FMCW LiDAR Variable Optical Splitting for Signal-to-Noise Control
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Solution Overview
Problem
Existing frequency modulated continuous wave (FMCW) LiDAR systems face challenges in adjusting the split ratio of optical signals to maintain signal-to-noise ratio and exposure time, leading to reduced detection performance due to ambient light interference and decreased maximum calculatable distance.
Innovation Solution
A LiDAR device with a split unit that adjusts the ratio of optical signals based on equations to optimize signal-to-noise ratio and exposure time, using components like half wave plates and polarizing beam splitters to dynamically adjust the split ratio in response to changes in ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the split ratio of optical signal is fixed, then the device structure is simple, but the signal-to-noise ratio cannot be maintained when ambient light changes
Solution Approach 1:
The patent applies the dynamics principle by making the split ratio adjustable rather than fixed. The optical signal is dynamically divided into reference light and measurement light with variable proportions, allowing the system to adapt to changing ambient light conditions and maintain optimal signal-to-noise ratio.
Solution Approach 2:
The patent implements parameter changes by modifying the split ratio parameter of the optical signal based on ambient light conditions. By changing this parameter, the system can optimize the signal-to-noise ratio for different measurement environments without requiring complete system redesign.
2Productivity
If the exposure time for one pixel is reduced to detect multiple pixels, then the detection speed increases, but the signal intensity decreases and maximum calculatable distance decreases
Solution Approach 1:
The patent applies dynamics by enabling dynamic adjustment of exposure time for different detection scenarios. The system can optimize exposure time based on the number of pixels to be detected, balancing detection speed and signal intensity requirements.
Solution Approach 2:
The patent implements parameter changes by adjusting the exposure time parameter according to detection requirements. This allows the system to maintain adequate signal intensity for maximum calculatable distance while adapting detection speed to the number of pixels being monitored.
3Length of moving object
If the frequency modulation speed is increased to maintain maximum calculatable distance, then the measurement range is preserved, but the laser intensity decreases
Solution Approach 1:
The patent implements parameter changes by adjusting the frequency modulation speed parameter based on ambient light conditions and detection requirements. This allows optimization of the balance between maximum measurement distance and laser intensity, avoiding unnecessary increases in modulation speed that would reduce laser power.
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 device enhances detection performance by maintaining signal-to-noise ratio and increasing exposure time, allowing for improved distance resolution and maximum measurement distance without increasing frequency modulation speed.
Implementation Method 1
using components like half wave plates and polarizing beam splitters to dynamically adjust the split ratio
Implementation Method 2
a receiving unit to receive a third optical signal, which is reflected light of the first optical signal from an object
Implementation Method 3
an interference unit to cause interference between the second optical signal and the third optical signal
Implementation Method 4
The FMCW LiDAR measures the speed using the Doppler effect. When waves are reflected from a moving object, a change in a frequency occurs due to the Doppler effect
Data Source
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AI summary
Disclosed in an embodiment is a LiDAR device, comprising: an output unit that outputs an optical signal; a distribution unit that distributes the optical signal into a first optical signal and a second optical signal; a receiving unit that receives a third optical signal, which is reflection light of the first optical signal on an object; an interference unit in which interference between the second optical signal and the third optical signal occurs; a detection unit that detects a fourth optical signal, which is interference light generated by means of interference between the second optical signal and the third optical signal, or a fifth optical signal, which is noise; and a depth information generation unit that generates depth information and speed information for an observation target on the basis of the optical signals, wherein the distribution unit adjusts the distribution ratio of the first optical signal and the second optical signal.