US Patent 8644620 Processing of matching regions in a stream of screen images

In one general aspect, a computer-readable storage medium can be configured to store instructions that when executed cause a host device to perform a process. The instructions can include instructions to calculate a set of hash values associated with a set of blocks of a first image, and calculate a hash value associated with a block of a second image. The instructions can include instructions to receive an indicator that the hash value of the block of the second image matches a hash value from the set of hash values associated with the first image, and designate, in response to the indicator, the block of the second image for duplication.