Spectrally Structured Light Imaging for Color Accuracy
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Solution Overview
Problem
Current imaging technologies, such as digital cameras, struggle to accurately capture true color and spectral information due to limitations in lighting sources and sensor designs, leading to errors in color representation and object classification, especially under varying ambient lighting conditions.
Innovation Solution
The use of multi-chip LEDs synchronized with frame pulses in CMOS sensors to create spectrally structured light, allowing common cameras to function as imaging spectrometers, capturing N-band images and enabling direct chromaticity capture by coordinating LED light sources with individual frames of the sensor, thereby improving color photography and object classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard digital cameras are used for color capture, then device complexity is low, but color accuracy and spectral information capture are insufficient
Solution Approach 1:
The patent enables a standard digital camera to perform both conventional photography and spectral imaging by integrating programmable LED light sources that can emit different wavelengths. The camera system becomes multi-functional, serving as both a regular imaging device and an imaging spectrometer, thereby improving color accuracy without requiring completely separate specialized equipment.
Solution Approach 2:
The system uses programmable LED light sources that can dynamically change wavelengths and intensities based on capture instructions. This dynamic control of illumination allows the camera to adapt to different spectral requirements, enabling accurate color capture across varying lighting conditions while maintaining a relatively simple camera hardware configuration.
2Loss of information
If spectrally structured light is used with multi-chip LEDs, then spectral information capture is improved, but device complexity increases
Solution Approach 1:
The patent employs periodic pulsing of multi-chip LEDs at different wavelengths in synchronization with the camera's frame capture rate. This periodic action allows sequential capture of spectral information at different wavelengths, enabling complete spectral data acquisition without requiring all LEDs to operate simultaneously, thereby reducing peak power requirements and simplifying control logic.
Solution Approach 2:
The illumination system is segmented into multiple independent LED chips, each emitting at a specific wavelength. This segmentation allows the system to capture spectral information wavelength-by-wavelength through sequential pulsing, transforming a complex simultaneous multi-wavelength measurement problem into a series of simpler sequential measurements that can be processed independently.
3Adaptability or versatility
If ambient lighting conditions vary, then adaptability is improved, but color representation accuracy deteriorates
Solution Approach 1:
The patent introduces programmable LED light sources as an intermediary between the ambient environment and the camera sensor. These LEDs provide controlled spectral illumination that mediates the interaction between varying ambient light conditions and the sensor, enabling accurate color capture by supplementing or replacing ambient light with known spectral characteristics.
Solution Approach 2:
The system changes the spectral parameters of illumination by selecting different LED wavelengths and intensities based on ambient lighting conditions. This parameter control allows the system to compensate for varying ambient light spectra, maintaining accurate color representation across different environmental conditions by adjusting the illumination spectrum to match or complement the ambient light.
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 approach enhances color accuracy and object classification by transforming standard cameras into hyper-spectral imaging devices, capable of capturing detailed spectral information even under complex lighting conditions, improving both consumer photography and industrial applications like produce recognition and counterfeit detection.
Implementation Method 1
A core approach, exploited in several embodiments, is to synchronize pulsing of different LED light sources with individual frames of a CMOS sensor
Implementation Method 2
synchronize pulsing of different LED light sources with individual frames of a CMOS sensor, thereby creating the informational basis for N-band imaging
Data Source
AI summary
An image capture device, such as a smartphone or point of sale scanner, is adapted for use as an imaging spectrometer, by synchronized pulsing of different LED light sources as different image frames are captured by the image sensor. A particular implementation employs the CIE color matching functions, and/or their orthogonally transformed functions, to enable direct chromaticity capture. These and various other configurations of spectral capture devices are employed to capture spectral images comprised of spectral vectors having multi-dimensions per pixel. These spectral images are processed for use in object identification, classification, and a variety of other applications. Particular applications include produce (e.g., fruit or vegetable) identification. A great variety of other features and arrangements are also detailed.