Digital Pixel Image Sensor Scanning for Noise-Resistant Readout
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Solution Overview
Problem
Conventional image sensors using analog pixels face challenges with noise and coupling, particularly when processing high-resolution image signals.
Innovation Solution
An image sensor device with a pixel array comprising digital pixels, each equipped with a photo detector, comparator, and memory circuit, is controlled by a high-speed scanner that generates reset enable signals and signal enable signals to facilitate high-speed output of sampling values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog pixels are used to process high-resolution image signals, then the image sensor can capture detailed images, but noise and coupling problems increase
Solution Approach 1:
The patent replaces the analog pixel system with a digital pixel system. Each pixel includes a photo detector, comparator, and memory circuit that directly output digital signals. This substitution of analog-to-digital conversion at the pixel level eliminates noise and coupling issues associated with analog signal processing while maintaining high-resolution image capture capability.
2Object-affected harmful factors
If digital signal processing is implemented at the pixel level, then noise and coupling are reduced, but device complexity increases
Solution Approach 1:
The patent divides the image sensor into independent digital pixel units, each containing a photo detector, comparator, and memory circuit. This segmentation allows each pixel to independently process and output digital signals, reducing noise and coupling while distributing the complexity across multiple simple, identical modules rather than one complex analog system.
Solution Approach 2:
Each digital pixel is self-contained with its own photo detector, comparator, and memory circuit, enabling independent digital signal processing. This self-service architecture eliminates the need for complex external analog signal routing and processing, reducing overall system complexity despite the added components per pixel.
3Productivity
If high-speed scanning is implemented to output sampling values rapidly, then processing speed increases, but signal timing control becomes more difficult
Solution Approach 1:
The high-speed scanner uses periodic clock signals to control the timing of reset enable signals and signal enable signals. This periodic action synchronizes the rapid output of sampling values from multiple pixels, achieving high processing speed while maintaining precise timing control through the regular clock cycle.
Solution Approach 2:
The scanner circuit uses feedback mechanisms where the clock signal and trigger signals are systematically processed through flip-flops to generate coordinated enable signals. This feedback-based timing control ensures that despite high-speed operation, the timing of reset and signal outputs remains precisely synchronized across all pixels.
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 improved performance by reducing noise and coupling issues, allowing for high-speed processing and output of digital signals, thereby enhancing image quality and processing efficiency.
Implementation Method 1
An image sensor may convert an optical signal into an electrical signal
Data Source
AI summary
An image sensor device includes a pixel array, including digital pixels, and a pixel driver including a high-speed scanner that generates reset enable signals and signal enable signals. Each of the digital pixels includes a photo detector, a comparator, and a memory circuit. The high-speed scanner includes a first flip-flop and a second flip-flop. The first flip-flop receives a clock signal and a read trigger signal and outputs a first reset enable signal of the reset enable signals. The second flip-flop receives the clock signal and the first reset enable signal and outputs a first signal enable signal of the signal enable signals. The pixel array outputs a reset sampling value stored in the memory circuit in response to the first reset enable signal and outputs a signal sampling value stored in the memory circuit in response to the first signal enable signal.