Two-Dimensional Code Boundary Detection in Low-Resolution Images

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional methods for detecting the boundary line of two-dimensional codes captured with low-resolution images, such as those from inexpensive digital cameras, often result in incorrect detection due to defocus and distortion, leading to inaccurate positioning of the code boundary.

Innovation Solution

An image processing apparatus that detects candidate points on the boundary of a two-dimensional code, calculates a first boundary line, selects points within a threshold distance from this line, and refines the boundary line detection using selected points, improving precision even in defocused or distorted images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional boundary line detection methods are used on low-resolution images, then processing speed is maintained, but measurement precision deteriorates due to defocus and distortion

Engineering Contradiction:
Improveboundary line detection precisionVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The boundary line detection process is divided into multiple stages: initial candidate point detection, first boundary line calculation, point selection based on distance threshold, and second boundary line detection. This segmentation allows each stage to focus on specific tasks, improving overall precision while maintaining manageable complexity through modular processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method performs preliminary actions by first detecting candidate points and calculating a first boundary line before final detection. This preliminary processing prepares the data for more accurate final boundary line detection, addressing defocus and distortion issues before they compromise the final measurement

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple processing steps are added to improve boundary detection precision, then measurement precision improves, but processing time increases

Engineering Contradiction:
Improveboundary line detection precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The method applies partial action by selecting only candidate points within a threshold distance from the first boundary line for the final detection. This selective processing reduces the number of points requiring detailed analysis, maintaining high precision while limiting the time cost of additional processing steps

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The distance threshold selection provides feedback control: candidate points are evaluated based on their distance from the first boundary line, and only those meeting the threshold criterion proceed to final detection. This feedback mechanism ensures precision while automatically filtering out unnecessary processing of distant points

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS8746572B2Image processing apparatus and image processing method
Publication Date: 2014.06.10 FUJITSU LTD
  • US8746572B2 patent drawing
  • US8746572B2 patent drawing
  • US8746572B2 patent drawing

AI summary

An image processing apparatus includes a candidate point detecting section configured to detect a plurality of candidate points on a boundary of a code region of a two-dimensional code in an image capturing the two-dimensional code, by scanning the image starting from an internal point of the two-dimensional code in the image, the two-dimensional code including a plurality of modules being arranged in two dimensions; a calculating section configured to calculate a first boundary line using the candidate points; a selecting section configured to select the candidate points located within a distance less than a threshold value from the first boundary line; and a boundary line detecting section configured to detect a second boundary line calculated using the selected candidate points selected by the selecting section.