| 摘要 |
PROBLEM TO BE SOLVED: To provide an image photographing apparatus capable of suppressing deterioration in image quality even when image data photographed by an optical system with a function of magnifying a middle region of an input image and compressing peripheral regions is reduced. SOLUTION: In the image photographing apparatus, an imaging element 2 converts an object image into image data, the object image having been formed by the optical system 1 with such a distortion aberration characteristic that the middle region is magnified and the peripheral region is compressed. A filter coefficient setting circuit 13 judges whether or not each pixel of the image data from the imaging element 2 is included in a Nyquist image region being a region with a spatial frequency in excess of the Nyquist frequency, and the filter coefficient setting circuit 13 reads a filter coefficient for shutting off the spatial frequency in excess of the Nyquist frequency from a first memory 11 and sets the filter coefficient to a filter circuit 9 when each pixel is included in the Nyquist image region. Then the filer circuit 9 carries out filter processing on the basis of the set filter coefficient, and thereafter a distortion correction circuit 10 corrects the distortion aberration characteristic of the image data. COPYRIGHT: (C)2007,JPO&INPIT
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