This standard specifies the measurement method of the photoelectric performance of pyroelectric television cameras. This standard is applicable to the measurement of the photoelectric performance of cameras that use 26mm camera tubes and have an operating wavelength of 8 to 14μm and comply with the provisions of GB12647. GB/T 15303-1994 Pyroelectric Television Camera Measurement Method GB/T15303-1994 Standard Download Decompression Password: www.bzxz.net

UDC 621. 397.61
National Standard of the People's Republic of China
GB/T15303—94
Methods of measurement for
pyroelectric television cameras1994-12-06Promulgated
State Administration of Technical Supervision
Implementation on 1995-07-01
National Standard of the People's Republic of China
Methods of measurement for
pyroelectric television camerasSubject content and scope of application
This standard specifies the measurement method for the optoelectronic performance of pyroelectric television cameras (hereinafter referred to as cameras). GB/T15303—94
This standard is applicable to the measurement of optoelectronic performance of cameras that use 26mm camera tubes and have an operating wavelength of 814μm and comply with the provisions of GB12647.
2 Reference standards
GB12647 Universal application television system
GB/T15302 General technical conditions for pyroelectric television cameras 3 Measuring equipment
3.1 Background black body
Temperature range: 0~100℃,
Black body form: flat type,
Radiance: 8 not less than 0.98
Temperature accuracy: <0.05℃;
Temperature non-uniformity: not more than 2%
3.2 Bar test card (black body)
TV lines: 0~300 lines;
Radiance: 8 not less than 0.98.
3.3 Infrared lens
Relative aperture: 1:1;
Transmittance: not less than 90%.
3.4 ​​Infrared radiation thermometer
Temperature measurement range: 0~100℃;
Temperature measurement accuracy: below 50℃, ±1% of reading value. 3.5 Line-selected oscilloscope
Bandwidth: 0~20MHz
Sensitivity: 10~5mV/cm,
Scanning time factor: 50ns/cm~10ms/cm. 3.6 Monitor
Image resolution: not less than 600 lines;
Brightness identification level: not less than 8 levels;
Approved by the State Administration of Technical Supervision on December 6, 1994 and implemented on July 1, 1995
Image replay rate: 100%
4 Measurement conditions
GB/T15303-94
Unless otherwise specified, the measurement of the optoelectronic performance of the camera shall be carried out under the following conditions. 4.1 Typical measurement conditions:
Temperature: 25±3℃;
Relative humidity: 48%67%;
Air pressure: 86~106kPa.
4.2No strong heat radiation source nearby.
4.3The temperature difference, test card translation speed and scanning area are specified as follows: Temperature difference: The black body temperature is higher than the test card temperature, and the step difference AT0.1℃ increases gradually. Test card translation speed: When working in translation mode, the infrared thermal image of the target moves relatively on the target surface of the camera tube, and the speed is 2~5mm/s. When working in chopping mode, the test card is stationary. Scanning area: 100% overscan, the scanning size of a 26mm pyroelectric camera tube is 18mm×24mm, and the scanning area is 4.3cm25 Measurement method
5.1 Output signal
5.1.1 Measurement arrangement
Connect the measuring equipment according to the method in Figure 1, adjust the distance S between the main plane of the camera lens and the test card, so that 8 is equal to L, which is the focal length of the lens and the width of the test card stripes when L is 17 TV lines, and adjust the lens focus to make the thermal image clear (test card, test distance see Appendix A (Supplement)).
Figure 1 Schematic diagram of the measuring device and connection method
5.1.2 Measurement steps
a. The output end of the camera is connected to a standard resistor of 75 ± 3.75Ω;
b. Use an infrared radiation thermometer to adjust the temperature difference between the test card and the background to 50°C, adjust the lens so that the aperture index F=1, and use an oscilloscope to measure the signal amplitude;
c. Use an oscilloscope to observe the signal polarity.
5.2 Minimum Detectable Temperature Difference (MDTD)
5.2.1 Measurement Arrangement
Connect the measurement equipment according to the method in Figure 1.
5.2.2 Measurement steps
5.2.2.1 Method
Use a test card with 0 TV lines (see Appendix A (Supplement)); b.
GB/T15303—94
Use an infrared thermometer to adjust the temperature difference △T between the test card and the background to 2℃; gradually reduce the lens aperture until the image of the test card can just be distinguished, read the aperture index F at this time, and use formula (1) to calculate the minimum detectable temperature difference. d.
5.2.2.2 Method 2 (Arbitration Method)
Use a test card with 0 TV lines (see Appendix A (Supplement)); a.
Fixed lens aperture index F=1;
.***.(1)
Use an infrared radiation thermometer to gradually increase the temperature difference between the test card and the background by 0.1°C until the image of the test card can just be distinguished. c.
The temperature difference between the test card and the background is the minimum detectable temperature difference MDTD. 5.3 Minimum Resolvable Temperature Difference (MRTD)
5.3.1 Measurement Arrangement
Connect the measurement equipment according to the method in Figure 1.
5.3.2 Measurement steps
5.3.2.1 Method
Use a test card with 100 TV lines;
Use an infrared radiation thermometer to adjust the temperature difference between the test card and the background to 2°C (adjust to 5-10°C when chopping modulation); gradually reduce the lens aperture until the test card stripe image can just be distinguished, and read the aperture index F at this time; use formula (2) to calculate the MRTD at 100 TV lines;AT
(2)
Use a test card with 200 TV lines, repeat steps 5.3.2.1.2 to 5.3.2.1.4, and use formula (2) to calculate the MRTD at 200 TV lines.
5.3.2.2 Method 2 (Arbitration Method)
Use a 100 TV line test card
Fix the lens aperture so that F=1,
Use an infrared radiation thermometer to gradually increase the temperature difference between the test card and the background by 0.1℃ until the test card stripe image can just be distinguished. The temperature difference between the test card and the background is the MRTD at 100 TV lines; d.
Use a 200 TV line test card and repeat steps 5.3.2.2.2~5.3.2.2.3 to read the MRTD at 200 TV lines. 5.4 Maximum Spatial Resolution (MSR)
5.4.1 Measurement Arrangement
Connect the measurement equipment according to the method in Figure 1.
5.4.2 Measurement steps
Fix the lens aperture so that F=1;
Use test cards with different spatial frequencies,
Adjust the temperature difference between the test card and the background to critical saturation, and the number of lines of sight corresponding to the image of the test card with the maximum spatial frequency that can be resolved is the maximum spatial resolution.
5.5 Noise equivalent temperature difference (NETD)
5.5.1 Measurement layout
Connect the measurement equipment and weighting network according to the method in Figure 2. 3
5.5.2 Measurement steps||tt| ... Peak-to-peak value b.
Use formula (3) to calculate the noise equivalent temperature difference (NETD)NETD
-channel current magnification;
Where: K—
RT—temperature response rate of the camera tube, nA/℃. 4
（3）
A1 Test card
A1.1 Test card stripe width calculation formula
GB/T15303-94
Appendix A
Test card, test distance
(Supplement)
Where: L—N (TV line) resolution stripe width, mm; s—distance between the test card and the lens principal plane, mmf——lens focal length,bzxz.net
N—number of TV lines corresponding to the spatial frequency;-effective diameter of the target surface of the pyroelectric camera tube. 17
A1.2Test card production
A1.2.1 Manufacturing method
Process on an aluminum plate with a length of 30mm, a width of 22mm, and a thickness of 4mm, and spray matte black paint on the surface to make: not less than 0.98. Calculate the processing stripe width L according to formula A1) with the integer multiple of 10 N. Process several test cards according to needs. A1.2.2 Test card schematic diagram
Test distance
A2.1 Definition
The distance between the test card and the main plane of the lens.
A2.2 Test distance calculation formula
Where: S——test distance, mm,
N——spatial frequency corresponding to the number of television lines;
N electrical specification
Figure A1 Test card schematic diagram
One test card stripe width corresponding to N, mm; One lens focal length.
(A2)
Additional instructions:
This standard is proposed by the Ministry of Machinery and Electronics Industry. GB/T15303—94
This standard was drafted by the 55th Research Institute of the Ministry of Machinery and Electronics Industry. The main drafters of this standard are Rong Dekang, Yu Hanping and Xi Shucun.
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