Image processing apparatus, image processing method, and non-transitory computer-readable storage medium

Patent metadata

Field	Value
Publication number	US-11288536-B2
Application number	US-201916685916-A
Country	US
Kind code	B2
Filing date	Nov 15, 2019
Priority date	Nov 30, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

An image processing apparatus includes a determination unit configured to determine a region of the image on which to perform character recognition processing, a decision unit configured to decide, based on a number of black pixels in contact with the region determined by the determination unit, whether to perform the character recognition processing on an expanded region obtained by expanding the region determined by the determination unit rather than on the region determined by the determination unit, and a character recognition unit configured to perform the character recognition processing on that region of the image decided by the decision unit.

First claim

What is claimed is:

1. An image processing apparatus comprising:
an extraction unit configured to extract a cluster of black pixels included in an image indicated by image data;
a detection unit configured to detect a contour of white pixels inside the cluster of black pixels extracted by the extraction unit;
a determination unit configured to determine, based on one or more clusters of black pixels inside the contour of white pixels, a region on which to perform character recognition processing;
a decision unit configured to decide, based on a number of black pixels that are in contact with the region determined by the determination unit and that are outside the region determined by the determination unit, whether to perform the character recognition processing on an expanded region obtained by expanding the region determined by the determination unit rather than on the region determined by the determination unit; and
a character recognition unit configured to perform the character recognition processing on that region decided by the decision unit.

2. The image processing apparatus according to claim 1 , wherein the decision unit decides, based on a number of black pixels that are in contact with the expanded region and that are outside the expanded region, whether the character recognition unit is to perform the character recognition processing on a further-expanded region obtained by further expanding the expanded region or performs the character recognition processing on the expanded region obtained by expanding the region determined by the determination unit.

3. The image processing apparatus according to claim 1 , further comprising:
a binarization unit configured to generate binarized image data by binarizing the image data; and
a generation unit configured to generate image data by reducing resolution of the binarized image data generated by the binarization unit,
wherein the determination unit determines a region of a character included in an image indicated by the image data generated by the generation unit.

4. The image processing apparatus according to claim 1 , further comprising a binarization unit configured to generate binarized image data by binarizing the image data,
wherein the determination unit determines a region of a character included in an image indicated by the binarized image data generated by the binarization unit.

5. The image processing apparatus according to claim 1 , further comprising a reading unit configured to read the image of a document and generate the image data.

6. The image processing apparatus according to claim 1 , further comprising a receiving unit configured to receive the image data from an external apparatus.

7. The image processing apparatus according to claim 3 , wherein the character recognition unit performs the character recognition processing on an expanded region obtained by expanding a region of the binarized image data generated by the binarization unit.

8. The image processing apparatus according to claim 3 , wherein the binarization unit uses simple binarization processing to generate the binarized image data.

9. The image processing apparatus according to claim 1 ,
wherein each of the region and the expanded region is a rectangular region, and
wherein the decision unit decides, based on a number of black pixels in a region expanded, by one pixel, from each of sides of an outer periphery of the region determined by the determination unit, whether the character recognition unit is to perform the character recognition processing on the expanded region obtained by expanding the region determined by the determination unit rather than on the region determined by the determination unit.

10. The image processing apparatus according to claim 9 , wherein the expanded region is expanded, by one pixel, in a direction of a side, of which a predetermined number of black pixels are present outside by one pixel, among the sides of the region determined by the determination unit.

11. The image processing apparatus according to claim 1 , wherein the character recognition processing is processing for recognizing characters, one by one, in the expanded region.

12. A method of controlling an image processing apparatus comprising:
extracting a cluster of black pixels included in an image indicated by image data;
detecting a contour of white pixels inside the extracted cluster;
determining, based on one or more clusters of black pixels inside the contour of white pixels, a region of the image on which to perform character recognition processing;
deciding, based on a number of black pixels that are in contact with the region determined in the determining and that are outside the region determined in the determining, whether to perform the character recognition processing on an expanded region obtained by expanding the region determined in the determining rather than on the region determined in the determining; and
performing the character recognition processing, on that region decided by the deciding.

13. A non-transitory computer-readable storage medium storing a program that, when executed by a computer, causes the computer to perform a method of controlling an image processing apparatus, the method comprising:
extracting a cluster of black pixels included in an image indicated by image data;
detecting a contour of white pixels inside the extracted cluster;
determining a region of the image on which to perform character recognition processing; and
deciding, based on a number of black pixels that are in contact with the region determined in the determining and that are outside the region determined in the determining, whether to perform the character recognition processing on an expanded region obtained by expanding the region determined in the determining rather than on the region determined in the determining; and
performing the character recognition processing, on that region decided by the deciding.

Assignees

• Canon Kk

Inventors

• Sakai Hiroyuki

Classifications

• H04N1/00331 Primary

  with an apparatus performing optical character recognition (character recognition G06V30/10) · CPC title

• G06V30/412

  Layout analysis of documents structured with printed lines or input boxes, e.g. business forms or tables · CPC title

• G06V30/155

  Removing patterns interfering with the pattern to be recognised, such as ruled lines or underlines · CPC title

• G06V30/10

  Character recognition · CPC title

• G06T7/136

  involving thresholding · CPC title