Observation Device RGB Filter Spectral Tuning
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Solution Overview
Problem
Existing optical observation techniques using color filters in a Bayer array suffer from insufficient resolution of capillaries due to the limited contribution of B pixels, and existing methods to enhance B range information through G pixels result in sub-sensitivity and image degradation.
Innovation Solution
An observation device with a light source unit that adjusts the ratio of illuminating light in the first B range (390-440 nm) to the second B range (440-490 nm) and an imaging element with RGB color filters, where the R color filter transmits more light in the R and first B ranges than the second B range, satisfying specific spectral sensitivity ratios to improve color reproducibility and resolution during both white light and narrow band imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color filters arranged in a primary color Bayer array are used for white light imaging, then color reproduction is maintained, but resolution of capillaries is insufficient due to limited B pixel contribution
Solution Approach 1:
The blue wavelength range is segmented into two distinct bands: first B range (390-440 nm) and second B range (440-490 nm). This segmentation allows the imaging system to selectively capture different wavelength components, with the first B range providing enhanced capillary resolution and the second B range contributing to color reproduction, thereby resolving the contradiction between resolution and color fidelity
Solution Approach 2:
The R color filter is designed with non-uniform spectral characteristics: it exhibits high transmittance in the R range and first B range (390-440 nm) for capillary detection, while having low transmittance in the second B range (440-490 nm). This local quality differentiation enables R pixels to contribute to both high-resolution capillary imaging and maintain color reproduction when needed
2Measurement precision
If B information is extracted from G pixels through image processing, then B range information is obtained, but image quality degrades due to sub-sensitivity
Solution Approach 1:
The R color filter acts as an intermediary that directly transmits first B range light (390-440 nm) to R pixels, eliminating the need for G pixel-based extraction methods. This direct transmission pathway provides reliable, high-quality B range information without the sub-sensitivity problems inherent in using G pixels for B range detection
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 solution enhances color reproducibility during white light imaging and improves resolution and information acquisition of superficial blood vessels during narrow band imaging by optimizing the sensitivity and light quantity ratios of the R and B pixels, while maintaining image quality and reducing noise.
Implementation Method 1
the R color filter transmits more light in an R range and the first B range than light in the second B range and has a spectral characteristic that satisfies conditional formulae (1) and (2)
Implementation Method 2
an imaging element that images reflected light from a subject irradiated with illuminating light emitted from the light source unit
Data Source
AI summary
An observation device includes a light source unit capable of adjusting a quantity of 390-490 nm illuminating light according to a B1 range and a B2 range having a longer wavelength than the B1 range, and an imaging element that images reflected light from a subject irradiated with illuminating light. The light source unit changes the light quantity ratio of the B1 range to the B2 range depending on whether white light imaging is conducted or narrow band imaging is conducted. The imaging element includes RGB color filters arranged according to pixels and the R color filter transmits more light in an R range and the B1 range than light in the second B range and has a spectral characteristic that satisfies a predetermined conditional formulae.