ToF Camera Pulse Timing for Multi-Camera Interference Suppression
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Solution Overview
Problem
In active distance measurement systems, particularly those using time-of-flight (ToF) cameras, multiple cameras measuring the distance to the same target can result in signal interference, leading to erroneous measurements due to mixed signals.
Innovation Solution
A signal generation apparatus is introduced, comprising a first pulse generator for the light source and a second pulse generator for the pixel, along with a signal selection section that outputs signals with different duties, to prevent signal interference by selectively generating and outputting pulses with varying duties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple ToF cameras measure the distance to the same target simultaneously, then the coverage and measurement capability are improved, but signal interference occurs leading to erroneous distance measurements
Solution Approach 1:
The patent implements periodic action by using pulse generators to emit light pulses and control pixel exposure in time-sequential intervals. Each camera system operates during specific time windows, creating a periodic measurement cycle that prevents signal overlap. The pulse generator emits light pulses at defined intervals, and the pixel exposure is controlled to occur only during designated time slots, ensuring that measurements from multiple camera systems do not interfere with each other.
Solution Approach 2:
The patent applies preliminary action by pre-defining and pre-assigning different time intervals to different camera systems before measurement begins. The pulse generator is configured in advance with specific duty cycles and timing parameters for each camera system. This preliminary temporal allocation ensures that when multiple cameras operate simultaneously, each captures signals only during its assigned time window, preventing cross-interference and ensuring reliable distance measurements.
2Reliability
If a single ToF camera system is used, then signal interference is avoided, but the measurement coverage and efficiency are reduced
Solution Approach 1:
The patent applies segmentation by dividing the measurement time into distinct segments or intervals, with each segment allocated to a specific camera system. The pulse generator creates separate time windows for different cameras, and the pixel exposure control ensures that each camera only processes signals during its assigned segment. This temporal segmentation allows multiple camera systems to operate concurrently without signal interference, maintaining both reliability and productivity.
3Area of stationary object
If multiple cameras operate simultaneously without time control, then measurement coverage is improved, but signal mixing causes erroneous measurements
Solution Approach 1:
The patent implements periodic action by establishing regular time intervals for each camera system's operation. The pulse generator emits light pulses in a periodic sequence, with each pulse designated for a specific camera system based on pre-assigned time windows. The pixel exposure is controlled to synchronize with these periodic pulses, ensuring that each camera receives and processes only the light pulses intended for it, thereby maintaining measurement precision across wide coverage areas.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the temporal allocation of measurement intervals to different camera systems before operation begins. The pulse generator is programmed with advance knowledge of which camera system should receive light pulses during specific time periods. This preliminary arrangement ensures that when multiple cameras operate simultaneously over large areas, signal mixing is prevented and each camera achieves accurate distance measurements.
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 configuration effectively suppresses erroneous distance measurements caused by multiple cameras measuring the same target, enhancing the accuracy of distance measurement in ToF camera systems with a simple setup.
Implementation Method 1
a pixel to receive the light reflected by the distance measurement target
Data Source
AI summary
[Problem]To provide a signal generation apparatus that is used in a ToF camera system especially adopting an indirect system and can suppress occurrence of erroneous distance measurement caused by distance measurement of a same target by a plurality of cameras with a simple configuration.[Solving means]There is provided a signal generation apparatus including a first pulse generator configured to generate a pulse to be supplied to a light source that irradiates light upon a distance measurement target, a second pulse generator configured to generate a pulse to be supplied to a pixel that receives the light reflected by the distance measurement target, and a signal generation section configured to generate a pseudo-random signal for inverting a phase of signals to be generated by the first pulse generator and the second pulse generator.