Lidar Distance Determination Using Phase-Shifted Reference Bitstreams
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Solution Overview
Problem
Existing Lidar technologies face challenges in efficiently processing large volumes of measurement data for determining distances to targets, particularly due to the need for complex processing power and resolution limitations in imaging large fields of view.
Innovation Solution
A method using a bitstream of binary digits representing light reflections is compared to a set of stored reference bitstreams to determine distances, eliminating the need for complex processing like Fourier transformations, and utilizing pairs of phase-shifted reference bitstreams for accurate distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Digital Fourier Transform (DFT) is used to analyze the digital signal for determining distance to target, then the distance measurement function is achieved, but the processing power requirement becomes excessively large and system complexity increases
Solution Approach 1:
The patent extracts only the essential features needed for distance determination from the full signal processing pipeline. Instead of performing complete DFT analysis, the system compares the digital signal directly with stored reference signals to extract distance information, eliminating unnecessary processing steps and reducing computational complexity while maintaining measurement accuracy
Solution Approach 2:
The patent performs preliminary action by pre-storing reference signals corresponding to different distance values in memory before the actual measurement process. During operation, the system only needs to compare the received digital signal with these pre-prepared references, avoiding complex real-time transformations and significantly reducing processing requirements
2Measurement precision
If light propagation time is considered for accurate distance measurement, then measurement accuracy is improved, but the processing time and data analysis complexity increase
Solution Approach 1:
The patent creates copies of reference signals that represent different time-of-flight scenarios and stores them in memory. The received signal is compared against these pre-created references, allowing the system to determine distance based on propagation time without performing complex real-time calculations, thus reducing processing time while maintaining accuracy
Solution Approach 2:
The system performs preliminary action by pre-calculating and storing reference signals for various distance values in memory before actual measurements. This allows the measurement process to simply involve signal comparison rather than complex time-based analysis, significantly reducing processing time while preserving the ability to accurately account for light propagation time
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
This approach allows for high-resolution, high-frame-rate distance determination with reduced processing resources, enabling efficient processing of large data volumes and large fields of view.
Implementation Method 1
light transmitted by a light source being reflected by the target
Implementation Method 2
Lidar involves a propagation time for the light, which may affect resolution of the imaging technology
Data Source
Figure 1
Figure 2~3
AI summary
A method for determining a distance to a target (10) comprises: receiving (202) a bitstream (112) of binary digits corresponding to a time-varying signal based on light transmitted by a light source (102) being reflected by the target (10), wherein each binary digit in the bitstream (112) is defined based on the time-varying signal at a time instance represented by the binary digit being above or below a threshold; comparing (204) the bitstream (112) to a set of stored reference bitstreams (114), wherein the set comprises pairs comprising a first reference bitstream (114a) and a second reference bitstream (114b) representing a common distance to the target (10), wherein the first reference bitstream (114a) is phase-shifted in relation to the second reference bitstream (114b); and determining (206) the distance to the target (10) based on selection of a pair of reference bitstreams (114) based on said comparing.