The design of a ball pod of image fusion system of a cooled infrared bolometer and a CCD camera

A compacted ball pod of image fusion system of middle wave band infrared and visible light image is designed and manufactured and tested. The system is composed of image collecting, processing and displaying part. Image collecting part includes a cooled infrared bolometer and a CCD camera. Image process part is a complex circuit penal composed of TMS320DM642, TVP5150, SAA7121H, SDRAM and other electronic components, while displaying part is computer or LCD. The focus length of cooled infrared bolometer is 300/75mm of Ge lens and that of CCD is continuous 10-300mm to match the field of view of bolometer. The optical axises of them are rectified to be parallel carefully, thus they can aim at the target in infinite distance. The response wavelength of the cooled infrared bolometer is 3.3-4.8μm and that of CCD is 0.2~1.1μm. The pixel of bolometer is 320×256 and that of CCD is 720×576. Images of bolometer and CCD are decoded in the input circuit of TVP5150 and form the digital signal of BT.656, then the decoded videos are transferred to TMS320DM642 circuit. The pixel number of bolometer is increased to 720×576 in the DM642 to match that of CCD camera, the decoded images are stored in SDRAM temporally, then the images of bolometer and CCD are fused under the weighted average algorithm in order to keep the real time response. The output image is encoded to PAL format in SAA7121H, so as to be displayed in monitor. The experiment in room and the experiments outside indicate the advantage of fusion algorithm in some degree. By comparing the observing result of three images of infrared, visible, fusing images, a primary conclusion is obtained that the weight coefficient will influence the fusing effect in different circumstances. Next a modified fusion algorithm of pixel comparing of infrared and visible images will implant to the DM642.