Endoscope Color Calibration via Reference Chart
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Solution Overview
Problem
Endoscope apparatuses face challenges in maintaining accurate color balance over time due to variations in individual characteristics of the imaging elements and light sources, leading to inconsistent image reproduction.
Innovation Solution
An endoscope apparatus that includes an imaging optical system and an illumination optical system with a control unit capable of performing a calibration process using a color chart with known chromaticity values, adjusting the color correction table to ensure accurate color representation by capturing images of color patches and matching measured chromaticity values to known values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual characteristic information is stored in advance to correct color variation, then color accuracy at the time of measurement is improved, but color balance deteriorates over time due to parameter variations
Solution Approach 1:
The system performs a calibration process before actual imaging by capturing an image of a color chart with known chromaticity values. This preliminary action creates a color correction table that compensates for individual characteristics of the imaging element and light source, ensuring accurate color reproduction from the start of operation.
Solution Approach 2:
The system continuously monitors color accuracy by comparing measured chromaticity values against known reference values from the color chart. Based on this feedback, the color correction table is dynamically adjusted and regenerated, allowing the system to adapt to temporal variations in light source and imaging element characteristics, thereby maintaining reliable color balance over time.
2Measurement precision
If individual characteristic information is stored for each apparatus, then initial color correction is achieved, but the system complexity increases
Solution Approach 1:
Instead of storing complex individual characteristic information for each apparatus, the system uses a color chart with known chromaticity values as a reference copy. The calibration process captures an image of this color chart and generates a color correction table based on the measured versus known values, simplifying the correction mechanism while maintaining accuracy.
Solution Approach 2:
The system changes the approach from storing fixed individual characteristics to dynamically generating correction parameters through calibration. The color correction table is created by comparing measured chromaticity values with known reference values, allowing the system to adapt to variations without requiring complex pre-stored data for each apparatus.
3Measurement precision
If color correction is performed using stored parameters, then initial color accuracy is improved, but the accuracy deteriorates due to temporal variations
Solution Approach 1:
The system performs calibration periodically by capturing images of the color chart at regular intervals or before each imaging session. This periodic recalibration ensures that the color correction table remains up-to-date with current characteristics of the light source and imaging element, preventing accuracy degradation over time while maintaining efficient operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures consistent and accurate color balance in captured images, eliminating the need for storing individual characteristic information and maintaining reliable color reproduction across different conditions.
Implementation Method 1
a light source unit connected to the endoscope and supplying at least excitation light to the illumination optical system so as to emit light from a fluorescent substance
Data Source
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AI summary
An endoscope apparatus includes: an endoscope which includes an imaging optical system and an illumination optical system; and a control unit which includes light source units and connected to the endoscope and supplying at least excitation light to the illumination optical system, and an image processing section correcting an image signal output from the imaging element on the basis of a predetermined color correction table. The control unit performs a calibration process in such a manner that an image of a color chart having a plurality of color patches with known chromaticity values is captured by an imaging element, chromaticity for each of the plurality of color patches is obtained from an imaging signal of the color chart, and the contents of the color correction table are changed.