Edge Code Histogram Pattern Matching for Fast Image Search

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Solution Overview

Problem

Existing image processing methods for pattern matching in Factory Automation require repeated model rotation and pattern matching processes across the entire image, leading to time-consuming searches for matching regions in input images.

Innovation Solution

An image processing method that involves registering edge code histograms for models, setting regions of interest, calculating coincidence between edge code histograms, and evaluating candidate points to efficiently search for matching regions by combining rough and detailed search processes, including rotation angle determination and removal of proximate matches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the model rotation process and pattern matching process are repeated over the entire range of the image to search for multiple patterns, then the position and orientation of patterns can be obtained, but the processing time becomes excessively long

Engineering Contradiction:
Improvepattern position and orientation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the image into multiple regions of interest (ROIs) and performs pattern matching separately in each ROI. By segmenting the search space, the system avoids processing the entire image uniformly, reducing overall processing time while maintaining detection accuracy in each segment. The edge code histograms are calculated and compared within each ROI independently, enabling parallel processing potential.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-calculates and stores edge code histograms for the model patterns before actual pattern matching. This preliminary preparation of histogram data allows the system to quickly compare candidate regions against pre-processed model representations, eliminating the need to recalculate histograms during the search process and significantly reducing processing time.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If edge code histograms are calculated and compared sequentially across the entire image to find matching regions, then accurate pattern matching is achieved, but the search speed is reduced

Engineering Contradiction:
Improvepattern matching accuracyVSAvoidsearch speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the image into multiple regions of interest and performs histogram comparison operations within each segment rather than across the entire image. This segmentation approach maintains matching accuracy within each region while enabling faster processing through localized operations that can be executed in parallel or sequentially with reduced computational overhead.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent focuses pattern matching efforts on specific regions of interest rather than uniformly processing the entire image. By identifying and prioritizing certain areas where patterns are more likely to occur, the system performs partial action on the most relevant portions of the image, improving search speed without sacrificing accuracy in critical regions.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If the entire image is processed to search for multiple patterns with different orientations, then comprehensive pattern detection is achieved, but computational complexity increases

Engineering Contradiction:
Improvemulti-pattern detection capabilityVSAvoidcomputational complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the complex task of multi-pattern detection into smaller sub-tasks by processing different regions of interest separately. Each ROI is analyzed for pattern matches independently, reducing the computational complexity of handling multiple patterns across the entire image. This segmentation allows the system to manage complexity through modular, region-based processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-processes model patterns into histogram representations and stores them for quick reference. This preliminary action of preparing model data in advance simplifies the actual pattern matching process, reducing computational complexity during the search phase. The pre-calculated histograms enable efficient comparison operations without requiring complex real-time calculations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8422759B2Image processing method and image processing device
Publication Date: 2013.04.16 OMRON CORP
  • US8422759B2 patent drawing
  • US8422759B2 patent drawing
  • US8422759B2 patent drawing

AI summary

An edge code histogram of a model generated in a model image is registered. A target region with respect to the input image is set. An edge code histogram for the target region is generated. A relative positional relationship between the edge code histogram of the model and the edge code histogram for the target region is sequentially changed, and a degree of coincidence between the edge code histograms at each relative position is calculated. A possibility that the region that matches the model is contained in the set target region from the sequentially calculated degree of coincidence between the edge code histograms is evaluated. Then a candidate point having a possibility of matching the model in the input image is specified while sequentially changing the position of the target region with respect to the input image and repeating steps above for each target region.