Imaging Apparatus Parallel Ray Optical Filter Wavelength Shift
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Solution Overview
Problem
Existing imaging apparatuses face difficulties in acquiring images at multiple wavelengths with minimal transmission wavelength shift, particularly when using curved optical filters, which complicates the configuration and processing, making it challenging to measure subjects accurately across different wavelengths.
Innovation Solution
The imaging apparatus employs a first and second optical filter arranged in different regions of the imaging optical system, with the first optical system causing high image height rays to be incident into both filters in a parallel state, thereby minimizing transmission wavelength shift, and a directional sensor for pupil-dividing and receiving light of different wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a curved optical filter is used to suppress transmission wavelength shift, then transmission wavelength stability is improved, but device complexity and processing difficulty increase
Solution Approach 1:
The optical filter is divided into multiple regions (first optical filter region and second optical filter region) with different curvature radii. Each region has a specific curvature designed for its location, allowing the system to suppress transmission wavelength shift across different incident angles without requiring a uniformly complex curved structure throughout the entire filter.
Solution Approach 2:
Different regions of the optical filter are assigned different local properties (curvature radii). The first optical filter region has a first curvature radius optimized for central rays, while the second optical filter region has a second curvature radius optimized for peripheral rays. This local differentiation allows each region to effectively handle its specific incident angle range.
2Reliability
If multiple optical filters with different curvatures are provided for different wavelengths, then transmission wavelength stability across wavelengths is improved, but device complexity and processing difficulty increase significantly
Solution Approach 1:
A single optical filter performs multiple functions by incorporating multiple regions with different curvature radii. This unified filter structure can handle multiple wavelengths and different incident angles simultaneously, eliminating the need for separate curved filters for each wavelength and simplifying the overall optical system.
Solution Approach 2:
Multiple functional regions (first optical filter region and second optical filter region) are merged into a single integrated optical filter. This combination allows the system to achieve wavelength-specific filtering and incident angle compensation in one component rather than requiring multiple separate filters.
3Area of stationary object
If high image height rays are allowed to incident at large angles, then image coverage is improved, but transmission wavelength shift increases
Solution Approach 1:
The optical filter is designed with spatially varying curvature properties where the first optical filter region (with first curvature radius) and second optical filter region (with second curvature radius) are positioned to handle different ray paths. This allows high image height rays to be filtered with appropriate local curvature compensation, maintaining wavelength accuracy across the full image area.
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 allows for the acquisition of images with a small transmission wavelength shift at multiple wavelengths, enabling accurate measurement of subjects, as demonstrated by reduced differences in transmission wavelengths between the periphery and center of the image.
Implementation Method 1
an optical filter composed of a first optical filter and a second optical filter where the first optical filter transmits light in a first wavelength band and the second optical filter transmits light in a second wavelength band different from the first wavelength band
Implementation Method 2
a directional sensor that has a plurality of pixels composed of two-dimensionally arranged photoelectric conversion elements, where the directional sensor pupil-divides each of rays incident through the optical filter and receives the rays selectively
Data Source
AI summary
Provided are an imaging apparatus capable of acquiring an image having a small transmission wavelength shift at a plurality of wavelengths and an image processing apparatus capable of measuring a subject on the basis of an image which has a small transmission wavelength shift and which is acquired at a plurality of wavelengths. High image height rays imaged at a position of which an image height is high is incident at a large angle with respect to the optical axis. Therefore, the transmission wavelength shift increases. However, in the imaging apparatus according to the first aspect, the first optical system causes the high image height rays to be incident into the first optical filter and the second optical filter in a state where the upper ray and the lower ray are parallel. Accordingly, in the first and second optical filters, the transmission wavelength shift due to an difference in incident angle of the high image height rays is suppressed, and an image with a small transmission wavelength shift can be acquired simultaneously at a plurality of wavelengths.