Text Localization in Images via Line and Graphic Elimination

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Solution Overview

Problem

Existing methods for text localization in images, particularly those with complex backgrounds or graphics, face challenges in accurately identifying and extracting text due to issues like superimposed text on natural images or complex graphics, leading to incomplete optical character recognition (OCR).

Innovation Solution

The approach involves a processor-implemented method that removes lines and graphics from images using geometric manipulations and the Hough transform, followed by horizontal and vertical projections to identify and extract text lines based on run-lengths of consecutive 1's and 0's in flag vectors, enabling effective text localization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing OCR methods are used on images with complex backgrounds and graphics, then processing speed is maintained, but text localization accuracy deteriorates due to inability to separate text from background elements

Engineering Contradiction:
Improvetext localization accuracyVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the image processing task into distinct stages: first removing lines using geometric manipulations, then removing graphics using Hough transform, and finally performing OCR on the cleaned image. This segmentation allows each stage to focus on specific elements, improving text localization accuracy by isolating text from interfering background elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by removing lines and graphics before executing the main OCR task. By pre-processing the image to eliminate background elements that would interfere with text recognition, the system improves subsequent OCR accuracy without requiring complex integration during the recognition phase itself.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If text is superimposed on complex backgrounds with natural images or graphics, then image information completeness is maintained, but OCR recognition rate deteriorates

Engineering Contradiction:
ImproveOCR recognition rateVSAvoidbackground information loss
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent extracts and removes specific interfering elements (lines and graphics) from the image while preserving the text and background information needed for OCR. By selectively removing only the elements that interfere with text recognition using geometric manipulations and Hough transform, the system improves OCR reliability without unnecessarily losing background context.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If traditional text localization methods are used on images with lines and graphics, then processing simplicity is maintained, but text extraction accuracy deteriorates due to interference from background elements

Engineering Contradiction:
Improvetext extraction accuracyVSAvoidprocessing method simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent divides the complex image processing task into simpler sequential sub-tasks: line removal, graphic removal, and text extraction. Each sub-task uses specialized techniques optimized for that specific element type, improving overall text extraction accuracy while keeping each individual processing step relatively simple and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary removal of lines and graphics before the main text extraction operation. This pre-processing simplifies the subsequent text extraction task by eliminating interfering elements, making the overall process more effective without requiring excessively complex algorithms in the final extraction stage.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10496894B2System and method for text localization in images
Publication Date: 2019.12.03 TATA CONSULTANCY SERVICES LTD
  • US10496894B2 patent drawing
  • US10496894B2 patent drawing
  • US10496894B2 patent drawing

AI summary

System and method for text localization in images are disclosed. In an embodiment, a line and graphic eliminated image is received. Further, horizontal projection is performed on rows of the image to obtain a first flag vector, the flag vector indicates whether there is text in each row. Furthermore, a number of run-lengths of consecutive 1's and 0's is computed in the first flag vector. Moreover, text lines is extracted in the image based on the computed number of run-lengths of consecutive 1's and 0's in the first flag vector. Also, vertical projection is performed on the text lines to obtain a second flag vector for the text lines. Further, a number of run-lengths of consecutive 1's and 0's is computed in the second flag vectors. Furthermore, text is localized in the image based on the computed number of run-lengths of consecutive 1's and 0's in the second flag vectors.