Patent ID: 8463048

Claim:
A method for difference measurement of an image, said method comprising: detecting said image by an image sensor array having N×N sensor elements, wherein N=2 n , n≧2, and n being an integer number, wherein a predetermined measurement template defines a plurality of measurement template blocks, each measurement template block including a subset of the sensor elements; reading each detected sample value as a positive or as a negative sample value according to at least one sign control pattern provided by a pattern control unit; and generating measurement values for the measurement template blocks of said image sensor array by using a computing unit to calculate for each measurement template block a weighted sum of the read sample values of the sensor elements of the respective measurement template block; wherein three sign control patterns are provided by said pattern control unit to said image sensor array; wherein a first sign control pattern sets the signs of sample values detected by said image sensor array for each column of said image sensor array in an alternating manner to a positive sign and to a negative sign; wherein a second sign control pattern sets the signs of the sample values detected by said image sensor array for each row of said image sensor array in an alternating manner to a positive sign and to a negative sign; and wherein a third sign control pattern is formed by a chessboard-like pattern which sets all signs of sample values detected by said image sensor array for all sensor elements in alternating manner to a positive sign and to a negative sign.