SPAD Pixel Binning for Longer-Range LiDAR Without Resolution Loss
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Solution Overview
Problem
Conventional SPAD lidar systems face a tradeoff between angular resolution and range due to the size of SPAD pixels, with smaller pixels decreasing range and larger pixels decreasing angular resolution, and increasing the overall size and cost of the sensor array.
Innovation Solution
A SPAD lidar system with a binning system that combines outputs of groups of SPAD pixels to generate combined outputs, allowing for increased range without decreasing angular resolution or increasing the overall size, by using overlapping groups and a binning system that can operate in either the digital or analog domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of SPAD pixels is decreased to increase angular resolution, then angular resolution is improved, but range is deteriorated due to fewer photons being collected
Solution Approach 1:
The patent combines outputs from multiple SPAD pixels into binned groups to increase the effective photon collection area. By merging signals from adjacent pixels, the system achieves enhanced photon detection probability while preserving the individual pixel resolution data, thus resolving the contradiction between small pixel size and photon collection efficiency
Solution Approach 2:
The patent segments the SPAD sensor array into multiple binnable groups that can be independently processed. This segmentation allows flexible combination of pixel outputs to optimize photon collection for different spatial regions, enabling improved range without sacrificing angular resolution in any particular group
2Quantity of substance
If the size of SPAD pixels is increased to increase range, then range is improved, but angular resolution is deteriorated
Solution Approach 1:
By combining outputs from multiple small pixels into binned groups, the system creates virtual larger detection areas that collect more photons while maintaining the underlying fine spatial resolution of individual pixels. This merging approach enables improved range without the angular resolution loss that would occur with physically larger pixels
3Measurement precision
If the number of SPAD pixels is increased to improve angular resolution, then angular resolution is improved, but the physical size and cost of the sensor array are increased
Solution Approach 1:
The binning system merges outputs from multiple pixels to create additional effective detection channels without requiring additional physical pixels. This allows the system to achieve higher effective angular resolution through computational combining rather than through physical multiplication of pixel elements, thereby reducing sensor array area and cost
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
The binning system enhances photon detection probability and signal-to-noise ratio, enabling increased range without compromising angular resolution or increasing the physical size of the sensor array, thus overcoming the tradeoff limitations of conventional systems.
Implementation Method 1
single-photon avalanche diode (SPAD) sensor arrays... The SPAD sensor array of such a lidar sensor system can be utilized for time-of-flight measurements
Implementation Method 2
the binning system can be configured to combine outputs of groups of the SPAD pixels to generate combined outputs for the groups... The binning system can also be configured to assign the combined outputs to SPAD pixels in the groups
Implementation Method 3
The transmitter can be configured to transmit a transmitted electromagnetic signal into an environment nearby the SPAD lidar system... A portion of the received electromagnetic signal can correspond to the transmitted electromagnetic signal. For instance, a portion of the transmitted electromagnetic signal can be reflected by an object (or objects) nearby the SPAD lidar system and return to the receiver
Data Source
AI summary
Various technologies described herein pertain to a SPAD lidar system that includes a transmitter and a receiver. The transmitter is configured to transmit a transmitted electromagnetic signal into an environment nearby the SPAD lidar system, and the receiver is configured to receive a received electromagnetic signal from the environment nearby the SPAD lidar system. The receiver includes a SPAD sensor array (which includes SPAD pixels) and a binning system. The received electromagnetic signal is inputted to the SPAD pixels of the SPAD sensor array. The binning system is configured to combine outputs of groups of the SPAD pixels to generate combined outputs for the groups and assign the combined outputs to SPAD pixels in the groups, where the groups are overlapping. A processing system of the SPAD lidar system can generate lidar data based on the combined outputs.