Co-Planar Hybrid LADAR for High Frame Rate 3D Imaging
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Solution Overview
Problem
Existing LADAR technologies face challenges in achieving real-time 3D vision with high-resolution imagery and high frame rates, while being cost-effective and power-efficient, due to limitations in signal-to-noise ratio, peak power of illumination sources, and overall cost and power consumption.
Innovation Solution
A hybrid LADAR system combining a 1D array of time-sensitive detectors with a fast 1D laser scanner in a co-planar configuration, allowing for the collection of one line of ToF data during each scan, and optionally scanning the planar FOV in an orthogonal direction to provide 2D coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical scanning LADAR is used to achieve high-resolution imagery, then measurement precision is improved, but productivity (frame rate) deteriorates due to slow scanning speeds
Solution Approach 1:
The patent segments the detection function by using a 1D array of time-sensitive detectors divided into multiple groups, where each group can be independently activated. This allows parallel processing of different spatial regions, enabling high-resolution imaging while maintaining high frame rates through simultaneous multi-region detection
Solution Approach 2:
The patent transitions from traditional 2D mechanical scanning to a hybrid approach combining 1D spatial segmentation with time-domain multiplexing. By adding the time dimension for signal integration and using co-planar geometry, the system achieves high resolution without mechanical movement, thereby increasing frame rate
2Productivity
If imaging time-of-flight focal-plane arrays are used to achieve real-time 3D vision, then productivity is improved, but signal-to-noise ratio deteriorates due to low light collection efficiency
Solution Approach 1:
The patent merges the advantages of scanning LADAR (high signal-to-noise ratio through concentrated light collection) with imaging LADAR (high frame rate and real-time capability). The co-planar configuration combines a 1D detector array with a scanning mechanism, allowing simultaneous high-speed detection and efficient light collection, thereby achieving both high productivity and high reliability
Solution Approach 2:
The patent uses time-sensitive detectors that integrate signals over predetermined time intervals before readout. This preliminary integration action accumulates photons from low-light conditions, improving signal-to-noise ratio while maintaining high frame rates through efficient time-multiplexed detection
3Reliability
If high peak power illumination sources are used to improve signal-to-noise ratio, then reliability is improved, but use of energy and cost worsen
Solution Approach 1:
The patent employs periodic illumination with short, intense laser pulses rather than continuous high-power illumination. The time-sensitive detectors synchronize with these periodic pulses, integrating signals only during active illumination periods. This reduces average power consumption while maintaining high signal-to-noise ratio through concentrated temporal energy delivery
Solution Approach 2:
The patent dynamically controls the activation of detector groups, enabling adaptive allocation of detection resources based on scene requirements. This dynamic operation allows the system to achieve high signal-to-noise ratio only when and where needed, reducing overall energy consumption compared to static high-power operation
4Adaptability or versatility
If 2D focal plane arrays are used to achieve omnidirectional coverage, then adaptability is improved, but device complexity and cost worsen
Solution Approach 1:
The patent segments the field-of-view coverage function by using a 1D array of detectors that can be dynamically activated in different groups. Combined with the scanning mechanism, this segmentation allows the system to achieve effective 2D coverage without requiring a complex 2D detector array, thereby reducing device complexity and cost while maintaining adaptability
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 hybrid LADAR system achieves improved signal-to-noise ratio, reduced peak power and cost, increased resolution, and real-time 3D vision capabilities, making it suitable for vehicular and autonomous applications.
Implementation Method 1
LADAR is generally based on emitting short pulses of light within certain Field-Of-View (FOV) at precisely-controlled moments, collecting the reflected light
Implementation Method 2
determining its Time-of-Arrival, possibly, separately from different directions. Subtraction of the pulse emission time from ToA yields ToF, and that, in turns, allows one to determine the distance to the target
Data Source
AI summary
A laser radar includes: a laser, an optical transmission system, a one-dimensional array of photo-detectors, an optical reception system, and an electronic control system. The laser emits a wavelength of light, and the optical transmission system shapes the light, and scans the beam along a fan of transmission light paths toward a target. The photo-detectors are sensitive to the wavelength of light and perform of time-of-arrival measurements. The optical reception system collects the light reflected from the target along a fan of reception light paths. The electronic control system synchronizes the scan of the beam with a respective time-of-arrival measurement from each of the photo-detectors, and analyzes the time-of-arrival measurements. The system is configured for all of the transmission light paths and all of the reception light paths to lie in one plane, with all of the reception light paths intersecting with at least one transmission light path.