Non-CDS Random-Access Pixel Array with SAR ADC for Power-Constrained Imaging
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Solution Overview
Problem
Current image sensor technologies face challenges in achieving high resolution and low power consumption while maintaining high signal-to-noise ratio (SNR) and data-rate, particularly in applications like laser Doppler imaging (LDI) and wireless multimedia sensor networks (WMSN), where high sampling rates and low thermal power budgets are required.
Innovation Solution
The implementation of a sensory array with non-correlated double sampling (CDS) random-access-reset pixels and a Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) with forward error correction and mixed-signal correlated-double-sampling, which includes a high-resolution readout channel for selected sensors and a compressive readout channel for the entire array, optimizing power consumption and SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling rates are used to achieve high resolution imaging, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The sensor array is divided into multiple blocks, with each block containing pixels that share common readout circuitry. This segmentation allows independent control and optimization of different regions, enabling high-resolution imaging in specific areas while reducing power consumption in others.
Solution Approach 2:
The patent implements dynamic control of pixel blocks, where only selected blocks are activated for high-resolution sampling based on scene requirements. This dynamic activation allows the system to adapt sampling rates and power consumption to actual imaging needs, achieving high measurement precision when required while conserving energy during normal operation.
2Measurement precision
If high sampling rates are used to capture fast-moving particles in LDI, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor array is segmented into multiple blocks with independent control, allowing high-speed sampling to be applied selectively to specific regions of interest rather than the entire array. This reduces the overall complexity of the sensor system while maintaining the capability for high-precision flow-rate measurement where needed.
Solution Approach 2:
The patent applies high sampling rates only to selected pixel blocks that are actively monitoring regions with fast-moving particles, rather than uniformly applying high sampling rates across the entire sensor array. This partial action approach maintains measurement precision for critical measurements while reducing device complexity and power consumption.
3Adaptability or versatility
If multiple readout channels are implemented to optimize different purposes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The readout system is divided into multiple independent readout channels, each optimized for specific purposes such as high-speed sampling or low-power operation. This segmentation allows the system to select appropriate readout modes based on application requirements, improving adaptability while managing complexity through modular design.
Solution Approach 2:
The patent designs readout channels with multi-functional capabilities, where the same hardware infrastructure can operate in different modes (high-speed, low-power, high-resolution) depending on the activation of specific pixel blocks. This universality improves system adaptability without proportionally increasing device complexity.
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 enables high-resolution imaging with reduced power consumption and improved SNR, allowing for efficient data processing and transmission, suitable for diverse imaging applications including LDI and WMSN.
Implementation Method 1
Each pixel can comprise a photo detector (e.g., a pinned photodiode),
Implementation Method 2
Laser Doppler imaging (LDI) needs very high sampling speed but does not need to sample every pixel... to estimate the corresponding particle flow-rate by the principle of laser Doppler (LD) effect. LD describes the difference in frequency the Doppler Shift-between the incident light and its scattered parts from moving particles.
Data Source
AI summary
Integration of high-fidelity readout and compressive readout channels in a signal sensor array system is provided. A high-fidelity representation of the sensor array is recovered by combining the data from both the high-resolution and compressive readout channels. The signal sensory array system uses a non-correlated-double-sampling (non-CDS) pixel block readout, random-access-reset pixel, ADC-integrated image compression, high-resolution successive-approximation-register (SAR) analog-to-digital-converters (ADC), SAR ADC self-calibration, and low-noise time-domain comparator.