Research On Imaging Uniformity Of Remote Camera With Wide Field Of View

China stretches across a vast territory with diversiform landscape. It is very important for economic development and national security to obtain detailed landscape of wide area about agriculture, forestry, animal husbandry and fishery in good time. Therefore, it is imperative under the situation to research and develop remote camera with wide-field-of-view (WFOV). As a topic of pre-research, imaging uniformity affects the image quality and subjective distinguishing effect, so that it is significant to the development of remote sensing.This paper focuses on the topic of how to ensure imaging quality from each process of remote camera to subsequent image uniformization. The whole pre-research follows the idea: design is foundation, correction is compensatory. In this paper, many functional module are incorporated on FPGA including imaging, correcting, self-check, etc. The primary coverage of this paper is as follows:First, the structure and principle of CCD detectors are introduced. This paper explains the push-scanning imaging principle through the analysis of detectors'clamp voltage and driving timing phase. From research on each parts of CCD image system, several subsystems which is the potential non-uniformity factor are enumerated for deep research.Second, with a view to hardware design, this paper elaborates on each subsystem's uniformity, including the CCD analog front-end circuit, distributed power supply, system clock network, etc. Especially, the paper researches intensively the drive-timing first-backup-switch module and excogitates the design techniques such as pins-place rules, operating conditions and supply voltage. Hardware identifying of different FPGA processors is insisted as basic precondition of multi-imaging-unit's uniformity. Afterward, software design is discussed deeply concerning the uniformity of timing signals which are impressible to CCD imaging. In addition, line-frequency precision of CCD push-scanning is touched upon in this paper.Third, residual non-uniformity after hardware design is settled as remedy of camera imaging uniformity. First of all, we adopt two-point correction arithmetic to establish the structure of correction data matrix, and succeed in simulation in MATLAB for a foregone non-uniform image. Then we utilize the parallel operating advantage of FPGA to define the multiplication and analyze the calculation error. On this condition, this paper achieves the purpose of non-uniformity correction for a image obtained in uniform luminance. After indispensable research of engineering, we carried out an experiment in TDI push-scanning operating mode to test the effect of correction and proved out.Fourth, self-check circuit is necessary for remote camera. This paper provides several solutions which aim at detectors'supply voltage monitor, analog self-check figure for video AD devices and digital distinguishing figure. All designs are implemented with VHDL language programming based FPGA. These figures have been applied and proved out in a CCD imaging system. Besides forenamed self-check means, this paper increases a function of"over-saturation"monitor module to prevent off-work of CCD system in glare luminance.