Content-Adaptive Document Image Scaling Preserving White Space

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Solution Overview

Problem

Existing image scaling methods for document thumbnails either prioritize geometric scaling over layout preservation or vice versa, failing to adapt scaling factors based on content and display device characteristics, which affects the visibility of white space and readability.

Innovation Solution

A method for content-adaptive scaling of document images that identifies spatial relationships between objects, determines separating white space, and calculates a scaling factor based on these measurements and display device characteristics, ensuring minimal recognizable layout features and visible white space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If geometric scaling is used for document thumbnails, then scaling operation is simple, but layout distortion occurs and white space visibility is lost

Engineering Contradiction:

Improvescaling operation simplicityVSAvoidlayout preservation accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the scaling parameter from a uniform geometric factor to a content-adaptive factor determined by white space measurements. The scaling factor is calculated based on the minimum white space distance between document objects, ensuring that scaled thumbnails preserve both layout structure and white space visibility while adapting to different document contents.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If layout distortion scaling is used to preserve white space, then white space visibility is maintained, but readable text display is compromised

Engineering Contradiction:

Improvewhite space preservation accuracyVSAvoidtext readability

Core Design Contradiction:

Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent applies local quality by differentiating between regions requiring preservation (white space between objects) and regions requiring readability (text content). The scaling process maintains white space distances while allowing text regions to be scaled uniformly, ensuring both layout structure and text readability are preserved in the thumbnail.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If content-adaptive scaling is implemented, then layout features and white space visibility are maintained, but computational complexity increases

Engineering Contradiction:

Improvelayout feature recognition accuracyVSAvoidscaling algorithm complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing white space distance metrics between document objects before generating thumbnails. This pre-computed spatial information is then used to determine the appropriate scaling factor, avoiding complex real-time calculations during thumbnail generation and reducing overall computational complexity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7623711B2White space graphs and trees for content-adaptive scaling of document images

Publication Date: 2009.11.24 RICOH CO LTD

AI summary

A method, article of manufacture, and apparatus for content-adaptive scaling of document images is described. In one embodiment, the method comprises identifying spatial relationships between document objects of a document image, determining space separating pairs of neighboring document objects, and determining at least one scaling factor based on the space separating the document objects in the document image and based on display device characteristics.