US6002804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tone dependent variable halftoning with adjustable algorithm selection
Assignee: Hewlett Packard Development Co LP
•
Filing: 1998-03-26
•
Granted: 1999-12-14
•
Expires: 2018-03-26
Abstract
Abstract Optimally determined halftoning algorithms are applied to tone values by selecting among combinations of at least two algorithms that best address the tradeoff between output quality and rendering performance. Input tone values are scrutinized and matched with the algorithm combination that processes the associated tone values in a manner that increases performance (including data compressibility) without sacrificing output quality. The selection process is computationally simple and fast. Reliability is ensured because the combinations of halftoning algorithms are tabulated as a result of analysis of test samples of the printed output.
Inventors
- 👤 Ranjit Bhaskar
- 👤 Kevin R. Hudson
- 👤 Jay S Gondek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:04
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/52
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
A method for selecting among at least two halftoning algorithms to apply to pixel tone value data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison; and based upon the results of the comparison, selecting for each colorant tone value a halftoning algorithm to apply to the colorant tone values for the given pixel, wherein the comparing step includes comparing the absolute and relative tone values of the two colorants.
Claim 2
Independent Claim
109 words
A method for selecting among at least two halftoning algorithms to apply to pixel tone value data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison; and based upon the results of the comparison, selecting for each colorant tone value a halftoning algorithm to apply to the colorant tone values for the given pixel, wherein the comparing step includes comparing the absolute and relative tone values of the two colorants.
Claim 3
Independent Claim
116 words
A method for selecting among at least two halftoning algorithms to apply to pixel tone value data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison: based upon the results of the comparison, selecting for each colorant tone value a halftoning algorithm to apply to the colorant tone values for the given pixel, wherein the selecting step includes the steps of: establishing a tabulation of predetermined halftoning algorithm combinations correlated to possible results of the comparing step.
Claim 4
Independent Claim
116 words
A method for selecting among at least two halftoning algorithms to apply to pixel tone value data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison: based upon the results of the comparison, selecting for each colorant tone value a halftoning algorithm to apply to the colorant tone values for the given pixel, wherein the selecting step includes the steps of: establishing a tabulation of predetermined halftoning algorithm combinations correlated to possible results of the comparing step.
Claim 5
Dependent Claim
18 words
The method of claim 2 including the steps of indexing the tabulation to serve as a lookup table.
Claim 6
Dependent Claim
34 words
The method of claim 2 wherein the comparing step includes producing an index that is representative of the results of the comparison, and matching that index with one of the indices of the tabulation.
Claim 7
Dependent Claim
48 words
The method of claim 4 wherein the pixel tone value data streams include bytes representing the tone value of particular colorants, and wherein the comparing steps includes comparing a selection of significant bits of the bytes of tone value data that are to be applied to a pixel.
Claim 8
Dependent Claim
27 words
The method of claim 2 wherein the establishing step includes combining the halftoning algorithms in combinations of at least one matrix-based algorithm and one error diffusion algorithm.
Claim 9
Dependent Claim
56 words
The method of claim 2 wherein the establishing step includes rendering on the display device a variety of image portions, each portion resulting from a variety of selected pixel tone values and selected combinations of halftoning algorithms thereby to provide observable output to use as an aid in establishing the tabulation of predetermined halftoning algorithm combinations.
Claim 10
Dependent Claim
135 words
A computer-readable medium having stored thereon instructions for controlling a digital computer in selecting among at least two halftoning algorithms to apply to pixel data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison; and selecting one of a number of halftoning algorithms to apply to each of the compared tone values, the selection being based upon the results of the comparing step, the instructions including a lookup table for carrying out the selecting step, wherein the lookup table includes predetermined combinations of halftoning algorithms associated with indices representative of possible results of the comparing step.
Claim 11
Dependent Claim
135 words
A computer-readable medium having stored thereon instructions for controlling a digital computer in selecting among at least two halftoning algorithms to apply to pixel data steams that represent the tone values of two or more colorants to be applied to pixels in rendering a colored image, the method including the steps of: comparing, for a given pixel, the tone values of at least two of the colorants; noting the results of the comparison; and selecting one of a number of halftoning algorithms to apply to each of the compared tone values, the selection being based upon the results of the comparing step, the instructions including a lookup table for carrying out the selecting step, wherein the lookup table includes predetermined combinations of halftoning algorithms associated with indices representative of possible results of the comparing step.
References Cited (Backward Citations)
US4413275A
Cited
US4500919A
Cited
US5091734A
Cited
US4680645A
Cited
US4866514A
Cited
EP0349234A2
Cited
US5131075A
Cited
EP0390473A2
Cited
US4974171A
Cited
US5031050A
Cited
EP0488534A2
Cited
EP0493085A2
Cited
US5168552A
Cited
US5519791A
Cited
US5731823A
Cited
US5602971A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-13 | 2003-06-14 | 2003-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-13 | 2007-06-14 | 2007-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-13 | 2011-06-14 | 2011-12-14 | $7700.00 | Window Closed / Lapsed |