Computational Pixel Imagers for Event-Based Sparse Frame Capture
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Solution Overview
Problem
Conventional imaging arrays, such as CCDs and CMOS devices, lack in-pixel data processing capabilities, limiting their efficiency and flexibility in signal detection and processing.
Innovation Solution
Incorporating integrated circuits within each pixel to digitize detected signals and perform advanced signal-processing functions, including event-based imaging and multi-frame acquisition with varying frequencies, using counters to accumulate and process digital signals for enhanced detection and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional imaging arrays (CCD/CMOS) are used, then the device structure is simple and manufacturing is easier, but in-pixel data processing capabilities are lacking
Solution Approach 1:
The patent merges the photodetector, signal converter, counter, and logic circuitry into an integrated pixel structure. The photodetector converts incident photons to electrical signals, which are then processed by the signal converter and counter within the same pixel, eliminating the need for separate processing units and enabling in-pixel computation.
Solution Approach 2:
The pixel circuit is designed to perform multiple functions: photodetection, signal conversion, counting/accumulation, and event detection. The same pixel structure can operate in different modes (integration mode, event-based mode) by controlling the counter operation, providing versatility without requiring multiple specialized devices.
2Productivity
If charge accumulates on capacitor at each pixel during exposure period, then the imaging process is simple, but the amount of data to be read out is large and processing is inefficient
Solution Approach 1:
The patent extracts only the meaningful information (changes in radiation levels) from the complete image data. The event-based pixel outputs signals only when a change exceeds a threshold, rather than transmitting all pixel values. This reduces data volume significantly while preserving the essential information about scene dynamics.
Solution Approach 2:
The counter performs preliminary accumulation and comparison operations within each pixel before data is read out. By pre-processing the signal at the pixel level (accumulating counts and comparing against thresholds), the system reduces the burden on external processing units and minimizes the amount of data that needs to be transmitted.
3Measurement precision
If digital focal plane arrays with in-pixel digitization are used, then signal processing capability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses parameter changes in the counter operation to achieve different processing modes. By changing the counting mode (incremental, decremental, reset) and threshold values, the same hardware structure can adapt to different signal processing requirements, maintaining manufacturing simplicity while providing precise signal detection capabilities.
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
Enables efficient, high-speed image processing with improved dynamic range and reduced latency, allowing for advanced image analysis and event detection, suitable for diverse applications including industrial inspection, surveillance, and autonomous vehicles.
Implementation Method 1
Each pixel can comprise a detector configured to generate an analog signal when exposed to radiation
Data Source
AI summary
A computational pixel imaging device that includes an array of pixel integrated circuits for event-based detection and imaging. Each pixel may include a digital counter that accumulates a digital number, which indicates whether a change is detected by the pixel. The counter may count in one direction for a portion of an exposure and count in an opposite direction for another portion of the exposure. The imaging device may be configured to collect and transmit key frames at a lower rate, and collect and transmit delta or event frames at a higher rate. The key frames may include a full image of a scene, captured by the pixel array. The delta frames may include sparse data, captured by pixels that have detected meaningful changes in received light intensity. High speed, low transmission bandwidth motion image video can be reconstructed using the key frames and the delta frames.