US 10,477,063 B2Granted

Character detection and binarization

AssigneeCanon Kabushiki Kaisha

InventorNaoki Ito

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Abstract

There is provided an image processing apparatus which can generate a vector image with a high image quality at a high speed in a small memory capacity. The present invention generates an image with low resolution by performing resolution conversion to a compressed image with high resolution and obtains information of a character object with low resolution by performing object division to the image with the low resolution. The compressed image with the high resolution is decompressed and an image showing a character contour with high resolution is generated by using the information of the character object with the low resolution obtained by the object dividing and the decompressed image with the high resolution. At the time of performing the decompression, the compressed image with the high resolution may be partially decompressed based upon the information of the character object.

Claims8

Dependent claims

An image processing method of an image processing apparatus for vectorizing an outline of a character in a compressed multivalued image, the method comprising:

generating a low resolution image having a lower resolution than that of the compressed multivalued image, from the compressed multivalued image;
obtaining coordinates of a character region in the low resolution image by analyzing the low resolution image;
calculating coordinates with the resolution of the compressed multivalued image based on the coordinates of the character region obtained in the low resolution image;
partially decompressing a region of the compressed multivalued image, wherein the partially decompressed region is a character region corresponding to the calculated coordinates;
specifying pixels where a character exists in the low resolution image;
generating, based on the specified pixels and the partially decompressed region, a binary character image having the resolution equal to that of the compressed multivalued image;
generating an outline of a character based on the generated binary character image having the resolution equal to that of the compressed multivalued image;
and
generating vector data by performing a function approximate process to the generated outline of the character.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/296,290Filed 4 Jun 2014 · continuation
Priority: JP 2008-23980418 Sep 2008
Published: US 2014/0285824 A125 Sep 2014
Granted: 12 Nov 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H04N 1/41
Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof: bandwidth or redundancy reduction
G06K 15/1872
Post-processing of the composed and rasterized print image: image enhancement
G06V 30/413
Analysis of document content: classification of content, e.g. text, photographs or tables
G06V 30/414
Analysis of document content: extracting the geometrical structure, e.g. layout tree; Block segmentation, e.g. bounding boxes for graphics or text