Abstract: A method for obtaining bitonal image data from a document obtains scanned color image data from at least two color channels and identifies, in the scanned color image data, at least one region of interest (R1) containing foreground content and background content. At least one threshold data value is obtained according to an image attribute that differs between the foreground content and the background content within the region of interest (R1). The scanned color image data of the document is converted to bitonal image data according to the at least one threshold data value obtained from the region of interest (R1).

Abstract: A method for determining skew angle (5) and location of a document in an over-scanned digital image is disclosed. A document is scanned to capture a gray scale image. The outline pixel (1) of a document from the captured gray scale image are connected (2). An initial angle is set at zero and a x-minimum, y-minimum, x-maximum, and y-maximum of the polygon are determined (3). A rectangular boundary (4) area based on the x-minimum, y-minimum, x-maximum, and y-maximum is calculated and recorded. The angle is recorded and the polygon is rotated z-degree. The process is repeated and a minimum boundary area is selected. An angle corresponding to the minimum boundary is the skew angle of the document.

Abstract: A process and system for automating the image quality inspection and correction for scanned document which previously required a human operator. For every scanned and thresholded image, the process and system performs an automatic evaluation through a binary image quality detection system which generates an image noise index indicative of the amount of image artifacts or image loss. When a poor quality scanned page is detected, for example, too much speckle noise, the gray scale image is retrieved or the image is rescanned. The gray scale image then automatically undergoes an image quality correction process to produce a clean, readable binary image.

Abstract: A scanner for digitizing a document includes a digitizer for digitizing the document into a first color space; a circuit for converting the digitized data into a second color space having a luminance channel and two chrominance channels; a multiplexer having text, approximate actual color of a uniform area and a predetermined color as input for selecting either the text, approximate actual color or the predetermined color as outputs; and multiplexer control input which determines which of the outputs will be selected as actual output based on a uniform area of the document.

Abstract: A vertical black line removal system (VBLR) is adapted to remove unwanted vertical lines produced on scanned document images by dust or other particles on the imaging apparatus. The VBLR system, placed in a document scanner after the binarization equipment, creates a stored histogram table including the difference values of “1” or “0” for the first and second image data. A vertical black line search processor compares each histogram value in the histogram table with a predetermined threshold value such that when the histogram value is greater than the threshold value the histogram value and the image address indicating the location of defect are stored in memory.

Abstract: A method for performing color dropout on a digitized document, the method comprises the steps of obtaining color values from the digitized document for background and a color of interest to a user; transforming the color values of the background and the color of interest into an identical gray scale value according to a color dropout function; obtaining a gray scale value different from the identical gray scale value for the remaining portion of the image according to the color dropout function; and thresholding the gray scale values obtained from the previous steps to obtain a binary image that substantially eliminates color classification error which retains character integrity by a functional transformation that suppresses color fringe artifacts.

Abstract: An automatic method for processing a color form includes: a) scanning the color form in color space, forming a digital color image, and converting the digital color image into a two-dimensional binary image in chrominance space; and b) conducting a color form dropout process.

Abstract: A method for determining skew angle (5) and location of a document in an over-scanned digital image is disclosed. A document is scanned to capture a gray scale image. The outline pixel (1) of a document from the captured gray scale image are connected (2). An initial angle is set at zero and a x-minimum, y-minimum, x-maximum, and y-maximum of the polygon are determined (3). A rectangular boundary (4) area based on the x-minimum, y-minimum, x-maximum, and y-maximum is calculated and recorded. The angle is recorded and the polygon is rotated z-degree. The process is repeated and a minimum boundary area is selected. An angle corresponding to the minimum boundary is the skew angle of the document.

Abstract: A process and system for automating the image quality inspection and correction for scanned document which previously required a human operator. For every scanned and thresholded image, the process and system performs an automatic evaluation through a binary image quality detection system which generates an image noise index indicative of the amount of image artifacts or image loss. When a poor quality scanned page is detected, for example, too much speckle noise, the gray scale image is retrieved or the image is rescanned. The gray scale image then automatically undergoes an image quality correction process to produce a clean, readable binary image.

Abstract: A vertical black line removal system (VBLR) is adapted to remove unwanted vertical lines produced on scanned document images by dust or other particles on the imaging apparatus. The VBLR system, placed in a document scanner after the binarization equipment, creates a stored histogram table including the difference values of “1” or “0” for the first and second image data. A vertical black line search processor compares each histogram value in the histogram table with a predetermined threshold value such that when the histogram value is greater than the threshold value the histogram value and the image address indicating the location of defect are stored in memory.

Abstract: A method for performing color dropout on a digitized document, the method comprises the steps of obtaining color values from the digitized document for background and a color of interest to a user; transforming the color values of the background and the color of interest into an identical gray scale value according to a color dropout function; obtaining a gray scale value different from the identical gray scale value for the remaining portion of the image according to the color dropout function; and thresholding the gray scale values obtained from the previous steps to obtain a binary image that substantially eliminates color classification error which retains character integrity by a functional transformation that suppresses color fringe artifacts.

Abstract: An automatic method for processing a color form includes: a) scanning the color form in color space, forming a digital color image, and converting the digital color image into a two-dimensional binary image in chrominance space; and b) conducting a color form dropout process.

Abstract: A scanner for digitizing a document includes a digitizer for digitizing the document into a first color space; a circuit for converting the digitized data into a second color space having a luminance channel and two chrominance channels; a multiplexer having text, approximate actual color of a uniform area and a predetermined color as input for selecting either the text, approximate actual color or the predetermined color as outputs; and multiplexer control input which determines which of the outputs will be selected as actual output based on a uniform area of the document.

Abstract: A region-based binarization system applies adaptive thresholding and image rendering to a gray scale image to generate first and second binary images. The gray scale image can also be subsampled to acquire a low resolution image and locations of photographic images are detected in the low resolution image. Further, photographic images of the detected photographic images which have a rectangular shape are identified and a classification map which distinguishes pixels in the rectangular shaped photographic images from remaining pixels is generated. A final binary image can then be formed from the first and second binary images based on the classification map. The binarization system of the present invention is effective when the gray scale image is captured from a document which contains at least both photographic and text portions.

Abstract: A method of generating an M-bit grayscale image from an N-bit grayscale image, where 1<M<N, includes the steps of: for each pixel in the N-bit image, determining a threshold, based on the values of neighboring pixels, for generating the most significant bit (MSB) of the M-bit image, and determining thresholds, based on the threshold determined in step i) and the values of surrounding pixels, for each successive less significant bit(s) (LSB) of the M-bit image. The thresholds are used to quantize the pixels in the N-bit image to produce the M-bit image. The resulting M-bit image can be displayed on a multilevel display device for good readability, and the most significant bit of the M-bit image can be archived and printed on a binary printer thereby minimizing long term storage requirements.

Abstract: A digital image processing system applies an edge-based adaptive thresholding technique with different contrast parameters to convert an image into first and second binary images. In the digital processing system of the invention, the first and second binary images are compared and a map of the difference between the first and second binary images is generated. A vertical profile of this map is projected and local peaks in the vertical profile which correspond to a vertical pattern or artifact in the map is detected. Pixels in the first binary image are reversed based on the vertical pattern or artifact in the map. This system is effective in reducing vertical artifacts produced by scanners.

Abstract: A digital image processing method and system is adapted to remove diagonally disposed artifacts such as lines, dots, dashes etc., from a scanned skew corrected document or image. The system and method converts a captured skew corrected image into first and second binary images and generates a map indicative of a difference between the first and second binary images. Black pixels in the map are projected based on a skew angle of the image to form a projection profile, and an image based on the map, detected peaks in the projection profile and the pixels is created.

Abstract: An image processing method for detection and removal of halftone dots includes converting a gray scale image into a binary thresholded image with halftone dots; identifying halftone regions within the binary thresholded image; and removing halftone dots from the identified halftone regions. The identifying halftone regions step is effected by classifying the binary thresholded image to produce a halftone classification map; reclassifying the halftone classification map to produce a halftone reclassification map of lines with plural halftone pixels in each line; merging the halftone pixels in each line in the halftone reclassification map to produce a halftone line map; and merging the lines of the halftone line map to produce a halftone region map.

Abstract: A method for scanning and detecting number and skew angle of photographs (12) and removing edge artifacts is disclosed. A plurality of photograph is placed on a scanner (11). A low resolution scan (34) is conducted of the photographs (12) to produce a plurality of low resolution images. A plurality of polygons is constructed, wherein each polygon contains at least one low resolution image. A number of polygons is determined and compared to the number of photographs. If the number of polygons is less than the number of photographs, the photographs are repositioned to separate overlapped photographs and the low resolution is repeated. A skew angle and location is determined for each of the photographs. A first photograph is selected and the first photograph is scanned at a high resolution to produce a high resolution image. The high resolution image is deskewed and cropped to remove the edge artifacts.

Abstract: A method of identifying business forms that uses contour polygons constructed from linear line segments. Wherein contour polygons are derived from a windowed raster scan of the forms' image. Each of the contour polygons is examined to determine if it represents a text component or a graphic component. All text contour polygons and graphic contour polygons are grouped and profiled. The accumulated profiles are compared against a library of stored profiles of known forms so as to determine a best match thereby identifying the unknown form.