3D Time-of-Flight Camera CCM/DCM Switching for Lower Power
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Solution Overview
Problem
Existing 3D time-of-flight cameras face high energy consumption due to continuous illumination, leading to inefficient power supply and degraded measurement performance, particularly in mobile applications.
Innovation Solution
A 3D time-of-flight camera with an illumination unit that emits light pulses, an image sensor, a switching regulator operable in continuous and discontinuous modes, and a control unit that dynamically switches between these modes based on illumination phases to optimize power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the switching regulator operates in continuous mode during illumination phases, then the lighting consistency is maintained, but the energy consumption increases
Solution Approach 1:
The switching regulator dynamically switches between continuous mode (CCM) and discontinuous mode (DCM) based on the illumination phase. During illumination phases, it operates in CCM to maintain stable current and lighting consistency. During non-illumination phases, it switches to DCM to reduce power consumption, thereby resolving the contradiction between lighting consistency and energy consumption.
Solution Approach 2:
The control unit periodically activates and deactivates the continuous mode of the switching regulator according to the illumination phase of the illumination unit. This periodic switching between CCM and DCM operates in a cyclic manner synchronized with the light pulse emission, achieving both consistent lighting during illumination and reduced energy consumption during idle periods.
2Loss of energy
If the switching regulator operates in discontinuous mode to reduce power loss, then the energy consumption decreases, but the response to load surges deteriorates
Solution Approach 1:
The switching regulator dynamically adapts its operating mode based on real-time illumination phase conditions. When load surges are anticipated during illumination phases, it switches to CCM which provides superior response to load changes. During non-illumination phases with lower power demands, it operates in DCM to minimize power loss, thus resolving the contradiction between energy efficiency and load response capability.
Solution Approach 2:
The control unit activates the continuous mode before the illumination phase begins, preparing the switching regulator to handle the upcoming load surge when the illumination unit is switched on. This preliminary switching to CCM ensures that the regulator is ready to respond immediately to the load increase, preventing performance degradation during the critical illumination period.
3Measurement precision
If the illumination is continuously switched on and off for phase estimation, then the depth measurement is obtained, but the load surges occur in power supply
Solution Approach 1:
The switching regulator dynamically changes its operating characteristics in response to the periodic switching of the illumination unit. During the brief illumination pulses used for TOF depth measurement, it operates in CCM to handle the high current demands and load surges. During the longer non-illumination periods for data processing, it switches to DCM to minimize power consumption, thereby managing the power delivery during repeated load surge cycles.
Solution Approach 2:
The control unit receives feedback about the illumination phase status and adjusts the switching regulator's mode accordingly. This feedback mechanism ensures that the regulator is in the appropriate mode (CCM or DCM) at the right time, enabling it to handle load surges during illumination while minimizing power loss during non-illumination periods, thus managing power delivery during repeated measurement cycles.
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 maintains consistent lighting and minimizes power loss, ensuring efficient image capture and reduced energy consumption, thereby improving measurement performance and runtime.
Implementation Method 1
a light beam is emitted as a light pulse into a monitored area. The light beam reflected by an object is received again and the received signal is then electronically evaluated. This allows the camera to measure a distance
Implementation Method 2
The light beam reflected by an object is received again
Data Source
Figure 1~2
AI summary
To enable high image acquisition with low energy consumption of a camera 1, a camera (1), in particular a 3D time-of-flight camera, is provided, comprising an illumination unit (2) that emits light pulses during an illumination phase (Bp), an image sensor (3) that generates images from the light pulses reflected by an object, a switching regulator (4) that controls current to the illumination unit (2), wherein the switching regulator (4) is operable in a continuous and a discontinuous mode (CCM; DCM), and a control unit (5) configured to activate and deactivate the continuous mode (CCM) of the switching regulator (4) depending on the illumination phase (Bp) of the illumination unit (2).