Patent ID: 7899261

Claim:
An imaging device comprising: an image pickup section that generates photographic image data by photoelectrically converting an object image obtained by an optical shooting system; a compression processing section that performs compression processing on said photographic image data; a correlation data holding section that holds a plurality of pieces of correlation data representing a correlation between a change in a scale factor for a data compression rate and a change in compressed data amount of sample image data; a first calculating section that calculates an initial scale factor from target compressed data amount and standard correlation data that is generated according to test pattern image data whose cyclic variation of a pattern in horizontal and vertical directions corresponds to a Nyquist frequency of said image pickup section, the test pattern image data being one of said sample image data; and a second calculating section that determines whether or not recompression processing needs to be performed by use of a different scale factor, according to a difference between said target compressed data amount and an amount of compressed photographic image data, and when the recompression processing is performed, calculates a scale factor according to the compressed photographic image data and said correlation data so that said data compression rate is decreased.