3D Imaging Optics With Single-Polarizer Time-of-Flight Detection
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Solution Overview
Problem
Conventional three-dimensional imaging systems face errors due to calibration and alignment requirements, complex optical designs, reduced energy flux, and low measurement accuracy due to the use of linear polarizers with electro-optical modulators, leading to increased costs and system complexity.
Innovation Solution
A three-dimensional imaging system utilizing an optical emitter, modulator, optical element array, and photoelectric detector, which includes at least three polarizers with different polarization directions, and a controller to modulate optical states into a function of time, enabling accurate distance and intensity calculations without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear polarizers are set in front of and behind an electro-optical modulator to detect optical signal intensity, then the polarization state can be used to determine time of flight, but the energy of the optical signal is significantly reduced and flux is low, resulting in low measurement accuracy
Solution Approach 1:
The patent changes the parameter of polarization detection by using a single linear polarizer at a specific angle (45 degrees) relative to the modulation axis, rather than using two polarizers in series. This parameter change maintains sufficient optical signal energy while still enabling accurate time of flight measurement through polarization state analysis
Solution Approach 2:
The patent extracts only the necessary polarization detection function by removing one of the two linear polarizers from the conventional setup. By using a single polarizer combined with computational analysis of the modulated signal, the system achieves the required measurement precision without the excessive energy loss caused by two sequential polarizers
2Measurement precision
If two linear polarizers are used to separate polarization states for time of flight determination, then measurement can be achieved, but the flux is low requiring more demanding requirements on imaging chip
Solution Approach 1:
The patent changes the detection parameter from intensity-only measurement to polarization-state-aware measurement. By analyzing the polarization modulation embedded in the reflected signal through a single polarizer, the system achieves accurate distance measurement while preserving optical signal flux, thereby reducing demands on imaging chip sensitivity
3Measurement precision
If conventional methods use separate focal plane arrays for two polarization components, then position information can be calculated, but calibration and alignment are required which easily introduce errors
Solution Approach 1:
The patent merges the polarization separation function and position detection function into a single optical path using a single linear polarizer. This combining eliminates the need for separate focal plane arrays and their associated calibration and alignment procedures, thereby reducing device complexity while maintaining position measurement capability through polarization-modulated signal analysis
Solution Approach 2:
The single linear polarizer in the patent serves multiple functions: it enables polarization state detection, facilitates time of flight measurement, and provides position information extraction. This multi-functionality replaces the need for multiple specialized components in conventional systems, reducing overall system complexity
4Measurement precision
If additional optical devices are added to separate polarization state, then polarization measurement can be achieved, but the optical design becomes more complex and costs as well as sizes and weights increase
Solution Approach 1:
The patent extracts the essential polarization detection capability by removing unnecessary optical components from the conventional two-polarizer setup. By using a single linear polarizer positioned at 45 degrees to the modulation axis, the system achieves sufficient polarization state detection accuracy without adding complex optical design elements, thereby reducing cost, size, and weight
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 system achieves precise distance and intensity measurements with reduced light energy loss, simplifying optical design and reducing system complexity while maintaining high accuracy.
Implementation Method 1
an optical modulator, configured to modulate an optical state of at least part of the light pulses emitted from the optical emitter and/or of at least part of a light pulses returned from the target scene
Implementation Method 2
an optical element array, configured to receive at least part of the modulated light pulses, where at least within a first preset time range before the emission of the light pulses and/or within a second preset time range after the emission of the light pulses, the optical element array has a function of transmitting light of at least three optical states different from each other
Implementation Method 3
a photoelectric detector, including an imaging lens, configured to receive an optical signal passing through the optical element array, and convert the received optical signal to an electrical signal
Data Source
AI summary
Disclosed is a three-dimensional imaging system. The system comprises: an optical emitter that emits light pulses to a target scene; an optical modulator that modulates the optical state of at least part of the light pulses emitted from the optical emitter and/or of at least part of light pulses returned from the target scene; an optical element array that receives a modulated light pulses; a photoelectric detector that comprises an imaging lens, and receives an optical signal passing through the optical element array and converts the received optical signal into an electrical signal; and a controller, wherein the controller applies a control to the optical modulator by means of a circuit, the optical modulator modulates the optical state of the light pulses into a function of time on the basis of the control.