EP0444290A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and system for reproducing monochromatic and color images using ordered dither and error diffusion
Assignee: HP Inc
•
Filing: 1990-12-19
•
Granted: —
•
Expires: 2010-12-19
Abstract
Abstract A method and system for color and monochromatic printing wherein ordered dither and error diffusion processes are combined to provide high quality printed images with good spatial resolution, good gray scale transitions, good low frequency and high frequency responses and a high computational speed. Using this process, gray scale numbers representative a of scanned (10, 36) image are summed (56, 58, 60, 62) for each super pixel of the scanned image and divided (72, 74, 76, 78) by a chosen gray level normalizing factor. This division operation is done to obtain a normalized ordered dither quotient number of drops (dots) (C Q , M Q , Y Q , K Q ) to be printed in super pixels and to further obtain an error remainder number of dots (C R , M R , Y R , K R ) to be dispersed to surrounding super pixels. The normalized ordered dither quotient number of dots are printed (146) in pre-assigned individual pixels within printed super pixels, and the error remainder number of drops are diffused (112, 114, 116, 118) to other pre-assigned surrounding or adjacent super pixels. In this manner, a combination of ordered dither and error diffusion signal processing and printing is achieved to simultaneously take advantage of some of the best characteristics of both types of signal processing printing. In color printing, the above operation is carried out in each of a plurality of separate color planes (C, M, Y, K), and all of the quotient information (C Q , M Q , Y Q , K Q ) is retained and printed (146) in a predetermined priority sequence for each color plane. Thus, this invention is not only operative to retain the maximum amount of image data for each color plane (C, Y, M, K), but it is printed in an output matrix of super pixels in such a manner as to maximize overall print quality of the reproduced color image.
Inventors
- 👤 C.S. Chan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:49
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/52; H04N1/40; H04N1/405; H04N1/4055
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
94 words
A method of converting scanned image information to a printed media output which includes the steps of: (a) scanning (10, 36) an image to generate input image data (15), (b) converting (56, 58, 60, 62 and 72, 74, 76, 78) said input image data to ordered dither quotient data, and (c) assigning (128, 130, 132, 134) all of said ordered dither quotient data in a predetermined priority sequence to a predefined number of pixels in each of a series of printed output super pixels or matrixes defining a given area of said printed media.
Claim 2
Dependent Claim
24 words
The method defined in Claim 1 wherein said ordered dither quotient data is obtained for each of a plurality of separate color planes (C,Y,M,K).
Claim 3
Independent Claim
94 words
A method of converting scanned image information to a printed media output which comprises the steps of: (a) scanning (10, 36) an image to generate input image data, (b) converting (72, 74, 76, 78) said image input data to ordered dither quotient data and error diffusion remainder data, (c) recombining (112, 114, 116, 118 and 120, 122, 124, 126) said error diffusion remainder data with said input image data, and (d) assigning (128, 130, 132, 134) said ordered dither quotient data in a predetermined printing sequence to each of a plurality of super pixels.
Claim 4
Dependent Claim
31 words
The method defined in Claim 3 wherein the data processed in each of steps (a), (b), (c), and (d) is done in each of a plurality of separate color planes (C,Y,M,K).
Claim 5
Independent Claim
74 words
The method defined in Claims 3 or 4 wherein error remainder data which is related to said ordered dither quotient data (C Q , M Q , Y Q , K Q ,) and is diffused (Figure 2) into super pixels adjacent to a just printed super pixel (m x n) and all ordered dither quotient information is retained and printed in said matrixes (146) and is not lost as a result of thresholding.
Claim 6
Independent Claim
74 words
The method defined in any one of Claims 3, 4 or 5 wherein said ordered dither quotient data and said error diffusion remainder data is generated in each color plane and said error diffusion remainder data is recombined (112, 114, 116, 118 and 120, 122, 124, 126) with said input image data in each color plane, and said ordered dither quotient data is processed in each color plane to said plurality of super pixels.
Claim 7
Independent Claim
206 words
A method for converting scanned color image information to printed media hardcopy output which comprises the steps of: (a) scanning (10, 36) a color image to generate information containing cyan (C), magenta (M), yellow (Y), and black (K) super pixel data, (b) adding (56, 58, 60, 62) said data in step (a) above in separate color planes to obtain super pixel summed data C sum , M sum , Y sum , and K sum for super pixel information in each color plane, (c) dividing (72, 74, 76, 78) the summed information in step (b) above by a chosen normalizing factor to obtain a quotient (Q) signal and a remainder (R) signal in each color plane, C Q , C R , M Q , M R ; Y Q , Y R ; and K Q , and K R , (d) distributing (112, 114, 116, 118) said error remainder signals in step (c) above in each color plane in an error diffusion process to selected super pixels in each color plane, and (e) distributing (128, 130, 132, 134) said quotient signals in each color plane in an ordered dither process to an ordered dither matrix from which a printed color image may be derived.
Claim 8
Dependent Claim
48 words
The method defined in Claim 7 wherein said quotient signals are assigned in a predetermined priority printing sequence to an output matrix (146) in such a manner as to optimize the printed colors per unit area and thereby maximize the print quality of a hardcopy color image reproduction.
Claim 9
Dependent Claim
48 words
An ordered dither process for image reproduction which includes: (a) generating (72, 74, 76, 78) ordered dither quotient data representative of a scanned image, and (b) assigning (128, 130, 132, 134) all of said quotient data in a predetermined priority sequence to individual pixels within a super pixel.
Claim 10
Dependent Claim
34 words
The process defined in Claim 9 which further includes diffusing (112, 114, 116, 118) error remainder information related to said quotient data to a plurality of other super pixels adjacent to said super pixel.
Claim 11
Dependent Claim
41 words
The process defined in Claims 9 or 10 wherein each step therein is done in each of a plurality of color planes (C, Y, M, K) and in a dot-next-to-dot print assignment sequence to said individual pixels within said super pixel.
Claim 12
Dependent Claim
40 words
The process defined in Claims 10 or 11, each step therein is done in each of a plurality of color planes (C, Y, M, K) and in a dot-next-to-dot print assignment sequence to said individual pixels within said super pixel.
Claim 13
Independent Claim
104 words
An apparatus for converting scanned image information to a printed media output which comprises: (a) means (10, 36) for scanning an image to generate input image data, (b) means (56, 58, 60, 62 and 72, 74, 76, 78) connected to said scanning means for converting said input image data to ordered dither quotient data, and (c) means (128, 130, 132, 134) connected to said converting means for assigning said ordered dither quotient data in a predetermined priority sequence to a predefined number of pixels in each of a series of printed output super pixels or matrixes defining a given area of said printed media.
Claim 14
Dependent Claim
27 words
The apparatus defined in Claim 13 wherein said ordered dither quotient data is obtained for each of a plurality of separate color planes (C, Y, M, K).
Claim 15
Independent Claim
112 words
An apparatus for converting scanned image information to a printed media output which comprises: (a) means (10, 36) for scanning an image to generate input image data, (b) means connected to said scanning means for converting (56, 58, 60, 62 and 72, 74, 76, 78) said image input data to ordered dither quotient data and error diffusion remainder data, (c) means (112, 114, 116, 118) connected to said converting means for recombining said error diffusion remainder data with said input image data, and (d) means (128, 130, 132, 134) connected to said converting means for assigning said ordered dither quotient data in a predetermined printing sequence to a plurality of super pixels.
Claim 16
Dependent Claim
35 words
The apparatus defined in Claim 15 wherein the data processed in each means of subparagraphs (a), (b), (c), and (d) is done in each of a plurality of separate color planes (C, Y, M, K).
Claim 17
Independent Claim
56 words
The apparatus defined in Claims 15 or 16 wherein said apparatus includes means (112, 114, 116, 118) for diffusing said error remainder data into super pixels adjacent to a just printed super pixel and all ordered dither quotient information is retained and printed in said matrixes (146) and is not lost as a result of thresholding.
Claim 18
Dependent Claim
39 words
The apparatus defined in Claim 17 further including means (72, 74, 76, 78) for generating said quotient and remainder data for each of a plurality of different color planes such as the cyan, yellow, magenta, and black color planes.
Claim 19
Independent Claim
75 words
The apparatus defined in any one of Claims 15-18 which includes means (72, 74, 76, 78) for generating said ordered dither quotient data and said error diffusion remainder data in each color plane, and means (112, 114, 116, 118) for recombining said error diffusion remainder data with said input image data in each color plane, and means (146) for processing said ordered dither quotient data in each color plane to said plurality of super pixels.
Claim 20
Independent Claim
238 words
An apparatus for converting scanned color image information to printed media hardcopy output which comprises: (a) means (10, 36) for scanning a color image to generate information containing cyan (C), magenta (M), yellow (Y), and black (K) super pixel data, (b) means (56, 58, 60, 62) connected to said scanning means for adding said data in step (a) above in separate color planes to obtain super pixel summed data C sum , M sum , Y sum , and K sum for super pixel information in each color plane, (c) means (72, 74, 76, 78) connected to said adding means for dividing the summed information in step (b) above by a chosen normalizing factor to obtain a quotient (Q) signal and a remainder (R) signal in each color plane, C Q , C R ; M Q , M R ; Y Q , Y R ; and K Q , and K R , (d) means (112, 114, 116, 118) connected to said dividing means for distributing said remainder signals in step (c) above in each color plane in an error diffusion process to recombine said remainder signals in each color plane with the information summed in step (b) above, and (e) means connected to said dividing means for distributing said quotient signals in each color plane in an ordered dither process to an ordered dither matrix (146) from which a printed color image may be derived.
Claim 21
Dependent Claim
58 words
The apparatus defined in Claim 20 which further includes means (146) connected to said quotient signal distributing means for assigning said quotient signals in a predetermined priority printing sequence to an output matrix in such a manner as to optimize the printed colors per unit area and thereby maximize the print quality of a hardcopy color image reproduction.
Claim 22
Dependent Claim
51 words
An ordered dither apparatus which includes: (a) means (128, 130, 132, 134) for generating ordered dither quotient data representative of a scanned image, and (b) means (146) connected to said generating means for assigning all of said quotient data in a predetermined priority sequence to individual pixels within a super pixel.
Claim 23
Dependent Claim
44 words
The apparatus defined in Claim 22, further including means (112, 114, 116, 118) connected to said generating means (72, 74, 76, 78) for diffusing error remainder information related to said quotient data to a plurality of other super pixels adjacent to said super pixel.
Claim 24
Independent Claim
35 words
The apparatus defined in Claims 22 or 23, further including means (72, 74, 76, 78) in each of a plurality of color planes for generating said ordered dither quotient data and said error remainder information.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.