Device and method for testing detection distance of infrared camera

Abstract

The invention discloses a device and method for testing the detection distance of an infrared camera, and solves the technical problems that an indoor test device is large in size and an external field test is seriously influenced by weather, and the device for testing the detection distance of the infrared camera comprises a collimator, an electric target wheel, a surface source black body, an infrared camera installation position and a control computer. An infrared camera mounting position is arranged at a preset distance away from the exit port of the collimator; an electric target wheel is arranged at an incident port of the collimator; the control computer is electrically connected with the electric target wheel and is used for controlling the automatic switching of a plurality of target positions of the electric target wheel, so that the target on any one of the plurality of target positions is positioned at the focal plane of the collimator; the surface source black body is located on the side, away from the collimator, of the electric target wheel and used for irradiating the target, and the radiation aperture of the surface source black body completely covers the target located on the focal plane of the collimator. The control computer is connected with the surface source black body to control the temperature of the surface source black body; and the control computer is connected with the infrared camera so as to receive an infrared image shot by the infrared camera.

Description

Technical Field

[0001] This invention relates to infrared camera detection distance testing equipment and methods, specifically to an infrared camera detection distance testing device and method. Background Technology

[0002] Detection range is a comprehensive performance indicator of an infrared camera, representing the maximum detection range of an infrared camera for a target with a specific radiation intensity under characteristic background and atmospheric conditions. Besides being affected by target radiation intensity, atmospheric conditions, and characteristic background, detection range is also influenced by factors such as optical system parameters, detector performance, integration time, gain, and stray radiation. In particular, the unique characteristics of the background and atmospheric conditions make it difficult to simulate the detection range of optical cameras indoors. Especially when simulating faint targets, the operating temperature requirements for the blackbody in existing experimental setups are extremely high. Ordinary blackbodies cannot meet this requirement, necessitating the use of vacuum cryogenic blackbodies and vacuum cryogenic collimators. The entire experimental setup must be placed in a vacuum environment, resulting in a particularly large and expensive setup.

[0003] Therefore, the detection range is usually verified and evaluated through field tests. However, the field environment is complex and changeable, and is greatly affected by the weather, resulting in a long test cycle, affecting the reliability of the test results, and requiring a lot of manpower, financial resources and material resources. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of existing indoor testing devices being bulky and expensive, and outdoor testing being severely affected by weather, resulting in long testing cycles and affecting the reliability of test results. This invention provides an infrared camera detection distance testing device and method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An infrared camera detection distance testing device is characterized by including a collimator, an electric target wheel, a surface source blackbody, and a control computer. The collimator has an inlet and an outlet, and an infrared camera mounting position is provided at a preset distance from its outlet for mounting an infrared camera; the electric target wheel is located at the inlet of the collimator; the electric target wheel has multiple target positions, each of which is used to mount a target. The control computer is electrically connected to the electric target wheel and is used to control the automatic switching of multiple target positions so that the target at any one of the multiple target positions is located at the focal plane of the collimator. The surface source blackbody is located on the side of the electric target wheel away from the collimator, and is used to irradiate the target located at the focal plane of the collimator. The radiation aperture of the surface source blackbody fully covers the target located at the focal plane of the collimator. The control computer is electrically connected to the surface source blackbody and is used to control the temperature of the surface source blackbody. The control computer has an interface connected to the infrared camera for receiving infrared images captured by the infrared camera.

[0006] Furthermore, the collimator is a total internal reflection type, and its structure is an off-axis single-reflector, or an off-axis double-reflector, or an off-axis triple-reflector.

[0007] Meanwhile, the present invention also provides a method for testing the detection distance of an infrared camera, which is characterized by including the following steps: Step 1: Construct the infrared camera detection distance testing device described above; obtain the infrared camera and install it in the infrared camera mounting position; Step 2, Obtain A diameter of The target is installed on the target position of the electric target wheel, and the temperature of the surface source blackbody is adjusted sequentially by the control computer. and Each time the temperature is adjusted, the electric target wheel is switched sequentially via a control computer. Each target is captured by an infrared camera at a specific temperature. The system images each target at a given temperature, creating a simulated image of the target at that temperature. This simulated image is then transmitted to a control computer for processing to obtain the temperature. The corresponding pixel grayscale value of the simulated target image and temperature The corresponding pixel grayscale value of the simulated target image ;in, , ; Step 3, Calculation Signal value of each target The calculation formula is as follows: ; Step 4: Obtain a square target and install it onto a target position on the electric target wheel. The square target is projected as a surface target by the infrared camera. The blackbody source is controlled by the computer to maintain its temperature at a certain level. The infrared camera images the square target, and the computer controls the data acquisition. The simulated target image of the square target is used to calculate the noise of the infrared camera. , Step 5, Calculation Target signal-to-noise ratio of each target The calculation formula is as follows: ; Step 6, according to Target signal-to-noise ratio of each target The detection range R of the infrared camera is obtained through interpolation calculation, thus completing the infrared camera detection range test.

[0008] Furthermore, in step 2, Laboratory temperature A diameter of Target acquisition and The calculation process includes the following steps: Step A1: Determine the theoretical detection range of the infrared camera. The working spectrum range is ; Step A2: Based on the theoretical detection distance ,Sure Each detection distance measurement point ; Step A3, Calculation Each detection distance measurement point In the operating spectrum of infrared cameras Within range Average atmospheric transmittance ; Step A4, Obtain There are multiple targets, each corresponding to a detection range measurement point. , The infrared radiation intensity of each target is [missing information]. The target imaging cross-sectional dimensions are all Where L is the length of the target imaging section and M is the width of the target imaging section; Step A5, based on the results obtained in step A3 Average atmospheric transmittance and Infrared radiation intensity of the target ,calculate The irradiance of each target at the entrance pupil of the infrared camera ; Step A6: Based on the target's cross-sectional dimensions ,calculate The diameter of each target According to diameter Cutting One target, and the cropped The target is installed on the target position of the electric target wheel; Step A7: Set the surface source blackbody temperature to... ,calculate The irradiance of each target at the exit of the collimator ; Step A8, Calculation The simulated irradiance for each target at the exit of the collimator is as follows. The calculation formula is as follows: ; Step A9, according to The simulated irradiance for each target at the exit of the collimator is as follows. Calculate the irradiance for each irradiance that needs to be simulated. The corresponding set temperature of the surface source blackbody .

[0009] Furthermore, step A2 specifically involves: Step A2.1: Based on the theoretical detection distance The range of the test distance is determined as follows: ; Step A2.2, at the test distance Within the range, select at equal intervals Each detection distance measurement point .

[0010] Further, in step A5, the irradiance of the target object at the entrance pupil of the infrared camera is calculated. The calculation formula is as follows: .

[0011] Furthermore, in step A6, the target to be tested requires... Target diameter The calculation formula is as follows: ; in, This is the focal length of the collimator.

[0012] Furthermore, in step A7, the target to be tested... Each detection distance measurement point At the outlet of the collimator irradiance The calculation formula is as follows: ; in, The transmittance of the collimator; Let be the focal length of the collimator (1); The emissivity of the surface-source blackbody; It is the first radiation constant; It is the second radiation constant; The wavelength of the infrared camera.

[0013] Furthermore, in step 4, the noise of the infrared camera... The calculation formula is as follows: ; ; Where m is the number of rows in the square target image region; n is the number of columns in the square target image region; N(r,c) is the noise of the pixel in the r-th row and c-th column of the square target image region; r = 1, 2, ..., m; c = 1, 2, ..., n; ; k is the number of frames in the simulated target image of the square target, k=1,2,...,p, where ; For the simulated target image of the square target in the k-th frame, the gray value of the pixel in the r-th row and c-th column of the square target image region.

[0014] Furthermore, in step A9 The calculation formula is as follows: .

[0015] The beneficial effects of this invention are: 1. The present invention provides an infrared camera detection distance testing device, which sets an electric target wheel at the entrance of a collimator. The electric target wheel has multiple target positions and can be configured with different types of target targets. A black body is placed behind the electric target wheel to illuminate the target target located at the focal plane of the collimator. This can simulate the target and background, and realize the measurement of infrared camera noise and target signal.

[0016] 2. This invention provides a method for testing the detection distance of an infrared camera. By adjusting the radiation temperature of a blackbody source, the target signal is simulated in a laboratory environment. The calculation method enables the measurement of the imaging signal of the infrared camera on the target, and combined with the measurement of the infrared camera noise, it enables indoor testing and verification of the infrared camera detection distance, thus solving the problem of infrared camera detection distance testing and verification.

[0017] 3. This invention provides a method for testing the detection distance of an infrared camera, through... The irradiance of each target at the entrance pupil of the infrared camera and The irradiance of each target at the exit of the collimator ,calculate The simulated irradiance for each target at the exit of the collimator is as follows. And based on the irradiance that needs to be simulated for each By reverse calculation, the set temperature of its corresponding surface source blackbody can be determined. , Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the working principle of an embodiment of an infrared camera detection distance testing device according to the present invention.

[0019] The attached figures are labeled as follows: 1. Collimator; 2. Motorized target wheel; 3. Target; 4. Blackbody; 5. Infrared camera; 6. Control computer. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, an infrared camera detection distance testing device provided in this embodiment of the invention includes a parallel light 1, an electric target wheel 2, a surface source blackbody 4, and a control computer 6. The collimator 1 has an inlet and an outlet, and an infrared camera mounting position is set at a preset distance from its outlet for mounting an infrared camera 5; the electric target wheel 2 is set at the inlet of the collimator 1; the electric target wheel 2 has multiple target positions, each of which is used to mount a target 3. The control computer 6 is electrically connected to the electric target wheel 2 and is used to control the automatic switching of multiple target positions so that the target 3 in any one of the multiple target positions is located at the focal plane of the collimator 1. The surface source blackbody 4 is located on the side of the electric target wheel 2 away from the collimator 1, and is used to irradiate the target 3 located at the focal plane of the collimator 1. The radiation aperture of the surface source blackbody 4 fully covers the target 3 located at the focal plane of the collimator 1. The control computer 6 is electrically connected to the surface source blackbody 4 and is used to control the temperature of the surface source blackbody 4. The control computer 6 has an interface for connecting to the infrared camera 5 to receive infrared images captured by the infrared camera 5.

[0022] In this embodiment, the collimator 1 is a total internal reflection type, and its structure is an off-axis single-lens reflex camera. In other embodiments, it can also be an off-axis double-lens reflex camera or an off-axis triple-lens reflex camera.

[0023] Meanwhile, the present invention also provides a method for testing the detection distance of an infrared camera, comprising the following steps: Step 1: Construct the infrared camera detection range testing device described above, obtain infrared camera 5, and install it in the infrared camera mounting position; determine the theoretical detection range of infrared camera 5. The working spectrum range is ; Step 2: Based on the theoretical detection distance ,Sure Each detection distance measurement point ,in , Specifically: Step 2.1: Based on the theoretical detection distance The range of the test distance is determined as follows: ; Step 2.2, at the test distance Within the range, select at equal intervals Each detection distance measurement point In this embodiment ; Step 3, Calculation Each detection distance measurement point In the infrared camera's 5 operating spectrum Within range Average atmospheric transmittance In this embodiment, the working spectral band of infrared camera 5 was obtained by analyzing atmospheric transmittance using atmospheric transmittance analysis software. Within range Average atmospheric transmittance ; Step 4, Obtain There are three targets, each target 3 corresponding to a detection range measurement point. , The infrared radiation intensity of target 3 is all The target imaging cross-sectional dimensions are all Where L is the length of the target imaging section and M is the width of the target imaging section; in this embodiment, the target 3 is an infrared target plate, which can be a metal target, with the required pattern engraved on a substrate of good conductors such as aluminum or copper, or a glass target, with the required pattern prepared by photolithography on an infrared material substrate such as zinc sulfide or zinc selenide.

[0024] Step 5, based on the results obtained in Step 3 Average atmospheric transmittance and the result obtained in step 4 Infrared radiation intensity of target 3 ,calculate The irradiance of each target 3 at the entrance pupil of infrared camera 5. , The calculation formula is as follows: ; Step 6: Based on the target imaging cross-sectional dimensions obtained in Step 4 ,calculate The diameter of each of the three targets According to diameter Cut to get Three targets were identified, and the cropped values ​​were... The target 3 is installed on the target position of the electric target wheel 2; The calculation formula is as follows: ; in, is the focal length of collimator 1.

[0025] Step 7: Set the temperature of the surface source blackbody 4 to... ,calculate The irradiance of each target at the exit of collimator 1 ; The calculation formula is as follows: ; in, Let be the transmittance of collimator 1; Let be the emissivity of the surface-source blackbody 4; It is the first radiation constant; It is the second radiation constant; The wavelength is for infrared camera 5.

[0026] Step 8, Calculation The required simulated irradiance for each target 3 at the exit of the collimator 1. The calculation formula is as follows: .

[0027] Step 9, according to The required simulated irradiance for each target 3 at the exit of the collimator 1. Calculate the irradiance for each irradiance that needs to be simulated. The corresponding set temperature of the surface source blackbody 4 The calculation formula is as follows: ; Step 10: The temperature of the surface source blackbody 4 is adjusted sequentially by the control computer 6. and ,in, To maintain the laboratory temperature, the electric target wheel 2 is switched sequentially via the control computer 6 after each temperature adjustment. Three targets, one infrared camera, and one infrared camera at each temperature. Image is taken from target 3 to obtain a simulated target image of the corresponding temperature. The simulated target image of the corresponding temperature is then transmitted to the control computer 6 for processing to obtain the temperature. The corresponding pixel grayscale value of the simulated target image and temperature The corresponding pixel grayscale value of the simulated target image In this embodiment, the simulated target image is processed and read using data processing and simulation analysis software installed in the control computer 6. and During the temperature adjustment of the blackbody 4, each temperature adjustment must wait until the temperature of the blackbody 4 stabilizes, i.e., the temperature stability of the blackbody 4 (referring to the amount of fluctuation around the set temperature value when the blackbody is working). ≤1mK.

[0028] Step 11, Calculation Signal value of target 3 The calculation formula is as follows: ; Step 12: Obtain a square target 3 and install it on a target position of the electric target wheel 2. The square target 3 is a surface target in the infrared camera 5. The blackbody 4 is controlled by the control computer 6 to achieve a temperature of [temperature value missing]. Infrared camera 5 images the square target 3, and control computer 6 collects the data. The simulated target image of the square target 3 is used to calculate the noise of the infrared camera 5. , The calculation formula is as follows: ; ; Where m is the number of rows in the square target 3-image region; n is the number of columns in the square target 3-image region; N(r,c) is the noise of the pixel in the r-th row and c-th column of the square target 3-image region; r = 1, 2, ..., m; c = 1, 2, ..., n; ; k is the number of frames in the simulated target image of the square target 3, k=1,2,...,p, where ; This is the grayscale value of the pixel in the r-th row and c-th column of the simulated target image of the square target 3 in the k-th frame. This embodiment uses data processing and simulation analysis software to... The simulated target image of the square target 3 is processed to obtain the noise from the infrared camera 5. .

[0029] Step 13, Calculation The signal-to-noise ratio of target 3 The calculation formula is as follows: ; Step 14, according to The signal-to-noise ratio of target 3 The detection range R of infrared camera 5 is obtained through interpolation calculation, thus completing the infrared camera detection range test. If the lowest signal-to-noise ratio of the detectable target is 5, then the interpolation yields... The detection range corresponding to the lowest signal-to-noise ratio of 5 R represents the detection distance of the infrared camera 5 to be tested.

[0030] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An infrared camera detection distance testing device, characterized in that: It includes a collimator (1), an electric target wheel (2), a surface source blackbody (4), and a control computer (6); The collimator (1) has an inlet and an outlet, and an infrared camera mounting position is provided at a preset distance from its outlet for mounting an infrared camera (5); the electric target wheel (2) is located at the inlet of the collimator (1); the electric target wheel (2) has multiple target positions, each of which is used to mount a target (3). The control computer (6) is electrically connected to the electric target wheel (2) and is used to control the automatic switching of multiple target positions so that the target (3) on any one of the multiple target positions is located at the focal plane of the parallel light tube (1). The black body (4) is located on the side of the electric target wheel (2) away from the parallel light tube (1) and is used to irradiate the target (3) located at the focal plane of the parallel tube (1). The radiation aperture of the black body (4) fully covers the target (3) located at the focal plane of the parallel tube (1). The control computer (6) is electrically connected to the black body (4) and is used to control the temperature of the black body (4). The control computer (6) has an interface connected to the infrared camera (5) for receiving infrared images captured by the infrared camera (5).

2. The infrared camera detection distance testing device according to claim 1, characterized in that: The collimator (1) is a total internal reflection type, and its structure is either an off-axis single reflector, an off-axis double reflector, or an off-axis triple reflector.

3. A method for testing the detection distance of an infrared camera, characterized in that, Includes the following steps: Step 1: Construct the infrared camera detection distance testing device as described in claim 1; obtain the infrared camera (5) and install it on the infrared camera mounting position; Step 2, Obtain A diameter of The target (3) is installed on the target position of the electric target wheel (2), and the temperature of the surface source blackbody (4) is adjusted sequentially by the control computer (6). and Each time the temperature is adjusted, the electric target wheel (2) is switched sequentially by the control computer (6). Each target (3) is monitored by an infrared camera (5) at a specific temperature. Imaging is performed on each target (3) to obtain a simulated target image of the corresponding temperature, and the simulated target image of the corresponding temperature is transmitted to the control computer (6) for processing to obtain the temperature. The corresponding pixel grayscale value of the simulated target image and temperature The corresponding pixel grayscale value of the simulated target image ;in, , ; Step 3, Calculation Signal values ​​of each target (3) The calculation formula is as follows: ； Step 4: Obtain a square target (3) and install it on a target position of the electric target wheel (2). The square target (3) is projected as a surface target by the infrared camera (5). The blackbody (4) is controlled by the control computer (6) to achieve a temperature of [temperature value missing]. The infrared camera (5) images the square target (3), and the control computer (6) collects the data. The simulated target image of the square target (3) is used to calculate the noise of the infrared camera (5). , Step 5, Calculation The target signal-to-noise ratio of each target (3) The calculation formula is as follows: ； Step 6, according to The target signal-to-noise ratio of each target (3) The detection distance R of the infrared camera (5) is obtained by interpolation calculation, and the infrared camera detection distance test is completed.

4. The infrared camera detection distance testing method according to claim 3, characterized in that, In step 2, Laboratory temperature A diameter of Target (3) acquisition and The calculation process includes the following steps: Step A1: Determine the theoretical detection distance of the infrared camera (5). The working spectrum range is ; Step A2: Based on the theoretical detection distance ,Sure Each detection distance measurement point ; Step A3, Calculation Each detection distance measurement point In the working spectrum of the infrared camera (5) Within range Average atmospheric transmittance ; Step A4, Obtain There are three target targets (3), each target target (3) corresponds to a detection range measurement point. , The infrared radiation intensity of each target (3) is The target imaging cross-sectional dimensions are all Where L is the length of the target imaging section and M is the width of the target imaging section; Step A5, based on the results obtained in step A3 Average atmospheric transmittance and The infrared radiation intensity of the target (3) ,calculate The irradiance of each target (3) at the entrance pupil of the infrared camera (5) ; Step A6: Based on the target's cross-sectional dimensions ,calculate The diameter of each target (3) According to diameter Cutting 3 targets, and the cropped ones The target (3) is installed on the target position of the electric target wheel (2); Step A7: Set the temperature of the surface source blackbody (4) to... ,calculate The irradiance of each target (3) at the outlet of the collimator (1) ; Step A8, Calculation The required simulated irradiance for each target (3) at the exit of the collimator (1) The calculation formula is as follows: ； Step A9, according to The required simulated irradiance for each target (3) at the exit of the collimator (1) Calculate the irradiance for each irradiance that needs to be simulated. The set temperature of the corresponding surface source blackbody (4) .

5. The infrared camera detection distance testing method according to claim 4, characterized in that, Step A2 is as follows: Step A2.1: Based on the theoretical detection distance The range of the test distance is determined as follows: ; Step A2.2, at the test distance Select at equal intervals within the range Each detection distance measurement point .

6. The infrared camera detection distance testing method according to claim 4, characterized in that, In step A5, the irradiance of the target at the entrance pupil of the infrared camera (5) is calculated. The calculation formula is as follows: 。 7. The infrared camera detection distance testing method according to claim 4, characterized in that, In step A6, the target to be tested needs... Target diameter (3) The calculation formula is as follows: ； in, Let be the focal length of the collimator (1).

8. The infrared camera detection distance testing method according to claim 4, characterized in that, In step A7, the target to be tested... Each detection distance measurement point At the outlet of the collimator (1) irradiance The calculation formula is as follows: ； in, The transmittance of the collimator (1); Let be the focal length of the collimator (1); Let be the emissivity of the surface-source blackbody (4); It is the first radiation constant; It is the second radiation constant; The wavelength of the infrared camera (5) is .

9. The infrared camera detection distance testing method according to claim 3, characterized in that, In step 4, the noise of the infrared camera (5) The calculation formula is as follows: ； ； Where m is the number of rows in the square target (3) image region; n is the number of columns in the square target (3) image region; N(r,c) is the noise of the pixel in the r-th row and c-th column of the square target (3) image region; r = 1, 2, ..., m; c = 1, 2, ..., n; ;k is the number of frames in the simulated target image of the square target (3), k=1,2,...,p, where ; For the simulated target image of the square target (3) in frame k, the gray value of the pixel in row r and column c of the square target (3) image area.

10. The infrared camera detection distance testing method according to claim 8, characterized in that: In step A9 The calculation formula is as follows: 。

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