Infrared emissivity testing device and method based on BRDF model parameter regression

Abstract

The invention relates to an infrared emissivity testing device and method based on BRDF model parameter regression, belongs to the technical field of infrared emissivity measurement, and solves the technical problem that an irradiation reflection method cannot be applied during non-contact measurement of the infrared emissivity of a non-diffuse reflection target. The testing device comprises a box body, a sliding rail, a rotating table, a computer, a blackbody radiation source, an electric control shielding device, an infrared detector, a circuit and a line. The blackbody radiation source and the infrared detector are installed on the sliding rail, the rotating table is located under the highest point of the sliding rail, the electric control shielding device is installed on the blackbody radiation source, and the computer is communicated with the sliding rail, the rotating table, the blackbody radiation source, the electric control shielding device and the infrared detector through lines. The testing method comprises the following steps: acquiring a irradiance calibration formula, acquiring a reflectance sequence, an incidence angle sequence and an emergence angle sequence of a tested target, performing regression processing on parameters of the BRDF model, and calculating the infrared emissivity of the tested target.

Description

Technical Field

[0001] This invention belongs to the field of infrared emissivity measurement technology, specifically relating to an infrared emissivity testing device and method based on BRDF model parameter regression. Background Technology

[0002] Emissivity is an important parameter for measuring an object's ability to radiate at a given temperature, and infrared emissivity is a key parameter for non-contact temperature measurement using infrared detectors. Accurately measuring the infrared emissivity of a target is of great significance for improving the accuracy of infrared temperature measurement and expanding its application range.

[0003] According to the law of conservation of energy and Kirchhoff's radiation law, for a general opaque object, there is a relationship between its emissivity ε and reflectivity ρ, which is ε = 1 - ρ. Therefore, obtaining emissivity indirectly by measuring reflectivity (i.e., the reflection method) has become a widely used method.

[0004] Currently, patent CN114235690A discloses a method and device for measuring the surface infrared emissivity of an aircraft coating. By emitting active radiation towards a diffuse reflective surface target and collecting the reflected radiation energy to solve for the reflectivity, a non-contact measurement of the target's infrared emissivity is achieved, which is called the irradiation reflection method. Patent CN115597718A discloses a method for measuring the infrared emissivity of a curved surface based on the irradiation reflection method. By introducing the physical illumination equation, the application scope of the irradiation reflection method is extended to curved diffuse reflective objects.

[0005] The methods described above are all for diffuse reflective targets. For non-diffuse reflective targets, the irradiation reflection method cannot be applied because the reflectance distribution function (BRDF) is related to the incident and outgoing directions of radiation. Therefore, it is necessary to provide an infrared emissivity testing device and method based on BRDF model parameter regression to solve the problem of non-contact measurement technology for the infrared emissivity of non-diffuse reflective targets. Summary of the Invention

[0006] To achieve non-contact measurement of infrared emissivity of non-diffuse reflective targets, this invention proposes an infrared emissivity testing device and method based on BRDF model parameter regression.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] An infrared emissivity testing device based on BRDF model parameter regression includes a housing, slide rail, rotating stage, computer, blackbody radiation source, electrically controlled shielding device, infrared detector, circuit, and wiring.

[0009] The slide rail, rotating platform, blackbody radiation source, electronically controlled shield, and infrared detector are located inside the enclosure, while the computer is located outside the enclosure.

[0010] The enclosure includes an outer cover and a base, with slide rails and a rotating platform mounted on the base. A blackbody radiation source and an infrared detector are respectively mounted on the slide rails.

[0011] The rotating stage is located directly below the highest point of the slide rail. The rotating stage includes a clamp and a calibration plate. The clamp is used to fix the target under test, and the calibration plate is used to position and calibrate the target under test.

[0012] The computer is connected to the slide rail, rotating platform, blackbody radiation source, electronically controlled shield, and infrared detector via a line used for signal transmission.

[0013] The blackbody radiation source is used to radiate the target under test, the infrared detector is used to obtain the reflectance of the target under test, and the computer is used to control and process the data; the circuit provides power to the slide rail, the rotating table, the computer, the blackbody radiation source, the electronically controlled shield, and the infrared detector.

[0014] The electronically controlled shielding device is installed on the blackbody radiation source to shield the radiation emitted by the blackbody radiation source.

[0015] The infrared emissivity testing device described above includes a slide rail comprising a first sliding mechanism, a second sliding mechanism, a first displacement limiter, and a second displacement limiter, with the first displacement limiter and the second displacement limiter located at both ends of the slide rail, respectively.

[0016] The blackbody radiation source is mounted on the first sliding mechanism, and the infrared detector is mounted on the second sliding mechanism.

[0017] The aforementioned infrared emissivity testing device includes a first line, a second line, a third line, a fourth line, a fifth line, and a sixth line. The first and second lines are used to transmit displacement control signals, the third line is used to transmit blackbody temperature control signals, the fourth line is used to transmit detector measurement signals, the fifth line is used to transmit angular displacement control signals, and the sixth line is used to transmit shielding switch signals.

[0018] The aforementioned infrared emissivity testing device further includes a front cooling fan and a rear cooling fan mounted on the outer casing for heat dissipation. The front cooling fan is located at the air inlet, and the rear cooling fan is located at the air outlet.

[0019] The infrared emissivity testing device described above has an emissivity of over 0.95, with the interior of the housing treated by sandblasting and blackening. The outer cover and base are separable.

[0020] The slide rail is semi-circular, with both ends fixed to the base. The slide rail is marked with graduations. The highest point of the semi-circle is 0°, end point A is -90°, and end point B is 90°. A graduation is marked every fixed angle between the two ends.

[0021] The calibration plate is a circular gold-plated reflector with a reflectivity of 0.98, which is embedded in the surface of the rotating stage.

[0022] The blackbody radiation source is a circular surface blackbody with a diameter of 5cm, an emissivity of 0.99, and a temperature range of 50℃ to 500℃. When a blackbody temperature control signal is received from the third line, the temperature of the blackbody is adjusted.

[0023] The infrared detector is a long-wave infrared thermal imager with a wavelength of 8μm to 12μm. Its output mode is a radiance image, and it transmits the detector measurement signal to the computer through the fourth line.

[0024] An infrared emissivity testing method based on BRDF model parameter regression, utilizing an infrared emissivity testing device, includes the following steps:

[0025] Step 1, Obtain the radiation calibration formula:

[0026] Adjust the positions of the blackbody radiation source, infrared detector, and rotating stage. Measure the radiance reflected by the calibration plate by opening and closing the electronically controlled shield. Calculate the transmittance τ using a computer to obtain the radiance calibration formula.

[0027] Step 2: Obtain the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test.

[0028] Adjust the positions of the blackbody radiation source and the infrared detector, and record the radiance collected by the infrared detector as R. i The incident angle formed by the blackbody radiation source and the test target is v. i The emission angle formed by the test target and the infrared detector is w. i The calibrated irradiance is obtained, and the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test are acquired.

[0029] Step 3: Perform regression processing on the parameters of the BRDF model:

[0030] The first step is BRDF model simplification. Based on the obtained reflectance sequence, incident angle sequence, and exit angle sequence of the tested target, a BRDF model is established. The BRDF model is then simplified into a Cook-Torrance model. The simplification uses the following formula:

[0031]

[0032] In the formula, F(v,w) is the reflectance, v is the incident angle, w is the exit angle, and k is the reflection ratio. dρ and α are model parameters, representing diffuse reflection ratio, macroscopic reflectivity, and macroscopic roughness, respectively. D(v,w,α) is the normal distribution function, G(v,w,α) is the geometric function, and F(w,ρ) is the Fresnel form.

[0033] The second step is to use a computer to obtain sequence C. F C v C w Using the sample, we employ stochastic gradient descent and regression processing to obtain the parameters k of the BRDF model. d0 , ρ0, α0.

[0034] Step 4: Calculate the infrared emissivity of the target being tested.

[0035] The infrared emissivity of the target under test is calculated using BRDF model parameters, and then substituted into the parameter k using a computer. d0 Substituting ρ0 and α0 into the BRDF model, the infrared emissivity ε(θ) of the tested target is calculated as follows:

[0036]

[0037] Thus, the infrared emissivity ε(θ) of the tested target is obtained.

[0038] The infrared emissivity testing method described above, wherein step 1, obtaining the irradiance calibration formula, further includes:

[0039] The first step is to power on the circuit, adjust the positions of the blackbody radiation source, infrared detector, and rotating platform, heat the blackbody radiation source to the set temperature, and open the electronically controlled shielding device.

[0040] The second step involves the infrared detector collecting the radiance reflected from the calibration plate and transmitting it to the computer. The computer then controls the electronically controlled shielding device to turn it off.

[0041] The third step is to use a computer to calculate the transmittance τ based on the radiance reflected by the calibration sheet.

[0042] The fourth step is to obtain the calibration formula for irradiance E, which is calculated as follows:

[0043]

[0044] In the formula, ΔA b Let be the area of ​​the blackbody radiation source, l be the radius of the slide rail, and v be the angle of incidence of the blackbody radiation source onto the rotating platform.

[0045] The infrared emissivity testing method described above, wherein step 2, acquiring the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test, further includes:

[0046] The first step is to install the target under test. Remove the outer cover, place the target under test on the rotating table, secure it with the clamps, and then install the outer cover onto the base.

[0047] The second step involves adjusting the positions of the blackbody radiation source and infrared detector using computer control. The normal direction of the rotating stage is aligned with the 0° mark, and an integer i = 1 is set.

[0048] The third step involves using computer control to open the electronically controlled shielding device and recording the radiance collected by the infrared detector as R. i The incident angle formed by the blackbody radiation source and the test target is v. i The emission angle formed by the test target and the infrared detector is w. i After recording is complete, turn off the electronically controlled shield.

[0049] The calibrated irradiance is obtained using the following formula:

[0050]

[0051] In the formula, E i Let be the irradiance calibrated for the i-th time.

[0052] The reflection ratio F of the i-th time i for:

[0053] F i =R i / E i

[0054] Record F in the computer i v i and w i .

[0055] The fourth step involves adjusting the position of the infrared detector a second time via computer control.

[0056] Fifth step, repeat step three.

[0057] The sixth step involves adjusting the positions of the blackbody radiation source and infrared detector for the third time under computer control. The normal direction of the rotating stage is aligned with the 0° mark, and i = i + 1 is set.

[0058] Step 7: Repeat step 3 for the third time.

[0059] Step 8: Adjust the positions of the blackbody radiation source and infrared detector for the fourth time under computer control. Align the normal direction of the rotating platform with the 0° mark, and set i = i + 1.

[0060] Step 9: Repeat steps 3 and 4 for the fourth time until the position of the second sliding mechanism can no longer be adjusted.

[0061] Step 10: Record the i-th reflection ratio F from the computer. i Arrange them sequentially to obtain the reflectance sequence C. F The recorded i-th incident angle is v. i Arrange them sequentially to obtain the incident angle sequence C. v The recorded i-th emission angle is w. i Arrange them sequentially to obtain the emission angle sequence C. w .

[0062] The infrared emissivity testing method described above, step 1, further includes:

[0063] When the circuit is powered on, the computer controls the first sliding mechanism to move to the -10° mark and the second sliding mechanism to the 10° mark. The rotary table is controlled to align its normal to the 0° mark. The blackbody radiation source is controlled to raise its temperature to 150°C. The electrically controlled shielding device is then opened.

[0064] The infrared emissivity testing method described above, wherein step 2, acquiring the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test, further includes:

[0065] In step 2, the first sliding mechanism is moved to the -30° scale position and the second sliding mechanism is moved to the 0° scale position.

[0066] In step 2, step 4, the position of the second sliding mechanism is increased by 5°.

[0067] In step 2, step 6, the first sliding mechanism is moved to the -45° scale position and the second sliding mechanism is moved to the 0° scale position.

[0068] In step 2, step 8, the first sliding mechanism is moved to the -60° scale position and the second sliding mechanism is moved to the 0° scale position.

[0069] The beneficial effects of this invention are:

[0070] An infrared emissivity testing method based on BRDF model parameter regression is proposed. This method achieves emissivity measurement of non-diffuse reflective targets by fitting BRDF model parameters. It requires fewer measurement points, is simple to operate, and has a wide range of applications.

[0071] An infrared emissivity testing method based on BRDF model parameter regression can obtain the directional emissivity of a target at any angle in a single measurement, resulting in high measurement efficiency.

[0072] An infrared emissivity testing device based on BRDF model parameter regression can calibrate the irradiance of the target surface, eliminate the influence of atmospheric transmission, and improve testing accuracy.

[0073] An infrared emissivity testing device based on BRDF model parameter regression is provided, which can realize non-contact measurement of infrared emissivity and obtain the infrared emissivity distribution of the target surface. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of the external structure of the testing device according to an embodiment of the present invention;

[0075] Figure 2 This is a schematic diagram of the test device structure according to an embodiment of the present invention;

[0076] Figure 3 This is a schematic diagram of the slide rail installation.

[0077] Figure 4 This is a flowchart of the infrared emissivity testing method according to an embodiment of the present invention.

[0078] Reference numerals in the attached drawings: 1. Housing; 11. Outer cover; 12. Base; 111. Front cooling fan; 112. Rear cooling fan; 2. Slide rail; 21. First sliding mechanism; 22. Second sliding mechanism; 23. First displacement limiter; 24. Second displacement limiter; 3. Rotating table; 31. Clamp; 32. Calibration plate; 4. Computer; 5. Blackbody radiation source; 51. Electrically controlled shield; 6. Infrared detector; 7. Circuit; 81. First circuit; 82. Second circuit; 83. Third circuit; 84. Fourth circuit; 85. Fifth circuit; 86. Sixth circuit. Detailed Implementation

[0079] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0080] Example 1

[0081] An infrared emissivity testing device and method based on BRDF model parameter regression is proposed. The device obtains the reflectance of the target at a finite number of incident and exit angles through a blackbody radiation source and an infrared detector. The device obtains the descriptive parameters of the target's reflectance distribution model through a BRDF regression model, and then obtains the directional emissivity of the target in the corresponding infrared band.

[0082] An infrared emissivity testing device based on BRDF model parameter regression, such as Figure 1 , Figure 2As shown, the device includes a housing 1, which consists of an outer cover 11 and a base 12. A front cooling fan 111 and a rear cooling fan 112 are installed on the outer cover 11. A relatively fixed slide rail 2 and a rotating platform 3 are provided on the base 12. A first sliding mechanism 21 and a second sliding mechanism 22 are provided on the slide rail 2. A blackbody radiation source 5 is installed on the first sliding mechanism 21. An electronically controlled shielding device 51 is installed on the blackbody radiation source 5. An infrared detector 6 is installed on the second sliding mechanism 22. A first displacement limiter 23 and a second displacement limiter 24 are also installed at both ends of the slide rail 2. A clamp 31 and a calibration plate 32 are provided on the rotating platform 3.

[0083] The interior of the housing 1 is treated with sandblasting and blackening, and its emissivity is above 0.95. Its reflection characteristics are close to those of a Lambertian reflector. The outer cover 11 and the base 12 of the housing 1 are separable.

[0084] The front cooling fan 111 and the rear cooling fan 112 are of the same specifications and run automatically after being powered on. The front cooling fan 111 is the air intake end, and the rear cooling fan 112 is the air exhaust end.

[0085] like Figure 3 As shown, the slide rail 2 is a semicircle with a radius of 0.5m. Both ends are fixed to the base 12. The slide rail 2 is marked with scales. The highest point of the semicircle is 0°, the endpoint A is -90°, and the endpoint B is 90°. There is a scale mark every 5° between the two ends. The rotating platform 3 is fixed on the base 12 and is located directly below the highest point of the slide rail 2.

[0086] Circuit 7 supplies power to the front cooling fan 111, the rear cooling fan 112, the first sliding mechanism 21, the second sliding mechanism 22, the blackbody radiation source 5, the infrared detector 6, the rotating platform 3, and the electrically controlled shielding device 51.

[0087] The computer 4 controls and processes the data, and connects to the first sliding mechanism 21, the second sliding mechanism 22, the blackbody radiation source 5, the infrared detector 6, the rotating platform 3, and the electrically controlled shielding device 51 via lines 81, 82, 83, 84, 85, and 86, respectively. Lines 81 and 82 transmit displacement control signals, line 83 transmits blackbody temperature control signals, line 84 transmits detector measurement signals, line 85 transmits angular displacement control signals, and line 86 transmits shielding device switching signals.

[0088] After receiving the displacement control signal transmitted by the first line 81, the first sliding mechanism 21 can perform a corresponding linear displacement on the slide rail 2; after receiving the displacement control signal transmitted by the second line 82, the second sliding mechanism 22 can perform a corresponding linear displacement on the slide rail 2. The displacements of the first sliding mechanism 21 and the second sliding mechanism 22 cannot overlap and cannot exceed the displacement limiters 23 and 24.

[0089] After receiving the angular displacement control signal transmitted by the fifth line 85, the rotating stage 3 can rotate the stage surface by the corresponding angle. The clamp 31 can fix the measurement target. The calibration plate 32 is a circular gold-plated reflector with a diameter of 5cm and a reflectivity of 0.98, which is embedded in the stage surface of the rotating stage 3.

[0090] The blackbody radiation source 5 is a circular blackbody with a diameter of 5 cm, an emissivity of 0.99, and a temperature range of 50℃-500℃. After receiving the blackbody temperature control signal transmitted by the third line 83, it can adjust the blackbody to the corresponding temperature. The electrically controlled shielding device 51 can shield the radiation emitted by the blackbody radiation source 5. After receiving the shielding device switch signal transmitted by the sixth line 86, it can switch to the corresponding off or on state.

[0091] Infrared detector 6 is a long-wave infrared thermal imager with a wavelength of 8-12μm. Its output mode is a radiance image, and it transmits the detector measurement signal to computer 4 through line 84.

[0092] An infrared emissivity testing method based on BRDF model parameter regression, such as Figure 4 As shown, the method includes the following steps:

[0093] Step 1, obtain the radiation calibration formula

[0094] (1) When the circuit 7 is powered on, the computer 4 controls the first sliding mechanism 21 to move to the -10° scale position and the second sliding mechanism 22 to move to the 10° scale position, controls the normal direction of the rotating table 3 to align with the 0° scale, controls the blackbody radiation source 5 to rise to 150° (423.15K), and controls the electric shielding device 51 to open.

[0095] At this time, the radiance of blackbody radiation source 5 is:

[0096]

[0097] In the formula, λ is the wavelength, and c1 = 3.7417749 × 10 8 W·μm 4 / m 2 The first radiation constant is c² = 1.438769 × 10⁻⁶. 4 μm·K is the second radiation constant, and T0 = 423.15K is the temperature of the blackbody radiation source 5.

[0098] (2) The infrared detector 6 collects the radiation brightness reflected by the calibration plate 32 and transmits it to the computer 4. The collected reflected radiation brightness is recorded as R0. The computer 4 controls the electronically controlled shield 51 to close.

[0099] (3) The transmittance τ is calculated using computer 4, and the formula is as follows:

[0100]

[0101] In the formula, ρ0 = 0.98 is the reflectivity of calibration plate 32.

[0102] (4) Thus, the radiation calibration formula is obtained:

[0103]

[0104] In the formula, ΔA b Let be the area of ​​the blackbody radiation source 5, l = 0.5m be the radius of the slide rail 2, and v be the angle of incidence of the blackbody radiation source 5 onto the rotating platform 3.

[0105] Step 2: Obtain the target's reflectance sequence, incident angle sequence, and exit angle sequence.

[0106] (1) Remove the outer cover 11, place the test target on the rotating table 3, fix it with the clamp 31, and then install the outer cover 11 onto the base 12.

[0107] (2) The computer 4 controls the first sliding mechanism 21 to move to the -30° scale position and the second sliding mechanism 22 to move to the 0° scale position, controls the normal direction of the rotating table 3 to align with the 0° scale, and sets an integer i = 1.

[0108] (3) The electronically controlled shielding device 51 is opened via computer 4, and the radiance collected by infrared detector 6 is recorded as R. i The incident angle formed by the blackbody radiation source 5 and the test target is v. i The emission angle formed by the test target and infrared detector 6 is w. i The electronically controlled shield 51 is turned off.

[0109] At this point, the irradiance calibrated according to formula (3) is:

[0110]

[0111] Reflectance F i =R i / E i F is recorded in computer 4. i v i and w i .

[0112] (4) The second sliding mechanism 22 is moved by 5° by computer 4, and i = i + 1.

[0113] (5) Repeat process (3) and (4) until the position of the second sliding mechanism 22 can no longer be increased.

[0114] (6) The computer 4 controls the first sliding mechanism 21 to move to the -45° scale position and the second sliding mechanism 22 to move to the 0° scale position, and controls the normal direction of the rotating table 3 to align with the 0° scale, and sets i = i + 1.

[0115] (7) Repeat process (3) and (4) until the position of the second sliding mechanism 22 can no longer be increased.

[0116] (8) The computer 4 controls the first sliding mechanism 21 to move to the -60° scale position and the second sliding mechanism 22 to move to the 0° scale position, and controls the normal direction of the rotating table 3 to align with the 0° scale, and sets i = i + 1.

[0117] (9) Repeat process (3) and (4) until the position of the second sliding mechanism 22 can no longer be increased.

[0118] (10) The reflectance F recorded by computer 4 i Arrange them sequentially to obtain the reflectance sequence C. F The recorded angle of incidence is v. i Arrange them sequentially to obtain the incident angle sequence C. v The recorded exit angle is w. i Arrange them sequentially to obtain the emission angle sequence C. w .

[0119] Step 3: Perform regression analysis on the parameters of the BRDF model.

[0120] (1) The BRDF model used in this embodiment is a simplified Cook-Torrance model:

[0121]

[0122] In the formula, F(v,w) is the reflectance, v is the incident angle, w is the exit angle, and k is the reflection ratio. d ρ and α are model parameters, representing diffuse reflection ratio, macroscopic reflectivity, and macroscopic roughness, respectively. D(v,w,α) is the normal distribution function, G(v,w,α) is the geometric function, and F(w,ρ) is the Fresnel formula.

[0123] (2) In computer 4, sequence C F C v C w Using the sample, the parameters k of the BRDF model are obtained by regression using stochastic gradient descent (SGD). d0 , ρ0, α0.

[0124] Step 4: Calculate the directional emissivity of the target using the BRDF model parameters.

[0125] Using computer 4, substitute parameter k d0Given ρ0 and α0, the directional emissivity ε(θ) of the target is calculated as follows:

[0126]

[0127] Thus, the directional emissivity ε(θ) of the target in the 8-12μm band is obtained.

Claims

1. An infrared emissivity testing device based on BRDF model parameter regression, characterized in that, Includes housing (1), slide rail (2), turntable (3), computer (4), blackbody radiation source (5), electronically controlled shield (51), infrared detector (6), circuit (7), and wiring; The slide rail (2), rotating table (3), blackbody radiation source (5), electronically controlled shielding device (51), and infrared detector (6) are located inside the box (1), while the computer (4) is located outside the box (1). The housing (1) includes an outer cover (11) and a base (12). The slide rail (2) and the rotating platform (3) are mounted on the base (12); the blackbody radiation source (5) and the infrared detector (6) are respectively mounted on the slide rail (2). The rotating stage (3) is located directly below the highest point of the slide rail (2). The rotating stage (3) includes a clamp (31) and a calibration plate (32). The clamp (31) is used to fix the target under test, and the calibration plate (32) is used to position and calibrate the target under test. The computer (4) is connected to the slide rail (2), the rotating table (3), the blackbody radiation source (5), the electronically controlled shield (51), and the infrared detector (6) via a line, which is used to transmit signals. The blackbody radiation source (5) is used to radiate the target under test, the infrared detector (6) is used to obtain the reflectance of the target under test, and the computer (4) is used to control and process data; the circuit (7) is used to power the slide rail (2), the rotating table (3), the computer (4), the blackbody radiation source (5), the electronically controlled shield (51), and the infrared detector (6). The electronically controlled shielding device (51) is installed on the blackbody radiation source (5) to shield the radiation emitted by the blackbody radiation source (5).

2. The infrared emissivity testing device according to claim 1, characterized in that, The slide rail (2) includes a first sliding mechanism (21), a second sliding mechanism (22), a first displacement limiter (23), and a second displacement limiter (24), with the first displacement limiter (23) and the second displacement limiter (24) located at both ends of the slide rail (2); The blackbody radiation source (5) is mounted on the first sliding mechanism (21), and the infrared detector (6) is mounted on the second sliding mechanism (22).

3. The infrared emissivity testing device according to claim 1, characterized in that, The circuit includes a first circuit (81), a second circuit (82), a third circuit (83), a fourth circuit (84), a fifth circuit (85), and a sixth circuit (86); the first circuit (81) and the second circuit (82) are used to transmit displacement control signals, the third circuit (83) is used to transmit blackbody temperature control signals, the fourth circuit (84) is used to transmit detector measurement signals, the fifth circuit (85) is used to transmit angular displacement control signals, and the sixth circuit (86) is used to transmit shielding switch signals.

4. The infrared emissivity testing device according to claim 1, characterized in that, The enclosure (1) also includes a front cooling fan (111) and a rear cooling fan (112). The front cooling fan (111) and the rear cooling fan (112) are mounted on the outer cover (11) for cooling the enclosure (1). The front cooling fan (111) is located at the air inlet end, and the rear cooling fan (112) is located at the air outlet end.

5. The infrared emissivity testing device according to claim 1, characterized in that, The interior of the housing (1) is sandblasted and blackened, with an emissivity of over 0.

95. The outer cover (11) and the base (12) are separable. The slide rail (2) is semi-circular, with both ends fixed to the base (12). The slide rail (2) is marked with scales. The highest point of the semi-circular top is 0°, end point A is -90°, end point B is 90°, and a scale is marked every fixed angle between the two ends. The calibration plate (32) is a circular gold-plated reflector with a reflectivity of 0.98, which is embedded in the table surface of the rotating stage (3); The blackbody radiation source (5) is a circular surface blackbody with a diameter of 5cm, an emissivity of 0.99, and a temperature range of 50℃~500℃. When the blackbody temperature control signal transmitted by the third line (83) is received, the temperature of the blackbody is adjusted. The infrared detector (6) is a long-wave infrared thermal imager with a wavelength of 8μm to 12μm. Its output mode is a radiance image, and it transmits the detector measurement signal to the computer (4) through the fourth line (84).

6. An infrared emissivity testing method based on BRDF model parameter regression, utilizing the infrared emissivity testing device according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1, Obtain the radiation calibration formula: Adjust the positions of the blackbody radiation source (5), infrared detector (6), and rotating stage (3), measure the radiance reflected by the calibration plate (32) by opening and closing the electronically controlled shield (51), calculate the transmittance τ using the computer (4), and obtain the irradiance calibration formula. Step 2: Obtain the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test. Adjust the positions of the blackbody radiation source (5) and the infrared detector (6), and record the radiance collected by the infrared detector (6) as R. i The incident angle formed by the blackbody radiation source (5) and the test target is v. i The emission angle formed by the test target and the infrared detector (6) is w. i The calibrated irradiance is obtained, and the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test are acquired. Step 3: Perform regression processing on the parameters of the BRDF model: The first step is to simplify the BRDF model. Based on the obtained reflectance sequence, incident angle sequence, and exit angle sequence of the tested target, a BRDF model is established. The BRDF model is then simplified into a Cook-Torrance model. The simplification uses the following formula: In the formula, F(v,w) is the reflectance, v is the incident angle, w is the exit angle, and k is the reflection ratio. d ρ and α are model parameters, representing diffuse reflection ratio, macroscopic reflectivity, and macroscopic roughness, respectively. D(v,w,α) is the normal distribution function, G(v,w,α) is the geometric function, and F(w,ρ) is the Fresnel form. The second step is to use a computer (4) to sequence C. F C v C w Using the sample, we employ stochastic gradient descent and regression processing to obtain the parameters k of the BRDF model. d0 , ρ0, α0; Step 4: Calculate the infrared emissivity of the target being tested. The infrared emissivity of the target under test is calculated using the BRDF model parameters. Then, the result is processed by a computer (4), with the parameter k substituted into the model. d0 Substituting ρ0 and α0 into the BRDF model, the infrared emissivity ε(θ) of the tested target is calculated as follows: Thus, the infrared emissivity ε(θ) of the tested target is obtained.

7. The infrared emissivity testing method according to claim 6, characterized in that, Step 1, obtaining the irradiance calibration formula, further includes: First, the circuit (7) is powered on and the positions of the blackbody radiation source (5), infrared detector (6), and rotating platform (3) are adjusted. The blackbody radiation source (5) is heated to the set temperature and the electronically controlled shield (51) is in the open state. The second step involves the infrared detector (6) collecting the radiance reflected from the calibration plate (32) and transmitting it to the computer (4). The electronically controlled shield (51) is controlled by computer (4) to turn off the electronically controlled shield (51); The third step is to use a computer (4) to calculate the transmittance τ based on the radiance reflected by the calibration plate (32). The fourth step is to obtain the calibration formula for irradiance E, which is calculated as follows: In the formula, ΔA b Let l be the area of ​​the blackbody radiation source (5), l be the radius of the slide rail (2), and v be the incident angle of the blackbody radiation source (5) on the rotating platform (3).

8. The infrared emissivity testing method according to claim 7, characterized in that, Step 2, which involves obtaining the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test, further includes: First step, install the target to be tested; remove the outer cover (11), place the target to be tested on the rotating table (3), fix it with the clamp (31), and then install the outer cover (11) onto the base (12); The second step is to adjust the positions of the blackbody radiation source (5) and the infrared detector (6) by controlling the computer (4); Align the normal direction of the rotating stage (3) with the 0° mark, and set an integer i = 1; The third step involves using a computer (4) to open the electronically controlled shield (51) and recording the radiance collected by the infrared detector (6) as R. i The incident angle formed by the blackbody radiation source (5) and the test target is v. i The emission angle formed by the test target and the infrared detector (6) is w. i After recording is complete, turn off the electronically controlled shield (51); The calibrated irradiance is obtained using the following formula: In the formula, E i Let be the irradiance calibrated for the i-th time; The reflection ratio F of the i-th time i for: F i =R i / E i Record F in computer (4) i v i and w i ; The fourth step involves adjusting the position of the infrared detector (6) for the second time using computer (4) control. Fifth step, repeat step three; Step 6: Controlled by computer (4), adjust the positions of blackbody radiation source (5) and infrared detector (6) for the third time; control the normal direction of the rotating stage (3) to align with the 0° scale, and set i = i + 1; Step 7: Repeat step 3 for the third time; Step 8: Controlled by computer (4), adjust the positions of blackbody radiation source (5) and infrared detector (6) for the fourth time; control the normal direction of the rotating stage (3) to align with the 0° scale, and set i = i + 1; Step 9: Repeat steps 3 and 4 for the fourth time until the position of the second sliding mechanism (22) cannot be adjusted. Step 10: Record the i-th reflection ratio F from the computer (4). i Arrange them sequentially to obtain the reflectance sequence C. F The recorded i-th incident angle is v. i Arrange them sequentially to obtain the incident angle sequence C. v The recorded i-th emission angle is w. i Arrange them sequentially to obtain the emission angle sequence C. w .

9. The infrared emissivity testing method according to claim 8, characterized in that, Step 1, the first step, further includes: When the circuit (7) is powered on, the computer (4) controls the first sliding mechanism (21) to move to the -10° scale position and the second sliding mechanism (22) to the 10° scale position; controls the rotating table (3) so that the normal direction of the rotating table (3) is aligned with the 0° scale; controls the blackbody radiation source (5) so that the temperature of the blackbody radiation source (5) rises to 150°; and controls the electric shielding device (51) to open.

10. The infrared emissivity testing method according to claim 9, characterized in that, Step 2, which involves obtaining the reflectance sequence, incident angle sequence, and exit angle sequence of the target under test, further includes: In the second step, the first sliding mechanism (21) is moved to the -30° scale position and the second sliding mechanism (22) is moved to the 0° scale position; In the fourth step, the position of the second sliding mechanism (22) is increased by 5°; In the sixth step, the first sliding mechanism (21) is moved to the -45° scale position and the second sliding mechanism (22) is moved to the 0° scale position; In the eighth step, the first sliding mechanism (21) is moved to the -60° scale position and the second sliding mechanism (22) is moved to the 0° scale position.

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