Image resolution conversion method that employs statistically generated multiple morphological filters
AssigneeXerox Corporation
InventorsRobert P. Loce, Michael S. Cianciosi, Jeffrey D. Kingsley
Life of this patent
Estimating the term…
Abstract
A method and apparatus for automating the design of morphological or template-based filters for print quality enhancement. A plurality of different phase, but same resolution, subsampled images are generated from training documents. Statistical data derived therefrom is then employed in an automated process to generate filters. The filters may be used for resolution enhancement and/or conversion of bitmap images. Furthermore, the statistical data is used to produce filters that are intended to not only optimize image structure, but image density as well.
Claims21
A method for automatically creating a set of filters to be used for filtering an image bitmap, wherein application of the filters will result in an enhancement of the image bitmap, comprising the steps of:
- (a) generating a first resolution image, represented as a plurality of image signals, from a document and storing the first resolution image in a first bitmap memory;
- (b) generating a second resolution image, represented as a plurality of image signals, from the document and storing the second resolution image in a second bitmap memory;
- (c) subsampling the second bitmap memory to produce a subsampled first resolution image;
- (d) storing, in a subsample memory, the subsampled first resolution image;
- (e) defining a multiple signal input window that may be passed through the first bitmap memory;
- (f) defining a single signal output window that may be passed through the subsample memory, so that the position of the output window within the subsample memory is a function of the position of the input window within the first bitmap memory;
- (g) storing a plurality.of entries in a database memory, each entry including a representation of the bitmap pattern within the multiple signal input window and corresponding state found within the single signal output window;
- and
- (h) deriving, from the database-memory, a set of filters for enhancement of the image bitmap.
A method for automatically creating a set of filters to be used for filtering an image bitmap, wherein application of the filters will result in an enhancement of the image bitmap, comprising the steps of:
- (a) generating a first resolution image, represented as a plurality of image signals, from a document and storing the first resolution image in a first bitmap memory;
- (b) generating a second resolution image, represented as a plurality of image signals, from the document and storing the second resolution image in a second bitmap memory;
- (c) subsampling the second bitmap memory to produce a plurality of subsampled first resolution images;
- (d) storing, in a plurality of subsample memories, each of the plurality of subsampled first resolution images;
- (e) defining a multiple signal input window that may be passed through the first bitmap memory;
- (f) defining a plurality of single signal output windows that may be passed through the subsample memories, so that the position of the output windows within each of the plurality of subsample memories is a function of the position of the input window within the first bitmap memory;
- (g) storing a plurality of entries in a database memory, each entry including a representation of the bitmap pattern within the multiple signal input window and corresponding states found within each of the plurality of single signal output windows;
- and
- (h) deriving, from the database memory, a set of filters for enhancement of the image bitmap.
Dependencies are inferred from the claim text.