Overlapping Passband Filters for High Wavelength Resolution Imaging
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Solution Overview
Problem
Existing image capturing technologies using spectral filters with narrow passbands in the near-infrared band struggle to achieve high wavelength resolution for capturing images of subjects, resulting in low discriminability of spectral variations in the final visible image.
Innovation Solution
An image capturing apparatus and method that employs a multi-wavelength variable light source emitting light with periodic spectral distributions, using a digital camera with bandpass filters having overlapping passbands, and irradiating the subject with two different light sources having distinct spectral distributions to enhance wavelength resolution and discriminability of spectral variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral filters with narrow passbands are used to achieve high wavelength resolution, then wavelength resolution is improved, but the discriminability of spectral variations in the final visible image deteriorates
Solution Approach 1:
The patent segments the spectral measurement process into multiple steps: first capturing images through overlapping passband filters to obtain broad spectral information, then using variable wavelength light sources to probe specific wavelength regions within each passband. This segmentation allows both broad spectral coverage and fine wavelength resolution to be achieved through coordinated operation of multiple components.
Solution Approach 2:
The patent adds a temporal dimension to spectral measurement by using variable wavelength light sources that can be tuned to different wavelengths at different times. Instead of relying solely on spatial separation of narrow bandpass filters, the system uses time-multiplexed wavelength scanning within each filter's passband, transforming a spatial problem into a temporal measurement approach.
2Loss of information
If multiple spectral filters with overlapping passbands are used to improve spectral discrimination, then discriminability of spectral variations is improved, but device complexity increases
Solution Approach 1:
The patent makes the light source universal by using a variable wavelength light source that can emit across multiple wavelength ranges. This single multi-functional light source replaces the need for multiple dedicated monochromatic light sources, reducing system complexity while maintaining the ability to probe different spectral regions through the overlapping passband filters.
Solution Approach 2:
The patent merges the functions of multiple narrow bandpass filters into a set of overlapping passband filters with broader transmission bands. By combining broader filters with temporal wavelength modulation, the system achieves spectral discrimination capability without requiring a large number of separate filter elements, thus reducing overall device complexity.
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 approach allows for improved discriminability of spectral variations in the captured images by detecting intensity differences across overlapping passbands, resulting in higher quality visible images with enhanced color and contour emphasis.
Implementation Method 1
a plurality of wavelength band filters having invisible wavelengths as passbands
Implementation Method 2
an image capturing device that captures an image of light from a subject
Data Source
AI summary
An image capturing apparatus includes an image capturing device that captures an image of light from a subject, the light passing through each of wavelength band filters having invisible wavelengths as passbands, in which parts of the passbands of the filters whose center wavelengths are adjacent to each other mutually overlap, and a control unit that causes the image capturing device to capture an image of the light from the subject on which a first irradiation light is irradiated, the first irradiation light having a first spectral distribution in which parts of the respective passbands of the filters overlap with one another, and causes the image capturing device to capture an image of the light from the subject on which a second irradiation light is irradiated, the second irradiation light having a second spectral distribution in which parts of the respective passbands of the filters overlap with one another.