Grayscale image de-speckle algorithm
AssigneeXerox Corporation
InventorsHui Cheng, Ying-wei Lin, Stuart A. Schweid
Life of this patent
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Abstract
An annular window-shaped structuring element is provided for image processing to remove speckles from a scanned image. The window-shaped structuring element is composed of two differently sized squares sharing the same geometric center-point. The pixel to be analyzed with the structuring element is at the center-point. The structuring element is used in a method to remove speckles from binary, grayscale, and/or color images by first eroding the image, detecting speckles relative to other pixels in the image, and removing declared speckles. The method may additionally include a halftoning module to protect halftone images.
Claims34
An image processing system including a de-speckle algorithm having an associated structuring element A for detecting and removing speckles from a scanned image comprising a window shape comprising two squares of different sizes sharing the same geometric center point, wherein the pixel to be evaluated is at the center point of the structuring element A, wherein an inner square of the structuring element A has a side dimension N, and an outer square has a side dimension M, wherein N represents a largest speckle that can be removed and M represents a dimension the speckle lies from other objects.
A method for removing speckles using an algorithm comprising
- (a) eroding a grayscale image if the background is light or dilating the grayscale image if the background is dark with a structuring element A for detecting and removing speckles from a scanned image comprising a window shape comprising two squares of different sizes sharing the same geometric center point, wherein the pixel to be evaluated is at the center point of the structuring element A;
- (b) detecting potential speckles by examining each eroded pixel within the structuring element by a pixel value and a pixel location relative to other pixels;
- (c) evaluating whether a detected potential speckle is an actual speckle;
- and
- (d) removing pixels determined to be actual speckles.
Dependencies are inferred from the claim text.