TOF System IR Light Power Envelope Shaping for Remote Control Interference
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Solution Overview
Problem
Time-of-flight (TOF) cameras interfere with remote control signals due to low-frequency power envelopes produced by their IR light modulation, causing operational issues with nearby consumer electronic devices such as televisions and media players, which are not effectively addressed by existing technologies.
Innovation Solution
The TOF system emits IR light with a shaped low-frequency power envelope to reduce frequency content within the range used by remote control devices, by ramping up or down pulse amplitudes, duty cycles, or temporal gaps in the drive signal, and emitting IR light during both integration and readout periods to minimize transitions and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TOF camera emits modulated IR light at high carrier frequency for depth detection, then depth measurement capability is improved, but low frequency power envelope interference is generated that disrupts remote control signals
Solution Approach 1:
The patent applies parameter changes by modifying the temporal characteristics of the IR light emission. Specifically, it adjusts the duty cycle of the modulated IR light source and shapes the power envelope to reduce low-frequency content. The system varies the illumination duty cycle dynamically and applies power envelope shaping that suppresses spectral components in the 10-100 kHz range, thereby reducing interference with remote control signals while maintaining depth measurement capability through preserved high-frequency modulation content.
2Reliability
If the TOF camera operates continuously for accurate depth mapping, then measurement reliability is improved, but interference with remote control devices increases
Solution Approach 1:
The patent implements periodic action by using pulsed IR illumination with variable duty cycles instead of continuous emission. The system employs periodic modulation at high frequencies for depth measurement while dynamically adjusting the overall illumination duty cycle and applying power envelope shaping to reduce low-frequency spectral content. This periodic operation with optimized temporal characteristics maintains depth mapping reliability while minimizing interference with remote control devices.
Solution Approach 2:
The system applies dynamics by dynamically adjusting the illumination duty cycle and power envelope characteristics in real-time. The TOF camera can adapt its emission profile based on operational conditions, varying the temporal structure of IR light pulses to balance depth measurement quality with interference reduction. This dynamic control allows the system to maintain measurement reliability while reducing harmful low-frequency content that interferes with remote control signals.
3Use of energy by moving object
If the TOF camera uses abrupt transitions in light emission for efficient operation, then energy efficiency is improved, but low frequency spectral content increases causing more interference
Solution Approach 1:
The patent applies parameter changes by modifying the temporal waveform characteristics of the IR light emission. Instead of using abrupt on/off transitions, the system shapes the power envelope with smooth rise and fall times, and dynamically adjusts the duty cycle parameters. This reshaping of the temporal parameters reduces the spectral content at low frequencies (10-100 kHz) while maintaining energy efficiency through optimized illumination timing and reduced overall duty cycle.
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 significantly reduces interference with remote control signals, allowing for reliable operation of consumer electronic devices in proximity to TOF systems without degrading TOF performance or increasing power usage.
Implementation Method 1
The TOF system emits RF modulated light in dependence on a drive signal and detects RF modulated light that has reflected off one or more targets
Implementation Method 2
emitting IR light having a low frequency (LF) power envelope that is shaped to substantially reduce frequency content within at least one frequency range known to be used by at least one other system
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Embodiments disclosed herein are directed to time-of-flight (TOF) systems, and methods for use therewith, that substantially reduce interference that the TOF system may cause to at least one other system that is configured to wirelessly receive and respond to IR light signals. Some such embodiments involve emitting IR light having a low frequency (LF) power envelope that is shaped to substantially reduce frequency content within at least one frequency range known to be used by at least one other system that may be in close proximity to the TOF system. Such embodiments can also involve detecting at least a portion of the emitted RF modulated IR light that has reflected off one or more objects. A TOF system can produce depth images in dependence on results of the detecting, as well as update an application in dependence on the depth images.