Integrated Hyperspectral Imaging Spectrometer with Photonic Lightwave Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hyperspectral imaging (HSI) systems are large, heavy, and vulnerable to scattered light, requiring platform motion for data collection and being difficult to produce in large quantities, with limitations in implementing Time Delay Integration (TDI) and achieving high Signal-to-Noise Ratio (SNR).
Innovation Solution
An integrated HSI spectrometer using a lenslet array coupled to photonic lightwave circuits with spectral grating filters and readout integrated circuitry, enabling compact, real-time 3D spatial/spectral image data capture, minimizing mass and volume, and incorporating TDI for improved SNR, while rejecting scattered light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pushbroom scanner is used, then spectral imaging capability is achieved, but device mass and volume increase
Solution Approach 1:
The patent merges the spectral dispersion function and detection function into a single integrated device. The micro-lens array focuses light directly onto the focal plane array where spectral information is encoded, eliminating the need for separate diffraction gratings and scan mechanisms. This integration dramatically reduces the mass and volume of the system while maintaining spectral imaging capability.
Solution Approach 2:
The patent extracts and eliminates the heavy components of traditional pushbroom scanners, specifically removing the diffraction gratings, scan mechanisms, and intermediate optics. By using a direct focal plane array detection approach with micro-lens array, the system achieves spectral imaging without the bulky components that traditionally defined this architecture.
2Measurement precision
If pushbroom scanner with diffraction gratings and FPA is used, then spectral data collection is enabled, but device volume increases
Solution Approach 1:
The patent combines the spectral encoding and detection functions into a single compact focal plane array. The micro-lens array directly focuses light onto the FPA, eliminating the need for separate diffraction gratings and scan optics, thereby dramatically reducing device volume while maintaining spectral data collection capability.
Solution Approach 2:
The patent removes the voluminous components of traditional spectrometers including diffraction gratings, scan mechanisms, and intermediate optics. The system achieves spectral imaging through a compact direct detection architecture using micro-lens array and focal plane array, reducing device volume significantly.
3Measurement precision
If pushbroom scanner is used, then spectral imaging is achieved, but scattered light vulnerability increases
Solution Approach 1:
The patent eliminates the diffraction gratings that are the primary source of scattered light in traditional pushbroom scanners. By using a direct focal plane array detection approach with micro-lens array, the system removes the optical elements that generate and propagate scattered light, thereby reducing vulnerability to this harmful factor while maintaining spectral imaging capability.
4Reliability
If multiple copies of spectrometer are used for TDI, then Time Delay Integration capability is achieved, but device complexity and mass increase
Solution Approach 1:
The patent merges multiple spectral channels and temporal integration functions into a single focal plane array. The array simultaneously captures multiple spectral bands at different spatial positions, enabling Time Delay Integration functionality without requiring multiple separate spectrometer copies. This integration reduces device complexity and mass while maintaining TDI capability.
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 results in a compact, high-resolution HSI system capable of rapid, cost-effective mass production, with enhanced SNR and reduced scattered light interference, enabling efficient spectral imaging without the need for scan mechanisms.
Implementation Method 1
a lenslet array with one lens for each image pixel that couples light from a scene image to photonic lightwave circuits (PLCs)
Implementation Method 2
Spectral grating filters are positioned along the length of each waveguide to extract the spectral components
Implementation Method 3
Spectral grating filters are positioned along the length of each waveguide to extract the spectral components as the light propagates to the end of the waveguide
Implementation Method 4
The filters route the optical energy to photodetectors and the detected electrical signals are captured by a read out integrated circuit (ROIC)
Data Source
AI summary
An integrated imaging spectrometer for hyperspectral imaging (HSI) system is disclosed. The integrated imaging spectrometer features photonic PLCs that include an array of input channel waveguides, one for each pixel of an image scene. Spectral grating filters are positioned along the length of each waveguide to extract the spectral components as the light propagates to the end of the waveguide. The filters route the optical energy to photodetectors and the detected electrical signals are captured by a read out integrated circuit (ROIC). Together the PLC, detectors, and ROIC form an imaging layer. Stacking imaging layers generates a device capable of recording an entire 3D high-resolution spatial/spectral image data cube in real-time.