Hyperspectral Sensor Using Polarization Diffraction Element
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Solution Overview
Problem
Existing hyperspectral detection devices struggle to obtain accurate spectral data due to the influence of ambient light colors and external reflections, such as those from water surfaces, which interfere with the acquisition of desired information.
Innovation Solution
A hyperspectral sensor and camera system utilizing a polarization diffraction element, specifically a liquid crystal diffraction element with a rotating optical axis, to split light components by wavelength and reduce the impact of external reflections by distinguishing between different polarized light components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrophotometer is used to split light into wavelength components, then spectral data can be acquired, but the influence of ambient light color and external reflections prevents accurate data acquisition
Solution Approach 1:
The sensor array is divided into multiple regions, with specific regions dedicated to detecting polarized light components. This segmentation allows selective measurement of different polarization states, enabling the system to distinguish between target light and reflected light based on their polarization characteristics.
Solution Approach 2:
A polarization diffraction element is introduced as an intermediary component between the spectrophotometer and sensor array. This element separates light based on polarization state, acting as a mediator that enables the detection system to differentiate between direct light from the subject and reflected light from external sources.
2Loss of information
If light is split by wavelength using a spectrophotometer, then spectral information is obtained, but external reflections from surfaces like water prevent desired information from being visible
Solution Approach 1:
The system converts the harmful effect of reflected light into a useful signal by detecting its polarization characteristics. Reflected light typically exhibits specific polarization patterns, which the polarization-sensitive sensor array can identify and distinguish from non-polarized or differently polarized target light, thereby transforming interference into a discrimination mechanism.
Solution Approach 2:
The detection approach changes from purely wavelength-based measurement to combined wavelength and polarization state measurement. By adding polarization as an additional parameter, the system gains the ability to distinguish between different light sources with the same spectral content, effectively separating target information from reflected light interference.
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
The system effectively reduces disturbances from external reflections, allowing for accurate acquisition of spectral data by separating and distinguishing between polarized light components, thereby enhancing the visibility of the subject by minimizing the influence of ambient light and reflective surfaces.
Implementation Method 1
light from a subject is split into light components in a plurality of wavelength ranges by a spectral optical element
Implementation Method 2
the spectral optical element is a polarization diffraction element that emits polarized light
Implementation Method 3
the polarization diffraction element is a liquid crystal diffraction element that is formed of a composition including a liquid crystal compound and has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating
Implementation Method 4
each of the light components in the wavelength ranges is received by a sensor array consisting of a plurality of photodetection elements to acquire spectral data
Data Source
AI summary
Provided are a hyperspectral sensor and a hyperspectral camera in which influence of external information such as a reflecting material is reduced such that the spectral data accuracy of a subject to be acquired can be improved. In the hyperspectral sensor in which light from a subject is split into light components in a plurality of wavelength ranges by a spectral optical element and each of the light components in the wavelength ranges is received by a sensor array consisting of a plurality of photodetection elements to acquire spectral data in which spectral information of the subject is associated with each of the photodetection elements, a polarization diffraction element that emits polarized light is used as the spectral optical element.