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US 4,680,645 AGranted
Method for rendering gray scale images with variable dot sizes
AssigneeHewlett-Packard Company
InventorsGary J. Dispoto, Larry R. Mather, John D. Meyer
Life of this patent
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Abstract
The capability of varying sizes of a dot in a printer is fully exploited to provide a gray scale image of superior quality. Errors in gray level are used to modulate the sizes of the dots in producing the image.
Claims6
A method of generating a gray scale image on a surface comprising a matrix of pixels, the method comprising the steps of:
- depositing a first dot of a predetermined size on a selected pixel on the surface;
- determining a gray level error of the deposited first dot;
- scaling the error and assigning the scaled error to a pixel adjacent to the selected pixel;
- determining a size of a second dot in response to the scaled error to provide a second dot of a predetermined size;
- depositing the second dot of a predetermined size on the adjacent pixel.
2 more elements
An apparatus for printing a gray scale image on a surface comprising:
- means for depositing a first dot of a predetermined size on a selected area of the surface;
- means for determining an error in gray level in the selected area;
- means for scaling the error and assigning the scaled error to an area adjacent to the selected area;
- and
- means for depositing a second dot of a predetermined size on the adjacent area, the second dot being of a size predetermined in response to the scaled error.
2 more elements
Dependencies are inferred from the claim text.