Polarization and ToF Pixel Array for Accurate 3D Shape Imaging
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Solution Overview
Problem
Current image sensors face challenges in generating accurate three-dimensional shape images due to registration errors between depth and polarization information, which are typically captured by separate sensors, leading to complex device configurations and reduced performance.
Innovation Solution
A combined image sensor with a pixel array that includes both polarization pixel cells and time-of-flight pixel cells, aligned with a polarization grid, to collect polarization and depth information simultaneously, eliminating the need for separate sensors and simplifying device architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sensors are used to capture depth and polarization information, then measurement completeness is improved, but device complexity and registration errors increase
Solution Approach 1:
The patent combines depth-sensing photodiodes and polarization-sensing photodiodes into a single pixel array, creating an integrated sensor that captures both types of information simultaneously. This merging eliminates the need for separate sensors and their associated alignment systems, directly reducing device complexity while maintaining measurement completeness through co-located detection elements.
Solution Approach 2:
The pixel array is designed with dual-functionality, where each pixel can operate as either a depth-sensing photodiode or a polarization-sensing photodiode based on its specific structure. This multi-functional design allows a single sensor system to perform multiple measurement tasks, improving measurement completeness without requiring separate specialized sensors for each function.
2Device complexity
If a combined sensor is used, then device complexity is reduced, but measurement precision may be compromised
Solution Approach 1:
The pixel array is segmented into distinct depth-sensing photodiodes and polarization-sensing photodiodes, with each segment optimized for its specific function. This segmentation allows each photodiode type to maintain high measurement precision for its designated task while being part of an integrated sensor, preventing the compromise of measurement precision that might occur in a fully unified design.
Solution Approach 2:
Different regions of the pixel array are designed with local quality optimizations specific to their function. Depth-sensing photodiodes have structural characteristics optimized for time-of-flight measurements, while polarization-sensing photodiodes have characteristics optimized for polarization detection. This local quality approach ensures high measurement precision for each function within the combined sensor system.
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 enables the generation of accurate three-dimensional shape images by combining depth and polarization information in a single sensor, reducing registration errors and simplifying device design, while enhancing performance metrics such as resolution and power consumption.
Implementation Method 1
The image sensor includes an array of pixels having photosensitive elements (e.g., photodiodes) that absorb a portion of the incident image light and generate image charge upon absorption of the image light
Implementation Method 2
time-of-flight pixel cells aligned with a polarization grid to collect polarization and depth information simultaneously
Implementation Method 3
polarization pixel cells aligned with a polarization grid to collect polarization and depth information simultaneously
Data Source
AI summary
In some embodiments, an imaging system is provided. The imaging system comprises an image sensor, a light source, control circuitry, and function logic. The image sensor comprises a pixel array that includes a plurality of polarization pixel cells and a plurality of time-of-flight pixel cells. The light source is configured to emit light pulses to an object. The control circuitry is coupled to the light source and the pixel array, and is configured to synchronize a timing of the emission of the light pulses with sensing of photons reflected from the object by the plurality of time-of-flight pixel cells to generate depth information. The function logic is configured to determine a set of ambiguous surface normals using signals generated by the plurality of polarization pixel cells, and to disambiguate the set of ambiguous surface normals using the depth information to generate a three-dimensional shape image.