grayscale level of the infrared dynamic scene simulation system, a corresponding scene image is generated, and then an infrared scene adapted to the scene image is generated; The infrared scene generated by the infrared dynamic scene simulation system is collected by a thermal imager, and the non-uniform deviation value of the image collected by the thermal imager is calculated; Based on the non-uniform deviation value of the image captured by the thermal imager, a threshold for calibrating the non-uniform micro-mirror element is set, the difference between the pixel response grayscale value of the image captured by the thermal imager and the pixel response grayscale mean is calculated, and all DMD micro-mirror element positions with a difference greater than or less than the threshold are calibrated as non-uniform micro-mirror elements; The image grayscale value corresponding to the micro-mirror element position calibrated as non-uniform is set to 0, and the average grayscale value of the collected image is calculated; Based on the average gray value of the acquired image, calculating the adjustment coefficient of the micro-mirror element calibrated as non-uniform; The adjustment coefficient of the micro-mirror element that is not calibrated as non-uniform is set to 1; The grayscale value of the dynamic scene image is multiplied by the adjustment coefficient to obtain a new grayscale value. The new grayscale value is used to modulate the DMD micro-mirror element flip time, and the infrared dynamic scene simulation system generates an infrared scene that matches the corrected scene image, thereby completing non-uniform compensation.

2. According to claim 1, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized by: The method for generating an infrared scene adapted to the scene image is as follows: according to the resolution M×N and gray level n of the infrared dynamic scene simulation system, a resolution of M×N and a gray level of 2 are generated. n-1 -1 scene image, the DMD micro-mirror element flipping time is modulated by the gray value of the generated scene image, and the infrared dynamic scene simulation system generates an infrared scene adapted to the scene image.

3. According to claim 2, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized in that: The calculation formula of the non-uniform deviation value NU0 of the image collected by the thermal imager is as follows: In the formula, G(i,j) is the pixel response grayscale value of the image collected by the thermal imager, i is the number of rows of the pixel in the image, j is the number of columns of the pixel in the image, M is the total number of rows in the image, and N is the total number of columns in the image. Represents the mean grayscale response of the pixels in the image captured by the thermal imager.

4. According to claim 3, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized in that: The grayscale mean of the pixel response of the image collected by the thermal imager The calculation formula is as follows:

5. According to claim 4, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized in that: The threshold is 10×NU0. or Then the position (i, j) in the image is marked as a non-uniform micro-mirror element.

6. According to claim 5, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized in that: The calculation formula for the average gray value of the collected image is: Where d is the number of calibrated non-uniform micro-mirror elements.

7. According to claim 6, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized by: The calculation formula of the adjustment coefficient of the micro-mirror element calibrated as non-uniform is: In the formula, G nu (i, j) is the image grayscale value of the non-uniform micro-mirror element.

8. According to claim 7, a non-uniform calibration method based on a DMD infrared dynamic scene simulation system is characterized by: The new grayscale value is obtained by multiplying the grayscale value of the dynamic scene image by the micro-mirror element adjustment coefficient. If it is greater than 2 n -1, then take 2 n -1; if less than or equal to 2 n -1, then round down to get the new grayscale value.

9. A DMD-based infrared dynamic scene simulation system, used to implement the DMD-based infrared dynamic scene simulation system non-uniform calibration method according to any one of claims 1 to 8; characterized in that: It includes an infrared scene simulator, an infrared thermal imager and a scene image source generating computer. The infrared scene simulator includes a signal processing circuit, a driving circuit, a black body, a black body illumination optical system and a projection matching optical system. The projection matching optical system is arranged relative to the optical entrance pupil of the infrared thermal imager, and the optical axis centers are aligned and parallel. The scene image source generating computer converts the scene image data constructed according to the infrared scene simulator into infrared radiation, and transmits it to the infrared thermal imager through the projection matching optical system to simulate the infrared scene.

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