The study on data processing based on CCD scanning and detecting device on wavelet transform

In order to increase accuracy of the linear array CCD edge detection system, a wavelet-based sub-pixel edge detection method is proposed, the basic process is likethis: firstly, according to the step gradient features, automatically calculate the pixel-level border of the CCD image. Then use the wavelet transform algorithm to devide the image´s edge location in sub-pixel level, thus detecting the sub-pixel edge. In this dissertation, real-time defects data processing technology based on Field Programmable Gate Array(FPGA) was developed for this purpose. This instrument was used for polymeric film inspection for the first time. The experimental results demonstrated that defects within 70 mum ~1000 mum were inspected effectively by the CCD scanning defects inspection instrument, that this method has a repetition error no more than 2.24 pixels, with high precision and good anti-noise ability.