Coded Access Optical Sensor High Dynamic Range Imaging
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Solution Overview
Problem
Conventional optical imagers, such as CCDs and CMOS sensors, face limitations in extreme contrast lighting conditions due to saturation, nonlinear response, limited spatial resolution, inter-pixel crosstalk, and diffraction limits, leading to high costs and restricted usage, while requiring high dynamic range, wavelength flexibility, and low inter-pixel crosstalk.
Innovation Solution
The Coded Access Optical Sensor (CAOS) employs an electronically agile pixel platform with hybrid space-time-frequency RF coded multiple-access and optical-electronic domain signal processing, allowing time modulation of pixel irradiance using binary codes and simultaneous detection of multiple light levels to generate a high dynamic range optical irradiance map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical imagers (CCD/CMOS) are used, then spatial resolution and measurement precision are improved, but inter-pixel crosstalk and saturation occur under extreme contrast lighting conditions
Solution Approach 1:
The patent divides the optical detection function into separate spatial and temporal domains. Instead of using fixed pixel arrays that suffer from crosstalk, the invention segments the measurement process into multiple time-resolved detections with a single point detector, eliminating spatial interference between pixels while maintaining high spatial resolution through temporal multiplexing.
Solution Approach 2:
The patent introduces coded aperture masks as intermediaries between the light source and detector. These masks encode spatial information into temporal patterns, allowing a single point detector to resolve spatial details without direct spatial overlap between detection channels, thereby eliminating inter-pixel crosstalk while preserving spatial resolution.
2Measurement precision
If custom fluorescence materials and precision lens are used to beat the diffraction limit, then measurement precision is improved, but system cost and complexity increase significantly
Solution Approach 1:
The patent replaces complex optical mechanical systems (precision lenses, custom fluorescence materials, coded optics) with a simpler temporal coding approach using programmable masks and time-resolved detection. This substitution achieves super-resolution through temporal multiplexing rather than requiring complex optical hardware, significantly reducing system complexity while maintaining measurement precision.
Solution Approach 2:
The patent changes the detection parameter from spatial domain to temporal domain. By measuring light intensity variations over time with coded aperture patterns rather than using complex spatial optical elements, the system achieves high resolution through temporal parameter changes, avoiding the need for expensive custom optical components.
3Device complexity
If fixed wavelength band operation is used, then device complexity is reduced, but adaptability and versatility are limited
Solution Approach 1:
The patent creates a universal imaging system that can operate across multiple wavelengths by using programmable aperture masks and time-resolved detection. The single point detector combined with temporal coding can process different wavelength bands sequentially or simultaneously, providing multi-functional capability without requiring separate optimized systems for each wavelength, thus achieving versatility without proportionally increasing complexity.
4Measurement precision
If massive read-out data is generated by multi-pixel devices, then measurement precision is improved, but loss of time and processing overhead increase
Solution Approach 1:
The patent extracts only the essential spatial and temporal information needed for imaging by using a single point detector with coded aperture patterns. Instead of generating massive data from all pixels simultaneously, the system extracts information through time-resolved measurements with coded masks, significantly reducing data volume while maintaining imaging quality, thereby reducing processing time and computational overhead.
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
CAOS achieves high dynamic range imaging with reduced inter-pixel crosstalk, flexible wavelength operation, and low cost, while overcoming the limitations of traditional imagers, enabling robust, portable, and energy-efficient imaging across diverse applications.
Implementation Method 1
time modulating the incident light irradiance of one or more of the pixels on the OAD using a binary code sequence to give each of the one or more pixels a spread spectrum in the electrical frequency domain
Implementation Method 2
setting the DMD micromirrors to its -θ degree tilt state to direct time static light from the object plane for detection of the optical irradiance values associated with pixels in a bright unwanted zone
Implementation Method 3
detecting by a point photo detector, PD, the optical irradiance values of those pixels in the bright unwanted zone
Data Source
AI summary
A method for performing high dynamic range optical image detection of a scene. The method comprises imaging incident light from a scene onto an object plane of an Optical Array Device, the OAD operating in time modulation mode; determining the locations of those pixels in the object plane of a first light level; detecting the optical irradiance values of those pixels of the first light level to produce a first detected image; detecting the optical irradiance values of those pixels of a second light level to produce a second detected image; and generating a high dynamic range optical irradiance map of the scene by combining the first detected image and the second detected image into a single image.