Image Processing Device for Workpiece Position Detection

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Solution Overview

Problem

Conventional image processing devices struggle to accurately determine the position of workpieces with shiny or variable colors, or those in shadow, leading to unreliable gripping operations, especially when the workpiece is made of metal, white, or black, or has a complex three-dimensional shape.

Innovation Solution

An image processing device that uses a color difference signal from brightness-color difference signals to detect the work region, allowing for more stable and accurate identification of the workpiece position, even in varying lighting conditions, by employing a light source with a complementary color to the background and workpiece, thereby enhancing the reliability of workpiece gripping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a brightness signal is used to detect the work region, then the detection process is simple, but halation occurs with shiny metal workpieces causing shadow regions and inaccurate work region identification

Engineering Contradiction:
Improvedetection process complexityVSAvoidwork region identification accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies color change detection by converting the captured image to a color space (such as HSV or LAB) and detecting work regions based on color differences rather than brightness. This allows the system to distinguish workpieces with shiny surfaces, white, black, or variable colors from the background by their unique color signatures, eliminating halation problems while maintaining detection simplicity through automated color-based segmentation.

Inventive Principle:
Principle #32Color changes

2Measurement precision

If the color of the loading stable is changed to match workpiece variations, then workpiece visibility is improved, but the device complexity and operational burden increase

Engineering Contradiction:
Improveworkpiece position determination accuracyVSAvoidsystem configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of changing the physical color of the loading stable, the patent changes the detection parameter by using color difference analysis in a transformed color space. The system detects work regions by identifying pixels that differ in color from the background, allowing any workpiece color to be detected against a fixed background without requiring physical modifications to the loading stable.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a light source that emits light over the entire workpiece is provided, then shadow regions are eliminated, but it becomes difficult to pick up the workpiece

Engineering Contradiction:
Improveworkpiece position determination accuracyVSAvoidworkpiece gripping reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses color-based detection that is independent of lighting conditions and shadow regions. By detecting workpieces based on their color properties in a transformed color space, the system can accurately identify workpiece positions even in the presence of shadows or varying lighting, eliminating the need for shadow-free illumination while maintaining reliable gripping through accurate position determination.

Inventive Principle:
Principle #32Color changes

4Ease of operation

If brightness-based detection is used, then processing is straightforward, but variations in background and lighting cause unreliable workpiece position determination

Engineering Contradiction:
Improvedetection processing simplicityVSAvoidworkpiece position determination reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transforms the detection parameter from brightness to color difference in a transformed color space. This parameter change makes the detection process robust against variations in background and lighting conditions, as color properties remain relatively stable under different illumination. The processing remains straightforward through automated color-based segmentation algorithms that naturally handle lighting variations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3466604B1Image processing device, workpiece transfer device, and image processing method
Publication Date: 2020.12.23 FUJI CORP
  • EP3466604B1 patent drawingFigure 1
  • EP3466604B1 patent drawingFigure 2
  • EP3466604B1 patent drawingFigure 3

AI summary

Work transfer device 20 is provided with an image processing device. The image processing device is provided with lighting section 26 that emits light to pickup loading section 13, imaging section 25 configured to capture a color image of pickup loading section 13, and a determining section configured to detect a work region using a color difference signal from among a brightness-color difference signal obtained from a signal output by imaging section 25, determine whether the workpiece of the work region can be picked up, and output a determining result. Work transfer device 20 picks up work W on pickup loading section 13 with pickup section 22 using the determining result of the image processing device.