Reflected Light Detection Using Polarization Segmentation
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Solution Overview
Problem
Existing methods for measuring the surface shape and color of non-planar objects using reflected light are inefficient due to insufficient removal of surface reflected light components, especially when measuring across a wide area, as they require time-consuming movement of light sources and struggle with varying incident angles and reflection directions.
Innovation Solution
A reflected light detecting device and method that uses multiple illuminating devices with adjustable optical axes and a polarization optical system to uniformly align and filter surface reflected light from different regions of a non-planar target object, allowing for collective extraction or removal of surface reflected light components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single second polarizing filter is placed between the face and the light receiver to remove surface reflected light, then the polarization filtering function is simple, but the surface reflected light cannot be sufficiently removed when measuring wide areas with varying incident angles
Solution Approach 1:
The single polarizing filter is divided into multiple polarizing filters (first, second, and third polarizing filters) arranged in different orientations. Each filter handles surface reflected light from specific angular ranges, collectively achieving complete surface reflected light removal across all incident angles while maintaining manageable system complexity through modular segmentation.
2Measurement precision
If light is cast onto a narrow region of the face, then the reflected rays have substantially the same direction and surface reflected light can be effectively removed, but the measurement time increases when moving the light source across the whole face
Solution Approach 1:
Multiple illuminating devices are merged to illuminate different regions of the face simultaneously, while multiple polarizing filters are combined to handle reflected light from all regions. This allows wide-area measurement without requiring sequential scanning, significantly improving measurement speed while maintaining the ability to remove surface reflected light effectively.
3Productivity
If rays of light are cast onto the whole human face or multiple spots to collectively measure reflected light, then the measurement efficiency improves, but the varying incident angles cause different oscillation directions and insufficient surface reflected light removal
Solution Approach 1:
Different polarizing filters are assigned to handle surface reflected light from different local regions or angular ranges. The first polarizing filter handles light from one angular range, the second filter handles another range, and the third filter handles remaining angles. This local specialization ensures that surface reflected light from all incident angles is effectively removed while maintaining high measurement efficiency.
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 approach enables efficient detection and separation of surface and internally reflected light components, improving measurement accuracy and sensitivity by ensuring a large amount of light passes through the polarization optical system, allowing for simultaneous detection of both components.
Implementation Method 1
When linearly polarized light is cast onto the surface of an object, surface reflection maintains the polarization state (oscillation direction) of the incident light, while internal reflections give non-polarized light since their reflecting directions and the oscillation directions are diverse.
Data Source
AI summary
Reflected light detecting device and method with surface reflected light components collectively be extracted/removed when detecting reflected light arising in casting light onto target-object range having non-planar surface. The device includes: a first illuminating device causing first-measurement light in predetermined polarization direction to enter target-object first region from first direction; polarization optical system position part of first-surface reflected light enters the polarization optical system, the first-surface reflected light being the first-measurement in the first region surface; a second illuminating device causing second-measurement light in the same first-measurement light polarization direction to enter second region from second direction, the second region being on the target-object surface, different from the first region; adjusting direction of the second-measurement light optical axis so part of second-surface reflected light enters the polarization optical system, the second-surface reflected light being the second-measurement in second region surface; and detecting light having passed through the polarization optical system.