Translucent Material Color Measurement Using Dual Illumination
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Solution Overview
Problem
Existing methods for determining the color of translucent materials, such as human skin, struggle to accurately account for the effects of translucency, leading to inaccuracies in color determination.
Innovation Solution
The apparatus employs two light sources positioned at different surface locations to alternately illuminate the translucent material, with a light spectral sensor detecting light from each source. This setup allows for the separation of diffusely reflected light from the surface and light scattered from within the material, enabling a combined light spectrum that accurately represents the material's color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light source is used to illuminate the translucent material, then the measurement process is simple, but the color determination accuracy is insufficient because it cannot separate surface reflected light from interior scattered light
Solution Approach 1:
The illumination system is segmented into two spatially separated light sources: a first light source positioned to illuminate the surface and a second light source positioned to illuminate the interior. This segmentation allows the system to separately capture surface reflected light and interior scattered light, thereby improving color determination accuracy for translucent materials without requiring overly complex illumination arrangements.
Solution Approach 2:
The patent introduces a spatial dimension separation by positioning light sources at different locations relative to the material surface. The first light source is positioned at a first location to primarily illuminate the surface, while the second light source is positioned at a second location to primarily illuminate the interior. This dimensional separation enables the spectral sensor to distinguish between surface and interior light contributions, resolving the measurement accuracy issue.
2Measurement precision
If both specular and diffusely reflected light are included in the measurement, then the measurement process is simple, but the perceived color is inaccurate because specular reflections do not contain information about surface properties
Solution Approach 1:
The measurement process is segmented into two separate illumination measurements: one capturing primarily surface reflected light (including diffuse reflection) and another capturing primarily interior scattered light. By processing these segmented measurements separately and combining them appropriately, the system excludes specular reflections that do not contain surface property information, thereby improving perceived color accuracy.
Solution Approach 2:
The patent extracts and separates the surface reflection component from the interior scattering component through spatially differentiated illumination. By using the first light source to capture surface reflected light and the second light source to capture interior scattered light, the system can extract the relevant surface property information while excluding irrelevant specular reflection components from the final color determination.
3Measurement precision
If light scattered from the interior of the translucent material is not taken into account, then the measurement process is simple, but the perceived color is inaccurate because interior scattering affects the observed color
Solution Approach 1:
The illumination system is segmented into two spatially distinct light sources: a first light source positioned to primarily illuminate the surface and a second light source positioned to primarily illuminate the interior. This segmentation enables the system to separately capture and process surface reflected light and interior scattered light, ensuring that interior scattering effects are properly accounted for in the color measurement without requiring complex multi-angle illumination geometries.
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 method improves the accuracy of color measurements for translucent materials by compensating for the effects of translucency, providing a more precise representation of the material's color that can be mapped to a reference system.
Implementation Method 1
light detected by the light spectral sensor originating from said first source is principally light diffusely reflected from said first surface location
Implementation Method 2
light detected by the detector originating from said second source is principally light scattered by scattering centres in the interior of the translucent material
Data Source
AI summary
An apparatus for determining a colour of a translucent material. The apparatus comprises a first light source configured to illuminate a translucent material at a first surface location, a second light source configured to illuminate the translucent material at a second surface location spaced apart from said first surface location, and a light spectral sensor configured to detect light at said first surface location. The apparatus is configured to operate the first and second light sources alternately, and such that light detected by the light spectral sensor originating from said first source is principally light diffusely reflected from said first surface location, whilst light detected by the detector originating from said second source is principally light scattered by scattering centres in the interior of the translucent material.