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US 2006/0133685 A1Published application
Image-adaptive quantization for JPEG compression
AssigneeHewlett-Packard Development Company, L.P.
InventorsYu-Wei Wang, Casey Miller
Life of this patent
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Abstract
In a method of digital image compression, the spatial frequency content of a digital image is characterized using a relatively sparse sampling of data blocks from the image, and a quantization table is constructed based on the characterization of the spatial frequency content.
Claims41
A method, comprising:
- characterizing a spatial frequency content of a digital image using a relatively sparse sampling of data blocks from the digital image;
- and
- constructing a quantization table based on the characterization of the spatial frequency content.
A method of selecting an image quality factor, comprising:
- compressing and reconstituting, using an image quality factor, a set of original digital images;
- testing the image quality of the reconstituted images;
- and
- when the reconstituted images are not of a desired image quality, adjusting the value of the image quality factor.
1 more element
A digital imaging device, comprising a logic unit, the digital imaging device configured to:
- characterize a spatial frequency content of a digital image using a relatively sparse sampling of data blocks from the digital image;
- and
- construct a quantization table based on the characterization of the spatial frequency content.
A computer-readable storage medium storing instructions for performing the following method:
- characterizing a spatial frequency content of a digital image using a relatively sparse sampling of data blocks from the digital image;
- and
- constructing a quantization table based on the characterization of the spatial frequency content.
A digital imaging device, comprising:
- means for characterizing the spatial frequency content of a digital image using a relatively sparse sampling of data blocks in the image;
- and
- means for constructing a quantization table in response to the characterization of the spatial frequency content.
Dependencies are inferred from the claim text.