Rotated read-out of jpeg compressed images
AssigneeXerox Corporation
InventorR. VICTOR KLASSEN
Life of this patent
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Abstract
This invention is a method and apparatus for processing compressed digital images. More particularly, this invention relates to methods and apparatus which accomplish rotation in conjunction with a variable-length decompression operation. A small amount of auxiliary information consisting of pointers to the starts of the scanlines is stored along with the DC coefficients in the decompressor, instead of the compressed image, to reduce the memory requirements for orthogonally rotating an image.
Claims40
A method for rotating an image represented by digital data, comprising:
- compressing the digital data to form compressed image data, the compressed digital data comprising a plurality of compressed units;
- storing additional information about a number of the plurality of compressed units;
- decompressing the compressed units based on the additional information;
- and
- combining the decompressed units to form a rotated image.
A method for processing an image represented by digital data, comprising:
- compressing the digital data to form compressed image data, the compressed digital data comprising a plurality of compressed units;
- storing additional information about a number of the plurality of compressed units, the additional information usable to form a rotated decompressed image.
An apparatus for rotating an image represented by digital data, comprising:
- a compressor that compresses the digital data to form compressed image data, the compressed digital data comprising a plurality of compressed units;
- a memory that stores additional information about a number of the plurality of compressed units;
- a decompressor that decompresses the compressed units based on the additional information;
- and
- a combiner that combines the decompressed units to form a rotated image.
An apparatus for processing an image represented by digital data, comprising:
- a compressor that compresses the digital data to form compressed image data, the compressed digital data comprising a plurality of compressed units;
- and
- a memory that stores additional information about a number of the plurality of compressed units, the additional information usable to form a rotated decompressed image.
Dependencies are inferred from the claim text.