TOF Camera Reference-Depth Calibration for Ground Obstacle Detection
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Solution Overview
Problem
The accuracy of obstacle detection during ground navigation using TOF cameras is compromised by the complexity of ground environments and multi-path reflection, leading to inaccuracies in identifying obstacles.
Innovation Solution
A method involving the use of a calibrated reference depth value based on a reference plane with a fixed height difference, where the actually measured depth values are compared to the reference depth value, and adjusted accordingly to distinguish obstacles from the ground, using a characteristic value to mark passable regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional TOF distance measurement is used in complex ground environments, then the measurement process is simple, but the measurement precision deteriorates due to multi-path reflection and ground reflectivity variations
Solution Approach 1:
The patent performs preliminary calibration by moving the TOF camera to multiple predetermined positions and measuring depth values before actual obstacle detection. These preliminary measurements are used to calculate reference depth values that compensate for ground reflectivity variations and multi-path reflection effects, thereby improving measurement precision without complicating the actual detection process
Solution Approach 2:
The patent implements a feedback mechanism where depth values measured at predetermined positions are used to calculate reference depth values, which then serve as correction references for actual obstacle detection. This feedback loop continuously compensates for environmental variations, maintaining high measurement precision in complex ground environments
2Measurement precision
If reference depth calibration is performed at multiple predetermined positions, then the obstacle detection accuracy is improved, but the detection time increases
Solution Approach 1:
The patent performs calibration at a limited number of predetermined positions (e.g., 3-5 positions) rather than exhaustive sampling of the entire environment. This partial action provides sufficient reference data to compensate for ground variations while minimizing the time loss during calibration and detection processes
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 enhances the accuracy of obstacle detection by isolating obstacles from the ground environment, improving recognition precision and simplifying the algorithm implementation.
Implementation Method 1
A time of flight (TOF) camera measures a distance, a three-dimensional structure, or a three-dimensional profile of a measured object by using a time interval from emission to reception of a pulsed signal emitted by a sensor
Implementation Method 2
a phase generated when laser reaches and returns from the measured object once
Data Source
AI summary
This application discloses a TOF camera, a ground obstacle detection method thereof, and a ground navigation device. The ground obstacle detection method of the TOF camera includes: using depth data of a reference plane as a reference depth value; performing distance detection, and comparing an actually measured depth value at a measured position with a corresponding reference depth value; replacing the actually measured depth value with a characteristic value if the actually measured depth value is greater than or equal to the reference depth value, and marking the corresponding position as a passable region; and using the actually measured depth value at the position as a measured depth value if the actually measured depth value is less than the reference depth value. The ground obstacle detection method can improve the accuracy of obstacle detection.