Compact Digital Image Representation via Segmentation

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Solution Overview

Problem

Current image segmentation methods for digital images, particularly in document analysis, face challenges such as loss of information in binary conversion, complexity in color segmentation, and inefficiencies in processing and accuracy due to reliance on binary hierarchies and unreliable text classification techniques.

Innovation Solution

A method involving the segmentation of digital images into connected components in a one-pass manner, using block-based processing to estimate representative colors, quantify, and merge components, while storing statistics for noise removal and efficient compression, and employing layout analysis to partition images into foreground and background for compact representation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If binary thresholding is used for segmentation, then processing speed is improved, but information loss occurs in complex color documents

Engineering Contradiction:
Improveprocessing speedVSAvoidinformation loss
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the image processing task into multiple passes: first performing binary thresholding for quick initial segmentation, then performing color-based segmentation on the segmented regions to recover color information. This multi-level segmentation approach resolves the contradiction by applying different processing strategies to different aspects of the image.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary binary thresholding segmentation to identify candidate regions before performing more sophisticated color analysis. This preliminary action allows the system to quickly eliminate large portions of the image that don't require detailed color processing, while still preserving color information where needed.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If color segmentation is performed to preserve document structure, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvesegmentation accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the color segmentation process into hierarchical levels: first segmenting into foreground and background using binary thresholding, then performing color-based segmentation only on the foreground regions. This reduces the overall complexity compared to full-image color segmentation while maintaining accuracy for document structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing quality levels to different regions: simple binary thresholding for background regions and full color segmentation for foreground regions containing document content. This local differentiation maintains segmentation accuracy where needed while reducing complexity in less critical areas.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If multi-pass segmentation algorithms are used, then segmentation quality is improved, but processing time increases

Engineering Contradiction:
Improvesegmentation qualityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary binary thresholding to identify candidate regions before performing color-based segmentation. This preliminary action creates a focused search space for the more time-consuming color analysis, reducing overall processing time while maintaining segmentation quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent performs color segmentation only on regions identified as foreground by the binary thresholding, rather than processing the entire image with full color analysis. This partial action approach maintains segmentation quality for document content while significantly reducing processing time by skipping background regions.

Inventive Principle:
Principle #16Partial or excessive action

4Measurement precision

If connected components are stored in detailed form, then measurement precision is improved, but memory usage increases

Engineering Contradiction:
Improvecomponent representation accuracyVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts and stores only the essential statistics of connected components (such as bounding box, area, color properties) rather than storing complete pixel data for each component. This extraction approach maintains measurement precision for layout analysis while significantly reducing memory requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent stores detailed component information only for foreground connected components that contain document content, while using simplified representations for background regions. This partial detail approach maintains precision where needed while reducing overall memory usage.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS7991224B2Segmenting digital image and producing compact representation
Publication Date: 2011.08.02 CANON KK
  • US7991224B2 patent drawing
  • US7991224B2 patent drawing
  • US7991224B2 patent drawing

AI summary

A method (100), an apparatus, and a computer program product for automatically producing a compact representation of a colour document are disclosed. In the method, a digital image of a colour-document page is segmented (110) into connected components in one-pass, block raster order. The digital image of the page is partitioned into foreground and background images using layout analysis (120) based on compact, connected-component statistics of the whole page. At least one portion of the background image where at least one portion of the foreground image obscures the background image is inpainting (520) in one-pass block raster order. The foreground and background images are combined (130) to form a compact document. A method, an apparatus, and a computer program product for segmenting a digital image comprising a plurality of pixels are also disclosed.