Design Of Array CCD Imaging System Based On FPGA

Laser speckle imaging (LSI) is a noninvasive and full-field optical imagingtechnique，it produces two-dimensional blood flow images of tissues by a CCD camera. Ithas a very good effect on the blood flow monitoring large area of superficial tissues suchas skin and the cavity, currently, this technology has already been used clinically. But,cause of the Size and cost, the application is limited. So portable device has great practicalsignificance.Therefore, the device is portable and has a very great practical significanceCharge-Coupled Device (CCD) imaging system has been widely applied in manyfields, such as life science, aerospace, security monitoring, digital products, etc. The labwho present this issue is doing a research of Laser Speckle Blood Flow Imaging, whichalso use the CCD as the imaging sensor for the advantages of wide field and excellentcharacters. This issue has developed a system based Filed Programmable Gate Array (FPGA)architecture with high resolution, high sensitivity, low dark current and12bit samplingprecision to meet the lab’s demand.This issue developed a system which is different from traditional Appication SpecificIntergrated Circuit(ASIC) architecture, it is based on programmable device FPGA. FPGAplay a central role in the hole system, it generates CCD drive signals and synchronoussampling signals, and by means of FPGA-specific soft-core processor technology, we setup a NIOS Ⅱ soft-core processor system with32-bit instruction set, data bus and addressspace, thus, we can easily control the image data transmission, connecting to imageinterface or directly display by a C program. Therefore, the system developed by this issuehas a high degree of flexibility and scalability.This system has3child modules: the CCD imaging module, FPGA central moduleand the imaging interface module.CCD imaging module finished the transform of opticalto electrical and analog to digital. FPGA central module controlled the CCD module,transferred image data to the memory device. Imaging interface module accomplished thedata transmission from our board to computer.This system realized high resolution, high sensitivity, low dark current and12bitsampling precision which is met the expected goal. Moreover, it has a high degree offlexibility and scalability, we can change the CCD type in different application, we canpromote it to be a portable device by download appropriate digital imaging processing algorithm. These flexibilities help the system to become a platform that we can do morework on it.