Patent ID: 7847841

Claim:
An image pickup system comprising: a block extracting unit for extracting a block area with a predetermined size from a signal of an image pickup device; a transforming unit for transforming the signal in the block area extracted by the block extracting unit into a signal in a frequency space; a noise estimator for estimating an amount of noise of a frequency component except for a zero-order component based on a zero-order component in the signal in the frequency space transformed by the transforming unit; a noise reducing unit for reducing noise of the frequency component except for the zero-order component based on the amount of noise estimated by the noise estimator; a compressing unit for compressing the zero-order component and the frequency component except for the zero-order component from which the noise is reduced, wherein the block extracting unit comprises a chart separating unit for separating a part corresponding to a gray chart from the signal obtained by picking-up an image for correction including at least three types of gray charts with different reflectances by the image pickup device, and the transforming unit transforms the part corresponding to the gray chart separated by the chart separating unit into the signal in the frequency space, and the image pickup system further comprises: a variance calculating unit for calculating a variance N of the frequency component except for the zero-order component of the corresponding part of the gray chart; and a fitting unit for calculating coefficients A, B, and C based on one of functional formulae N=AL B +C and N=AL 2 +BL+C where L is the zero-order component and N is the variance.