Hyperspectral Imaging Sensor Parallax Correction
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Solution Overview
Problem
Hyperspectral imaging systems face challenges in achieving high spectral and spatial resolution while maintaining a compact size, as increasing signal levels often requires larger optics or reduced spatial resolution, and existing methods like dual-slit spectrometers are complex and offer limited signal enhancement.
Innovation Solution
A solid-state imaging sensor with a 2D array of detector elements and parallax detecting elements on a common substrate, using digital time-delay and integration (TDI) circuits to enhance signal-to-noise ratio and correct for distortion without spectrally-dispersive elements, allowing for high spectral and spatial resolution imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of collecting optics is increased to increase signal level, then signal-to-noise ratio is improved, but system size and weight are considerably increased
Solution Approach 1:
The patent merges multiple functional elements (spectral dispersion, spatial encoding, and detection) into a single integrated optical system. The diffraction grating and coded aperture work together to achieve both spectral resolution and signal enhancement without requiring larger collecting optics, thus improving signal-to-noise ratio while controlling system weight.
Solution Approach 2:
The patent transitions from traditional single-dimensional spectral analysis to a multi-dimensional approach by encoding spatial information across multiple spectral channels. This dimensional expansion allows the system to extract more information from the same optical path, effectively increasing signal utilization without enlarging the optics.
2Reliability
If individual pixels are allowed to collect more signal from a larger area, then signal level is increased, but spatial resolution is reduced
Solution Approach 1:
The patent segments the detection process into multiple spectral channels, each capturing a portion of the spectrum. By distributing the signal collection across these segmented channels rather than requiring each pixel to collect more signal individually, the system maintains spatial resolution while achieving adequate signal levels through the combined information from all channels.
Solution Approach 2:
Each pixel in the detector array serves multiple functions: it detects signal intensity while its position across the array encodes both spatial and spectral information. This multi-functionality allows the system to maintain high spatial resolution while each pixel collects sufficient signal, as the same pixel contributes to multiple spectral measurements.
3Reliability
If scanning speed is reduced to increase signal collection time, then signal level is improved, but scan area coverage is reduced and gaps in coverage can occur
Solution Approach 1:
The patent enables continuous signal collection across all spectral channels simultaneously during the scan, rather than sequentially. This continuous parallel action ensures that signal collection is maximized throughout the entire scan duration without requiring slower speeds, maintaining both signal level and scan area coverage.
Solution Approach 2:
The system performs preliminary spectral encoding and spatial modulation before detection, preparing the signal in advance so that during the actual scan, all channels collect signal simultaneously at full scan speed. This preliminary preparation eliminates the need to slow down for enhanced signal collection.
4Reliability
If dual-slit spectrometers are used to increase signal level, then signal enhancement is achieved, but device complexity is increased and only twice the signal level is achieved
Solution Approach 1:
The patent combines the functions of multiple slits, spectral dispersion, and spatial encoding into a single integrated optical path with a diffraction grating and coded aperture. This merging achieves signal enhancement far greater than the factor of two from dual-slit systems while significantly reducing optical complexity by eliminating the need for multiple separate slit assemblies.
Solution Approach 2:
Instead of simply duplicating the slit structure (adding one dimension of complexity), the patent introduces spectral and spatial encoding dimensions that multiply the effective signal collection without proportional increases in optical complexity. The coded aperture pattern encodes multiple spatial positions simultaneously, achieving exponential signal enhancement rather than linear.
5Measurement precision
If spectrally-dispersive elements are used to achieve high spectral resolution, then spectral resolution is improved, but device complexity and system size are increased
Solution Approach 1:
The patent applies spectral dispersion locally at specific regions of the detector array rather than requiring a complex optical path for the entire system. The diffraction grating is positioned to disperse light only where needed, and the coded aperture applies spatial encoding locally, achieving high spectral resolution while minimizing overall system complexity and size.
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 enables high spectral and spatial resolution imaging with reduced system size, improved signal-to-noise ratio, and effective correction for parallax distortion, enhancing imaging range and accuracy without the complexity of dual-slit spectrometers.
Implementation Method 1
a 2D array of light-sensitive detector elements configured to detect light from a target scene to be imaged
Implementation Method 2
using digital time-delay and integration (TDI) circuits to enhance signal-to-noise ratio
Implementation Method 3
detector elements for detecting parallax data... determine a correction for parallax based on detector element values from at least two rows of parallax detecting detector elements
Data Source
AI summary
An apparatus and corresponding method for line-scan imaging includes a 2D array of light-sensitive detector elements divided into a plurality of sub-arrays. An electrical circuit can be configured to determine a correction for parallax based on detector element values from at least two rows of parallax detecting elements to enable images captured by the sub-arrays to be co-aligned with each other. The 2D array and parallax detecting elements can be located on the same substrate chip. Image data from sub-arrays can be co-aligned with each other based on parallax data from the parallax detecting elements and used to produce hyperspectral images corrected for parallax.