Optical Recognition System Using Single-Slope ADC for Wide Dynamic Range
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Solution Overview
Problem
Existing optical recognition systems require additional memory for storing exposure information, leading to increased hardware costs and power consumption, and are limited by the need for separate frame memories for each pixel array.
Innovation Solution
The system employs a single-slope analog-to-digital converter (SSADC) to differentiate between long and short exposure signals using a threshold voltage, eliminating the need for additional memory by determining exposure duration and using a digital-to-analog converter for one-time exposure, thereby improving hardware speed and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional memory is used to store exposure information for each pixel array, then the system can handle multiple illumination areas, but the hardware cost and power consumption increase
Solution Approach 1:
The patent merges the exposure time control function into the transfer transistor gate electrode, which simultaneously controls both the exposure timing and the charge transfer operation. This eliminates the need for separate memory structures to store exposure information, as the transfer transistor's gate voltage timing directly encodes the exposure duration. By combining these functions, the system handles multiple illumination areas without requiring additional memory, thereby reducing power consumption and hardware cost.
Solution Approach 2:
The transfer transistor is designed to serve multiple functions: it controls the exposure time by its gate voltage application timing, it transfers charges from the photodiode to the floating diffusion, and it enables the system to adapt to different illumination conditions. This multi-functional design eliminates the need for dedicated memory structures, reducing both power consumption and hardware complexity while maintaining the capability to handle various illumination areas.
2Adaptability or versatility
If additional memory is used to store exposure information, then the system can differentiate illumination areas, but the hardware complexity and cost increase
Solution Approach 1:
The patent combines the exposure control function with the charge transfer mechanism by applying gate voltage to the transfer transistor at specific timing. This merged approach allows the system to differentiate between highly-illuminated and lowly-illuminated areas without requiring separate memory structures, thereby simplifying the hardware architecture while maintaining the capability to handle multiple illumination conditions.
Solution Approach 2:
The patent extracts the exposure information storage function from dedicated memory structures and embeds it directly into the transfer transistor's operational timing. By removing the separate memory component and integrating its function into the existing transfer mechanism, the system achieves illumination area differentiation with reduced hardware complexity and lower cost.
3Productivity
If separate frame memories are used for each pixel array, then the system can process different illumination areas independently, but the power consumption and hardware cost increase
Solution Approach 1:
The patent merges the frame memory function into the transfer transistor mechanism, where the timing of gate voltage application serves as both the exposure control and the memory storage mechanism. This allows independent processing of different illumination areas through temporal multiplexing rather than spatial separation, maintaining productivity while significantly reducing power consumption by eliminating redundant memory structures.
Solution Approach 2:
The system uses periodic application of gate voltage to the transfer transistor to achieve independent processing of different illumination areas. By controlling the timing and duration of gate voltage pulses, the system can sequentially handle highly-illuminated and lowly-illuminated areas without requiring simultaneous dedicated memory structures, thereby reducing power consumption while maintaining independent processing capability.
4Adaptability or versatility
If timing-dependent photosensor reset is used to extend dynamic range, then the system can handle varying light intensities, but additional memory is required
Solution Approach 1:
The patent combines the dynamic range extension mechanism with the charge transfer operation by using the transfer transistor's gate voltage timing to control both the exposure duration and the charge transfer timing. This merged approach allows the system to handle varying light intensities across different illumination areas without requiring additional memory structures, thereby extending dynamic range while simplifying the hardware architecture.
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 allows for extended application scope without additional memory, enhancing the speed and efficiency of the optical recognition system while minimizing power consumption and hardware costs.
Implementation Method 1
adopts a single-slope analog-to-digital converter to proceed a single-slope analog-to-digital conversion
Implementation Method 2
a pinned photodiode (PD)
Data Source
AI summary
The present invention is related to an optical recognition system and a method thereof, and more particularly to an optical recognition system and a method that adopts a single-slope analog-to-digital converter to proceed a single-slope analog-to-digital conversion in order to have an image with a wide dynamic range.