Camera and ToF Sensor Switching for Low-Power Distance Measurement
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Solution Overview
Problem
Existing time of flight (ToF) sensors in electronic devices face limitations in distance measurement accuracy and high power consumption beyond a certain range, leading to unacceptably large errors and inefficient energy use.
Innovation Solution
An electronic device is equipped with a camera module and a ToF sensor, where the ToF sensor operation is paused when the measured distance exceeds a threshold, and distance is recalculated using the camera module, thereby reducing power consumption and enhancing accuracy by resuming ToF sensor operation when within the designated distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ToF sensor operates continuously to provide depth data, then measurement coverage is improved, but power consumption increases
Solution Approach 1:
The ToF sensor operates periodically rather than continuously. The processor controls the ToF sensor to pause operation when the measured distance exceeds a threshold distance, and resume operation when the distance is within the threshold. This periodic activation reduces power consumption while maintaining measurement coverage when needed.
2Loss of information
If the ToF sensor measures distance continuously, then distance information availability is improved, but measurement accuracy deteriorates beyond certain range
Solution Approach 1:
The camera module acts as an intermediary for distance measurement when the ToF sensor is paused. The processor uses the camera module to measure distance by analyzing the position of the target object in the captured image, providing continuous distance information availability while allowing the ToF sensor to conserve energy when its measurements would be inaccurate.
Solution Approach 2:
The system changes the measurement method based on distance parameters. When the measured distance exceeds a threshold, the system switches from using the ToF sensor to using the camera module for distance measurement. This parameter-based switching ensures measurement accuracy by using the appropriate method for the current distance range.
3Reliability
If the ToF sensor operates at full capacity, then depth data quality is improved, but energy efficiency deteriorates
Solution Approach 1:
The ToF sensor operation is made dynamic rather than static. The processor continuously monitors the measured distance and dynamically adjusts the ToF sensor operation state (active or paused) based on whether the target distance is within or exceeds the threshold. This dynamic control improves energy efficiency by activating the sensor only when high-quality depth data is needed.
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 reduces power consumption and improves distance measurement accuracy by selectively using the camera module for long-range measurements, while maintaining precise depth data through strategic ToF sensor operation.
Implementation Method 1
An electronic device may include a time of flight (ToF) module to acquire distance information for a target object
Implementation Method 2
a camera module configured to acquire an image, wherein the image comprises a portion depicting at least one target object
Data Source
AI summary
According to an embodiment, an electronic device comprises: a camera module configured to acquire an image, wherein the image comprises a portion depicting at least one target object; a Time of Flight (ToF) sensor configured to generate depth data regarding the at least one target object; at least one processor operatively connected with the camera module and the ToF sensor; and at least one memory operatively connected with the at least one processor, wherein the at least one memory stores instructions that, when being executed, cause the at least one processor to perform a plurality of operations, the plurality of operations comprising: while acquiring the image by using the camera module, measuring a first distance between the at least one target object and the electronic device, based on the depth data from the ToF sensor; pause an operation of the ToF sensor when the measured first distance is longer than a designated distance; while the operation of the ToF sensor is paused, measure a second distance between the at least one target object and the electronic device, using the camera module; and when the measured second distance is within the designated distance, resume the operation of the ToF sensor.