ToF Imaging System Using Optical Splitter and Electronic Mirror
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Solution Overview
Problem
Conventional Time of Flight (ToF) imaging systems face challenges in detecting remote targets with large angular detection fields while maintaining light power efficiency and compact form factors, often requiring bulky and expensive optics and mechanical mirrors.
Innovation Solution
The ToF imaging system employs an electronically-controlled mirror and a flash and scan process to split light beams into multiple beamlets, distributing light power across a larger field of view, enhancing signal-to-noise ratio and frame rate, and using spatial-temporal multiplexing to achieve higher resolution and field of regard without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mechanical mirrors and optics are used to achieve large angular detection field of view for remote targets, then the detection capability is improved, but the system becomes bulky and expensive
Solution Approach 1:
The patent divides the detection field into multiple angular regions and uses an optical splitter to divide the light beam into multiple beamlets, each directed at different angles. This segmentation allows the system to achieve large angular detection field of view without requiring bulky mechanical mirrors, as each beamlet can be independently controlled by simpler optical elements
Solution Approach 2:
The patent replaces conventional mechanical scanning mirrors with an electronically-controlled mirror that can be actuated by electrical signals. This substitution eliminates the need for bulky mechanical drive systems while maintaining the ability to scan and detect targets across large angular ranges, thereby reducing system complexity and cost
2Measurement precision
If light power is concentrated into a single beam for remote target detection, then the signal-to-noise ratio is improved, but the field of view is limited
Solution Approach 1:
The optical splitter divides the high-power light beam into multiple beamlets, each with sufficient power to maintain good signal-to-noise ratio. The beamlets are directed at different angular regions, allowing the system to simultaneously cover a large field of view while each individual beamlet retains enough intensity for accurate remote target detection
Solution Approach 2:
The patent extends the detection capability from a single angular dimension to multiple angular dimensions by creating a multi-beamlet configuration. Each beamlet covers a specific angular sector, and together they provide comprehensive three-dimensional coverage of the target scene, effectively multiplying the field of view without sacrificing signal strength in any particular direction
3Adaptability or versatility
If scanning is performed sequentially across the field of view, then the field of regard is improved, but the frame rate is reduced
Solution Approach 1:
By dividing the field of view into multiple angular regions covered by separate beamlets, the system can capture multiple regions simultaneously within a single frame. This parallel acquisition approach eliminates the time penalty of sequential scanning, maintaining high frame rates while achieving comprehensive field of regard coverage through the combined data from all beamlets
Solution Approach 2:
The patent combines the detection data from multiple beamlets that simultaneously cover different angular regions. By merging these parallel measurements into a single composite image or data set, the system achieves wide field of regard coverage without the time loss associated with sequential scanning, thereby maintaining high frame rates while expanding the observable scene
4Adaptability or versatility
If the light beam is divided into multiple beamlets, then the field of view is expanded, but the power per beamlet is reduced
Solution Approach 1:
The patent employs a flash-and-scan process where the light source emits periodic light flashes that illuminate multiple angular regions. By synchronizing the detection of reflected light from multiple beamlets during these periodic flashes, the system accumulates sufficient signal energy across the expanded field of view while maintaining adequate power distribution to each beamlet for effective detection
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 results in a more compact, lightweight, and cost-effective ToF imaging system with improved signal-to-noise ratio, frame rate, and field of regard, capable of accurately imaging larger or multiple targets with reduced power consumption.
Implementation Method 1
an optical splitter that splits the light beam from a light source into multiple transmitting light beams
Implementation Method 2
An electronically-controlled mirror is used to change the angular position of the transmitting light beams incident on the target(s)
Implementation Method 3
A ToF imaging system may include a light emission apparatus that emits light towards a target and a light receiving apparatus that receives light returned (e.g., reflected) from the target. The ToF imaging system may determine information about the target, such as depth information, based on one or more properties of the return light
Data Source
AI summary
Described are systems and methods for ToF imaging of a target. The ToF imaging system includes an optical splitter that splits the light beam from a light source into multiple transmitting light beams. The transmitting light beams are directed towards a target, and one or more portions return as reflected light beams. A detector generates detector signals, representative of the reflected light beams. An electronically-controlled mirror is used to change the angular position of the transmitting light beams incident on the target, so that different regions of the target can be measured at different time instants. The ToF imaging system uses a flash and scan process to flash one region(s) of the target with the transmitting light beams during one sub-frame exposure and to scan other region(s) of the target during subsequent sub-frame exposures. An image processing apparatus constructs target information from multiple sub-frame exposure.