Nonuniformity correction and calibration method in the high-precision CCD measurement and servo control system

The CCD pixels nonuniformity may give a greater margin of error to measurement results in the high-precision CCD measurement and servo control system. The paper analyzes the image pixels nonuniformity caused by noises, and establishes the corresponding image model. Adaptive threshold value segmentation algorithm is used for image binarization. An algorithm using two point linear method for pixel nonuniformity correction, getting center coordinates of facula by calculating the zeroth order moment and first moment of image is put forward, and a new image calibrated method that transforms the image coordinates into the real is introduced. Experimental results show that the algorithm can separate light intensity parts from the image, correct pixel nonuniformity, and stabilize pixel gray value of light intensity spots. It will make the center coordinates of image light intensity spots stable and decrease the error of the real coordinates after conversion, if the images are acquired under the same condition. The measurement precision as well as the control precision is improved greatly.