Pixel Value Homogenization for ToF Arrays with Sensitivity Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Time of Flight (ToF) sensors suffer from non-uniform pixel sensitivity due to defects and malfunctions in Single Photon Avalanche Diodes (SPADs), leading to false detection holes and the need for accurate decision-making on whether to fill these holes.
Innovation Solution
A method and system that analyzes neighboring pixel patterns and computes an equivalent target detection confidence indicator to determine if holes are real or not, using parameters like sensitivity, ambient noise, and target features to decide whether to fill or not fill the holes through interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If systematic hole filling is performed without considering real target holes, then detection accuracy improves, but false positive rate increases
Solution Approach 1:
The patent applies local quality by analyzing the specific characteristics of each hole pixel's neighborhood rather than applying uniform filling. It examines target patterns, sensitivity variations, and confidence indicators locally around each hole to determine whether filling is appropriate, thus maintaining detection accuracy while avoiding false positives from real target holes.
Solution Approach 2:
The patent performs preliminary analysis of hole pixels before filling decisions are made. It calculates equivalent target detection confidence indicators and analyzes neighborhood patterns in advance to predict whether a hole represents a real target feature or a detection failure, enabling accurate distinction before the actual filling operation.
2Manufacturing precision
If sensitivity compensation is applied to correct pixel variations, then detection uniformity improves, but computational complexity increases
Solution Approach 1:
The patent changes parameters by computing equivalent target detection confidence indicators that incorporate pixel sensitivity information. Instead of directly correcting pixel values through complex calibration, it transforms the sensitivity variation problem into a confidence indicator calculation that can be integrated into existing detection pipelines with minimal additional complexity.
Solution Approach 2:
The patent introduces an intermediary calculation - the equivalent target detection confidence indicator - that mediates between raw pixel values and final detection decisions. This intermediary incorporates sensitivity compensation information without requiring direct modification of pixel values or complex calibration procedures, simplifying the overall system.
3Measurement precision
If advanced hole analysis algorithms are implemented, then hole filling accuracy improves, but processing time increases
Solution Approach 1:
The patent applies partial action by selectively analyzing only the necessary neighborhood information around hole pixels rather than processing the entire image. It focuses computational resources on calculating confidence indicators and analyzing patterns only where needed (at hole locations and their immediate neighborhoods), reducing overall processing time while maintaining accuracy.
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 mitigates pixel sensitivity variations, corrects dead pixels, and increases the maximum detection range without introducing latency, providing accurate hole filling decisions.
Implementation Method 1
A photon may generate a carrier in the SPAD through the photoelectric effect
Implementation Method 2
The photo-generated carrier may trigger an avalanche current in one or more of the SPADs in a SPAD pixel array
Implementation Method 3
This method comprises sending a light signal towards the object and measuring the time taken by the signal to travel to the object and to travel back to the device
Implementation Method 4
iToF (indirect Time of Flight) devices calculate the time taken by the signal for this travel by measuring the phase shift between the signal coming out of the light source and the signal reflected from the object
Data Source
AI summary
A method for homogenizing values of a pixel array comprises identifying pixels where a target has been detected, and correctable hole pixels where no target has been detected, surrounded with at least one neighboring pixel where a target has been detected, computing an equivalent target detection confidence indicator for each correctable hole pixel, according to target feature values calculated for the neighboring pixels of the correctable hole pixel, the equivalent target detection confidence indicator being representative of the target detection confidence indicator that the target detected in the neighborhood would have at the correctable hole pixel if the target detected in the neighborhood was also present at the correctable hole pixel position, in accordance with parameters including a sensitivity of the hole pixel, and if the computed equivalent target detection confidence indicator is lower than a detection threshold, computing a correction target feature value, associated to the hole pixel.