Patent ID: 9294743
Filing Date: 2016-03-22
CPC Classification: H04N

Claim Text:
1. A pixel interpolation apparatus for carrying out a pixel interpolation process on an image signal which is obtained by an image capture unit including color filters of a first color filter, a second color filter, and a third color filter in three different colors which are arranged in a predetermined pattern, the image signal including a first-color pixel signal obtained via the first color filter, a second-color pixel signal obtained via the second color filter, and a third-color pixel signal obtained via the third color filter, the pixel interpolation apparatus comprising: a signal correction unit configured to correct a signal level of each of the first-color pixel signal, the second-color pixel signal, and the third-color pixel signal, in accordance with its corresponding color filter, and to output an image signal including the first-, second-, and third-color pixel signals which are corrected, as a first image signal; a saturation evaluation value calculation unit configured to evaluate saturation of a predetermined image area in an image formed of the first image signal, based on the first image signal output from the signal correction unit, and to obtain a saturation evaluation value of the predetermined image area; a gray correlation value calculation unit configured to obtain correlation degrees of a plurality of pairs of two directions which are perpendicular to each other on the image formed of the first image signal, using data of those pixels that are located in an image area including and surrounding an observed pixel which is being processed, as a gray correlation degree; a color correlation value calculation unit configured to obtain correlation degrees of a plurality of pairs of two directions which are perpendicular to each other on the image formed of the image signal including the first-, second-, and third-color pixel signals, using data of those pixels that are located in an image area including and surrounding the observed pixel and are of the same color, as a color correlation degree; a pixel interpolation method determination unit configured to determine a pixel interpolation method for the observed pixel, based on the saturation evaluation value obtained by the saturation evaluation value calculation unit, the gray correlation degree obtained by the gray correlation value calculation unit, and the color correlation degree obtained by the color correlation value calculation unit; an interpolation unit configured to carry out a pixel interpolation process on the observed pixel by the pixel interpolation method determined by the pixel interpolation method determination unit, to obtain a second image signal which is a signal provided after the pixel interpolation process; and a correction unit configured to perform color space conversion on the second image signal obtained by the interpolation unit in accordance with an arrangement pattern of the color filters, to obtain a predetermined output image signal.