Dynamic Shot Assembly for Time-of-Flight Sensor Linearity
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Solution Overview
Problem
Existing image and time-of-flight sensors face challenges in generating high-quality resulting images due to non-linear photodiode responses caused by manufacturing variations, temperature changes, and intensity variations, leading to degraded image quality.
Innovation Solution
A method for assembling two shots of a scene by determining weighted combinations based on the content of the data itself, using a dynamic assembly coefficient that adjusts for noise levels and signal-to-noise ratios to ensure shots are at the same brightness level, improving image quality and representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear weighting coefficients based on exposure time are used to assemble shots, then the assembly process is simple, but the image quality is degraded due to non-linear photodiode responses
Solution Approach 1:
The patent changes the weighting coefficient determination from fixed linear exposure-time-based values to dynamic content-based values. The processing unit calculates weighting coefficients by comparing actual signal intensities between shots, allowing adaptation to non-linear photodiode responses while maintaining reasonable computational complexity
Solution Approach 2:
The patent introduces feedback by using the actual measured signal content from each shot to determine the weighting coefficients. The processing unit analyzes the relationship between shots and adjusts weights based on observed signal variations, creating a closed-loop system that compensates for manufacturing variations and temperature effects
2Loss of information
If shots are acquired sequentially by time-of-flight sensor, then the sensor can capture dark zone information, but temperature variations between pixels cause non-linear responses
Solution Approach 1:
The patent applies local quality by determining weighting coefficients independently for different spatial zones or regions of the image. This allows each region to be compensated according to its specific characteristics, addressing local temperature variations and pixel response differences across the sensor array
Solution Approach 2:
The patent dynamically adjusts weighting coefficients based on actual measured signal relationships rather than using fixed values. This adaptation compensates for temperature-induced non-linearities that occur during sequential shot acquisition by time-of-flight sensors
3Adaptability or versatility
If transmission device operates in transition zone with different intensities for each shot, then the sensor can adapt to varying light conditions, but intensity variations generate non-linear pixel signals
Solution Approach 1:
The patent uses feedback by measuring the actual intensity relationship between shots and using this information to determine appropriate weighting coefficients. The processing unit analyzes how the transmission device intensity varies between shots and adjusts weights to maintain linear signal relationships despite operating in transition zones
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 enhances the quality of the resulting scene by accounting for noisy signals and sensor variations, optimizing processing times, and maintaining consistent brightness across different zones with varying texture characteristics.
Implementation Method 1
a first photodiode for acquiring the first shot and a second photodiode for acquiring the second shot
Implementation Method 2
converting a light signal received on each pixel of the sensor of the time-of-flight type into a first signal containing a first data set indicative of the first shot of the scene
Data Source
AI summary
A device for assembling at least two shots of a scene acquired by at least one sensor includes a memory and processing circuitry. The processing circuitry is configured to save, in the memory, a first data set contained in a first signal generated by each pixel of the sensor and indicative of a first shot of the scene, and a second data set contained in a second signal generated by each pixel of the sensor and indicative of a second shot of the scene. The processing circuitry is further configured to assemble the first and second shots on the basis of the content of the first and second data sets of a plurality of pixels in order to form a resulting scene.