Computational Pixel Imager With In-Pixel Histogram and HDR Sensing
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Solution Overview
Problem
Conventional imaging arrays, such as CCDs and CMOS devices, lack advanced signal processing capabilities within pixels, limiting their dynamic range and efficiency in capturing and processing image data, especially in high dynamic conditions.
Innovation Solution
The development of computational pixel imagers with integrated circuits at each pixel, featuring detectors, signal converters, multiplexers, and multiple counters that perform advanced signal processing functions, including in-pixel histogram acquisition and infinite dynamic range sensing, enabling concurrent processing and digital down-sampling of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional imaging arrays (CCD or CMOS) are used, then the structure is simple and manufacturing is easier, but the dynamic range and signal processing capabilities are limited
Solution Approach 1:
The patent combines multiple functional components (detector, signal converter, multiplexer, and multiple counters) into a single integrated pixel circuit. This merging enables advanced signal processing capabilities including histogram acquisition and high dynamic range sensing within each pixel, resolving the contradiction between enhanced adaptability and increased device complexity by integrating functions that would otherwise require separate processing stages.
Solution Approach 2:
The pixel circuit is designed with multi-functional capability, where a single pixel can perform detection, signal conversion, multiplexing, and multiple counting operations simultaneously. The counters can be configured for different functions (histogram acquisition, high dynamic range sensing) making the pixel structure universally applicable to various imaging requirements, thus improving adaptability without proportionally increasing complexity.
2Productivity
If multiple counters are integrated at each pixel for concurrent processing, then processing capabilities and dynamic range are enhanced, but the pixel area and manufacturing complexity increase
Solution Approach 1:
Multiple counters are integrated within each pixel along with the detector and signal converter, enabling concurrent signal processing operations. This integration improves productivity by allowing histogram acquisition and high dynamic range sensing to occur simultaneously at the pixel level, rather than requiring separate processing stages that would increase overall system area.
Solution Approach 2:
The patent implements time-multiplexed operation of the counters, where counters are sequentially activated during different time intervals within an exposure period. This temporal dimension allows multiple counting operations to share the same physical hardware resources, effectively increasing processing capacity without proportionally increasing pixel area.
3Measurement precision
If in-pixel digitization and processing are implemented, then signal fidelity is improved and noise is reduced, but the device complexity and power consumption increase
Solution Approach 1:
Signal conversion from analog to digital format is performed preliminarily at the pixel level before signals are read out. This preliminary digitization improves measurement precision by converting weak analog signals to digital format early in the signal chain, where subsequent processing operations (counting, histogram acquisition) can be performed with high fidelity without the noise and degradation that would occur with analog processing.
Solution Approach 2:
Each pixel performs its own signal conversion and processing operations independently without requiring external intervention. The pixel circuit autonomously executes histogram acquisition and high dynamic range sensing functions, improving signal fidelity through localized processing while the modular self-service architecture helps manage device complexity by distributing processing tasks across independent pixel units.
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 enhances the dynamic range and processing capabilities of imaging arrays, allowing for efficient capture and processing of image data across a wide range of conditions, including high dynamic range scenarios, with reduced noise and improved signal fidelity.
Implementation Method 1
photocurrent generated by illumination of a photodiode
Data Source
AI summary
A computational pixel imaging device can include multiple counters per pixel that can be used to acquire in-pixel histogram data representative of a signal detected by a pixels detector. Multiple pixel counters can also be used to execute simultaneous signal-processing threads on acquired image data. The imaging device can also include infinite dynamic range sensing and perform signal down-sampling.