Patent ID: 7769239

Claim:
A method to provide bit-exact lossless compression of an original image comprising a number of pixels each having a value, the method comprising: preparing a sorted list of pixel values by examination of pixels in the original image, each of the values in the sorted list of pixel values being located in a corresponding bin, each bin being represented by an integer index value; encoding and then decoding the original image using a lossy process to produce a decompressed image, the decompressed image including a number of pixels each having a value; comparing each pixel value from the decompressed image to the sorted list of pixel values to determine a nearest bin for each pixel; determining a bin delta between the index value of the nearest bin determined for each pixel in the decompressed image and the index value of the bin identified for the corresponding pixel in the original image; outputting the bin delta for each pixel; and outputting the sorted list of pixel values.