3D TOF Pulse Timing With Random Latency Against Camera Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Interference occurs during distance measurement due to non-exclusive transmit pulse signals among multiple 3D depth cameras and within a single camera, leading to inaccurate measurements and increased power consumption.
Innovation Solution
A distance measurement apparatus and method that involves sequentially sending M transmit pulses with a predetermined rule, receiving N feedback pulses, and using time of flight information from these pulses to determine a target time of flight, while employing random latencies to distinguish transmit rules and eliminate interference, thereby improving measurement reliability and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple 3D depth cameras transmit pulses simultaneously using the same pulse repetition frequency, then the measurement speed and coverage are improved, but mutual interference occurs between cameras leading to measurement errors
Solution Approach 1:
The patent applies parameter changes by modifying the pulse repetition frequency (PRF) of each 3D depth camera to be different from others. Specifically, each camera is assigned a unique PRF value, which transforms the identical transmission parameters into distinct ones. This allows multiple cameras to operate simultaneously without their reflected pulses overlapping in time, thereby eliminating mutual interference while maintaining high measurement speed and accuracy
2Device complexity
If a single 3D depth camera uses a fixed pulse repetition frequency, then the timing and processing are simplified, but interference occurs when distant high-reflectivity targets cause returned signals to exceed the current pulse transmit period
Solution Approach 1:
The patent applies dynamics by making the pulse repetition frequency variable rather than fixed. The controller dynamically adjusts the PRF based on the measurement requirements and target characteristics. This dynamic adjustment allows the system to handle distant high-reflectivity targets by extending the measurement period when needed, preventing signal overflow into subsequent pulse periods while maintaining simple timing logic through automated adaptation
3Reliability
If multiple transmit pulses are sent sequentially with random latencies, then interference is eliminated and measurement reliability is improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by implementing an automated control system that generates and manages random latencies without requiring manual intervention. The controller automatically assigns random time offsets to each transmit pulse sequence, and the system self-adjusts based on received feedback pulses. This automation eliminates interference through randomized timing while keeping the user interface simple, as the complexity is handled internally by the self-managing control algorithm
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
Accurate time values are obtained through normal distribution, effectively eliminating interference and enhancing measurement reliability while reducing power consumption by using random latencies and specific transmit rules.
Implementation Method 1
The pulse receiver converts a received photon into an electron
Implementation Method 2
The time to digital converter is controlled, by using a 'start' signal, to start timing, and controlled, by using an 'end' signal, to stop timing
Data Source
AI summary
A time of flight (TOF) measurement method and apparatus are provided, including a controller, a time to digital converter, a pulse transmitter, and a pulse receiver. The controller is configured to control, in a working period according to a predetermined transmit rule, the pulse transmitter to sequentially send M transmit pulses. The pulse receiver is configured to receive N feedback pulses in the working period. The time to digital converter is configured to obtain time of flight information corresponding to the N feedback pulses. The controller is further configured to obtain a target time of flight based on the time of flight information corresponding to the N feedback pulses, and obtain a target distance based on the target time of flight.