Document Skew Correction Interface with Dynamic Candidate Line Display

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Users face difficulties in accurately capturing frontal images of documents using mobile terminals due to challenges in maintaining camera alignment and detecting document edges, leading to skewed images that require correction before printing.

Innovation Solution

An information processing apparatus and method that allows users to easily designate quadrilateral areas for skew correction by displaying candidate lines only for the selected side, enabling intuitive selection and correction without cluttering the screen with unnecessary candidates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If all contour candidate sides are displayed on the image when switching among contour candidates, then the user can see all available options, but the displayed image becomes convoluted with extremely low visibility

Engineering Contradiction:
Improvecontour candidate display completenessVSAvoidimage visibility
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent divides the contour candidates into multiple groups based on their spatial relationships. Instead of displaying all candidates simultaneously, the system segments them and displays one group at a time, allowing users to navigate through different groups using operation buttons. This segmentation resolves the contradiction by maintaining visibility while preserving access to all candidates through sequential display.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements periodic display of contour candidate groups, where different groups are displayed in sequence rather than all at once. Users can switch between groups using operation buttons, creating a periodic action pattern that allows comprehensive candidate exploration without overwhelming the display with all candidates simultaneously, thus maintaining image visibility.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If the user directly designates the position of vertex and side, then the precision of quadrilateral area designation is improved, but the operation complexity and user effort increase

Engineering Contradiction:
Improvequadrilateral area designation precisionVSAvoiduser operation effort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs automatic contour detection and generates candidate quadrilateral areas based on edge information from the captured image. This self-service approach allows the system to automatically identify potential document boundaries, reducing the user's workload from manually positioning all four vertices to simply selecting from pre-computed candidates or making minor adjustments, thereby maintaining precision while reducing operation effort.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary contour detection and candidate generation before user selection. By pre-processing the image to identify edge information and compute multiple candidate quadrilateral areas, the system prepares the groundwork for accurate designation, allowing users to make informed selections without performing complex manual positioning tasks, thus achieving precision with reduced effort.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If automatic detection of document area sides using edge information is used, then the processing load on the user is minimized, but the detection may fail when edges cannot be detected due to low contrast or excessive edges

Engineering Contradiction:
Improveuser processing loadVSAvoidedge detection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system introduces an intermediary manual selection mechanism between automatic detection and final document area designation. When automatic edge detection fails or produces unreliable results due to low contrast or excessive edges, users can intervene to manually select from candidate areas or adjust the detected contours. This intermediary approach maintains low processing load while compensating for detection failures, ensuring reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements a dynamic approach where the detection method can switch between automatic and manual modes based on detection confidence. When edge detection succeeds with high confidence, the system operates automatically with minimal user involvement. When detection fails or confidence is low, the system dynamically transitions to allow manual intervention, thus maintaining low processing load overall while ensuring reliability when needed.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3054662B1Apparatus, method and computer program for facilitating scanned document area designation for skew correction>
Publication Date: 2020.11.04 CANON KK
  • EP3054662B1 patent drawingFigure 1A~1B
  • EP3054662B1 patent drawingFigure 2
  • EP3054662B1 patent drawingFigure 3

AI summary

A detected quadrilateral area is displayed and no group of candidate lines is displayed in a normal state. While a user is selecting a side that the user desires to change, a group of candidate lines corresponding to the selected side is displayed. Then, whether to replace a position of the selected side with a position of a candidate line is determined based on a movement destination position of the selected side.