Image interpolating device

An image interpolating device comprising:

• a color filter having a first row, in which red (R) and green (G) color filter elements are alternately aligned in the horizontal direction, and a second row, in which G and blue (B) color filter elements are alternately aligned in the horizontal direction, said second row being adjacent to one of an upper side and a lower side of said first row;
• an imager that generates first R, G, and B-signals which are pixel signals corresponding to said color filter elements;
• a pattern-setter that extracts images belonging to a first pattern, in which a pixel having said first R-signal is positioned at the upper-left corner of a 2×2 pixel matrix, a second pattern, in which a pixel having said first G-signal is positioned at the upper-right corner of said 2×2 pixel matrix, a third pattern, in which a pixel having said first G-signal is positioned at the lower-left corner of said 2×2 pixel matrix, and a fourth pattern, in which a pixel having said first B-signal is positioned at the lower-right corner of said 2×2 pixel matrix, from said first R, G, and B-signals generated by said imager;
• a first G-interpolator that, regarding a first objective pixel contained in said images belonging to said first pattern, obtains a first interpolated G-signal based on a first difference signal, which is a difference between said first G-signals of pixels offset from said first objective pixel in the right and left directions or the upper and lower directions by one pixel, second difference signals, each of which is a difference between said first R-signal of said first objective pixel and said first R-signal of a pixel offset from said first objective pixel in the right, left, upper, or lower direction by two pixels, third difference signals, each of which is a difference between said first R-signal of said first objective pixel and said first G-signal of a pixel offset from said first objective pixel in the right, left, upper, or lower direction by one pixel;
• a second G-interpolator that, regarding a fourth objective pixel contained in said images belonging to said fourth pattern, obtains a second interpolated G-signal based on a fourth difference signal, which is a difference between said first G-signals of pixels offset from said fourth objective pixel in the right and left directions or the upper and lower directions by one pixel, fifth difference signals, each of which is a difference between said first B-signal of said fourth objective pixel and said first B-signal of a pixel offset from said fourth objective pixel in the right, left, upper, or lower direction by two pixels, sixth difference signals, each of which is a difference between said first B-signal of said fourth objective pixel and said first G-signal of a pixel offset from said fourth objective pixel in the right, left, upper, or lower direction by one pixel;
• an R/B-interpolator that, regarding second and third objective pixels contained in said images belonging to said second and third patterns, obtains second R and B-signals by utilizing said first R and B-signals of pixels adjacent to said second and third objective pixels;
• a B-interpolator that extracts a first similar pixel which has the closest luminance value to that of said first objective pixel, from pixels adjacent to said first objective pixel, and obtains a third B-signal based on a pixel signal of said first similar pixel;
• and
• an R-interpolator that extracts a second similar pixel which has the closest luminance value to that of said fourth objective pixel, from pixels adjacent to said fourth objective pixel, and obtains a third R-signal based on a pixel signal of said second similar pixel.