Pixel Driving Circuit Event Storage for Vision Sensor Artifact Reduction
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Solution Overview
Problem
Vision sensors face challenges in processing event information from pixels due to complex analog circuitry, leading to image artifacts from simultaneous event processing with different timestamps, and difficulties in detecting changes in a matrix-form pixel array.
Innovation Solution
A digital pixel driving circuit with a column driver, row driver, controller, and address generator is implemented, along with a pixel circuit including a photoelectric device, current readout unit, event determination unit, and event output unit, using storage circuitry like capacitors to store event information and prevent overwriting, allowing simultaneous processing and reducing image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If event information from multiple pixels is processed individually or via predetermined pixel groups, then processing can be performed with existing circuitry, but image artifacts occur because events from different pixels have different timestamps even when they occur simultaneously
Solution Approach 1:
The patent applies preliminary action by storing event information from multiple pixels in buffer memory before processing. This allows all events to be captured with their original timestamps preserved, and then processed together to determine if they occur simultaneously within a threshold period, eliminating image artifacts while maintaining detection accuracy
Solution Approach 2:
The patent introduces an intermediary processing stage between pixel detection and final output. The buffer memory and control circuit act as intermediaries that collect, timestamp, and coordinate events from multiple pixels, allowing simultaneous events to be identified and processed together, thus preventing image artifacts
2Ease of operation
If analog circuitry is used to process pixels, then event detection can be performed, but the circuitry becomes complicated and difficult to design
Solution Approach 1:
The patent replaces complex analog circuitry with a digital processing system. Digital circuits are used to detect pixel events, store information in buffer memory, and process timestamps through logical operations. This substitution significantly simplifies circuit design while maintaining event detection capability, as digital systems are more straightforward to design and manufacture than equivalent analog systems
3Speed
If events are processed immediately upon occurrence, then real-time detection is achieved, but events from other pixels may be lost or new events may arise during processing causing timestamp inconsistencies
Solution Approach 1:
The patent uses preliminary action by pre-allocating buffer memory to store event information from multiple pixels simultaneously. This allows the system to capture all events without loss while maintaining their original timestamps, and then process them together to ensure consistency, preventing both information loss and timestamp inconsistencies
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 solution improves vision sensor performance by enabling efficient detection and storage of event occurrences across a pixel array, reducing image distortion and allowing for global shutter operations, thereby enhancing the accuracy of event detection in dynamic environments.
Implementation Method 1
a photoelectric device PD
Data Source
AI summary
A pixel includes a photoelectric device, a current readout unit configured to detect an electric current flowing in the photoelectric device to generate an input voltage, an event determination unit configured to determine an event occurrence and an event type responsive to the input voltage, and configured to output an event detection signal, and an event output unit configured to store the event detection signal for an event-storage period and configured to output the stored event detection signal responsive to an expiration of the event-storage period.