Method and system for preserving image quality in an economy print mode
First Claim
Patent Images
1. A system for maintaining edge pixels in a reduced coverage image, comprising:
- a halftoning circuit to convert pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage, the halftone screen having a predetermined number of thresholds, the halftone screen having a first number of thresholds set to a first value, the first number being a first percentage of the predetermined number, the first percentage being equal to 100% minus the predetermined reduced coverage percentage, the halftone screen having a second number of linearly scaled thresholds, the second number being a second percentage of the predetermined number, the second percentage being equal to the predetermined reduced coverage percentage; and
an edge detection circuit to determine a non-edge pixel in the binary image data;
said edge detection circuit determining if a target pixel of binary image data in a window of pixels of binary image data is a non-white pixel;
said edge detection circuit comparing, when said edge detection circuit determines that the target pixel of binary image data in a window of pixels of binary image data is a non-white pixel, the window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to the predetermined reduced coverage percentage, said predetermined pattern of pixels of binary image data not including pixels of binary image data converted from the pixels of continuous image data;
said edge detection circuit determining that the target pixel is a non-edge pixel when said edge detection circuit determines that every non-white pixel location in the predetermined pattern of pixels of binary image data corresponds to a non-white pixel location in the window of pixels of binary image data.
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Abstract
A system and method converts pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage; determines if a target pixel of binary image data is a non-white pixel; compares a window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to the predetermined reduced coverage percentage; determines that the target pixel is a non-edge pixel; and reduces the number of non-white pixels in the binary image data based upon the determination that the target pixel is a non-edge pixel.
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Citations
18 Claims
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1. A system for maintaining edge pixels in a reduced coverage image, comprising:
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a halftoning circuit to convert pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage, the halftone screen having a predetermined number of thresholds, the halftone screen having a first number of thresholds set to a first value, the first number being a first percentage of the predetermined number, the first percentage being equal to 100% minus the predetermined reduced coverage percentage, the halftone screen having a second number of linearly scaled thresholds, the second number being a second percentage of the predetermined number, the second percentage being equal to the predetermined reduced coverage percentage; and an edge detection circuit to determine a non-edge pixel in the binary image data; said edge detection circuit determining if a target pixel of binary image data in a window of pixels of binary image data is a non-white pixel; said edge detection circuit comparing, when said edge detection circuit determines that the target pixel of binary image data in a window of pixels of binary image data is a non-white pixel, the window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to the predetermined reduced coverage percentage, said predetermined pattern of pixels of binary image data not including pixels of binary image data converted from the pixels of continuous image data; said edge detection circuit determining that the target pixel is a non-edge pixel when said edge detection circuit determines that every non-white pixel location in the predetermined pattern of pixels of binary image data corresponds to a non-white pixel location in the window of pixels of binary image data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for maintaining edge pixels in a reduced coverage image, comprising:
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(a) converting pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage, the halftone screen having a predetermined number of thresholds, the halftone screen having a first number of thresholds set to a first value, the first number being a first percentage of the predetermined number, the first percentage being equal to 100% minus the predetermined reduced coverage percentage, the halftone screen having a second number of linearly scaled thresholds, the second number being a second percentage of the predetermined number, the second percentage being equal to the predetermined reduced coverage percentage; (b) determining if a target pixel of binary image data in a window of pixels of binary image data is a non-white pixel; (c) comparing, when it is determined that the target pixel of binary image data in a window of pixels of binary image data is a non-white pixel, the window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to the predetermined reduced coverage percentage, the predetermined pattern of pixels of binary image data not including pixels of binary image data converted from the pixels of continuous image data; and (d) determining that the target pixel is a non-edge pixel when it is determined that every non-white pixel location in the predetermined pattern of pixels of binary image data corresponds to a non-white pixel location in the window of pixels of binary image data. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for maintaining edge pixels in a reduced coverage image, comprising:
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(a) converting pixels of continuous image data to pixels of binary image data using a halftone screen corresponding to a predetermined reduced coverage percentage, the halftone screen having a predetermined number of thresholds, the halftone screen having a first number of thresholds set to a first value, the first number being a first percentage of the predetermined number, the first percentage being equal to 100% minus the predetermined reduced coverage percentage, the halftone screen having a second number of linearly scaled thresholds, the second number being a second percentage of the predetermined number, the second percentage being equal to the predetermined reduced coverage percentage; (b) determining if a target pixel of binary image data in a window of pixels of binary image data is a non-white pixel; (c) comparing, when it is determined that the target pixel of binary image data in a window of pixels of binary image data is a non-white pixel, the window of pixels of binary image data with a predetermined pattern of pixels of binary image data corresponding to a reduced coverage percentage that is less than the predetermined reduced coverage percentage, the predetermined pattern of pixels of binary image data not including pixels of binary image data converted from the pixels of continuous image data; (d) determining that the target pixel is a non-edge pixel when it is determined that every non-white pixel location in the predetermined pattern of pixels of binary image data that is less than the predetermined reduced coverage percentage corresponds to a non-white pixel location in the window of pixels of binary image data; and (e) reducing, corresponding to the predetermined reduced coverage percentage, the number of non-white pixels in the binary image data based upon the determination that the target pixel is a non-edge pixel. - View Dependent Claims (18)
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Specification