Patent attributes
An image acquisition apparatus includes an optical system having such distortion aberration characteristics as a central region is expanded and a peripheral region is compressed. An imaging element converts a subject image formed image data. A first memory stores filter factors which are used for interrupting a spatial frequency exceeding a Nyquist frequency of the image data. A second memory stores parameters which define an outer edge of a Nyquist image region. A filter factor setting circuit judges whether each pixel position of the image data is included in the Nyquist image region based on the parameter, and reads the filter factors from the first memory when each pixel position is included. A filter circuit executes filter processing with respect to the image data in accordance with the read filter factors. A distortion correcting circuit corrects the distortion aberration characteristics with respect to the image data.
