542
16 Scientific Instrument Technology of Lunar Lander
Camera to be
tested
Image acquisition
equipment
Temperature
monitoring equipment
Color standard board Standard light source
Colorimeter
Fig. 16.5 Principle diagram of color calibration
Table 16.10 Calibration and
special tests of LUT
Tests
Purpose
Flat fielding calibration
Camera dark current detection
and relative radiation
calibration
Spectral response test
To measure the spectral
response of the camera system
Focal spot test
To measure the size of the focal
spot
Full field imaging test
To test the full field imaging
effect
Ultimate detection capability
test
To detect the ultimate detection
capability
16.5.3 Calibration and Special Testing of LUT
1. Tests
The calibration and special testing of LUT are listed in Table 16.10.
2. Test Principle and Method
1) Principle and method of flat field calibration
The flat field calibration method of LUT was the same of descent camera. The CCD
should be cooled to the predetermined temperature before the dark current detection
and relative radiation calibration. Ultraviolet light source should be used for relative
radiation calibration.
2) Principle and method of spectral response test
The spectral response test was to test the response characteristic of the telescope in
the working band.
The method of spectral response was shown. With different wavelengths of
monochromatic light source and under the condition of same radial brightness,
the CCD was refrigerated to predetermined temperature and images were obtained