Adaptive color plane interpolation in single sensor color electronic camera

Abstract

Apparatus is described for processing a digitized image signal obtained from an image sensor having color photosites aligned in rows and columns that generate at least three separate color values but only one color value for each photosite location, and a structure for interpolating color values for each photosite location so that it has three different color values. The apparatus includes a memory for storing the digitized image signal and a processor operative with the memory for generating an appropriate color value missing from a photosite location by the interpolation of an additional color value for such photosite locations from color values of different colors than the missing color value at nearby photosite locations. The processor also includes structure for obtaining Laplacian second-order values, gradient values and color difference bias values in at least two image directions from nearby photosites of the same column and row and for adding the Laplacian second-order values, gradient values and color difference bias values to define a classifier and for selecting a preferred orientation for the interpolation of the missing color value based upon a classifier. Finally, a arrangement is provided for interpolating the missing color value from nearby multiple color values selected to agree with the preferred orientation.

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