CMOS Compressive Sensing Pixel Logic for Exposure Control
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Solution Overview
Problem
Conventional CMOS Image Sensors face a trade-off between signal-to-noise ratio (SNR) and frame rate due to exposure time, leading to low SNR at high frame rates and motion blurring at low light intensities, with existing solutions increasing system size and power consumption through optical apparatus for exposure control.
Innovation Solution
The implementation of Compressive Sensing Pixel-Wise Coded Exposure (CS-PCE) technique, which uses an array of pixels with in-pixel logic gates to control exposure time and reset detectors, allowing variable exposure times and reducing system size and power consumption by eliminating the need for optical exposure control elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical apparatus (DMD, LCOS) is used for exposure control, then exposure precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the exposure control function from external optical apparatus (DMD, LCOS) and relocates it directly to the image sensor chip. The exposure control circuit is integrated into the sensor itself, eliminating the need for separate optical modulators and reducing system complexity while maintaining exposure precision.
Solution Approach 2:
The patent merges the exposure control function with the image sensor by integrating the exposure control circuit directly onto the sensor chip. This consolidation combines multiple functions (detection and control) into a single integrated unit, reducing device complexity and power consumption while preserving exposure precision.
2Measurement precision
If optical apparatus (DMD, LCOS) is used for exposure control, then exposure precision is improved, but power consumption increases
Solution Approach 1:
The patent extracts the exposure control function from power-hungry external optical apparatus and relocates it to the low-power image sensor chip. This extraction eliminates the need for high-power optical modulators while maintaining exposure precision through integrated control.
Solution Approach 2:
The patent merges exposure control with the image sensor, leveraging the sensor's low-power operation. The integrated exposure control circuit operates at the same low power level as the sensor itself, dramatically reducing overall power consumption compared to using separate optical modulators.
3Productivity
If short exposure time is used, then frame rate is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent implements dynamic exposure control where each pixel can independently adjust its exposure time based on scene requirements. This dynamic adjustment allows the system to use short exposure times for high frame rates when needed, while extending exposure times for low-light conditions to maintain signal-to-noise ratio, optimizing both productivity and reliability.
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
CS-PCE enhances SNR and reduces motion blurring by prolonging exposure times, achieving high frame rates with improved image quality and reduced noise, while maintaining low power consumption and miniaturization potential.
Implementation Method 1
a first detector to generate a first electrical signal in response to irradiation by incident radiation
Data Source
AI summary
An apparatus includes an array of pixels. At least a first pixel in the array of pixels includes a first detector to generate a first electrical signal in response to irradiation by incident radiation, a first transistor electrically coupled to the first detector, and at least one logic gate to implement a Boolean AND logic function. The logic gate includes a first input terminal to receive a first exposure signal, a second input terminal to receive a first reset signal, and an output terminal, electrically coupled to the first transistor, to output to the first transistor a first control signal to variably control a first variable exposure time of the first detector and to reset the first detector.