US5122884A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line rasterization technique for a non-gray scale anti-aliasing method for laser printers
Assignee: Hewlett Packard Development Co LP
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Filing: 1990-11-14
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Granted: 1992-06-16
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Expires: 2010-11-14
Abstract
Abstract A line rasterization technique for a non-gray scale anti-aliasing method smoothes the edges of a single pixel width line image to be printed by a binary imaging printer. The line image is generated by rasterizing an ideal line image as a plurality of raster lines to form a pixel representation of the line image to be communicated to the binary imaging printer. For each vertical transition point created by the ideal line image crossing two adjacent raster lines, the present invention smooths the line image by selectively modifying the on and off states of one or more pixels in an adjacent raster line on either side of the vertical transition point. The pixel representation of the line image is then communicated to the printer such that the printer may print the smoothed line image.
Inventors
- 👤 John M. Gilbert
- 👤 Lawrence J. Luckis
- 👤 Leonard R. Steidel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:12
CPC Classifications
G; G06; G06T; G06T11/00; G06T11/20; G06T11/23; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/128; G06K2215/00; G06K2215/0002; G06K2215/0062; G06K2215/0071
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
148 words
A method for rasterizing a single pixel width line image to be printed by a binary imaging printer having a specified horizontal and vertical resolution, comprising the steps of: providing a processor means with an ideal line image; rasterizing the ideal line image using the processor means to determine which pixels to turn on in a frame buffer memory means for storing a pixel representation of the image to be printed as a plurality of raster lines; for each vertical transition point created by the ideal line image crossing two adjacent raster lines, smoothing the line image by selectively modifying the on and off states of one or more pixels in an adjacent raster line on either side of the vertical transition point; and communicating the pixel representation stored in the frame buffer memory means to the printer such that the printer may print the smoothed line image.
Claim 2
Independent Claim
148 words
A method for rasterizing a single pixel width line image to be printed by a binary imaging printer having a specified horizontal and vertical resolution, comprising the steps of: providing a processor means with an ideal line image; rasterizing the ideal line image using the processor means to determine which pixels to turn on in a frame buffer memory means for storing a pixel representation of the image to be printed as a plurality of raster lines; for each vertical transition point created by the ideal line image crossing two adjacent raster lines, smoothing the line image by selectively modifying the on and off states of one or more pixels in an adjacent raster line on either side of the vertical transition point; and communicating the pixel representation stored in the frame buffer memory means to the printer such that the printer may print the smoothed line image.
Claim 3
Dependent Claim
105 words
The method of claim 1 wherein the step of smoothing the line image is accomplished by: for each pixel in the raster line currently being processed, determining an error height E for each pixel by comparing the height of the ideal line image with the height of a center line of the raster line currently being processed; adding the error height to an accumulated error value; if the accumulated error value is less than a predefined threshold, turning on the pixel; and if the accumulated error value is greater than or equal to predefined threshold, turning on a corresponding pixel in the adjacent raster line.
Claim 4
Dependent Claim
154 words
A non-gray scale anti-aliasing method for rasterizing a single pixel width line image to be printed by a binary imaging printer comprising the steps of: rasterizing an ideal representation of the line image using a processor means for processing a plurality of raster lines to form a pixel representation of the image to be communicated to the binary imaging printer; and for each pixel in a raster line where the ideal representation of the line image intersects the pixel currently being processed: accumulating an error value representing a fractional pixel error height of the ideal representation of the line image from an edge of the raster line for the pixel currently being processed; if the error value is less than a predefined comparison value, turning on the pixel currently being processed, otherwise turning on an associated pixel in a raster line adjacent to the raster line currently being processed and resetting the error value.
Claim 5
Dependent Claim
154 words
A non-gray scale anti-aliasing method for rasterizing a single pixel width line image to be printed by a binary imaging printer comprising the steps of: rasterizing an ideal representation of the line image using a processor means for processing a plurality of raster lines to form a pixel representation of the image to be communicated to the binary imaging printer; and for each pixel in a raster line where the ideal representation of the line image intersects the pixel currently being processed: accumulating an error value representing a fractional pixel error height of the ideal representation of the line image from an edge of the raster line for the pixel currently being processed; if the error value is less than a predefined comparison value, turning on the pixel currently being processed, otherwise turning on an associated pixel in a raster line adjacent to the raster line currently being processed and resetting the error value.
Claim 6
Dependent Claim
18 words
The method of claim 3 wherein the predefined comparison value is the total pixel height of a pixel.
Claim 7
Dependent Claim
27 words
The method of claim 3 wherein the step of resetting the error value is accomplished by subtracting the total height of a pixel from the error value.
Claim 8
Dependent Claim
153 words
A non-gray scale anti-aliasing method for rasterizing a single pixel width line image to be printed by a binary imaging printer comprising the steps of: rasterizing an ideal representation of the line image using a processor means for processing a plurality of raster lines to form a pixel representation of the image to be communicated to the binary imaging printer; and for each pixel in a raster line where the ideal representation of the line image intersects the pixel currently being processed: turning on the pixel currently being processed; accumulating an error value representing a fractional pixel error height of the ideal representation of the line image from an edge of the raster line for the pixel currently being processed; if the error value is greater than a predefined comparison value, turning on an associated pixel in a raster line adjacent to the raster line currently being processed and resetting the error value.
Claim 9
Dependent Claim
153 words
A non-gray scale anti-aliasing method for rasterizing a single pixel width line image to be printed by a binary imaging printer comprising the steps of: rasterizing an ideal representation of the line image using a processor means for processing a plurality of raster lines to form a pixel representation of the image to be communicated to the binary imaging printer; and for each pixel in a raster line where the ideal representation of the line image intersects the pixel currently being processed: turning on the pixel currently being processed; accumulating an error value representing a fractional pixel error height of the ideal representation of the line image from an edge of the raster line for the pixel currently being processed; if the error value is greater than a predefined comparison value, turning on an associated pixel in a raster line adjacent to the raster line currently being processed and resetting the error value.
Claim 10
Dependent Claim
132 words
An improved method for smoothing a line image to be printed by a binary imaging printer, the line image being supplied by a processor means for rasterizing an ideal representation of the line image to determine which pixels to turn on and which pixels to turn off in a frame buffer memory means for storing a pixel representation of the line image as a plurality of raster lines to be communicated to and printed by the printer, the improvement comprising the step of: smoothing the pixel representation of the line image in the frame buffer memory means by selectively modifying the on and off states of one or more pixels on either side of each vertical transition point created by the ideal representation of the line image crossing two adjacent raster lines.
Claim 11
Dependent Claim
132 words
An improved method for smoothing a line image to be printed by a binary imaging printer, the line image being supplied by a processor means for rasterizing an ideal representation of the line image to determine which pixels to turn on and which pixels to turn off in a frame buffer memory means for storing a pixel representation of the line image as a plurality of raster lines to be communicated to and printed by the printer, the improvement comprising the step of: smoothing the pixel representation of the line image in the frame buffer memory means by selectively modifying the on and off states of one or more pixels on either side of each vertical transition point created by the ideal representation of the line image crossing two adjacent raster lines.
Claim 12
Independent Claim
186 words
A method for smoothing an ideal line image to be printed by a binary imaging printer having a specified horizontal and vertical resolution, comprising the steps of: rasterizing the ideal line image using a processor to process a plurality of horizontal raster lines comprised of a plurality of pixels, each pixel having a given total area, to form a pixel representation of the line image in a frame buffer; and smoothing the horizontal components of the ideal line image by performing the following steps for each of pair of adjacent horizontal raster lines having a vertical transition point created by the ideal line image crossing two adjacent raster lines: accumulating an error value representing a fractional pixel error height of the ideal line image from a predefined reference point for a plurality of pixels in the raster line; determining if the error value is greater than a predefined comparison value; and if the error value is greater than the predefined comparison value, turning on a pixel in the adjacent raster line that is vertically adjacent to the pixel currently being processed and resetting the error value.
Claim 13
Independent Claim
186 words
A method for smoothing an ideal line image to be printed by a binary imaging printer having a specified horizontal and vertical resolution, comprising the steps of: rasterizing the ideal line image using a processor to process a plurality of horizontal raster lines comprised of a plurality of pixels, each pixel having a given total area, to form a pixel representation of the line image in a frame buffer; and smoothing the horizontal components of the ideal line image by performing the following steps for each of pair of adjacent horizontal raster lines having a vertical transition point created by the ideal line image crossing two adjacent raster lines: accumulating an error value representing a fractional pixel error height of the ideal line image from a predefined reference point for a plurality of pixels in the raster line; determining if the error value is greater than a predefined comparison value; and if the error value is greater than the predefined comparison value, turning on a pixel in the adjacent raster line that is vertically adjacent to the pixel currently being processed and resetting the error value.
Claim 14
Dependent Claim
18 words
The method of claim 8 wherein the predefined comparison value is the total pixel height of a pixel.
Claim 15
Dependent Claim
27 words
The method of claim 8 wherein the step of resetting the error value is accomplished by subtracting the total height of a pixel from the error value.
Claim 16
Dependent Claim
33 words
The method of claim 8 further comprising the step of: if the error value is greater than the predefined comparison value, turning off the pixel currently being processed before resetting the error value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-16 | 1995-12-16 | 1996-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-16 | 1999-12-16 | 2000-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-16 | 2003-12-16 | 2004-06-16 | $7700.00 | Window Closed / Lapsed |