Computational Pixel Imager With Multi-Counter Dynamic Range
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Solution Overview
Problem
Conventional imaging technologies rely on analog CMOS and CCD arrays that lack advanced in-pixel processing capabilities, limiting their dynamic range and efficiency in digital imaging applications.
Innovation Solution
The development of computational pixel imagers (CPIs) with integrated circuits within each pixel for digitizing photocurrent signals and performing advanced signal processing, including multi-thread processing and infinite-dynamic-range sensing, to enhance imaging capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analog CMOS and CCD arrays are used for imaging, then the imaging system is simpler in structure, but the dynamic range and processing capability are limited
Solution Approach 1:
The pixel circuit is divided into multiple independent counters (e.g., first counter, second counter, third counter) that can operate simultaneously to capture different aspects of the optical signal. This segmentation allows the system to achieve extended dynamic range by combining measurements from multiple counters with different integration times or gain settings, while keeping each individual counter relatively simple in structure.
Solution Approach 2:
The pixel circuit is designed to perform multiple functions through its multi-counter architecture. The same photodetector and readout circuitry serve multiple counters that can be configured for different exposure times, gain levels, or signal processing modes. This multi-functionality enables the system to handle a wide range of lighting conditions and signal intensities within a single pixel, effectively extending the dynamic range without requiring separate imaging systems.
2Adaptability or versatility
If analog CMOS and CCD arrays are used, then manufacturing is easier, but advanced in-pixel processing capabilities are lacking
Solution Approach 1:
The complex processing functionality is segmented into multiple independent counters within each pixel, where each counter handles a specific aspect of signal processing (e.g., different integration times, gain settings). This segmentation allows the complex overall functionality to be achieved through simpler, more manufacturable individual counter circuits that can be replicated across the array using standard CMOS fabrication processes.
Solution Approach 2:
Multiple counter circuits and their associated control logic are merged within a single pixel structure, integrating what would traditionally require separate processing components into a compact in-pixel architecture. This merging enables advanced processing capabilities while maintaining a footprint compatible with standard imaging array fabrication, as the counters share common elements such as the photodetector, reset circuitry, and readout paths.
3Productivity
If multiple in-pixel counters are implemented for advanced processing, then processing efficiency and dynamic range improve, but the pixel area increases
Solution Approach 1:
Multiple counter circuits are merged within a single pixel by sharing common structural elements such as the photodetector, reset transistors, and readout circuitry. The counters are implemented using compact digital logic that can be densely packed, and they share control signals and data paths, thereby reducing the total area required compared to having separate processing units for each counter.
Solution Approach 2:
The multiple counters are arranged in a time-multiplexed or spatially interleaved configuration within the pixel, utilizing the temporal dimension for signal processing. Different counters can be activated at different times or for different portions of the optical signal, allowing efficient use of the pixel area by not requiring all counters to operate simultaneously with full independence.
4Measurement precision
If conventional imaging arrays are used, then the system is simpler to operate, but imaging efficiency and detail capture are reduced
Solution Approach 1:
The multi-counter pixel circuit performs signal processing automatically within each pixel, with the counters independently integrating and processing the optical signal based on pre-programmed parameters. This self-service capability allows the pixel to autonomously capture multiple aspects of the scene (different exposure times, gain levels) without requiring complex external control, thereby maintaining operational simplicity while achieving high measurement precision through in-pixel processing.
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
CPIs enable efficient digital down-sampling, multi-thread processing, and infinite-dynamic-range sensing, improving imaging efficiency and dynamic range, allowing for more accurate and detailed image capture in various environments.
Implementation Method 1
Each pixel may include a photodetector configured to detect light and to produce photocurrent signals from the detected light
Data Source
AI summary
A stereo imaging system includes an optical assembly and a computational pixel imager (CPI) having a plurality of pixels. Each pixel includes a light sensor and counters that convert a photocurrent from the light sensor to a digital signal. The optical assembly, which directs light from a light field to the CPI, includes an optical field combiner and first and second primary lens assemblies, which are configured to receive first and second portions of the light from the light field, respectively, and to direct the first and second portions of the light to the optical field combiner. The optical field combiner includes a modulator configured to modulate the first and second portions of the light and to direct modulated first and second portions of the light onto the CPI. The counters are configured to perform digital signal processing on the digital signal.