Digital image coding system having self-adjusting selection criteria for selecting a transform function

A computer-implemented method for transforming a block of pixels within a frame of a digitized video image using a selectable one of a set of transform functions, each transform function having an inverse transform function, and each block having a predetermined set of image characteristics, the method comprising:

• establishing adjustable selection criteria for selecting a transform function;
• detecting respective characteristic values for the image characteristics of a block;
• selecting a first transform function from said set of transform functions based on said characteristic values and said adjustable selection criteria;
• applying said first transform function to said block to form a transformed block;
• quantizing said transformed block to form a quantized block;
• selecting an inverse transform function whose application minimally covers said quantized block;
• inversely quantizing said quantized block to form an inversely quantized block;
• applying said inverse transform function to said inversely quantized block to form a decoded block;
• establishing a quality value for said decoded block for improving subsequent coded images;
• updating said adjustable selection criteria based on said quality value and said characteristic values;
• and
• establishing historical records of quality values and characteristic values and associated transform functions and quantization values.

A computer-implemented method for transforming a block of pixels within a frame of a digitized video image using a selectable one of a set of transform functions, each transform function having an inverse transform function, and each block having a predetermined set of image characteristics, the method comprising:

• associating the transform functions with the set of image characteristics, with predetermined quantization values, and with adjustable thresholds associated with the image characteristics;
• obtaining respective characteristic values for the image characteristics of a block;
• selecting a transform function from the set of transform functions based on comparisons between said characteristic values and said adjustable thresholds;
• applying said transform function to the block to form a transformed block;
• quantizing said transformed block using a quantization value to form a quantized block;
• selecting an inverse transform function whose application minimally covers said quantized block;
• inversely quantizing said quantized block to form an inversely quantized block;
• applying said inverse transform function to said inversely quantized block to form a decoded block;
• obtaining a quality value for said decoded block for improving images;
• updating said adjustable thresholds based on said quality value and said characteristic values;
• and
• establishing historical records of quality values and characteristic values and associated transform functions and quantization values.

A processor for coding a block of pixels of a digitized video image using a selectable one of a plurality of coding functions, comprising:

• establishment means for establishing adjustable selection criteria used to select a coding function;
• measurement means for measuring a predetermined characteristic of the block to obtain a characteristic value;
• selection means for selecting a coding function based on said adjustable selection criteria and said characteristic value;
• code means for coding the block according to said coding function selected to obtain a coded block;
• performance means for performing a quality measurement of said coded block;
• adjustment means for adjusting said adjustable selection criteria for selecting a coding function, utilizing said quality measurement such that quality measurements of subsequent blocks are improved;
• and
• establishment means for establishing historical records of quality values and characteristic values and associated coding functions and quantization values.

A computer-readable medium comprising program instructions for causing a processing system to perform a method to code a block of pixels of a digitized video image using a selectable, one of a plurality of coding functions, the method comprising:

• establishing adjustable selection criteria for selecting a coding function;
• measuring a predetermined characteristic of the block to obtain a characteristic value;
• selecting a coding function based on said adjustable selection criteria and said characteristic value;
• coding the block according to said coding function selected to obtain a coded block;
• performing a quality measurement of said coded block;
• adjusting said adjustable selection criteria for selecting a coding function, utilizing said quality measurement such that quality measurements of subsequent blocks are improved;
• and
• establishing historical records of quality values and characteristic values and associated coding functions and quantization values.