Rotating Prism Hyperspectral Camera for Compact Endoscope Imaging
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Solution Overview
Problem
Existing endoscopic hyperspectral imaging systems face challenges due to large mechanical assemblies that require powerful motors and are prone to calibration issues and mechanical failures, making them unsuitable for medical scopes that need to be compact and inexpensive.
Innovation Solution
A compact hyperspectral imaging device with a rotating prism that rotates with respect to the optical axis, allowing for sequential acquisition of multiple frames to create a hyperspectral data cube, using a dispersive element to disperse light perpendicular to the slit and a focal plane array sensor to detect dispersed light, with optional beamsplitter for white light imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional spectrograph design with moving optical assembly is used, then spectral imaging capability is achieved, but the device size and mechanical complexity increase significantly
Solution Approach 1:
Instead of moving the spectrograph optical assembly to scan the slit (traditional approach), this invention moves the light source relative to the stationary spectrograph. The illumination source is positioned to rotate about the optical axis, causing different portions of the scene to be illuminated and imaged through the fixed slit sequentially, thereby inverting the scanning mechanism from moving optics to moving illumination.
Solution Approach 2:
The invention replaces the mechanical scanning system (motors, actuators, moving optical components) with a rotating illumination source that can be implemented with simpler mechanics. The rotating source eliminates the need for large, complex mechanical assemblies required in traditional spectrographs, reducing both size and mechanical failure points while maintaining spectral scanning capability.
2Productivity
If a large mechanical assembly with powerful motors is used to move the spectrograph, then spectral scanning is achieved, but the device size increases and mechanical failures occur more frequently
Solution Approach 1:
The scanning function is achieved by rotating the illumination source rather than moving the spectrograph assembly. This inversion allows the use of a small, simple rotation mechanism for the light source instead of large motors and complex mechanical assemblies, thereby maintaining spectral scanning capability while dramatically reducing mechanical complexity and failure risk.
Solution Approach 2:
The invention extracts the scanning function from the main spectrograph body and implements it separately through the rotating illumination source. This separation allows the spectrograph optical assembly to remain stationary and simple, while the scanning capability is provided by the independent rotating source mechanism, reducing overall mechanical complexity.
3Measurement precision
If the entire spectrographic optical assembly is moved to position the slit, then spectral imaging is achieved, but the device becomes too large for medical scope applications
Solution Approach 1:
Instead of moving the spectrograph to achieve scanning, the invention inverts the approach by rotating the illumination source to present different scene portions to the fixed slit. This allows the spectrograph optical assembly to remain small and stationary while still achieving full spectral scanning capability, making the device compact enough for medical scope applications.
Solution Approach 2:
The rotating illumination source serves multiple functions: it provides scene illumination, performs the scanning function by rotating to present different portions of the scene to the slit, and enables spectral acquisition across the entire field of view. This multi-functionality eliminates the need for separate scanning mechanisms, reducing device volume.
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 provides improved mechanical stability, ease of manufacture, and compact size, enabling stable hyperspectral imaging suitable for medical scopes while maintaining high imaging quality and spectral resolution.
Implementation Method 1
A rotating prism is located distally to the slit and adapted to rotate with respect to a central optical axis of the optical channel and by its rotation to rotate the image that is focused onto the first imaging plane
Implementation Method 2
A dispersive element is constructed and arranged to receive incident light from the slit and spectrally disperse it along a direction perpendicular to a width of the slit
Implementation Method 3
A focusing lens is arranged to focus the spectrally dispersed light at a second image plane such that the spectral dispersion is imaged along a first axis of the second image plane
Data Source
AI summary
A hyperspectral imaging system includes an optical channel arranged to focus light at a first image plane. A spectrometer includes a slit formed at the first image plane to allow a portion of the light to pass. A dispersive element receives light from the slit and spectrally disperses it along a direction perpendicular to a width of the slit. A focusing lens focuses the spectrally dispersed light at a second image plane such that the spectral dispersion is imaged along a first axis of the second image plane, and a spatial image of the slit width is imaged along a second axis. A sensor at the second image plane detects the spectrally dispersed light. A rotating prism is located distally to the slit and rotates, thereby rotating the image at the first imaging plane so that the portion of the image transmitted into the spectrometer varies.