Image Capturing Unit Asymmetric Illumination for Color Measurement
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Solution Overview
Problem
In offset printing, there is a challenge in maintaining consistent color reproduction due to device-specific properties and fluctuations in ink discharge, leading to variations in color output between the intended and actual printed results, which is exacerbated by the instability of image capturing conditions in conventional color measurement systems.
Innovation Solution
An image capturing unit with a sensor section, a reference chart section, and an illumination light source is designed to image a subject and a reference chart simultaneously, with the illumination light source positioned to avoid mirror reflection, ensuring stable imaging conditions and accurate color measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrophotometric color measuring device is used to perform color measurement on the reference color patch image, then color measurement accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent uses an image capturing device with sensor sections to capture images of color patches, creating a visual copy that can be analyzed for color information. This replaces the need for expensive spectrophotometric hardware while maintaining measurement capability through image-based color analysis
Solution Approach 2:
The invention employs standard image sensors and illumination sources that are inexpensive and widely available, replacing costly spectrophotometric devices. The system uses software-based color analysis on captured images rather than expensive hardware measurement, achieving cost-effective color measurement
2Illumination intensity
If the illumination light source is positioned to provide adequate lighting for color measurement, then measurement capability is improved, but mirror reflection may enter the sensor section causing measurement errors
Solution Approach 1:
The patent positions the illumination light source and sensor section at asymmetric angles relative to the color patch surface. The illumination angle is specifically designed to be different from the sensor viewing angle, preventing mirror reflection from entering the sensor while maintaining adequate illumination for accurate color measurement
Solution Approach 2:
The system acknowledges that mirror reflection is inevitable with certain lighting angles, but designs the geometry so that the reflection path does not intersect the sensor section. The illumination configuration converts the potential harmful reflection into a benign situation where light illuminates the patch without creating interfering reflections in the sensor path
3Reliability
If color adjustment processing is performed using conventional methods, then color reproducibility is improved, but the process requires expensive spectrophotometric equipment
Solution Approach 1:
The patent replaces the mechanical/optical measurement system (spectrophotometer) with an electronic image capture and processing system. Color measurement is achieved through digital image analysis of captured photos, substituting complex hardware measurement with software-based color extraction from images
Solution Approach 2:
The image capturing device serves multiple functions: it captures images for color measurement, stores the captured images, and enables color adjustment processing. This multi-functional approach eliminates the need for dedicated spectrophotometric equipment while maintaining color measurement and adjustment capabilities
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 configuration enhances color reproducibility by stabilizing the imaging process and improving the accuracy of color measurement, allowing for consistent and high-quality color output despite device-specific fluctuations.
Implementation Method 1
an illumination light source arranged at a position where a mirror reflection region that mirror reflects light entering from the illumination light source to the sensor section is outside a region of the subject and the reference chart section
Implementation Method 2
a mirror reflection region that mirror reflects light entering from the illumination light source to the sensor section
Data Source
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AI summary
An image capturing unit includes a sensor section that images a predetermined range including a subject; a reference chart section that is imaged by the sensor section with the subject; and an illumination light source that illuminates the subject and the reference chart section. The illumination light source is arranged at a position where a mirror reflection region that mirror reflects light entering from the illumination light source to the sensor section is outside a region of the subject and the reference chart section.