Image filtering for improved lossless compression

A method of image compression, the method comprising:

• receiving a raster image comprising an array of pixels;
• dividing the raster image into regions of the pixels;
• identifying a region size limit for the regions;
• and
• for each region of the regions, performing image filtering on the region with an image filter that operates based on a filter parameter, wherein the filter parameter is adjustable between a first value where minimal filtering is performed and a second value where maximum filtering is performed;
• wherein the image filtering for each region comprises:
• measuring a compressed region size of the region when compressed with a run-length encoding scheme;
• computing the filter parameter for the region based on the compressed region size and the region size limit;
• and
• applying the image filter on the region based on the filter parameter computed for the region to generate a filtered region having increased redundant patterns of pixel values.

A non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method of image compression, the method comprising:

• receiving a raster image comprising an array of pixels;
• dividing the raster image into regions of the pixels;
• identifying a region size limit for the regions;
• and
• for each region of the regions, performing image filtering on the region with an image filter that operates based on a filter parameter, wherein the filter parameter is adjustable between a first value where minimal filtering is performed and a second value where maximum filtering is performed;
• wherein the image filtering for each region comprises:
• measuring a compressed region size of the region when compressed with a run-length encoding scheme;
• computing the filter parameter for the region based on the compressed region size and the region size limit;
• and
• applying the image filter on the region based on the filter parameter computed for the region to generate a filtered region having increased redundant patterns of pixel values.