LiDAR Histogram Noise Filtering for Sunlight and Sensor Interference
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Solution Overview
Problem
Lidar sensors face challenges in achieving high-sensitivity signal sensing while effectively removing noise, particularly in external environments with background noise such as sunlight, and also suffer from interference between sensors.
Innovation Solution
A Lidar sensor design that includes a light reception part, a weight generation part, and dual histogram processing units to extract data values above reference thresholds, along with a light emitting unit that varies pulse emission delay times and time differences to manage noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If excess voltage is increased to improve sensitivity, then signal sensing capability is improved, but noise is also increased
Solution Approach 1:
The patent divides the histogram processing into two separate stages: a first histogram processing unit that performs initial noise removal by extracting data values greater than or equal to a first reference value, and a second histogram processing unit that performs secondary noise removal by extracting accumulated data values greater than or equal to a second reference value. This segmentation allows the system to maintain high sensitivity while systematically removing noise in multiple passes.
Solution Approach 2:
The patent extracts only the necessary data values from the histogram bins that meet the reference value criteria, separating the useful signal data from the noise. By extracting only data values greater than or equal to the reference values from the histogram bins, the system removes noise while preserving the meaningful signal information.
2Object-generated harmful factors
If dual histogram processing is implemented to remove noise, then noise removal capability is improved, but device complexity is increased
Solution Approach 1:
The patent segments the histogram processing function into two distinct processing units operating in sequence. The first histogram processing unit handles initial noise removal, and the second histogram processing unit handles secondary noise removal. This segmentation makes the complex noise removal task manageable by breaking it into smaller, more straightforward processing stages.
Solution Approach 2:
The first histogram processing unit performs preliminary noise removal before the second histogram processing unit performs secondary noise removal. By removing a portion of the noise in the first stage, the second stage operates on already partially cleaned data, making the overall process more efficient despite the added complexity.
3Object-generated harmful factors
If light pulse emission delay time and time difference are varied to remove interference, then interference removal capability is improved, but control complexity is increased
Solution Approach 1:
The patent makes the light emitting unit dynamic by allowing it to vary the light pulse emission delay time and the light pulse time difference between first light and second light. Instead of fixed timing parameters, the system dynamically adjusts these parameters to avoid interference between multiple Lidar sensors, enabling the sensor to adapt to different operational environments and interference conditions.
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 design enables high-sensitivity signal sensing with effective noise removal and minimizes interference between sensors, even in noisy conditions, by using dual histogram processing and controlled light pulse variations.
Implementation Method 1
a light reception part configured to sense reflected light reflected from an object
Implementation Method 2
when an excess voltage, which is a reverse voltage of a single photon avalanche photo diode (SPAD), is increased
Data Source
AI summary
The present invention relates to a Lidar sensor capable of removing background noise and a method of removing the noise of the same, and the Lidar sensor may include: a light reception part configured to sense reflected light reflected from an object; a weight generation part configured to generate a weight based on a sensing rate of the reflected light of the light reception part; a first histogram processing unit configured to perform histogram processing of a sensing signal of the light reception part based on the generated weight, and extract data values greater than or equal to a first reference value from bins of the histogram to firstly remove noise; and a second histogram processing unit configured to accumulate the data values extracted from the first histogram processing unit to perform histogram processing, and extract accumulated data values greater than or equal to a second reference value from bins of the histogram in which the data values are accumulated to secondarily remove the noise.