ToF Camera Signal Timing for Multi-Camera Interference Suppression
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Solution Overview
Problem
In active distance measurement systems, multiple cameras measuring the distance to the same target can cause signal interference, leading to erroneous measurements.
Innovation Solution
A signal generation apparatus with a first pulse generator for the light source and a second pulse generator for the pixel, along with a signal selection section that outputs a duty signal from either a first duty or a second duty, is used to prevent signal interference by adjusting the pulse timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple 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 assigning different duty cycles (on/off time ratios) to each camera's light source and pixel activation signals. This creates distinct periodic measurement cycles for each camera, allowing simultaneous operation without signal interference. For example, the first camera uses a 50% duty cycle while the second camera uses a 25% duty cycle, ensuring their measurement periods do not overlap and thus preventing erroneous measurements while maintaining multi-camera measurement capability
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the duty cycle parameter for each camera's light source and pixel signals. By varying the duty cycle parameter (the ratio of on-time to total period), each camera operates with unique timing characteristics. This parameter differentiation allows multiple cameras to measure the same target simultaneously without signal mixing, resolving the contradiction between enhanced measurement capability and maintained measurement accuracy
2Measurement precision
If the duty cycle is adjusted to prevent signal interference, then measurement accuracy is improved, but the complexity of the signal generation system increases
Solution Approach 1:
The patent implements dynamics by making the duty cycle parameter adjustable and variable rather than fixed. The signal generation device can dynamically change the duty cycle for each camera based on operational requirements. This dynamic capability allows the system to optimize measurement accuracy through duty cycle adjustment while maintaining flexibility to adapt to different measurement scenarios, balancing precision improvement with manageable system complexity
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.
Implementation Method 1
light is emitted from a light source and light reflected by an object of the distance measurement target is detected to perform distance measurement to the distance measurement target
Implementation Method 2
A time-of-flight (ToF) camera system is a system in which a period of time after light is emitted from a light source until the light returns after it is reflected by an object is analyzed to derive information relating to the distance to the object
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
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.