Technique for image processing

Patent metadata

Field	Value
Publication number	US-9451126-B2
Application number	US-201514662317-A
Country	US
Kind code	B2
Filing date	Mar 19, 2015
Priority date	Mar 31, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

An image processing device may perform: obtaining first original image data generated by scanning a document including an object, the first original image data representing a first original image which includes a first object image indicating the object; detecting two or more straight lines in the first original image; specifying a first relationship between a first straight line among the two or more straight lines and the first object image; selecting, based on the first relationship, a particular straight line among the two or more straight lines; outputting, based on a direction in which the particular straight line extends, an output image represented by output data, the output data being generated by using the first original image data.

First claim

What is claimed is:

1. A non-transitory computer-readable recording medium storing computer-readable instructions for an image processing device,
the computer-readable instructions, when executed by a processor of the image processing device, causing the image processing device to perform:
obtaining first original image data generated by scanning a document including an object, the first original image data representing a first original image which includes a first object image indicating the object;
detecting two or more straight lines in the first original image;
specifying a first relationship between a first straight line among the two or more straight lines and the first object image;
selecting, based on the first relationship, a particular straight line among the two or more straight lines; and
generating, based on a direction in which the particular straight line extends, output data by using the first original image data,
wherein the generating of the output data is performed by:
generating rotated image data representing a rotated image, the rotated image being an image in which the first original image is rotated by a rotation angle, the rotation angle being determined based on the direction in which the particular straight line extends; and

generating the output data by using the rotated image data.

2. The non-transitory computer-readable recording medium as in claim 1 , wherein
the computer-readable instructions, when executed by the processor, cause the image processing device to further perform:
specifying a second relationship between a second straight line among the two or more straight lines and the first object image, the second straight line being different from the first straight line,
wherein the particular straight line is selected based on the first relationship and the second relationship.

3. The non-transitory computer-readable recording medium as in claim 1 , wherein
the first original image data includes object pixel data representing the first object image and background pixel data representing a background of the first object image, and
wherein the computer-readable instructions, when executed by the processor, cause the image processing device to further perform:
generating a first projection histogram by projecting K pieces (the K being an integer of 2or more) of target pixel data along a direction orthogonal to the first straight line, the K pieces of target pixel data being included in a plurality of target pixel data configuring first target image data, the first target image data being obtained by using the first original image data, the first projection histogram representing a distribution of an appearance frequency of related target pixel data which is related to the object pixel data,
wherein the first relationship is specified by using the first projection histogram.

4. The non-transitory computer-readable recording medium as in claim 3 , wherein
the computer-readable instructions, when executed by the processor, cause the image processing device to further perform:
generating the first target image data by converting a plurality of original pixel data configuring the first original image data, the first target image data including high-intensity pixel data and low-intensity pixel data, the high-intensity pixel data having an edge intensity higher than a predetermined threshold, the low-intensity pixel data having an edge intensity equal to or lower than the predetermined threshold,
wherein the related target pixel data is the high-intensity pixel data.

5. The non-transitory computer-readable recording medium as in claim 3 , wherein
the first relationship is a number of target projection lines among all projection lines used in generating the first projection histogram, the target projection lines being projection lines in which the appearance frequency of the related target image data is equal to or less than a first threshold.

6. The non-transitory computer-readable recording medium as in claim 3 , wherein
the K pieces of target pixel data are a part of the plurality of target pixel data configuring the first target image data.

7. The non-transitory computer-readable recording medium as in claim 6 , wherein
the computer-readable instructions, when executed by the processor, cause the image processing device to further perform:
generating the first target image data by converting a plurality of original pixel data configuring the first original image data, the first target image data including high-intensity pixel data and low-intensity pixel data, the high-intensity pixel data having an edge intensity higher than a predetermined threshold, the low-intensity pixel data having an edge intensity equal to or lower than the predetermined threshold,
wherein the related target pixel data is the high-intensity pixel data,
the computer-readable instructions, when executed by the processor, cause the image processing device to further perform:
generating a second projection histogram by projecting, along a predetermined first direction, the plurality of target pixel data configuring the first target image data, the second projection histogram representing a distribution of an appearance frequency of the high-intensity pixel data,
wherein the generating of the first projection histogram is performed by:
specifying, by using the second projection histogram, one or more target pixel data from among the plurality of target pixel data configuring the first target image data, the one or more target pixel data being target pixel data on a projecting line in which the appearance frequency of the high-intensity pixel data is equal to or less than a second threshold;
specifying the K pieces of target pixel data by removing the specified one or more target pixel data from the plurality of target pixel data configuring the first target image data; and
generating the first projection histogram by projecting the specified K pieces of target pixel data along the direction orthogonal to the first straight line.

8. The non-transitory computer-readable recording medium as in claim 1 , wherein
the detecting of the two or more straight lines is performed by:
detecting the first straight line among the two or more straight lines from a first partial image represented by first partial image data, the first partial image data being a part of second target image data, the second target image data being obtained by using the first original image data; and
detecting a second straight line among the two or more straight lines from a second partial image represented by second partial image data, the second straight line being different from the first straight line, the second partial image data being a part of the second target image data and being different from the first partial image data.

9. The non-transitory computer-readable recording medium as in claim 8 , wherein
the detecting of the first straight line is performed by detecting the longest straight line included in the first partial image, and
the detecting of the second straight line is performed by detecting the longest straight line included in the second partial image.

10. The non-transitory computer-readable recording medium as in claim 1 , wherein
the detecting of the two or more straight lines is performed by detecting two straight lines which are the longest straight line included in the first original image and the second longest straight line included in the first original image,
wherein the two straight lines do not intersect each other while not being orthogonal nor parallel to each other.

11. The non-transitory computer-readable recording medium as in claim 1 , where

Assignees

• Brother Ind Ltd

Inventors

• Ozawa Ryohei

Classifications

• H04N1/3876

  Recombination of partial images to recreate the original image · CPC title

• H04N1/3878 Primary

  Skew detection or correction · CPC title