SPAD 3D Imaging System for High-Speed Depth Resolution
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Solution Overview
Problem
Current 3D sensors face limitations in acquisition speed and measurement distance due to the need for precise timing of light pulses, which restricts their ability to capture moving objects with high depth resolution, especially at long distances, and they lack efficient data processing capabilities for real-time imaging.
Innovation Solution
The use of Single Photon Avalanche Diode (SPAD) sensors with ultrashort light pulses and mode-locked lasers, combined with local data processing and pulse trains, allows for precise timing and high-speed data acquisition, enabling the generation of high-resolution 3D images of moving objects at longer distances by optimizing pulse power and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging techniques are used to achieve high depth resolution, then measurement precision is improved, but acquisition speed deteriorates
Solution Approach 1:
The patent replaces conventional mechanical scanning systems with a SPAD-based optical detection system that captures entire 3D scenes simultaneously using parallel photon counting across multiple detectors, eliminating the trade-off between resolution and speed
Solution Approach 2:
The invention transitions from sequential 2D imaging to parallel 3D scene reconstruction by capturing depth information across multiple spatial dimensions simultaneously through the SPAD array, enabling real-time 3D visualization
2Object-affected harmful factors
If multiple low-power pulses are used to maintain eye safety, then harmful factors are reduced, but measurement distance and acquisition speed deteriorate
Solution Approach 1:
The patent employs continuous pulse trains rather than discrete pulses, maintaining constant illumination at safe power levels while the SPAD detectors continuously count photons, enabling both eye safety and long-distance measurement through sustained detection capability
Solution Approach 2:
The invention changes the detection parameter from single-pulse energy measurement to photon counting rate measurement, allowing the system to operate at lower power levels while maintaining detection sensitivity through statistical accumulation of photon events
3Productivity
If pulse trains with high repetition rates are used to increase acquisition speed, then productivity is improved, but timing precision and depth resolution deteriorate
Solution Approach 1:
The patent implements feedback mechanisms where the SPAD detectors continuously monitor photon arrival times and provide timing information that is fed back to the processing system, enabling precise depth calculation even at high pulse repetition rates through real-time adjustment
Solution Approach 2:
The system performs preliminary timing calibration and reference synchronization before measurement, establishing precise time references that enable accurate depth measurement even when pulse trains operate at high repetition rates
4Device complexity
If common optics are used for emission and reception of pulses, then device complexity is reduced, but measurement distance and acquisition speed deteriorate
Solution Approach 1:
The patent segments the optical detection function into multiple independent SPAD detector elements, each capable of independent photon counting, replacing the need for complex common optics while enabling parallel processing and high-speed acquisition
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 significantly reduces measurement time and enhances depth resolution, enabling the capture of moving objects in real-time with improved data processing efficiency, overcoming the limitations of existing 3D sensors.
Implementation Method 1
SPAD (Single Photon Avalanche Diodes) devices in which a single photon can generate an electrical signal when it impinges on a photosensitive layer
Implementation Method 2
mode-locked lasers, combined with local data processing and pulse trains, allows for precise timing and high-speed data acquisition
Implementation Method 3
utilize the precise timing information carried by these light pulses to generate depth (relief) 3D data concerning the position and detail of the targets
Data Source
AI summary
The present invention relates to a 3D landscape real-time imager. It also relates to methods for operating such an imager. Such an imager comprises: —at least one illuminating part which is designed to scan at least a portion of the landscape at a given range and having an ultra-short laser pulse source emitting at least one wavelength, and an optical rotating block, with a vertical axis of rotation, and controlled such that given packets of pulses are shaped in a pattern of rotating beams sent toward the said at least partial landscape; —at least one receiving part which comprises a set of SPAD detector arrays, each arranged along a vertical direction and rotating at a given speed in synchronism with the optical rotating block of the illuminating part, the detection data of the SPAD detector arrays being combined to acquire 3D imaging data of the said at least partial landscape in a central controller.