Antialiasing apparatus and method for computer printers
First Claim
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1. In a computer system having a digital processor, a printer, and means for generating a bitonal bitmap to support printer printout of processor output, the bitonal bitmap having a plurality of pixels, each pixel having a value, printer apparatus comprising:
- a plurality of predetermined grayscale values derived from a learning pattern, the learning pattern representing typical continuous data; and
a mapping member coupled between means for generating a bitonal bitmap and the printer for forming a grayscale bitmap from the bitonal bitmap, the grayscale bitmap having a plurality of pixels, each pixel of the grayscale bitmap corresponding to a respective pixel of the bitonal bitmap, the mapping member receiving the bitonal bitmap from the generating means and for each pixel of the bitonal bitmap, assigning a predetermined grayscale value to the corresponding pixel in the grayscale bitmap.
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Abstract
Printer apparatus provides a grayscale bitmap from a bitonal bitmap of desired output data. The apparatus includes a mapping function implemented as a lookup table for assigning predetermined grayscale values to bitonal bitmap pixels according to the neighborhood or subset of bitonal bitmap pixels including the subject pixel. From the grayscale values the laser of the laser printer is modulated to produce shades of gray during the printing of the desired data.
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Citations
25 Claims
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1. In a computer system having a digital processor, a printer, and means for generating a bitonal bitmap to support printer printout of processor output, the bitonal bitmap having a plurality of pixels, each pixel having a value, printer apparatus comprising:
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a plurality of predetermined grayscale values derived from a learning pattern, the learning pattern representing typical continuous data; and a mapping member coupled between means for generating a bitonal bitmap and the printer for forming a grayscale bitmap from the bitonal bitmap, the grayscale bitmap having a plurality of pixels, each pixel of the grayscale bitmap corresponding to a respective pixel of the bitonal bitmap, the mapping member receiving the bitonal bitmap from the generating means and for each pixel of the bitonal bitmap, assigning a predetermined grayscale value to the corresponding pixel in the grayscale bitmap. - View Dependent Claims (2, 3, 4, 5, 15, 16, 17)
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6. Printer apparatus for use in a computer system comprising:
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bitmap generating means for receiving from a digital processor a desired data and for generating a bitonal bitmap to support printout of the desired data, the bitonal bitmap having a plurality of pixels each having a respective pixel value; a plurality of predetermined grayscale values derived from a learning pattern, the learning pattern representing typical continuous data; a mapping member coupled to receive the bitonal bitmap from the bitmap generating means, the mapping member forming a grayscale bitmap from the bitonal bitmap according to a predefined mapping function, the grayscale bitmap having a plurality of pixels, each pixel of the grayscale bitmap corresponding to a respective pixel of the bitonal bitmap and having a grayscale value, the predetermined mapping function including for each subject pixel of the bitonal bitmap, mapping a subset of pixels of the bitonal bitmap including the subject pixel to a predetermined grayscale value; and print means coupled to the mapping member for receiving therefrom the formed grayscale bitmap, the print means being capable of grayscale printing and the formed grayscale bitmap enabling the print means to printout, in grayscale, the desired data. - View Dependent Claims (7, 8, 9, 18, 19, 20)
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10. In a computer network having a digital processor, a printer, and means for generating a bitonal bitmap to support printer printout of desired processor output data, the bitonal bitmap having a plurality of pixels each pixel having a respective value, a method of printing desired processor output data comprising the steps of:
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providing a plurality of predetermined grayscale values; forming a grayscale bitmap of the desired processor output data from the bitonal bitmap of the desired processor output data, the grayscale bitmap having a plurality of pixels, each pixel of the grayscale bitmap corresponding to a respective pixel of the bitonal bitmap and having a grayscale value, said step of forming a grayscale bitmap including, for each pixel of the bitonal bitmap assigning a predetermined grayscale value to the corresponding pixel in the grayscale bitmap; and providing the grayscale bitmap to print means capable of grayscale printing, the grayscale bitmap enabling the print means to printout in grayscale the desired processor output data. - View Dependent Claims (11, 12, 13, 14, 21, 22, 23, 24, 25)
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Specification