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US 2015/0146975 A1Published application
Lossless color image compression adaptively using spatial prediction or inter-component prediction
AssigneeEMC Corporation
InventorsAlexey Valentinovich Romanovskiy, Marat Ravilevich Gilmutdinov, Nikolay Dmitrievich Egorov, Victor Anatolievich Yastrebov, Dmitry Vadimovich Novikov, Roman Alexandrovich Sokolovskiy
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Abstract
An improved lossless image compression technique involves adaptively selecting between spatial prediction and inter-component prediction techniques depending on which allows better results for any given component of a digital image pixel.
Claims14
A method performed by a computing device, the method comprising:
- receiving an image file, the image file having a set of pixels arranged in a grid, each pixel of the set of pixels having a plurality of color components;
- for each pixel of a subset of the set of pixels:
- for a first color component of the plurality of color components:
- predicting a value of the first color component of that pixel using a first prediction technique to yield a first predicted color value, the first prediction technique including median edge detection;
- and
- computing a difference between the first predicted color value and the value of the first color component to yield a first error value for that pixel;
- for a second color component of the plurality of color components, the second color component being distinct from the first color component:
- predicting a value of the second color component of that pixel using the first prediction technique to yield a second predicted color value;
- predicting the value of the second color component of that pixel using a second prediction technique to yield a third predicted color value, the second prediction technique lacking median edge detection, the second prediction technique utilizing inter-component prediction with respect to the first color component;
- selecting whichever of the second predicted color value and the third predicted color value is closer to the value of the second color component to yield a selected predicted color value;
- and
- computing a difference between the selected predicted color value and the value of the second color component to yield a second error value for that pixel;
- and
- encoding the first error value for that pixel and the second error value for that pixel in a compressed color image output stream;
- and
- writing the compressed color image output stream to persistent storage as an output compressed image file.
13 more elements
A data storage apparatus comprising:
- a host interface;
- memory;
- persistent storage;
- and
- a processor, the processor being configured to perform the operations of:
- receiving an image file into memory from the host interface, the image file having a set of pixels arranged in a grid, each pixel of the set of pixels having a plurality of color components;
- for each pixel of a subset of the set of pixels:
- for a first color component of the plurality of color components:
- predicting a value of the first color component of that pixel using a first prediction technique to yield a first predicted color value, the first prediction technique including median edge detection;
- and
- computing a difference between the first predicted color value and the value of the first color component to yield a first error value for that pixel;
- for a second color component of the plurality of color components, the second color component being distinct from the first color component:
- predicting a value of the second color component of that pixel using the first prediction technique to yield a second predicted color value;
- predicting the value of the second color component of that pixel using a second prediction technique to yield a third predicted color value, the second prediction technique lacking median edge detection, the second prediction technique utilizing inter-component prediction with respect to the first color component;
- selecting whichever of the second predicted color value and the third predicted color value is closer to the value of the second color component to yield a selected predicted color value;
- and
- computing a difference between the selected predicted color value and the value of the second color component to yield a second error value for that pixel;
- and
- encoding the first error value for that pixel and the second error value for that pixel in a compressed color image output stream;
- and
- writing the compressed color image output stream to the persistent storage as output compressed image file.
18 more elements
A computer program product comprising a non-transitory computer-readable storage medium storing a set of instruction, which, when executed by a computer, cause the computer to perform the following operations:
- receiving an image file, the image file having a set of pixels arranged in a grid, each pixel of the set of pixels having a plurality of color components;
- for each pixel of a subset of the set of pixels:
- for a first color component of the plurality of color components:
- predicting a value of the first color component of that pixel using a first prediction technique to yield a first predicted color value, the first prediction technique including median edge detection;
- and
- computing a difference between the first predicted color value and the value of the first color component to yield a first error value for that pixel;
- for a second color component of the plurality of color components, the second color component being distinct from the first color component:
- predicting a value of the second color component of that pixel using the first prediction technique to yield a second predicted color value;
- predicting the value of the second color component of that pixel using a second prediction technique to yield a third predicted color value, the second prediction technique lacking median edge detection, the second prediction technique utilizing inter-component prediction with respect to the first color component;
- selecting whichever of the second predicted color value and the third predicted color value is closer to the value of the second color component to yield a selected predicted color value;
- and
- computing a difference between the selected predicted color value and the value of the second color component to yield a second error value for that pixel;
- and
- encoding the first error value for that pixel and the second error value for that pixel in a compressed color image output stream;
- and
- writing the compressed color image output stream to persistent storage as an output compressed image file.
13 more elements
Dependencies are inferred from the claim text.