Patent ID: 7643074
Filing Date: 2010-01-05
Classification: H04N

Abstract:
1. A pixel signal processing apparatus for generating a pixel signal having a k-th spectral sensitivity characteristic at a pixel position of interest where there is a pixel signal having an h-th spectral sensitivity characteristic in a group of pixel signals from pixels arrayed on a two-dimensional plane, each pixel having one of a first to an N-th spectral sensitivity characteristic, h and k being different integers between 1 and N, inclusive, the pixel signal processing apparatus comprising: a first comparison and selection means that, for each of a plurality of first neighboring pixels having the h-th spectral sensitivity characteristic, disposed in a neighborhood of the pixel position of interest, decides whether an absolute value of a first difference between its signal value and the signal value of the pixel signal of the h-th spectral sensitivity characteristic at the pixel position of interest is larger than a predetermined first threshold value, selects the signal value of the pixel signal of the h-th spectral sensitivity characteristic at the pixel position of interest if the absolute value of the first difference is larger than the first threshold value, and selects the signal value of the first neighboring pixel if the absolute value of the first difference is smaller than the first threshold value; a first mean value calculating means for calculating a mean value of the plurality of pixel signal values selected by the first comparison and selection means; an h-signal nonlinear low-pass filter for making a result calculated by said first mean value calculating means a low-frequency component of the pixel signal of the h-th spectral sensitivity characteristic at the pixel position of interest; a second comparison and selection means that, for each of a plurality of second neighboring pixels having the k-th spectral sensitivity characteristic, disposed in a neighborhood of the pixel position of interest, decides whether an absolute value of a second difference between its signal value and a mean value of the signals of a plurality of pixels of the k-th spectral sensitivity characteristic adjacent to the pixel position of interest is larger than a predetermined second threshold value, selects said mean value of the signals of said plurality of pixels of the k-th spectral sensitivity characteristic if the absolute value of the second difference is greater than the second threshold value, and selects the signal value of the second neighboring pixel if the absolute value of the second difference is less than the second threshold value; a second mean value calculating means for calculating a mean value of the signal values of the plurality of pixels selected by the second comparison and selection means; a k-signal nonlinear low-pass filter for making a result calculated by said second mean value calculating means a low-frequency component of the pixel signal with the k-th spectral sensitivity characteristic at the pixel position of interest; and a calculating means for adding a difference between the values obtained by the k-signal nonlinear low-pass filter and the h-signal nonlinear low-pass filter to the value of the pixel signal of the h-th spectral sensitivity characteristic at the pixel position of interest to obtain the pixel signal of the k-th spectral sensitivity characteristic at the pixel position of interest.