Image Processing Apparatus Dynamic Range Extension

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Solution Overview

Problem

In the FA field, visual sensors face challenges in accurately capturing luminance and color information of measuring objects due to limited dynamic range, leading to overexposure or underexposure issues, especially with objects having varying reflectance and curvature, which complicates proper imaging and requires frequent adjustments of exposure conditions.

Innovation Solution

An image processing apparatus that controls an image pickup section to capture images under multiple exposure conditions, generates composite image data by calculating luminance distribution, and displays processing time, allowing for proper setting of photographing conditions considering time constraints and user expertise levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the exposure time is prolonged to capture luminance information, then luminance information can be acquired, but overexposure occurs and color information cannot be accurately acquired

Engineering Contradiction:
Improveluminance information accuracyVSAvoidcolor information accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent segments the imaging process into multiple exposures with different exposure times. One exposure captures luminance information with prolonged exposure, while another exposure captures color information with shorter exposure, avoiding overexposure. This segmentation allows each parameter to be optimized independently.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the exposure time is shortened to avoid overexposure, then color information can be acquired, but underexposure occurs and effective luminance information cannot be acquired

Engineering Contradiction:
Improvecolor information accuracyVSAvoidluminance information accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent divides the imaging task into multiple exposures: a shorter exposure captures color information without overexposure, while a longer exposure captures luminance information. This segmentation resolves the contradiction by assigning different exposure durations to different information types.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If the number of times of photographing is increased to extend dynamic range and improve accuracy, then extension of dynamic range and improvement of accuracy can be expected, but processing time is prolonged

Engineering Contradiction:
Improvecomposite image accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing only the necessary number of exposures (typically 2-3 times with different exposure times) rather than excessive photographing. This selective approach extends the dynamic range sufficiently while keeping processing time within acceptable limits for production environments.

Inventive Principle:
Principle #16Partial or excessive action

4Measurement precision

If fine adjustment of photographing conditions is performed for each workpiece change, then proper imaging can be achieved, but operation complexity increases

Engineering Contradiction:
Improveimaging accuracyVSAvoidoperation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent implements self-service through automatic photographing condition determination. The system automatically selects appropriate exposure times and number of exposures based on the workpiece characteristics and required accuracy, eliminating the need for operators to manually adjust settings for each workpiece change.

Inventive Principle:
Principle #25Self-service

5Manufacturing precision

If multiple exposures with different exposure conditions are performed to extend dynamic range, then accurate image capture is achieved, but processing time increases

Engineering Contradiction:
Improveimage capture accuracyVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs partial action by conducting only the minimum necessary exposures (typically 2-3 exposures with different exposure times) to extend the dynamic range sufficiently for accurate image capture. This avoids excessive photographing that would unnecessarily prolong processing time while still achieving the required accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2056591B1Image processing apparatus
Publication Date: 2013.06.19 OMRON CORP
  • EP2056591B1 patent drawingFigure 1
  • EP2056591B1 patent drawingFigure 2
  • EP2056591B1 patent drawingFigure 3A~3C

AI summary

There is provided an image processing apparatus capable of properly setting a photographing condition in consideration of time allowable for each processing; the image processing apparatus capable of properly setting the photographing condition while referring to an actually generated composite image; the image processing apparatus capable of properly setting the photographing condition even by a user who has no background knowledge; and the image processing apparatus capable of determining whether or not image composition processing is properly executed even by the user who has no background knowledge. A setting mode screen displays a composite image based on generated output image data, together with "processing time", being expected time required for generating one output image data. The composite image is updated every time the output image data is generated.