This paper describes the design and realization of a refocusing system for a space TDICCD camera of 2.2-meter focal length, which, features a three mirror anastigmatic(TMA) optical system along with 8 TDICCDs assemble at the focal plane, is high resolution and wide field of view. TDICCDs assemble is a kind of major method of acquiring wide field of view for space camera. In this way, the swath width reach 60km. First, the design of TMA optical system and its advantage of this space TDICCD camera was introduced; Then, the refocusing system as well as the technique of mechanical interleaving assemble for TDICCDs focal plane of this space camera was discussed in detail, At last, the refocusing system was measured. Experimental results indicated that the precision of the refocusing system is ± 3.12μm(3σ), which satisfy the refocusing control system requirements of higher precision and stabilization.
As a key technology to improve the imaging quality of remote multispectral CCD camera, the performance of a focusing system for multispectral CCD camera was presented in detail in this paper. Firstly, the focusing precision required was calculated in the optical system. The method of direct adjusting multispectral CCD focal plane was proposed, which was suitable for this multispectral CCD camera optical system. Secondly, we developed a focusing system which has the advantages of lower constructional complexity, easier hardware implementation and high focusing sensitivity. Finally, experimental test was constructed to evaluate the focusing precision performance of the focusing system. The result of focusing precision test is 3.62μm(3σ) in a focusing range of ±2.5mm. The experimental result shows that the focusing system we proposed is reasonable, and reliability as well as stable, which meet the focusing precision requirements for multispectral CCD camera.
Multilinear CCD Sensor was often used on space cameras to obtain multispectral images with each line representing
different band channels. However images of different band channels obtained at the same time didn't coincide as there
were spaces between lines. Pixel numbers to be adjusted between images of different channels varied when the space
camera worked by swaying forward and backward or adjusted row transfer period to compensate image movement. An
automatic multispectral images synthesis algorithm of space camera was put forward on the basis of analysis of such
phenomenon. In this algorithm a new evaluation function was used to determine pixel numbers to be adjusted and the
image regions of each band channel to be clipped. In this way images of different band channels could be synthesized
automatically to obtain an accurate colorful image. This algorithm can be used to dispose a large mount of images from
space camera directly without any manual disposal so that efficiency could be improved remarkably. In validation
experiments the automatic multispectral images synthesis algorithm was applied in synthesis of images obtained from
outside scene experiment of a multispectral space camera. Result of validation experiments proved that the automatic
multispectral images synthesis algorithm can realize accurate multispectral images synthesis of space camera and the
efficiency can be improved markedly.