Infrared scene simulator response dynamic range evaluation method

Abstract

The invention discloses an infrared scene simulator response dynamic range evaluation method, and belongs to the technical field of infrared imaging semi-physical simulation dynamic scene simulation. The method comprises the following steps: constructing a test image; imaging the test image by using the thermal infrared imager, comparing the effective imaging pixels in the row direction of the thermal infrared imager with the effective pixels in the row direction of the infrared scene simulator, and resetting the gray values of the rows and columns of the test image according to the comparison result; respectively setting an infrared scene simulator and an infrared thermal imager by taking the test image as an input scene; acquiring and recording an imaging picture projected to the infrared scene simulator by the thermal infrared imager; and eliminating an abnormal value of each row and column in the image, analyzing the column-direction data difference between the image and the constructed test image, and performing evaluation. According to the method, the workload can be greatly reduced, meanwhile, the test image can effectively reflect the resolution performance of the simulator on different gray levels of a real complex scene, and the method is high in operability and has good engineering practicability.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared imaging semi-physical simulation dynamic scene simulation, and in particular relates to an infrared scene simulator response dynamic range evaluation method. Background Art

[0002] Infrared scene simulator is the key technology of infrared imaging semi-physical simulation system. The response dynamic range of the infrared scene simulator projected scene reflects the grayscale level of infrared scene that the simulator can distinguish, determines the degree of realism of computer-generated image projection, and is the core indicator of infrared scene simulator. The quality of the infrared scene simulator projected scene directly affects the accuracy of the semi-physical simulation system to test and evaluate the infrared imaging system. The traditional infrared scene simulator response dynamic range evaluation constructs N test images with grayscale levels from 0 to N-1 according to the dynamic range of the simulator. The infrared thermal imager collects N images projected by the simulator in turn, and the infrared scene simulator response dynamic range evaluation is realized by analyzing the N images collected by the infrared thermal imager. This method has the disadvantages of complex operation and large amount of data. At the same time, this method only projects a single grayscale image at the same time, which is quite different from the real complex scene projected by the simulator. Especially with the development of infrared scene simulator technology, the response dynamic range has developed from 256 to 1024 or even higher. The shortcomings of the traditional evaluation method are more prominent, and it is impossible to simulate the infrared scene truly and accurately.

[0003] Therefore, the present invention proposes a method for evaluating the dynamic range of response of an infrared scene simulator. 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 an infrared scene simulator response dynamic range evaluation method, which can quickly complete the dynamic range evaluation of the infrared scene simulator under dynamic scenes by constructing a test image adapted to the infrared scene simulator response dynamic range. The present invention can greatly reduce the workload, and the test image can effectively reflect the simulator's resolution performance of different gray levels of real complex scenes, and the method is highly operable and has good engineering practicality.

[0006] The technical solution of the present invention is: a method for evaluating the dynamic range of response of an infrared scene simulator, characterized in that the specific steps are as follows:

[0007] Constructing an adaptive test image according to the dynamic range of the infrared scene simulator response, wherein the test image is an image with grayscale levels gradually changing in the row direction;

[0008] An infrared thermal imager is used to image the test image, and the effective imaging pixels in the row direction of the infrared thermal imager are compared with the effective pixels in the row direction of the infrared scene simulator, and the grayscale values ​​of the rows and columns of the test image are reset according to the comparison results;

[0009] Calculate the number of rows corresponding to each gray level upward in the test image row;

[0010] When the effective imaging pixels of the infrared thermal imager in the row direction are greater than or equal to the effective pixels of the infrared scene simulator in the row direction, the image grayscale value is increased from 0 to the maximum value in the heading direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval;

[0011] When the effective imaging pixel of the infrared thermal imager in the row direction is smaller than the effective pixel of the infrared scene simulator in the row direction, the grayscale value of the image is changed from 0 to the maximum value in the heading direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval;

[0012] The reconfigured test image is used as the input scene to configure the infrared scene simulator and the infrared thermal imager respectively;

[0013] Adjust the positions of the infrared thermal imager and the infrared scene simulator so that the entrance and exit pupils of the two devices coincide and the optical axis centers are aligned and parallel. Use the infrared thermal imager synchronization signal to trigger the test image projected by the infrared scene simulator, and collect and record the imaging screen projected by the infrared thermal imager on the infrared scene simulator.

[0014] The outliers in each row and column of the image are removed, and the difference in column data between the image and the constructed test image is analyzed for evaluation.

[0015] A further technical solution of the present invention is that the effective pixel numbers of the infrared scene simulator are R×C, and the pixel resolution of the constructed test image is R×C.

[0016] A further technical solution of the present invention is: the method for calculating the number of rows corresponding to each gray level upward in the test image row is to divide the effective pixel R of the infrared scene simulator row by the gray level N of the response dynamic range of the infrared scene simulator and round down the value obtained, that is, to obtain the number of rows R corresponding to each gray level upward in the row R. Nfloor .

[0017] A further technical solution of the present invention is that the grayscale values ​​of the test image rows and columns are reset as follows:

[0018] When the infrared thermal imager has an effective imaging pixel R IR ≥R, then in the test image row R direction with R Nfloor To set the image grayscale values ​​to 0 to (N-1) at equal intervals, the (RNfloor ×N+1)~R row image grayscale value is set to N-1;

[0019] When the infrared thermal imager has an effective imaging pixel R IR <R, then in the test image row R direction with R Nfloor Set the image grayscale value to start from 0 and R IRceil The gradient increases until the maximum value (N-1), and the R direction (N / R IRceil +1)~R row image grayscale values ​​are set to N-1.

[0020] A further technical solution of the present invention is: the specific configuration of the infrared scene simulator and the infrared thermal imager is based on the temperature resolution of the infrared scene simulator. and the gray level N of the response dynamic range, and the temperature difference between the low-temperature black body and the high-temperature black body of the infrared scene simulator is set to be no less than According to the temperature difference range between the low-temperature blackbody and the high-temperature blackbody of the infrared scene simulator, select the integration time gear of the infrared thermal imager, and set the integration time of the infrared scene simulator to be consistent with the integration time of the infrared thermal imager.

[0021] A further technical solution of the present invention is: the method for removing the outliers in each row and column of the image is to divide the recorded imaging picture into three equal parts in the column direction, randomly select three groups of data of R×10 in the three-divided area, and use the selected three groups of data as the evaluation data set R×30; calculate the row mean array R of the evaluation data set μ ×1 and standard deviation R σ ×1, if the absolute value of the difference between the row data and its mean in the evaluation data set is greater than 3 times the standard deviation, replace it with the mean to obtain a new evaluation data set, repeat the above steps until there is no data with an absolute value greater than 3 times the standard deviation between the row data and its mean in the evaluation data set, and obtain the final evaluation data set that removes the outliers in each row and column of the image, and calculate the row mean array R of the final evaluation data set <μ> ×1.

[0022] A further technical solution of the present invention is: the evaluation method is: the row-wise mean array R <μ> The absolute value of the difference between ×1 and the row value of the test image is divided by the row value of the test image to obtain the deviation rate of the infrared scene simulator in response to different gray levels. The mean of the deviation rate of the response to different gray levels can be calculated to complete the evaluation of the dynamic range of the infrared scene simulator response. The lower the response deviation rate, the better the dynamic range of the infrared scene simulator response.

[0023] An infrared scene simulator response dynamic range evaluation system, characterized in that it 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;

[0024] The scene image source generating computer converts the test image data constructed according to the response dynamic range of 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.

[0025] Beneficial Effects

[0026] The beneficial effects of the present invention are as follows: the method of the present invention combines the performance and dynamic range index of the infrared scene simulator and the index of the infrared thermal imager of the test equipment to construct a grayscale gradient test image that can simulate the infrared scene simulator projecting a real complex scene. Based on the comparison of the imaging effective pixels in the row direction of the infrared thermal imager and the effective pixels in the row direction of the infrared scene simulator, the grayscale value in the row direction of the test image is reset to obtain an image that can react to the dynamic response of the reactor. The processed image is then used as input to collect and record the imaging picture of the infrared thermal imager projecting the infrared scene simulator; after the abnormal values ​​in the image are removed, an evaluation is performed to complete the dynamic range evaluation of the response of the infrared scene simulator. The method does not need to construct a large number of test images, which can greatly reduce the workload. At the same time, the test image can effectively reflect the simulator's resolution performance of different grayscale levels of real complex scenes. The method is highly operable and has good engineering practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart for implementing the dynamic range evaluation of the infrared scene simulator response.

[0028] Figure 2 The figure shows the comparison between the generated test image and the infrared scene simulator projection image. It can be seen from the figure that the infrared scene simulator can complete the test image projection well, but the resolution ability is reduced in the dynamic range with lower grayscale levels. This method can effectively reflect the resolution performance of the infrared scene simulator for different grayscale levels, and can quickly and conveniently complete the evaluation of the dynamic range of the infrared scene simulator response. DETAILED DESCRIPTION

[0029] 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.

[0030] The traditional infrared scene simulator response dynamic range evaluation method has the disadvantages of complex operation and large amount of data. At the same time, this method only projects a single grayscale image at the same time, which is quite different from the real complex scene projected by the simulator. Especially with the development of infrared scene simulator technology, the response dynamic range has developed from 256 to 1024 or even higher. The shortcomings of the traditional evaluation method are more prominent, and it is impossible to simulate the infrared scene truly and accurately. The present invention provides an infrared scene simulator response dynamic range evaluation method, and the specific steps are as follows:

[0031] Step 1: construct an adapted test image according to the dynamic range of the infrared scene simulator response, wherein the test image is an image with grayscale levels gradually changing in the row direction;

[0032] Step 2: Use an infrared thermal imager to image the test image, compare the effective pixels in the row direction of the infrared thermal imager with the effective pixels in the row direction of the infrared scene simulator, and reset the grayscale values ​​of the rows and columns of the test image according to the comparison results;

[0033] Step 2.1: Calculate the number of rows corresponding to each gray level in the test image row upward;

[0034] Step 2.2 When the effective imaging pixels of the infrared thermal imager in the row direction are greater than or equal to the effective imaging pixels of the infrared scene simulator in the row direction, the grayscale value of the image is increased from 0 to the maximum value in the heading direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval;

[0035] Step 2.3 When the effective imaging pixel of the infrared thermal imager in the row direction is smaller than the effective pixel of the infrared scene simulator in the row direction, the grayscale value of the image is increased from 0 in the heading direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval, and the gradient value of the grayscale value in the row direction of the test image is used as the transformation gradient value to the maximum value;

[0036] Step 3: Use the reconfigured test image as the input scene to set the infrared scene simulator and the infrared thermal imager respectively;

[0037] Step 4: Adjust the positions of the infrared thermal imager and the infrared scene simulator so that the entrance and exit pupils of the two devices coincide and the optical axis centers are aligned and parallel. Use the infrared thermal imager synchronization signal to trigger the test image projected by the infrared scene simulator, and collect and record the imaging screen projected by the infrared thermal imager on the infrared scene simulator.

[0038] Step 5: Remove outliers in each row and column of the image, analyze the difference in column data between the image and the constructed test image, and make an evaluation.

[0039] The invention discloses an infrared scene simulator response dynamic range evaluation system, comprising an infrared scene simulator, an infrared thermal imager and a scene image source generation computer. The infrared scene simulator comprises 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 an optical entrance pupil of the infrared thermal imager, and the optical axis centers are aligned and parallel. The scene image source generation computer converts test image data constructed according to the response dynamic range of the infrared scene simulator into infrared radiation, and transmits the infrared radiation to the infrared thermal imager through the projection matching optical system to simulate the infrared scene.

[0040] The present invention only needs to construct a test image to complete the response dynamic range evaluation, and the method is simple and has strong operability. The above technical solution is further explained in conjunction with specific examples below:

[0041] Reference Figure 1 As shown, the present embodiment provides an infrared scene simulator response dynamic range evaluation method, and the specific steps are as follows:

[0042] Step 1: According to the effective pixel R×C of the infrared scene simulator, a grayscale gradient test image is constructed, and the pixel resolution of the test image is R×C;

[0043] Step 2: Use an infrared thermal imager to image the test image, and compare the effective pixels of the infrared thermal imager in the row direction with the effective pixels of the infrared scene simulator in the row direction;

[0044] The grayscale level of the infrared scene simulator response dynamic range is N. Calculate R / N and round down to get the number of rows R corresponding to each grayscale level above row R. Nfloor ;

[0045] If the infrared thermal imager has an effective imaging pixel R IR ≥R, then the test image row R is R Nfloor To set the image grayscale values ​​to 0 to (N-1) at equal intervals, the (R Nfloor ×N+1)~R row image grayscale value is set to N-1;

[0046] If R IR <R, calculate R / R IR And round up to get the change gradient R of the gray value of the test image row IRceil , then in the test image row R to R Nfloor Set the image grayscale value to start from 0 and R IRceil The gradient increases until the maximum value (N-1), and the R direction (N / R IRceil +1)~R row image grayscale values ​​are set to N-1;

[0047] Step 3: The infrared scene simulator uses the test image as the input scene and calculates the temperature resolution of the infrared scene simulator. and the gray level N of the response dynamic range, and the temperature difference between the low-temperature black body and the high-temperature black body of the infrared scene simulator is set to be no less than According to the temperature difference range between the low-temperature blackbody and the high-temperature blackbody of the infrared scene simulator, select the integration time gear of the infrared thermal imager, and set the integration time of the infrared scene simulator to be consistent with the integration time of the infrared thermal imager;

[0048] Step 4: Adjust the positions of the infrared thermal imager and the infrared scene simulator so that the entrance and exit pupils of the two devices coincide and the optical axis centers are aligned and parallel, and use the infrared thermal imager synchronization signal to trigger the test image projected by the infrared scene simulator, and collect and record the imaging screen projected by the infrared thermal imager on the infrared scene simulator;

[0049] Step 5: Divide the recorded image into three equal parts in the column direction, randomly select three groups of data of R×10 in the three-divided area, and use the selected three groups of data as the evaluation data set R×30; calculate the row-wise mean array R of the evaluation data set μ ×1 and standard deviation R σ ×1, if the absolute value of the difference between the row data and its mean in the evaluation data set is greater than 3 times the standard deviation, replace it with the mean to obtain a new evaluation data set, repeat the above steps until there is no data with an absolute value greater than 3 times the standard deviation between the row data and its mean in the evaluation data set, and obtain the final evaluation data set that removes the outliers in each row and column of the image, and calculate the row mean array R of the final evaluation data set <μ> ×1;

[0050] Calculate the mean value array R of each row and column of three sets of data μ ×1 and standard deviation R σ ×1, remove the outliers whose absolute difference between the mean and the data in each row and column is greater than 3 times the standard deviation, and repeat the above steps until a set of mean arrays R of each row and column without abnormal data is obtained <μ> ×1; analyze and compare the row mean array R <μ> The absolute value of the difference between ×1 and the row value of the test image is divided by the row value of the test image to obtain the deviation rate of the infrared scene simulator in response to different gray levels, and the mean of the deviation rates of the responses to different gray levels is calculated to complete the evaluation of the response dynamic range of the infrared scene simulator. The lower the response deviation rate, the better the response dynamic range of the infrared scene simulator, and the evaluation of the response dynamic range of the infrared scene simulator can be completed.

[0051] 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 method for evaluating the dynamic range of response of an infrared scene simulator, characterized in that The specific steps are as follows: Constructing an adaptive test image according to the dynamic range of the infrared scene simulator response, wherein the test image is an image with grayscale levels gradually changing in the row direction; An infrared thermal imager is used to image the test image, and the effective imaging pixels in the row direction of the infrared thermal imager are compared with the effective pixels in the row direction of the infrared scene simulator, and the grayscale values ​​of the rows and columns of the test image are reset according to the comparison results; Calculate the number of rows corresponding to each gray level upward in the test image row; When the effective imaging pixels of the infrared thermal imager in the row direction are greater than or equal to the effective pixels of the infrared scene simulator in the row direction, the grayscale value of the image is increased from 0 to the maximum value in the row direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval; When the effective imaging pixel of the infrared thermal imager in the row direction is smaller than the effective pixel of the infrared scene simulator in the row direction, the grayscale value of the image is changed from 0 to the maximum value in the heading direction of the test image, with the number of rows corresponding to each grayscale level in the row direction of the test image as the interval; The reconfigured test image is used as the input scene to configure the infrared scene simulator and the infrared thermal imager respectively; Adjust the positions of the infrared thermal imager and the infrared scene simulator so that the entrance and exit pupils of the two devices coincide and the optical axis centers are aligned and parallel. Use the infrared thermal imager synchronization signal to trigger the test image projected by the infrared scene simulator, and collect and record the imaging screen projected by the infrared thermal imager on the infrared scene simulator. The outliers in each row and column of the image are removed, and the difference in column data between the image and the constructed test image is analyzed for evaluation.

2. The method for evaluating the response dynamic range of an infrared scene simulator according to claim 1, characterized in that: The infrared scene simulator has effective row and column pixels of R×C, and the pixel resolution of the constructed test image is R×C.

3. The method for evaluating the response dynamic range of an infrared scene simulator according to claim 2, characterized in that: The method for calculating the number of rows corresponding to each gray level upward in the test image is to divide the effective pixel R of the infrared scene simulator row by the gray level N of the response dynamic range of the infrared scene simulator and round down the value obtained, that is, to obtain the number of rows R corresponding to each gray level upward in the row R. Nfloor .

4. The method for evaluating the response dynamic range of an infrared scene simulator according to claim 3, characterized in that: The operation of resetting the grayscale values ​​of the test image rows and columns is as follows: When the infrared thermal imager has an effective imaging pixel R IR ≥R, then in the test image row R direction with R Nfloor To set the image grayscale values ​​to 0 to (N-1) at equal intervals, the (R Nfloor ×N+1)~R row image grayscale value is set to N-1; When the infrared thermal imager has an effective imaging pixel R IR <R, then in the test image row R direction with R Nfloor Set the image grayscale value to start from 0 and R IRceil The gradient increases until the maximum value (N-1), and the R direction (N / R IRceil +1)~R row image grayscale values ​​are set to N-1.

5. The method for evaluating the response dynamic range of an infrared scene simulator according to claim 4, characterized in that: The specific configuration of the infrared scene simulator and the infrared thermal imager is as follows: and the gray level N of the response dynamic range, and the temperature difference between the low-temperature black body and the high-temperature black body of the infrared scene simulator is set to be no less than According to the temperature difference range between the low-temperature blackbody and the high-temperature blackbody of the infrared scene simulator, select the integration time gear of the infrared thermal imager, and set the integration time of the infrared scene simulator to be consistent with the integration time of the infrared thermal imager.

6. The method for evaluating the dynamic range of response of an infrared scene simulator according to claim 5, characterized in that: The method for removing outliers in each row and column of the image is to divide the recorded imaging picture into three equal parts in the column direction, randomly select three groups of data of R×10 in the three-divided areas, and use the selected three groups of data as the evaluation data set R×30; calculate the row mean array R of the evaluation data set μ ×1 and standard deviation R σ ×1, if the absolute value of the difference between the row data and its mean in the evaluation data set is greater than 3 times the standard deviation, replace it with the mean to obtain a new evaluation data set, repeat the above steps until there is no data with an absolute value greater than 3 times the standard deviation between the row data and its mean in the evaluation data set, and obtain the final evaluation data set that removes the outliers in each row and column of the image, and calculate the row mean array R of the final evaluation data set <μ> ×1.

7. The method for evaluating the response dynamic range of an infrared scene simulator according to claim 6, characterized in that: The evaluation method is to use the row-wise mean array R <μ> The absolute value of the difference between ×1 and the row value of the test image is divided by the row value of the test image to obtain the deviation rate of the infrared scene simulator in response to different gray levels, and the mean of the deviation rate of the response to different gray levels is calculated to complete the evaluation of the response dynamic range of the infrared scene simulator. The lower the response deviation rate, the better the response dynamic range of the infrared scene simulator.

8. An infrared scene simulator response dynamic range evaluation system, used to implement the infrared scene simulator response dynamic range evaluation method according to any one of claims 1 to 7; 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 test image data constructed according to the response dynamic range of 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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