REDUNDANT ASPECT RATIO DECODING OF DEVANAGARI CHARACTERS

• US 20140023275A1
• Filed: 03/15/2013
• Published: 01/23/2014
• Est. Priority Date: 07/19/2012
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Krishna Kumar, Raj Kumar, Baheti, Pawan Kumar
• Application Number:
  US13/844,641
• Publication Number:
  US 20140023275A1
• Time in Patent Office: Days
• US Class Current: 382/182
• CPC Class Codes: G06F 18/254 of classification results, e.g. of results related to same input data
• CPC Class Codes: G06F 18/285 Selection of pattern recognition techniques, e.g. of classifiers in a multi-classifier system
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/19113 Selection of pattern recognition techniques, e.g. of classifiers in a multi-classifier system
• CPC Class Codes: G06V 30/1918 Fusion techniques, i.e. combining data from various sources, e.g. sensor fusion
• CPC Class Codes: G06V 30/244 using graphical properties, e.g. alphabet type or font
• CPC Class Codes: G06V 30/293 of characters other than Kanji, Hiragana or Katakana

Abstract

An electronic device and method receive a block sliced from a rectangular portion of an image of a scene of real world captured by a camera and use a property of the block to operate one of multiple optical character recognition (OCR) decoders. In an illustrative aspect, a first OCR decoder is configured to recognize characters whose property satisfies the test based on a first limit, the first limit being obtained by reducing a predetermined limit by an overlap amount. In this illustrative aspect, a second OCR decoder is configured to recognize characters whose property does not satisfy the test based on a second limit, the second limit being obtained by increasing the predetermined limit by the overlap amount. When the property of the block satisfies the test, the first OCR decoder is operated and alternatively the second OCR decoder is operated, resulting in candidates for a character being identified.

Claims

1. A method to identify words of text in images, the method comprising:

receiving a rectangular portion of an image of a scene of real world captured by a camera;

using the rectangular portion to determine whether a predetermined test is satisfied;

when the predetermined test is not satisfied, operating an OCR decoder on a block, and storing in a first hypothesis in memory, first candidates for recognition as a character in the block;

when the predetermined test is satisfied, operating one or more OCR decoders, and storing in the first hypothesis the first candidates to be recognized as the character in the block, and predetermined amount additionally storing second candidates to be recognized as the character in a second hypothesis

using a word decoder, to output a first word comprising at least one first candidate in the first hypothesis, and a first confidence level associated with the first word; and

using the word decoder a second time, to output a second word comprising at least one second candidate in the second hypothesis, and a second confidence level associated with the second word;

storing in memory, one of the first word and the second word identified as being recognized in the rectangular portion, based on at least comparison of the first confidence level and the second confidence level;

wherein at least the receiving, the checking, and the storing are performed by at least one processor.

2. The method of claim 1 wherein:

the predetermined test comprises a predetermined limit on an attribute of the block.

3. The method of claim 2 wherein:

the attribute is aspect ratio.

4. The method of claim 1 wherein:

the at least one first candidate is a normal character in a predetermined language; and

the at least one second candidate is a compound character formed by combining a left-most part of a first consonant with a second consonant.

5. The method of claim 4 wherein:

when the predetermined test is satisfied, a first OCR decoder is operated on the block and a second OCR decoder is additionally operated on the block; and

wherein when the predetermined test is not satisfied, the second OCR decoder is operated on the block.

6. The method of claim 1 wherein:

the predetermined test comprises checking if a lower maatra is present in the rectangular portion.

7. The method of claim 6 further comprising:

preparing a cropped image, by removing at least the lower maatra in a copy of the rectangular portion;

the rectangular portion is hereinafter uncropped image;

wherein when the predetermined test is satisfied, the OCR decoder is operated on a first block extracted from the uncropped image and the OCR decoder is additionally operated on a second block extracted from the cropped image; and

wherein when the predetermined test is not satisfied, the OCR decoder is operated on the first block extracted from the uncropped image.

8. The method of claim 1 wherein:

when the predetermined test is not satisfied, a first OCR decoder is operated on the block, wherein the first OCR decoder is configured to recognize characters with the property that does not satisfy the test based on a first limit, the first limit being obtained by increasing a predetermined limit by a predetermined amount;

when the predetermined test is satisfied, a second OCR decoder is operated on the block, wherein the second OCR decoder is configured to recognize the characters with the property that satisfies the test based on a second limit, the second limit being obtained by reducing the predetermined limit by said predetermined amount.

9. At least one non-transitory computer readable storage media comprising a plurality of instructions to be executed by at least one processor to identify words of text in an image of a scene of real world, the plurality of instructions comprising:

instructions to receive a rectangular portion of an image of a scene of real world captured by a camera;

instructions to use the rectangular portion to determine whether a predetermined test is satisfied;

when the predetermined test is not satisfied, instructions to operate an OCR decoder on a block, and instructions to store in a first hypothesis in memory, first candidates for recognition as a character in the block;

when the predetermined test is satisfied, instructions to operate one or more OCR decoders, and storing in the first hypothesis the first candidates to be recognized as the character in the block, and additionally storing second candidates to be recognized as the character in a second hypothesis

instructions to use a word decoder, to output a first word comprising at least one first candidate in the first hypothesis, and a first confidence level associated with the first word; and

instructions to use the word decoder a second time, to output a second word comprising at least one second candidate in the second hypothesis, and a second confidence level associated with the second word;

instructions to store in memory, one of the first word and the second word identified as being recognized in the rectangular portion, based on at least comparison of the first confidence level and the second confidence level.

10. The at least one non-transitory computer readable storage media of claim 9 wherein:

the predetermined test comprises a predetermined limit on an attribute of the block.

11. The at least one non-transitory computer readable storage media of claim 10 wherein:

the attribute is aspect ratio.

12. The at least one non-transitory computer readable storage media of claim 9 wherein:

the at least one first candidate is a normal character in a predetermined language; and

the at least one second candidate is a compound character formed by combining a left-most part of a first consonant with a second consonant.

13. The at least one non-transitory computer readable storage media of claim 9 wherein:

when the predetermined test is satisfied, a first OCR decoder is operated on the block and a second OCR decoder is additionally operated on the block; and

wherein when the predetermined test is not satisfied, the second OCR decoder is operated on the block.

14. The at least one non-transitory computer readable storage media of claim 9 wherein:

the predetermined test comprises checking if a lower maatra is present in the rectangular portion.

15. A mobile device to decode text in real world images, the mobile device comprising:

a camera;

a memory operatively connected to the camera to receive at least an image therefrom, the image comprising one or more text regions;

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 rectangular portion of an image of a scene of real world captured by a camera;

use the rectangular portion to determine whether a predetermined test is satisfied;

when the predetermined test is not satisfied, operate an OCR decoder on a block, and storing in a first hypothesis in memory, first candidates for recognition as a character in the block;

when the predetermined test is satisfied, operate one or more OCR decoders, and storing in the first hypothesis the first candidates to be recognized as the character in the block, and additionally storing second candidates to be recognized as the character in a second hypothesis

use a word decoder, to output a first word comprising at least one first candidate in the first hypothesis, and a first confidence level associated with the first word; and

use the word decoder a second time, to output a second word comprising at least one second candidate in the second hypothesis, and a second confidence level associated with the second word;

store in memory, one of the first word and the second word identified as being recognized in the rectangular portion, based on at least comparison of the first confidence level and the second confidence level.

16. The mobile device of claim 15 wherein:

the predetermined test comprises a predetermined limit on an attribute of the block.

17. The mobile device of claim 15 wherein:

the attribute is aspect ratio.

18. The mobile device of claim 15 wherein:

the at least one first candidate is a normal character in a predetermined language; and

the at least one second candidate is a compound character formed by combining a left-most part of a first consonant with a second consonant.

19. A mobile device comprising:

a camera to capture an image of an environment outside the mobile device;

a memory coupled to the camera for storing the image;

means for receiving a rectangular portion of an image of a scene of real world captured by a camera;

means for using the rectangular portion to determine whether a predetermined test is satisfied;

responsive to the predetermined test being not satisfied, means for operating an OCR decoder on a block, and storing in a first hypothesis in memory, first candidates for recognition as a character in the block;

responsive to the predetermined test is satisfied, means for operating one or more OCR decoders, and storing in the first hypothesis the first candidates to be recognized as the character in the block, and additionally storing second candidates to be recognized as the character in a second hypothesis

means for using a word decoder, to output a first word comprising at least one first candidate in the first hypothesis, and a first confidence level associated with the first word; and

means for using the word decoder a second time, to output a second word comprising at least one second candidate in the second hypothesis, and a second confidence level associated with the second word; and

means for storing in memory, one of the first word and the second word identified as being recognized in the rectangular portion, based on at least comparison of the first confidence level and the second confidence level.