BILATERAL ALPHA OMEGA: CALCULATING LUT ARGUMENT WITH FEW ARITHMETIC OPERATIONS

摘要

According to a first aspect, a method is provided. The method includes obtaining an MxN array of pixel values an image; determining a weight selection value for position x,y in the MxN array; and using the weight selection value to obtain a weight value for use in a filter for filtering the image. Determining the weight selection value for position x,y (omega_x,y) includes: a) retrieving a previously determined weight selection value for position x,y-1 (omega_x,y-1); b) retrieving a previously determined alpha value (a) for position x,y-1; c) calculating a delta value (d); and d) calculating omega_x,y = omega_x,y-1 - a + d. Calculating d includes: i) retrieving a first previously determined value (omega_row); i) retrieving a second previously determined value (alpha_row); and ii) calculating d = omega_row - alpha_row + abs(A_x+1,y+1 - A_x+1,y+2), wherein A_x+1,y+1 is the value stored in position x+1,y+1 of the array and A_x+1,y+2 is the value stored in position x+1,y+2 of the array.