Method of Perspective Correction For Devanagari Text
First Claim
1. A method to improve automatic recognition of text, the method comprising:
- receiving a plurality of regions of text in an image of a scene of real world captured by a camera;
wherein a plurality of pixels of a common binary value, in a word in a region in said plurality of regions of text, are arranged along a first line oriented in a predetermined direction;
wherein a first height at a first end of said word along said predetermined direction is different from a second height at a second end of said word along said predetermined direction;
detecting a plurality of second lines that satisfy at least a predetermined test and pass through a portion of the word having a predetermined relationship to said first line;
determining an angle θ
based on a plurality of angles of the plurality of second lines relative to a common direction;
using the angle θ
to change first coordinates of at least said plurality of pixels in said word, whereby the first height and the second height remain unchanged after the using; and
storing in a memory, at least changed first coordinates generated by the using;
wherein the receiving, the processing, the determining, the using and the storing are performed by one or more processors.
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Accused Products
Abstract
An electronic device and method identify regions that are likely to be text in a natural image or video frame, followed by processing as follows: lines that are nearly vertical are automatically identified in a selected text region, oriented relative to the vertical axis within a predetermined range −max_theta to +max_theta, followed by determination of an angle θ of the identified lines, followed by use of the angle θ to perform perspective correction by warping the selected text region. After perspective correction in this manner, each text region is processed further, to recognize text therein, by performing OCR on each block among a sequence of blocks obtained by slicing the potential text region. Thereafter, the result of text recognition is used to display to the user, either the recognized text or any other information obtained by use of the recognized text.
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Citations
25 Claims
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1. A method to improve automatic recognition of text, the method comprising:
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receiving a plurality of regions of text in an image of a scene of real world captured by a camera; wherein a plurality of pixels of a common binary value, in a word in a region in said plurality of regions of text, are arranged along a first line oriented in a predetermined direction; wherein a first height at a first end of said word along said predetermined direction is different from a second height at a second end of said word along said predetermined direction; detecting a plurality of second lines that satisfy at least a predetermined test and pass through a portion of the word having a predetermined relationship to said first line; determining an angle θ
based on a plurality of angles of the plurality of second lines relative to a common direction;using the angle θ
to change first coordinates of at least said plurality of pixels in said word, whereby the first height and the second height remain unchanged after the using; andstoring in a memory, at least changed first coordinates generated by the using; wherein the receiving, the processing, the determining, the using and the storing are performed by one or more processors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A non-transitory computer-readable storage medium comprising a plurality of instructions to at least one processor to improve automatic recognition of text, the plurality of instructions comprising:
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first instructions to receive a plurality of regions of text in an image of a scene of real world captured by a camera; wherein a plurality of pixels of a common binary value, in a word in a region in said plurality of regions of text, are arranged along a first line oriented in a predetermined direction; wherein a first height at a first end of said word along said predetermined direction is different from a second height at a second end of said word along said predetermined direction; second instructions to detect a plurality of second lines that satisfy at least a predetermined test and pass through a portion of the word having a predetermined relationship to said first line; third instructions to determine an angle θ
based on a plurality of angles of the plurality of second lines relative to a common direction;fourth instructions to use the angle θ
to change first coordinates of at least said plurality of pixels in said word, whereby the first height and the second height remain unchanged after execution of the fourth instructions; andfifth instructions to store in a memory, at least changed first coordinates generated by execution of the fourth instructions. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A mobile device comprising:
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a camera; a memory operatively connected to the camera to receive at least an image therefrom; at least one processor operatively connected to the memory to execute a plurality of instructions stored in the memory; wherein the plurality of instructions cause the at least one processor to; receive a plurality of regions of text in the image of a scene of real world captured by the camera; wherein a plurality of pixels of a common binary value, in a word in a region in said plurality of regions of text, are arranged along a first line oriented in a predetermined direction; wherein a first height at a first end of said word along said predetermined direction is different from a second height at a second end of said word along said predetermined direction; detect a plurality of second lines that satisfy at least a predetermined test and pass through a portion of the word having a predetermined relationship to said first line; determine an angle θ
based on a plurality of angles of the plurality of second lines relative to a common direction;use the angle θ
to change first coordinates of at least said plurality of pixels in said word, whereby the first height and the second height remain unchanged after the using; andstore in the memory, at least changed first coordinates generated by the use. - View Dependent Claims (21, 22, 23, 24)
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25. An apparatus to improve automatic recognition of text, the apparatus comprising:
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means for receiving a plurality of regions of text in an image of a scene of real world captured by a camera; wherein a plurality of pixels of a common binary value, in a word in a region in said plurality of regions of text, are arranged along a first line oriented in a predetermined direction; wherein a first height at a first end of said word along said predetermined direction is different from a second height at a second end of said word along said predetermined direction; means for detecting a plurality of second lines that satisfy at least a predetermined test and pass through a portion of the word having a predetermined relationship to said first line; means for determining an angle θ
based on a plurality of angles of the plurality of second lines relative to a common direction;means for using the angle θ
to change first coordinates of at least said plurality of pixels in said word, whereby the first height and the second height remain unchanged after the using; andmeans for storing in a memory, at least changed first coordinates generated by the means for using.
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Specification