Study On The Image Acquisition And Pretreatment Of Reconfigurable Vision Inspection

The technology of reconfigurable vision inspection is the main way of computer vision inspection in the future, and the speed of high image acquisition and pretreatment is the key to realize the real-time inspection.For the dissertation, the reconfigurable vision inspection system is first put forward. This system can fast adjust its inspection function by recomposing or adjusting itself's hardware or software to meet the new requirements. Then the image acquisition and pretreatment system is researched based on FPGA.For the hardware, the design of the video decoder, memory, FPGA and USB controller interface is done after choosing the configure devices of the hardware system.For the software, the I~2C bus is researched in detail, and the initialization program of the SAA7111A is done, which includes the mode settings, timing cycle of horizontal synchronization (HS) and vertical synchronization (VS) reference signals settings and the digital signal output format settings. Then, the image acquisition and USB data transmission are studied. At last, the firmware and driver is developed under the development kits provided by the Cypress Corporation.For the image pretreatment, a large amount of pixels can be operated use the same algorithm, but it need high bandwidth data change, which will cost much time in image processing system. A better way to settle this problem is adopted by using FPGA, which can easily realize the convolution algorithm by its internal multiplicative module. On the base of the analysis and validation of the traditional filter methods, such as mean filter, gauss filter, median filter and extremum filter, the median filter method is chosen to pretreat image using FPGA in this system.On the base of the above work, the key technology for vision inspection is discussed in detail, and the image acquisition and pretreatment system based on FPGA is developed.