EP0735741A2
Expired / Lapsed
EP
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Method and system for converting multi-gradated image data into binary image data
Assignee: Seiko Epson Corp
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Filing: 1996-04-01
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Granted: —
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Expires: 2016-04-01
Abstract
Abstract An image processing system and method for varying the resolution of multi-gradated image data to output binary gradated image data having a different resolution. In the system and method, the resolution of the multi-gradated image data is converted to prepare image data having alternating dots arranged in lines and rows such that those of said dots present in odd-numbered lines and those of said dots present in even-numbered lines are positioned in alternate rows. The image data having alternating dots is transformed into binarization data. The binarization data is converted into binary gradated image data by using an error diffusion method or an average error minimization method. The dot arrangement of the binary gradated image data is then transformed into a dot arrangement equal to that of the image data having alternating dots. The system and method thus obtains a high quality reproduced image at a speed as high as possible.
Inventors
- 👤 Toshiaki Kakutani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:10
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4051; H04N1/4052
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
107 words
An image processing method for varying the resolution of multi-gradated image data to output binary gradated image data having a different resolution, characterised by comprising the steps of: converting the resolution of the multi-gradated image data to prepare image data having alternating dots arranged in lines and rows such that those of said dots present in even-numbered lines are positioned in alternate rows; transforming the image data having alternating dots into binarization data; converting said binarization data into binary gradated image data; and transforming the dot arrangement of the binary gradated image data into a dot arrangement equal to that of the image data having alternating dots.
Claim 2
Dependent Claim
136 words
An image processing system for varying the resolution of multi-gradated image data to output binary gradated image data having a different resolution, and characterised by comprising; a resolution converter (5) which converts the resolution of the multi-gradated image data to prepare image data having alternating dots arranged in lines and rows such that those of said dots present in odd-numbered lines and those of said dots present in even-numbered lines are positioned in alternate rows; a first transforming device (6) which transforms the image data having alternating dots into binarization data; a binarization converter (7) which converts said binarization data into binary gradated image data; and a second transforming device (8) which transforms the dot arrangement of the binary gradated image data into a dot arrangement equal to that of the image data having alternating dots.
Claim 3
Dependent Claim
37 words
An image processing system as claimed in claim 2, wherein the resolution converter converts a predetermined low resolution or a predetermined high resolution to an intermediate resolution which is between the high resolution and the low resolution.
Claim 4
Dependent Claim
50 words
An image processing system as claimed in claim 3, wherein the predetermined low resolution is defined as A dpi x A dpi (A = natural number), the predetermined high resolution is defined as 2A dpi x 2A dpi, and the intermediate resolution is defined as A√2 dpi x A√2 dpi.
Claim 5
Dependent Claim
49 words
An image processing system as claimed in any one of claims 2 to 4, wherein said first transforming device transforms the image data having alternating dots to binarization data by shifting the dots in the odd-numbered lines or the dot in the even-numbered lines in a main scanning direction.
Claim 6
Dependent Claim
50 words
An image processing system as claimed in any one of claims 2 to 5, wherein the resolution converter comprises a system which applies one weighted matrix to dots surrounding a selected dot in an even-numbered line and another weighted matrix to dots surrounding another selected dot in an odd-numbered line.
Claim 7
Dependent Claim
68 words
An image processing system as claimed in any one of claims 2 to 6, for varying low resolution multi-gradated image data to higher resolution binary gradated output data, wherein the resolution converter comprises a copier which copies the gradation value of each dot of the image data having a predetermined low resolution at a position of a predetermined adjoining dot to increase the resolution of the image data.
Claim 8
Dependent Claim
78 words
An image processing system as claimed in any one of claims 2 to 6, for varying high resolution multi-gradated image data to lower resolution binary gradated output data, wherein the resolution converter groups adjoining two dots of the image data as one set, and shifts the one of said dots having a lower gradation value than the other dot in each set to a location of the other dot to decrease the resolution of said multi-gradated image data.
Claim 9
Dependent Claim
68 words
An image processing system as claimed in any one of claims 2 to 6, for varying high resolution multi-gradated image data to lower resolution binary gradated output data, wherein the resolution converter groups adjoining two dots of the image data as one set, and selects only the one of said dots having a higher gradation value for further processing, to decrease the resolution of said multi-gradated image data.
Claim 10
Dependent Claim
39 words
An image processing system as claimed in any one of claims 2 to 9, wherein said binarization converter converts said binarization data into binary gradated image data by using an error diffusion method or an average error minimization method.
References Cited (Backward Citations)
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