TOF Depth Sensing Optics for Higher-Resolution Scanned Imaging
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Solution Overview
Problem
Conventional pulsed TOF technology suffers from low spatial resolution due to the limitations of common photodetectors like single-photon avalanche diodes (SPADs), which require complex interfaces and processing circuits, failing to meet high spatial resolution requirements in depth sensing.
Innovation Solution
A TOF depth sensing module comprising a light source, polarization filter, beam shaper, first and second optical elements, and a control unit, which generates and filters light in multiple polarization states, adjusts the field of view, and controls beam directions to improve spatial resolution through time division multiplexing scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-photon avalanche diode (SPAD) is used as the photodetector in pulsed TOF technology, then the sensitivity for detecting single photons is improved, but the spatial resolution deteriorates due to complex interface and processing circuits
Solution Approach 1:
The patent replaces the complex electronic processing system of SPAD with a simplified optical detection system using a photodetector and timing circuit. The beam shaping optical system substitutes for the complex SPAD interface, achieving depth measurement without requiring single-photon detection capability.
Solution Approach 2:
The patent extracts and removes the SPAD component and its complex processing circuitry from the system. By eliminating the SPAD, the system avoids the spatial resolution limitations while maintaining depth measurement functionality through alternative optical methods.
2Device complexity
If a conventional photodetector is used without beam shaping, then the device complexity is reduced, but the spatial resolution of the depth image deteriorates
Solution Approach 1:
The patent introduces a beam shaping optical system as an intermediary component between the light source and the photodetector. This optical system shapes the light beam to improve spatial resolution, acting as a mediator that enhances image quality without requiring complex photodetector electronics.
3Area of stationary object
If the field of view is increased to improve coverage, then the area coverage is improved, but the spatial resolution deteriorates due to reduced light intensity per unit area
Solution Approach 1:
The patent employs dynamic beam shaping that can adjust the light distribution pattern according to the field of view requirements. The optical system dynamically optimizes the beam profile to maintain appropriate light intensity across the entire field of view, preserving spatial resolution while expanding coverage area.
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 module enhances spatial resolution by increasing the field of view and performing scanning in a time division multiplexing manner, resulting in improved depth image quality.
Implementation Method 1
the light source is configured to generate light in a plurality of polarization states, and the polarization filter is located between the light source and the beam shaper
Implementation Method 2
the beam shaper is configured to increase a FOV of the beam in the single polarization state to obtain a first beam
Implementation Method 3
the control unit is configured to control the first optical element to control a direction of the first beam to obtain an emergent beam. The control unit is further configured to control the second optical element to deflect, to the receiving unit, a reflected beam
Implementation Method 4
A time of flight (time of flight, TOF) technology is a common depth or distance measurement technology, whose basic principle is as follows: A transmit end emits continuous-wave light or pulsed light. The continuous-wave light or the pulsed light is reflected after irradiating a to-be-measured object. Then, a receive end receives reflected light of the to-be-measured object. Next, a distance or a depth of the to-be-measured object to a TOF system may be calculated by determining a time of flight of the light from the transmit end to the receive end.
Data Source
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AI summary
A TOF depth sensing module (300) and image generation method are provided. The TOF depth sensing module (300) includes a light source (310), a polarization filter (320), a beam shaper (330), a first optical element (340), a second optical element (350), a receiving unit (360) and a control unit (370). The light source (310) is configured to generate a beam. The polarization filter (320) is configured to filter the beam to obtain a beam in a single polarization state. The beam shaper (330) is configured to increase a FOV of the beam in the single polarization state to obtain a first beam whose FOV meets a first preset range. The control unit (370) is configured to control the first optical element (340) to control a direction of the first beam to obtain an emergent beam. The control unit (370) is further configured to control the second optical element (350) to deflect, to the receiving unit (360), a reflected beam obtained by reflecting the emergent beam by a target object. In the method, a spatial resolution of a finally obtained depth image of the target object can be improved.