Patent Document ID: 8396309
Application ID: 12994516
Patent Status: 1

Claim One:
1. A method of compressing a pixel block comprising multiple pixels, each pixel having a property value, said method comprising: determining a minimum reference property value and a maximum reference property value based on at least a portion of said property values of said multiple pixels; determining a distribution of said property values of said multiple pixels in an interval from said minimum reference property value to said maximum reference property value; determining a mode index based on said distribution of said property values in said interval; determining at least one quantization parameter based on said minimum reference property value and said maximum reference property value, by: if said mode index indicates that at least a minimum portion of said property values of said multiple pixels is within a predefined sub-interval: determining, based on said minimum reference property value and said maximum reference property value, a first quantization parameter applicable in said predefined sub-interval; and determining, based on said minimum reference property value and said maximum reference property value, a second, different quantization parameter applicable in a remaining portion of said interval, and if said mode index indicates that said at least a minimum portion of said property values of said multiple pixels is not within said predefined sub-interval, determining one quantization parameter based on said minimum reference property value and said maximum reference property value, determining at least one step parameter based on said at least one quantization parameter; defining at least one additional reference property value based on said at least one step parameter and at least one of said minimum reference property value and said maximum reference property value, to thereby determine a reference set that comprises said minimum reference property value, said maximum reference property value and said at least one additional reference property value; assigning, for each pixel of said multiple pixels and based on a property value of said pixel, a value index associated with a reference property value of said reference set; providing, for at least one pixel of said multiple pixels, a prediction of said value index assigned to said at least one pixel based on said value index assigned to at least one neighboring pixel in said pixel block; calculating a prediction error based on said value index assigned to said at least one pixel and said prediction of said value index; and generating an encoded representation of said prediction error, to determine a compressed pixel block that comprises said encoded representation of said prediction error, an encoded representation of said minimum reference property value, an encoded representation of said maximum reference property value, and said mode index.