Patent ID: 7477804
Filing Date: 2009-01-13
Classification: G06T

Abstract:
1. An interpolation method, comprising: sequentially setting a plurality of pixels close to a pixel to be interpolated to a central pixel, wherein, in the step of setting the central pixel, four pixels around the pixel to be interpolated are sequentially set to the central pixel; calculating pixel differences between the central pixel and a plurality of pixels around the central pixel, wherein, in the step of calculating the pixel differences, the central pixel and eight pixels around the central pixel are respectively calculated; calculating an interpolation ratio when a pixel difference closest to a threshold value among the pixel differences belongs to a quasi-edge decision range to determine whether the central pixel is a quasi-edge pixel, wherein the threshold value is one of a maximum threshold value and a minimum threshold value, wherein a first quasi-edge decision range is larger than a minimum lowest limit value and smaller than a minimum upper limit value at a center of minimum threshold value; calculating an interpolation coefficient based on the interpolation ratio; and interpolating the pixel to be interpolated based on the interpolation coefficient when an edge exists between the interpolation pixel and the close pixels, wherein an interpolation ratio is calculated when a pixel difference closest to the minimum threshold value among the pixel differences belongs to the first quasi-edge decision range in the step of calculating the interpolation ratio, wherein when the pixel difference closest to the minimum threshold value among the pixel differences is larger than the minimum lowest limit value and smaller than the minimum upper value, the interpolation ratio is where, TH_L represents the minimum threshold value, LU represents the minimum upper limit value, dm represents a pixel difference closest to the minimum threshold value, and m represents a roll-off of the upper limit value and the lowest limit value, wherein, in the interpolation step, the pixel value of the interpolation pixel is PNW*(W_NW)+PNE*(W_NE)+PSW*(W_SW)+PSE*(W_SE), where, PNW, PNE, PSW and PSE are four pixels close to the pixel to be interpolated, and W_NW, W_NE, W_SW and W_SE are interpolation coefficients, which are calculated in the step of calculating the interpolation coefficient, wherein the interpolation coefficients W_NW, W_NE, W_SW and W_SE are where, t represents a mixing ratio calculated in the step of calculating the mixing interpolation ratio, WNWE, WNEE, WSWE and WSEE are edge interpolation coefficients calculated from a position of a coordinate transformation of the interpolation pixel, WNWB, WNEB, WSWB and WSEB are bilinear interpolation coefficients, and the bilinear interpolation coefficients are where, KX and KY are respectively a position of a pixel to be interpolated.