Continuous-Wave LiDAR DRNU Compensation Using Reflectivity Calibration
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Solution Overview
Problem
Continuous wave ranging systems suffer from low ranging precision due to distance response non-uniformity (DRNU) among receiving units in the receiving chip, leading to inaccuracies in distance measurements.
Innovation Solution
A compensation method and apparatus that calculates the reflectivity of an object using a receiving unit, queries a DRNU calibration compensation matrix associated with the reflectivity, and compensates for the detected distance using a target DRNU calibration compensation matrix to improve precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous wave ranging is used to achieve fast and continuous depth measurement, then measurement speed is improved, but measurement precision deteriorates due to DRNU errors
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple DRNU calibration compensation matrices corresponding to different reflectivity values before actual measurement. During ranging operations, the system only needs to query the appropriate pre-computed matrix based on measured reflectivity, avoiding real-time complex calculations and enabling fast compensation that maintains both measurement speed and precision
Solution Approach 2:
The patent applies parameter changes by using reflectivity as a key parameter to select different compensation matrices. The system measures object reflectivity and uses it to index into a lookup table of pre-computed compensation matrices, dynamically adapting the compensation approach to match the specific optical properties of the target, thereby improving precision without sacrificing measurement speed
2Measurement precision
If DRNU calibration compensation is applied to improve ranging precision, then measurement precision is improved, but device complexity increases due to multiple compensation matrices
Solution Approach 1:
The patent applies copying by creating multiple copies of the compensation matrix for different reflectivity levels. Instead of implementing a single complex adaptive algorithm, the system pre-computes and stores multiple simplified compensation matrices corresponding to different reflectivity conditions, allowing the system to select the appropriate copy based on measured reflectivity, thereby reducing real-time computational complexity while maintaining precision
Solution Approach 2:
The patent reduces device complexity by performing the complex matrix computation work in advance during a calibration phase. The pre-computed compensation matrices are stored in memory, and during actual operation, the system only performs simple matrix selection and application, significantly reducing the computational burden and hardware requirements during measurement
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 method and apparatus enhance ranging precision by correcting for distance errors caused by DRNU, providing more accurate distance measurements.
Implementation Method 1
a receiving chip (for example, a CMOS device) includes a plurality of receiving units (for example, a pixel circuit), and the receiving unit is configured to convert a received optical signal into an electrical signal
Data Source
AI summary
This application discloses a compensation method and apparatus for continuous wave ranging and a LiDAR. The compensation method includes: calculating a reflectivity of an object detected by a receiving unit, querying, based on a preset mapping relation, for a target distance response non-uniformity (DRNU) calibration compensation matrix associated with the reflectivity, and compensating, using the target DRNU calibration compensation matrix, for a distance of the object detected by the receiving unit.