Alternating Light Source Control for Motion Sensor Power Reduction
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Solution Overview
Problem
Existing motion sensor devices face high power dissipation when using multiple light sources continuously, which can lead to decreased distance measuring accuracy and increased costs when attempting to reduce power consumption through additional sensors or reduced light output.
Innovation Solution
A motion sensor device with control circuitry that alternates the use of first and second light sources to capture frames and adjusts their light emission quantities based on previous image capturing sessions, allowing for accurate distance measurement while minimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple light sources are kept ON continuously for distance measurement, then distance measuring capability is maintained, but power dissipation increases significantly
Solution Approach 1:
The patent implements periodic action by alternately turning ON and OFF multiple light sources in a time-sequenced manner. The control circuitry captures images with light from each source at different times, allowing the system to maintain distance measuring capability while significantly reducing power dissipation compared to keeping all light sources ON continuously.
Solution Approach 2:
The patent applies segmentation by dividing the light source operation into separate temporal segments. Each light source is activated in its own time slot, and the image sensor captures images during each segment. This segmentation allows the system to measure distance using multiple light sources without the energy cost of all sources being active simultaneously.
2Loss of energy
If the optical output power of light source unit is reduced to cut down power dissipation, then power consumption decreases, but distance measuring accuracy declines
Solution Approach 1:
By using periodic action with multiple light sources activated alternately, the system can use lower optical output power for each individual light source while maintaining overall measurement accuracy. The cumulative information from multiple time-sequenced images compensates for the reduced power of each individual source.
Solution Approach 2:
The patent merges the measurements from multiple light sources activated at different times. The control circuitry combines the image data from each light source activation to calculate distance, effectively merging the information to achieve accurate distance measurement even when each individual light source operates at reduced power levels.
3Loss of energy
If additional sensors are provided to cut down power dissipation, then power consumption decreases, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by having a single image sensor perform multiple functions: capturing images with light from different light sources at different times to enable distance measurement. This eliminates the need for additional sensors while maintaining power efficiency, as the existing image sensor is reused across multiple measurement cycles.
Solution Approach 2:
The system uses periodic action with existing light sources and the image sensor to achieve power-efficient operation. By time-sequencing the activation of multiple light sources and capturing images during each period, the system avoids the need for additional sensors while maintaining measurement capability and reducing power consumption.
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
The solution effectively reduces power dissipation without compromising distance measuring accuracy or increasing costs, enabling real-time measurement of moving objects with optimized light usage.
Implementation Method 1
making the image sensor capture a first frame with light emitted from the first light source at a first time
Implementation Method 2
the distance is estimated by a so-called TOF (Time of Flight) method in which the object is irradiated with optical pulses
Data Source
AI summary
A motion sensor device including: an image sensor; first and second light sources; and control circuitry configured to control the image sensor and the first and second light sources. The control circuitry is configured to: repeatedly perform the operation of making the image sensor capture a first frame with light emitted from the first light source at a first time, the operation of making the image sensor capture a second frame with light emitted from the second light source at a second time, and the operation of generating information about the distance to an object based on first and second images that have been gotten by capturing the first and second frames, respectively, and control the respective quantities of light emitted from the first and second light sources individually by reference to information that has been collected through the previous or earlier image capturing session.