Method and system for measuring and calculating signal-to-noise ratio of uncooled infrared detection system

Abstract

The invention discloses a method and a system for measuring and calculating a signal-to-noise ratio of an uncooled infrared detection system, relates to the technical field of infrared target detection, and solves the problems that parameters of an uncooled detector are lost during research and development of a low-cost infrared system and detection effects of different view field angles of a large-view-field system are different. The radiance at the entrance pupil is calculated through the target radiance and the atmospheric transmittance, the irradiance and the illuminance from the pupil to the center of an image plane are derived based on optical system parameters, the irradiance related to a field angle is obtained according to a geometrical relationship for large-field edge illuminance attenuation, and the irradiance related to the field angle is obtained according to a geometrical relationship for a point target which is not filled with a photosensitive element. Calculating the projection on the photosensitive element and the signal radiation quantity received by the pixel; the noise equivalent temperature difference is tested by adopting a collimation method, and the value is obtained by combining a collimator and the spectral transmittance of an optical system so as to calculate the noise power; and the signal-to-noise ratio is calculated by combining the signal amplitude-flux. The method solves the problem of parameter loss through actually measured noise equivalent temperature difference value estimation, considers view field energy attenuation in the evaluation process, and is suitable for fine evaluation of a large view field system.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared target detection, and in particular to a method and system for measuring the signal-to-noise ratio of an uncooled infrared detection system. Background Art

[0002] In the field of infrared target detection, the signal-to-noise ratio (SNR) is often used to evaluate system performance. When the SNR exceeds a set threshold, the system is considered to be able to effectively detect the target. Existing evaluation techniques simulate the target's radiation intensity and calculate the signal power at the center of the field of view. This is converted into the number of signal electrons using the detector's quantum efficiency to obtain the target signal. The noise intensity is then calculated using parameters such as detectivity, bandwidth, dark current noise, readout noise, and quantization noise provided by the detector manufacturer.

[0003] Existing infrared detection system evaluation techniques are mostly targeted at cooled detector systems with large apertures and small fields of view. Manufacturers of cooled detectors provide detailed parameters and do not consider attenuation at the edges of the field of view. Low-cost uncooled detectors often provide less comprehensive parameters due to commercial confidentiality concerns, making it impossible to calculate noise intensity based on these manufacturer-provided parameters. Summary of the Invention

[0004] The technical solution of the present invention is used to solve the problems of missing parameters of non-cooled detectors during the development of low-cost infrared systems and differences in detection effects at different field of view angles in large field of view systems.

[0005] The present invention solves the above technical problems by the following technical means: a method for measuring the signal-to-noise ratio of an uncooled infrared detection system, comprising the following steps: S1. Calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation. S2. Based on the optical system parameters that satisfy the Abbe sine condition, derive the irradiance from the pupil to the center of the image plane and the central field of view illuminance. For the attenuation of the edge illumination of the large field of view optical system, obtain the irradiance associated with the field of view angle based on the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that do not fill the photosensitive element, calculate the projection of the point target on the photosensitive element. Calculate the radiant flux of the point target signal received by the pixel based on the irradiance associated with the field of view angle and the projection of the point target on the photosensitive element. S3. Use the collimation method to test the noise equivalent temperature difference. Set the integration time of the camera system to the integration time when performing the target detection task. Collect blackbody data for testing after collimation through a collimator. Based on the spectral transmittance of the collimator, obtain the noise equivalent temperature difference at the entrance pupil of the camera optical system or the noise equivalent temperature difference at the entrance pupil of the collimator. S4. Calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, the spectral transmittance of the optical system, the spectral transmittance of the collimator, the instantaneous solid angle of view, the blackbody temperature and its spectral differential radiance; S5. Calculate the target detection signal-to-noise ratio by combining the target signal radiant flux of the pixel receiving point calculated in step S2 and the noise power tested in step S4.

[0006] The present invention adopts the collimation method to collect blackbody data, sets the integration time of the camera system to be tested to the integration time when performing the target detection task, and obtains the noise equivalent temperature difference value in combination with the spectral transmittance, thereby improving the reliability of the test results and being able to comprehensively evaluate the characteristics of the noise.

[0007] Furthermore, the calculation formula for the radiance reaching the entrance pupil is:

[0008] in, is the atmospheric transmittance, is the target radiance.

[0009] The present invention can accurately evaluate the loss of target energy during atmospheric transmission by calculating the radiance of the target reaching the entrance pupil after atmospheric attenuation.

[0010] Furthermore, the calculation formula for the irradiance from the exit pupil to the center of the image plane is:

[0011] in, is the transmittance of the optical system, is the maximum aperture angle on the image side, when the radiance reaches the entrance pupil When the value is constant, the irradiance at the center of the image plane is proportional to the square of the sine of the maximum aperture angle on the image side.

[0012] Furthermore, the calculation formula for the central field of view illuminance is:

[0013] Among them, in a large field of view optical system, the relative aperture , , is the focal length, is the entrance pupil diameter; because , thus obtaining the following formula: .

[0014] Furthermore, the calculation formula of the irradiance related to the field of view angle is:

[0015] Among them, for the edge illumination attenuation of the large field of view optical system, according to the aperture angle at the edge of the field of view Aperture angle at the center of the image plane The geometric relationship is , is the field of view angle.

[0016] Furthermore, the calculation formula for the projection of the point target on the photosensitive element is as follows:

[0017] in, is the point target area, R is the distance to the point target.

[0018] Furthermore, the calculation formula of the target signal radiant flux at the pixel receiving point is as follows: .

[0019] The present invention is based on optical system parameters that satisfy the Abbe sine condition, derives the pupil-to-center irradiance and the central field of view illuminance, ensures that the optical system design complies with the imaging principle, and for the attenuation of edge illumination in a large field of view optical system, obtains the irradiance related to the field of view angle according to the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane, which can comprehensively evaluate the energy distribution in the field of view. For point targets that are not filled with photosensors, the projection of the point target on the photosensor is calculated, and the radiant flux of the point target signal received by the pixel is calculated based on the irradiance related to the field of view angle and the projection of the target on the photosensor, which can accurately evaluate the reception of the point target signal.

[0020] Furthermore, the noise power is calculated as follows:

[0021] in, is the noise equivalent temperature difference at the entrance pupil of the camera optical system, is the noise equivalent temperature difference at the entrance pupil of the collimator, For the band, ∈[ , , is the entrance pupil area, is the spectral transmittance of the optical system, is the spectral transmittance of the collimator. When the wavelength is constant, the two can be constants. is the instantaneous solid angle of view, is the blackbody temperature corresponding to the noise equivalent temperature difference, For a black body at temperature The spectral differential radiance at .

[0022] The present invention can accurately calculate the noise power based on the noise equivalent temperature difference value obtained by testing, combined with the entrance pupil area, the spectral transmittance of the optical system, the spectral transmittance of the collimator, the instantaneous field of view solid angle, the blackbody temperature and its spectral differential radiance.

[0023] Furthermore, the target detection signal-to-noise ratio is calculated as follows:

[0024] in, is the detector integration time.

[0025] The present invention combines the calculated pixel receiving point target signal amplitude flux and the tested noise power to finally calculate the signal-to-noise ratio, quantify the system detection limit, and guide parameter optimization.

[0026] The present invention also provides a signal-to-noise ratio measurement system for an uncooled infrared detection system, comprising the following modules: The energy calculation module at the entrance pupil is used to calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation; The field of view signal power calculation module is used to derive the irradiance from the pupil to the center of the image plane and the central field of view illuminance based on the optical system parameters that satisfy the Abbe sine condition. For the attenuation of the edge illumination of the large field of view optical system, the irradiance related to the field of view angle is obtained according to the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that are not filled with photosensitive elements, the projection of the point target on the photosensitive element is calculated. The radiant flux of the point target signal received by the pixel is calculated based on the irradiance related to the field of view angle and the projection of the point target on the photosensitive element. The noise equivalent temperature difference test module is used to test the noise equivalent temperature difference using the collimation method. The integration time of the camera system to be tested is set to the integration time when performing the target detection task. Blackbody data is collected after collimation through a collimator for testing. Based on the spectral transmittance of the collimator, the noise equivalent temperature difference value at the entrance pupil of the camera optical system or the noise equivalent temperature difference value at the entrance pupil of the collimator is obtained; The noise power estimation module is used to calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, optical system spectral transmittance, collimator spectral transmittance, instantaneous field of view solid angle, blackbody temperature and its spectral differential radiance; The detection signal-to-noise ratio calculation module is used to calculate the target detection signal-to-noise ratio by combining the target signal radiance of the pixel receiving point calculated by the field of view signal power calculation module and the noise power tested by the noise power estimation module.

[0027] Furthermore, the calculation formula for the radiance reaching the entrance pupil is:

[0028] in, is the atmospheric transmittance, is the target radiance.

[0029] Furthermore, the calculation formula for the irradiance from the exit pupil to the center of the image plane is:

[0030] in, is the transmittance of the optical system, is the maximum aperture angle on the image side, when the radiance reaches the entrance pupil When the value is constant, the irradiance at the center of the image plane is proportional to the square of the sine of the maximum aperture angle on the image side.

[0031] Furthermore, the calculation formula for the central field of view illuminance is:

[0032] Among them, in a large field of view optical system, the relative aperture , , is the focal length, is the entrance pupil diameter; because , thus obtaining the following formula: .

[0033] Furthermore, the calculation formula of the irradiance related to the field of view angle is:

[0034] Among them, for the edge illumination attenuation of the large field of view optical system, according to the aperture angle at the edge of the field of view Aperture angle at the center of the image plane The geometric relationship is , is the field of view angle.

[0035] Furthermore, the calculation formula for the projection of the point target on the photosensitive element is as follows:

[0036] in, is the point target area, R is the distance to the point target.

[0037] Furthermore, the calculation formula of the target signal radiant flux at the pixel receiving point is as follows: .

[0038] Furthermore, the noise power is calculated as follows:

[0039] in, is the noise equivalent temperature difference at the entrance pupil of the camera optical system, is the noise equivalent temperature difference at the entrance pupil of the collimator, For the band, ∈[ , , is the entrance pupil area, is the spectral transmittance of the optical system, is the spectral transmittance of the collimator. When the wavelength is constant, the two can be constants. is the instantaneous solid angle of view, is the blackbody temperature corresponding to the noise equivalent temperature difference, For a black body at temperature The spectral differential radiance at .

[0040] Furthermore, the target detection signal-to-noise ratio is calculated as follows:

[0041] in, is the detector integration time.

[0042] The advantages of the present invention are: The present invention obtains the noise equivalent temperature difference through testing, solves the problem of missing parameters, and makes the performance evaluation results more accurate. During the evaluation process, the edge illumination attenuation of the large field of view optical system is taken into account, and the missing or inaccurate noise signals of the system are estimated through laboratory measurements, thereby realizing a refined evaluation of the detection performance of the system in different fields of view. The present invention can provide a reference for the design, selection, and indicator evaluation of infrared detection systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of a method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to embodiment 1 of the present invention; Figure 2 This is a diagram of the exit pupil and image plane of the large field of view system in Example 1 of the present invention; Figure 3 This is a schematic diagram of the NETD testing equipment of Example 1 of the present invention. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0045] Example 1 like Figure 1 The flowchart of the method for calculating the signal-to-noise ratio of an uncooled infrared detection system is shown, which includes the following steps: S1. Calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation. Assume that the target radiance is After atmospheric attenuation, the radiance calculation formula reaching the entrance pupil is:

[0046] in, is the atmospheric transmittance.

[0047] S2. Based on the optical system parameters that satisfy the Abbe sine condition, derive the pupil-to-image center irradiance and the central field of view illuminance. For the attenuation of edge illumination in a large field of view optical system, obtain the irradiance associated with the field of view angle based on the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that do not fill the photosensitive element, calculate the projection of the point target on the photosensitive element. Calculate the radiant flux of the point target signal received by the pixel based on the irradiance associated with the field of view angle and the projection of the point target on the photosensitive element. First, assume that there is a well-corrected lens that satisfies the Abbe sine condition and focuses a uniform Lambertian light source onto a focal plane detector. Given the radiance of the target at the entrance pupil of the optical system, the irradiance from the exit pupil to the center of the image plane can be expressed as:

[0048] in, is the transmittance of the optical system, is the maximum aperture angle on the image side. When the value is constant, the irradiance from the exit pupil to the center of the image plane is proportional to the square of the sine of the maximum aperture angle on the image side.

[0049] For optical systems with a large field of view, such as Figure 2 The figure shows the exit pupil and image plane of a large field of view system. The F number is often small, and the relative aperture , the calculation formula for the central field of view illuminance is:

[0050] Where F is the effective F number, , is the focal length, is the entrance pupil diameter.

[0051] because , thus obtaining the following formula:

[0052] The edge illumination attenuation of the large field of view optical system is relatively serious, based on the aperture angle at the edge of the field of view. Aperture angle at the center of the image plane The geometric relationship is , and the field of view angle The associated irradiance is:

[0053] When the size of the target is much smaller than the field of view of the photosensitive element, the target can be regarded as a point target. When the field of view of the photosensitive element is not filled, the projection calculation formula of the point target on the photosensitive element is:

[0054] in, is the point target area, R is the distance to the point target.

[0055] The calculation formula for the target signal radiant flux at the pixel receiving point is: .

[0056] S3. Use the collimation method to test the noise equivalent temperature difference. Set the integration time of the camera system to the integration time when performing the target detection task. Collect blackbody data for testing after collimation through a collimator. Based on the spectral transmittance of the collimator, obtain the noise equivalent temperature difference at the entrance pupil of the camera optical system or the noise equivalent temperature difference at the entrance pupil of the collimator. In the process of comparing and selecting infrared cameras for actual engineering applications, the system-level noise of the camera can be obtained more accurately through experimental testing. The noise equivalent temperature difference test is conducted under laboratory conditions using the collimation method, and the test equipment is as follows: Figure 3 As shown, the integration time of the camera system to be tested is set to the integration time when performing the target detection task. The blackbody data is collected after collimation through a collimator for testing. The test method refers to the national standard "Infrared Focal Plane Array Parameter Test Method". The spectral transmittance of the collimator needs to be considered in the calculation. The noise equivalent temperature difference obtained by the test is the value at the entrance pupil of the camera optical system. Or collimator entrance pupil The collimation method uses parallel light to simulate distant targets, allowing the optical system to be tested under laboratory conditions to equivalently test the characteristics of actual detection scenarios.

[0057] S4. Calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, the spectral transmittance of the optical system, the spectral transmittance of the collimator, the instantaneous solid angle of view, the blackbody temperature and its spectral differential radiance; The calculation formula of the noise power is:

[0058] in, is the noise equivalent temperature difference at the entrance pupil of the camera optical system, is the noise equivalent temperature difference at the entrance pupil of the collimator, For the band, ∈[ , , is the entrance pupil area, is the spectral transmittance of the optical system, is the spectral transmittance of the collimator, is the instantaneous solid angle of view, is the blackbody temperature corresponding to the noise equivalent temperature difference, For a black body at temperature The spectral differential radiance at , in units .

[0059] S5. Calculate the target detection signal-to-noise ratio (SNR) by combining the target signal radiant flux at the pixel receiving point calculated in step S2 and the noise power measured in step S4. The target detection SNR is calculated as follows:

[0060] in, is the detector integration time.

[0061] Calculation example: The input parameters are shown in Table 1: Table 1 Parameters of the detection system to be evaluated

[0062] S1. Calculation of radiance reaching the entrance pupil:

[0063] S2. Calculation of target signal radiance at pixel receiving point The calculation of irradiance related to field of view angle is:

[0064] in The range is -57.5°~57.5°. The projection of a point target on the image plane photosensitive element can be calculated as:

[0065] The calculation formula for the target signal radiant flux at the pixel receiving point is:

[0066] S3. Use the collimation method to test the noise equivalent temperature difference. Set the integration time of the camera system to the integration time when performing the target detection task. Collect blackbody data for testing after collimation through a collimator. Based on the spectral transmittance of the collimator, obtain the noise equivalent temperature difference at the entrance pupil of the camera optical system or the noise equivalent temperature difference at the entrance pupil of the collimator. Refer to the national standard "Infrared focal plane array parameter test method", at the black body temperature When the test is completed, the system .

[0067] S4. Calculate the noise power:

[0068]

[0069]

[0070] S5. Detection signal-to-noise ratio calculation:

[0071] From this we can see that at the center field angle When the signal-to-noise ratio is 10.61; at the edge of the field of view When , the signal-to-noise ratio is 0.88.

[0072] Example 2 The present invention also provides a signal-to-noise ratio measurement system for an uncooled infrared detection system, comprising the following modules: The energy calculation module at the entrance pupil is used to calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation; The calculation formula of the radiance reaching the entrance pupil is:

[0073] in, is the atmospheric transmittance, is the target radiance.

[0074] The field of view signal power calculation module is used to derive the irradiance from the pupil to the center of the image plane and the central field of view illuminance based on the optical system parameters that satisfy the Abbe sine condition. For the attenuation of the edge illumination of the large field of view optical system, the irradiance related to the field of view angle is obtained according to the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that are not filled with photosensitive elements, the projection of the point target on the photosensitive element is calculated. The radiant flux of the point target signal received by the pixel is calculated based on the irradiance related to the field of view angle and the projection of the point target on the photosensitive element. The calculation formula for the irradiance from the exit pupil to the center of the image plane is:

[0075] in, is the transmittance of the optical system, is the maximum aperture angle on the image side, when the radiance reaches the entrance pupil When the value is constant, the irradiance at the center of the image plane is proportional to the square of the sine of the maximum aperture angle on the image side.

[0076] The calculation formula for the central field of view illuminance is:

[0077] Among them, in a large field of view optical system, the relative aperture , , is the focal length, is the entrance pupil diameter; because , thus obtaining the following formula:

[0078] The calculation formula of irradiance related to field of view angle is:

[0079] Among them, according to the aperture angle at the edge of the field of view Aperture angle at the center of the image plane The geometric relationship is , is the field of view angle.

[0080] When the target is a point target and does not fill the field of view of the photosensitive element, the calculation formula for the point target's projection on the photosensitive element is as follows:

[0081] in, is the point target area, R is the distance to the point target.

[0082] The calculation formula of the target signal radiant flux of the pixel receiving point is as follows: .

[0083] The noise equivalent temperature difference test module is used to test the noise equivalent temperature difference using the collimation method. The integration time of the camera system to be tested is set to the integration time when performing the target detection task. Blackbody data is collected after collimation through a collimator for testing. Based on the spectral transmittance of the collimator, the noise equivalent temperature difference value at the entrance pupil of the camera optical system or the noise equivalent temperature difference value at the entrance pupil of the collimator is obtained; The noise power estimation module is used to calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, optical system spectral transmittance, collimator spectral transmittance, instantaneous field of view solid angle, blackbody temperature and its spectral differential radiance;

[0084] in, is the noise equivalent temperature difference at the entrance pupil of the camera optical system, is the noise equivalent temperature difference at the entrance pupil of the collimator, For the band, ∈[ , , is the entrance pupil area, is the spectral transmittance of the optical system, is the spectral transmittance of the collimator. When the wavelength is constant, the two can be constants. is the instantaneous solid angle of view, is the blackbody temperature corresponding to the noise equivalent temperature difference, For a black body at temperature The spectral differential radiance at .

[0085] The detection signal-to-noise ratio calculation module is used to calculate the target detection signal-to-noise ratio by combining the target signal radiance of the pixel receiving point calculated by the field of view signal power calculation module and the noise power tested by the noise power estimation module.

[0086] The target detection signal-to-noise ratio is calculated as follows:

[0087] in, is the detector integration time.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for calculating the signal-to-noise ratio of an uncooled infrared detection system, characterized in that: The following steps are involved: S1. Calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation. S2. Based on the optical system parameters that satisfy the Abbe sine condition, derive the irradiance from the pupil to the center of the image plane and the central field of view illuminance. For the attenuation of the edge illumination of the large field of view optical system, obtain the irradiance associated with the field of view angle based on the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that do not fill the photosensitive element, calculate the projection of the point target on the photosensitive element. Calculate the radiant flux of the point target signal received by the pixel based on the irradiance associated with the field of view angle and the projection of the point target on the photosensitive element. S3. Use the collimation method to test the noise equivalent temperature difference. Set the integration time of the camera system to the integration time when performing the target detection task. Collect blackbody data for testing after collimation through a collimator. Based on the spectral transmittance of the collimator, obtain the noise equivalent temperature difference at the entrance pupil of the camera optical system or the noise equivalent temperature difference at the entrance pupil of the collimator. S4. Calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, the spectral transmittance of the optical system, the spectral transmittance of the collimator, the instantaneous solid angle of view, the blackbody temperature and its spectral differential radiance; S5. Calculate the target detection signal-to-noise ratio by combining the target signal radiant flux of the pixel receiving point calculated in step S2 and the noise power tested in step S4.

2. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The calculation formula of the radiance reaching the entrance pupil is: in, is the atmospheric transmittance, is the target radiance.

3. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The calculation formula of the irradiance from the exit pupil to the center of the image plane is: in, is the transmittance of the optical system, is the maximum aperture angle on the image side, when the radiance reaches the entrance pupil When the value is constant, the irradiance at the center of the image plane is proportional to the square of the sine of the maximum aperture angle on the image side.

4. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The calculation formula of the central field of view illuminance is: Among them, in a large field of view optical system, the relative aperture , , is the focal length, is the entrance pupil diameter; because , thus obtaining the following formula: 。 5. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 4, wherein: The calculation formula of the irradiance related to the field of view angle is: Among them, for the edge illumination attenuation of the large field of view optical system, according to the aperture angle at the edge of the field of view Aperture angle at the center of the image plane The geometric relationship is , is the field of view angle.

6. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The calculation formula for the projection of the point target on the photosensitive element is as follows: in, is the point target area, R is the distance to the point target.

7. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 6, characterized in that: The calculation formula of the target signal radiant flux of the pixel receiving point is as follows: 。 8. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The calculation formula of the noise power is: in, is the noise equivalent temperature difference at the entrance pupil of the camera optical system, is the noise equivalent temperature difference at the entrance pupil of the collimator, For the band, ∈[ , , is the entrance pupil area, is the spectral transmittance of the optical system, is the spectral transmittance of the collimator, is the instantaneous solid angle of view, is the blackbody temperature corresponding to the noise equivalent temperature difference, For a black body at temperature The spectral differential radiance at .

9. The method for calculating the signal-to-noise ratio of an uncooled infrared detection system according to claim 1, wherein: The target detection signal-to-noise ratio is calculated as follows: in, is the detector integration time.

10. The signal-to-noise ratio measurement system of the uncooled infrared detection system is characterized by: Includes the following modules: The energy calculation module at the entrance pupil is used to calculate the radiance at the entrance pupil based on the target radiance and the transmittance after atmospheric attenuation; The field of view signal power calculation module is used to derive the irradiance from the pupil to the center of the image plane and the central field of view illuminance based on the optical system parameters that satisfy the Abbe sine condition. For the attenuation of the edge illumination of the large field of view optical system, the irradiance related to the field of view angle is obtained according to the geometric relationship between the aperture angle at the edge of the field of view and the aperture angle at the center of the image plane. For point targets that are not filled with photosensitive elements, the projection of the point target on the photosensitive element is calculated. The radiant flux of the point target signal received by the pixel is calculated based on the irradiance related to the field of view angle and the projection of the point target on the photosensitive element. The noise equivalent temperature difference test module is used to test the noise equivalent temperature difference using the collimation method. The integration time of the camera system to be tested is set to the integration time when performing the target detection task. Blackbody data is collected after collimation through a collimator for testing. Based on the spectral transmittance of the collimator, the noise equivalent temperature difference value at the entrance pupil of the camera optical system or the noise equivalent temperature difference value at the entrance pupil of the collimator is obtained; The noise power estimation module is used to calculate the noise power based on the noise equivalent temperature difference value obtained from the test, combined with the entrance pupil area, optical system spectral transmittance, collimator spectral transmittance, instantaneous field of view solid angle, blackbody temperature and its spectral differential radiance; The detection signal-to-noise ratio calculation module is used to calculate the target detection signal-to-noise ratio by combining the target signal radiance of the pixel receiving point calculated by the field of view signal power calculation module and the noise power tested by the noise power estimation module.

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