Automotive Image Sensor Pixel Array Verification Circuitry
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Solution Overview
Problem
Conventional automotive image sensors face challenges in verifying their integrity and safety compliance due to the inability to impose a known photonic scene while embedded in a vehicle, which is crucial for adhering to safety standards like ISO 26262.
Innovation Solution
Incorporating verification circuitry within the image sensor that injects test voltages into the pixel array to continuously monitor and verify the functionality of the imaging system, allowing for real-time verification and comparison with a predetermined standard to ensure proper operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional automotive image sensors are embedded within the automobile, then the imaging system can be integrated into the vehicle for safety applications, but the ability to perform self-checking procedures and verify pixel array integrity is lost
Solution Approach 1:
The image sensor performs self-verification by injecting test voltages into its own pixel array through integrated verification circuitry. The sensor monitors its own functionality without requiring external test equipment, enabling continuous self-checking while embedded in the vehicle. This resolves the contradiction by making the system both integrated and self-verifying.
Solution Approach 2:
The verification circuitry continuously injects test voltages into the pixel array before actual imaging operations to pre-validate pixel functionality. By performing verification in advance and continuously, the system ensures reliability without disrupting normal operation, maintaining both integration and self-checking capability.
2Reliability
If test voltages are injected into the pixel array to verify functionality, then pixel array integrity can be continuously monitored, but additional verification circuitry is required within the image sensor
Solution Approach 1:
The verification circuitry is merged with the image sensor chip, integrating the test voltage injection functionality directly into the sensor's existing structure. This combination allows pixel array verification to be performed without adding separate external test equipment, resolving the contradiction between verification capability and device complexity by consolidating functions into a single integrated unit.
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 continuous on-the-fly verification of the imaging system's status, ensuring safety and reliability by detecting any deviations from the expected performance criteria, thereby preventing faulty data from being input into critical vehicle control systems.
Implementation Method 1
Each pixel receives incident photons (light) and converts the photons into electrical signals
Data Source
AI summary
An imaging system may include an array of image pixels and verification circuitry. The verification circuitry may inject test voltages into the image pixel array during the photodiode reset operation. The test signals may then be read out using a correlated double sampling operation. Verification circuitry may compare the test signals to reference data to determine whether the imaging system is functioning properly (e.g., to determine whether the array of image pixels satisfies performance criteria). If the amount of mismatch between the test signals and the reference data exceed a predetermined threshold, the imaging system may be disabled and/or a warning signal may be presented to a user of the system.