Abstract: A method for generating a background statistics that distinguishes between gray level information from document areas and non-document areas. The method includes determining a full page background statistics from selected pixels within a scanned area; determining a sub-region background statistics from selected pixels within a sub-region of the scanned area; determining if the sub-region background statistics corresponds to image data from a non-document area; determining if the full page background statistics is corrupted; and generating a validated full page background statistics if the full page background statistics is corrupted.

Abstract: A system and method for method of cleaning segmentation tags is disclosed. A method in accordance with the present invention comprises receiving a plurality of segmentation tags; generating block level tags in response to the received segmentation tags wherein each block level tag is a representative tag for a block of received segmentation tags; and cleaning selected ones of the received segmentation tags using a window of neighboring block level tags.

Abstract: A system and method of processing segmentation tags is disclosed. In accordance with the present invention, a method for processing segmentation tags that receives blocks of segmentation tags each of which has an associated block level tag that is representative of the segmentation tags within the block. The method positions a neighborhood window about a current block and a neighboring block and cleans a target segmentation tag within the current block based upon the block level tags within the neighborhood window using a set of tag cleaning rules.

Abstract: A first aspect of the of the present invention is a system and method for classifying an input document based a segmentation tag statistics. The method includes receiving first pass segmentation tags for a plurality of pixels within a block of image data; determining an image type for the block of image data using statistics compiled from the first pass segmentation tags; and generating rendering tags for pixels within the block of image data as function of second pass segmentation tags and the image type. Beneficially, the image type identified for the block of image data is used to optimize the rendering process.

Abstract: A method and apparatus are provided for classifying image data. A neighborhood average gray value may be determined for the input image data. A threshold value may then be determined based on the neighborhood average gray value. Pixels are evaluated to determine if a gray level difference between the pixel and the neighborhood average gray level is greater than the threshold.

Abstract: A method and system implements selective, memory efficient, control over the amount of error diffused in a hybrid screening system. An image context error computer receives a pixel classification and an error value. Upon receiving these data, a set of shift registers supplies a fractional portion of the error value to an error diffusion circuit. A bypass thresholder receives screened video and applies simple thresholding. In parallel with the simple thresholding, an error diffuser receives screened video and applies error diffusion. The results of the two processes are output to a multiplexer which outputs one based on the pixel classification.

Abstract: A system for processing segmentation tags to generate a block level tag representative of a group of segmentation tags. The system includes first and second statistic compilation circuits, each of the compilation circuits being connected to receive segmentation tags and compile a statistic for a plurality of the received segmentation tags. An address controller connected to the first and second statistic compilation circuits operates to select one of the first and second compilation circuits to receive the segmentation tags.

Abstract: A high addressable multibit screening device and method for use in a PDL interpreter environment achieve improved printing resolution and quality. A PDL interpreter receives a PDL document from a host source, which identifies one or more objects that can be fully toned (black) or partially toned (line art or images). Each of these objects can be processed differently. Fully toned objects are processed within the interpreter and directly output in a predetermined output. Partially toned objects are sent to a high addressable screening module within the interpreter for processing prior to outputting in a desired output format. The high addressable screening module screens the partially toned objects to obtain multibit screened data for output.

Abstract: A high addressable multibit screening device and method for use in a PDL interpreter environment achieve improved printing resolution and quality. A PDL interpreter receives a PDL document from a host source, which identifies one or more objects that can be fully toned (black) or partially toned (line art or images). Each of these objects can be processed differently. Fully toned objects are processed within the interpreter and directly output in a predetermined output. Partially toned objects are sent to a high addressable screening module within the interpreter for processing prior to outputting in a desired output format. The high addressable screening module screens the partially toned objects to obtain multibit screened data for output.

Abstract: A method for generating a background statistics that distinguishes between gray level information from document areas and non-document areas. The method includes determining a full page background statistics from selected pixels within a scanned area; determining a sub-region background statistics from selected pixels within a sub-region of the scanned area; determining if the sub-region background statistics corresponds to image data from a non-document area; determining if the full page background statistics is corrupted; and generating a validated full page background statistics if the full page background statistics is corrupted.

Abstract: A method and system implements selective, memory efficient, control over the amount of error diffused in a hybrid screening system. An image context error computer receives a pixel classification and an error value. Upon receiving these data, a set of shift registers supplies a fractional portion of the error value to an error diffusion circuit. A bypass thresholder receives screened video and applies simple thresholding. In parallel with the simple thresholding, an error diffuser receives screened video and applies error diffusion. The results of the two processes are output to a multiplexer which outputs one based on the pixel classification.

Abstract: The present invention provides a method and apparatus for classifying image data. A video peak/valley counter may count peaks and valleys within a window of the input image data. The apparatus and method checks whether any peaks or valleys are located within a neighborhood of a pixel under consideration.

Abstract: The present invention provides a method and apparatus for classifying image data. A white class detector may receive input image data and determine a white class of a specified pixel based on local roughness, peak or count or valley count and a brightness. A pattern detection device may detect a pattern of pixels across a scan line or matrix of input data and compare the pattern with a plurality of predetermined pixel patterns.

Abstract: The present invention provides a method and apparatus for classifying image data. A video peak/valley counter may count peaks and valleys within a window of the input image data. The apparatus and method checks whether any peaks or valleys are located within a neighborhood of a pixel under consideration.

Abstract: A system and method suppresses automatically a background of a document being scanned. A histogram circuit generates a histogram from a predetermined group of scanlines of image data collected at a lead edge of the document being scanned, and a gain correction circuit calculates a gain value from the histogram and applies the gain to the image data. The histogram circuit generates a next histogram from a next predetermined group of scanlines of image data collected from the document being scanned. The gain correction circuit then calculates a next gain value from the next histogram. A comparator enables the application of the next gain value to the image data if the next gain value is less than a previously calculated gain value.

Abstract: A system electronically registers an image on an input document. The system includes a scanner for generating an image data stream representing an electronic image of the image on the input document and an edge detecting circuit for detecting edge data within the image data stream A circuit detects a first corner of a leading edge of the input document based on the detected edge data and for establishing a first coordinate value therefrom and a second corner of a leading edge of the input document based on the detected edge data and for establishing a second coordinate value therefrom. The system further determines a minimum and maximum location for a leading edge of the scanned document and determines a minimum and maximum location for a trailing edge of the scanned document.

Abstract: A system electronically registers an image on an input document. The system includes a scanner for generating an image data stream representing an electronic image of the image on the input document and an edge detecting circuit for detecting edge data within the image data stream. A circuit detects a first corner of a leading edge of the input document based on the detected edge data and for establishing a first coordinate value therefrom and a second corner of a leading edge of the input document based on the detected edge data and for establishing a second coordinate value therefrom. The system further determines a minimum and maximum location for a leading edge of the scanned document and determines a minimum and maximum location for a trailing edge of the scanned document.

Abstract: A method and apparatus are provided for classifying image data. A neighborhood average gray value may be determined for the input image data. A threshold value may then be determined based on the neighborhood average gray value. Pixels are evaluated to determine if a gray level difference between the pixel and the neighborhood average gray level is greater than the threshold.

Abstract: The present invention provides a method and apparatus for classifying image data. A white class detector may receive input image data and determine a white class of a specified pixel based on local roughness, peak or count or valley count and a brightness. A pattern detection device may detect a pattern of pixels across a scan line or matrix of input data and compare the pattern with a plurality of predetermined pixel patterns.

Abstract: The present invention provides a method and apparatus for classifying image data. A video average may be determined from the image data. Peak detection may then be limited to an area within the image data where the video average is above a first threshold. Valley detection may be limited to an area where the video average is below a second threshold.