Automated Digital Image De-tilting via Edge Analysis

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Solution Overview

Problem

Digital images captured with tilted cameras or scanners often result in undesirably rotated images, with existing solutions requiring manual input to correct tilt, especially in images containing non-textual features.

Innovation Solution

An automated method that analyzes digital images to determine a dominant edge direction, selects an angle based on this direction, and rotates the image pixels to generate a de-tilted version, using edge detection, filtering, and histogram-based angle selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual tilt correction is used, then tilt removal accuracy is improved, but user input requirement increases operation complexity

Engineering Contradiction:
Improvetilt removal accuracyVSAvoiduser input requirement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically detects edges, determines dominant orientations, and corrects tilt without requiring user input. The image processing algorithm independently identifies the tilt angle through edge analysis and applies correction automatically, making the system self-sufficient and eliminating manual intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system transforms the image by applying a rotation transformation parameter based on the detected dominant edge orientation. By changing the orientation parameter of the image pixels, the system achieves automatic tilt correction while maintaining accuracy.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If automatic deskew is used for text documents, then operation simplicity is improved, but applicability to non-textual images deteriorates

Engineering Contradiction:
Improveoperation simplicityVSAvoidapplicability to non-textual images
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The edge detection-based tilt correction system is universally applicable to all types of images including photographs, scanned documents, and non-textual images. Unlike text-specific deskew algorithms, this system works with any image containing edge structures, making it multi-functional and highly adaptable.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces text-specific recognition mechanisms with general edge detection and orientation analysis mechanisms. By substituting the specialized text analysis system with a universal edge-based geometric analysis system, the solution achieves broad applicability across different image types while maintaining automatic operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If edge detection and angle analysis are performed, then automatic tilt correction capability is improved, but processing complexity increases

Engineering Contradiction:
Improveautomatic tilt correction capabilityVSAvoidprocessing complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The image processing is segmented into distinct stages: edge detection, edge filtering, dominant orientation determination, and image rotation. By dividing the complex automatic correction process into manageable segments, the system achieves high automation while keeping each processing stage relatively simple and well-defined.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS9092884B2Automatic image straightening
Publication Date: 2015.07.28 MICROSOFT TECHNOLOGY LICENSING LLC
  • US9092884B2 patent drawing
  • US9092884B2 patent drawing
  • US9092884B2 patent drawing

AI summary

Tilt is reduced or eliminated in captured digital images. Edges in a first image are detected. Angles corresponding to the detected edges are determined. A dominant angle is selected from the determined angles. The first image is rotated according to the selected dominant angle to generate a second image. The second image is a de-tilted version of the first image.