Patent ID: 7065251

Claim:
A method for image compression while maintaining high resolution in selected areas within an image, comprising: a) representing an acquired image by a two dimensional array of M×N pixels; b) dividing said array into blocks of identical rectangular areas, each of said blocks having a block size of A×B pixels, wherein A<M,N and B<M,N and M=m*A (m=2,3, . . . ); and N=n*B (n=2,3, . . . ); c) storing data related to the division of said array into blocks; d) for each pixel, defining a pixel attribute value; e) for each pixel, determining a represented value, being a representation of said pixel attribute value; f) determining a threshold value for said pixel attribute value; g) calculating a represented value for each block and storing said represented value; h) comparing the represented value of each block to the represented value of its adjacent blocks; i) whenever the difference between the represented values of two adjacent compared blocks is greater than said threshold level and as long as the block size is larger than one pixel: i.1) dividing said adjacent compared blocks into sub-blocks, each of which containing A/2×B/2 pixels and storing data related to the division of said adjacent compared blocks into sub-blocks; i.2) calculating the represented value for each sub-block and for its adjacent sub-blocks; i.3) comparing the stored represented value of each sub-block to the stored represented value of its adjacent sub-blocks; and j) whenever the difference between two adjacent compared blocks or sub-blocks is lower than, or equal to, said threshold level, representing said blocks or sub-blocks by representative pixels with identical attribute level which is equal to the represented value of the pixels that correspond to said compared block or sub-block, thereby compressing said image.