Iterative Contour Identification for Digital Image Processing

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Solution Overview

Problem

Current methods for identifying contours in digital images, especially curved contours, are limited in their ability to accurately detect contours relevant for subsequent automated digital-image processing tasks, such as optical character recognition, due to constraints on local curvature and intensity gradients.

Innovation Solution

The method identifies seed points in digital images, extends line segments to form initial contours, and iteratively adds segments while applying filters to selectively combine and refine contours, ensuring only relevant contours are identified for subsequent processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional contour identification methods are used, then the processing speed is maintained, but the accuracy of detecting curved contours is insufficient

Engineering Contradiction:
Improvecontour detection accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the contour detection process into multiple stages: identifying seed points, extending initial line segments, iteratively adding segments, and filtering/combining contours. This segmentation allows each stage to be optimized independently, improving overall accuracy without sacrificing processing speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by first identifying seed points and extending initial line segments before performing the main contour detection. This preliminary structuring of the detection process enables more accurate curved contour detection while maintaining efficiency through pre-computed information.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If contour identification is constrained to orthogonal intensity gradients, then the relevance of detected contours for OCR is improved, but the number of detectable contours is reduced

Engineering Contradiction:
Improvecontour relevance for OCRVSAvoidnumber of contours
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the parameter constraints for contour detection by applying orthogonal intensity gradient constraints selectively during the iterative extension process. This allows the system to maintain high relevance for OCR applications while still detecting sufficient contours through adaptive parameter adjustment during processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial constraints by enforcing orthogonal intensity gradient requirements only at critical stages of contour extension rather than throughout the entire process. This partial application maintains OCR relevance while detecting a sufficient quantity of contours for effective character recognition.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If iterative contour extension with filtering is applied, then the precision of relevant contour identification is improved, but the computational complexity increases

Engineering Contradiction:
Improvecontour identification precisionVSAvoidalgorithm complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex iterative process into distinct, manageable stages: seed point identification, initial segment extension, iterative contour growth, and final filtering/combination. This segmentation reduces algorithmic complexity by making each stage independently optimizable and easier to implement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary filtering and combination operations during the iterative extension process rather than as a separate post-processing step. This preliminary action reduces the overall computational complexity by eliminating redundant contours earlier in the process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10387744B2Method and system for identifying extended contours within digital images
Publication Date: 2019.08.20 ABBYY DEVELOPMENT INC
  • US10387744B2 patent drawing
  • US10387744B2 patent drawing
  • US10387744B2 patent drawing

AI summary

The current document is directed to automated methods and systems, controlled by various constraints and parameters, that identify contours in digital images, including curved contours. Certain of these parameters constrain contour identification to those contours in which the local curvature of a contour does not exceed a threshold local curvature and to those contours orthogonal to intensity gradients of at least threshold magnitudes. The currently described methods and systems identify seed points within a digital image, extend line segments from the seed points as an initial contour coincident with the seed point, and then iteratively extend the initial contour by adding line segments to one or both ends of the contour. The identified contours are selectively combined and filtered in order to identify a set of relevant contours for use in subsequent image-processing tasks.