Lidar Light Detection Device Dynamic Threshold Control
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Solution Overview
Problem
Existing light detection systems face challenges in performing highly accurate and speedy light detection due to the need for a separate period to set thresholds based on noise levels when no light is projected, making it difficult to quickly and accurately detect reflected light amidst ambient noise.
Innovation Solution
A light detection device comprising a light projector, a light receiver, and a controller that dynamically sets thresholds by comparing light reception results across different portions of the light receiving region, allowing for simultaneous detection of ambient and reflected light, thereby improving detection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the threshold is set based on noise level when no light is projected, then the detection accuracy is improved, but the detection speed is reduced due to the need for a separate threshold setting period
Solution Approach 1:
The patent combines the threshold setting process with the light detection process by using the light receiver to detect both projected light and ambient noise simultaneously. The controller sets the threshold based on the detected signal when no light is projected, allowing threshold calibration to occur during normal operation rather than requiring a separate calibration period, thus merging two previously separate functions into one unified process
Solution Approach 2:
The patent performs preliminary threshold setting by detecting the noise level in advance before actual light detection begins. The controller measures the signal level when no light is projected and uses this pre-acquired information to establish the threshold, so that when light detection starts, the threshold is already ready, eliminating the need to wait for threshold calibration during the detection process
2Measurement precision
If a separate period is allocated for threshold setting, then the threshold can be accurately determined, but the overall detection time is increased
Solution Approach 1:
The patent ensures continuous useful action by having the light receiver continuously detect signals in both the projected light range and non-projected ranges. The controller continuously monitors the signal levels and updates the threshold as needed, so that threshold setting and light detection occur simultaneously without interruption, maximizing the utilization of detection time for both purposes
3Measurement precision
If the light receiver detects light in the projected range, then reflected light can be detected, but ambient light interference increases
Solution Approach 1:
The patent segments the light receiving region into two distinct portions: a first portion corresponding to the projected light range and a second portion corresponding to the non-projected range. By detecting signals in both segments separately, the system can distinguish between reflected light (in the first portion) and ambient noise (in the second portion), allowing for accurate reflected light detection while characterizing ambient interference without confusion
Solution Approach 2:
The patent uses the non-projected portion of the light receiving region as an intermediary to measure ambient noise levels. This separate measurement area acts as a mediator that allows the controller to characterize ambient light interference independently, so that the threshold can be set to account for this interference when detecting reflected light in the projected range, effectively separating the measurement of useful signal from harmful interference
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
Facilitates speedy and accurate light detection by dynamically setting thresholds based on real-time light reception results, reducing the impact of ambient light and enhancing the precision of distance measurements in lidar devices.
Implementation Method 1
a light receiver (4) that has a light receiving region (R1) in which light is received
Data Source
AI summary
A light detection device includes a light projector, a light receiver, a detector, and a controller. The light projector projects light to a predetermined range. The light receiver has a light receiving region in which light is received. The detector detects light by comparing a light reception result by the light receiver with a predetermined threshold. The controller controls the threshold. The controller shifts in turn a range where light is projected from the light projector. The controller, causes the detector to detect light per a portion of the light receiving region, the portion corresponding to a range with light being projected from the light projector, and sets the threshold based on a light reception result by the light receiver in a different portion of the light receiving region from the portion corresponding to the range with light being projected.