Conversion of halftone bitmaps to continuous tone representations
First Claim
1. A method comprising:
- identifying text and image regions defined by a halftone bitmap;
converting the text region to a first continuous tone representation using a first conversion process; and
converting the image region to a second continuous tone representation using a second conversion process.
2 Assignments
0 Petitions
Accused Products
Abstract
Techniques for converting images defined by halftone bitmaps to continuous tone (CT) representations can better preserve geometric information from the original halftone bitmaps, enhancing the accuracy of CT proofs produced by lower resolution proofers such as inkjet and electrophotographic devices. The conversion techniques may involve the application of different conversion processes to text/linework and image regions of the bitmaps. For example, the conversion process for image regions may involve application of bandwidth limitation to remove halftone dot structures prior to downsampling. On the contrary, the conversion process for text/linework regions may exclude bandwidth limitation in order to preserve sharpness of text and linework. The conversion techniques may use a variety of analysis modes to distinguish text and image regions such as connected component analysis to identify regions of contiguous pixels, followed by pixel count analysis, histogram analysis, or a combination thereof, to classify the connected components as either text/linework or imagery.
66 Citations
39 Claims
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1. A method comprising:
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identifying text and image regions defined by a halftone bitmap;
converting the text region to a first continuous tone representation using a first conversion process; and
converting the image region to a second continuous tone representation using a second conversion process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A computer-readable medium comprising instructions to cause a processor to:
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identify text and image regions defined by a halftone bitmap;
convert the text region to a first continuous tone representation using a first conversion process; and
convert the image region to a second continuous tone representation using a second conversion process. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A printing device comprising:
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a processor to identify text and image regions defined by a halftone bitmap, convert the text region to a first continuous tone representation using a first conversion process, and converting the image region to a second continuous tone representation using a second conversion process; and
a print engine that forms an image on image output medium based on the first and second continuous tone representations. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification