Distance Image Capturing Device Power Saving Mode Switching
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Solution Overview
Problem
Distance image capturing devices face challenges in detecting moving objects in human flow detection scenarios due to high power consumption when continuously measuring, as they struggle to transition from a sleep state back to active capturing mode without the object present in the target space.
Innovation Solution
A distance image capturing device with a light source unit, a light receiving unit including photoelectric conversion elements and charge accumulation units, and a processing unit that switches between normal and power-saving modes to conserve energy, determining object presence based on charge accumulation, allowing for efficient detection and transition between modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance image capturing device continuously performs measurement in normal mode, then the detection reliability of moving objects is improved, but the power consumption increases
Solution Approach 1:
The device dynamically switches between normal mode and power saving mode based on detection needs. The light receiving unit operates at full capability in normal mode for reliable detection, while transitioning to reduced operation in power saving mode when objects are not present, optimizing the balance between detection reliability and power consumption
Solution Approach 2:
The device performs periodic measurement cycles alternating between normal mode and power saving mode. During power saving mode, measurements are performed at reduced frequency or with reduced light receiving unit operation, while normal mode measurements occur periodically to ensure detection reliability when objects are present
2Use of energy by moving object
If the device enters power saving mode to reduce power consumption, then the power consumption is reduced, but the ability to detect moving objects that enter the space is delayed
Solution Approach 1:
The device uses feedback from the light receiving unit during power saving mode to detect changes in the measurement space. When the light receiving unit detects a change indicating a moving object has entered the space, the device receives feedback and transitions from power saving mode back to normal mode, ensuring timely detection while maintaining power efficiency during idle periods
3Use of energy by moving object
If the device uses a sleep function to suppress power consumption, then the power consumption is reduced, but the device cannot detect when a moving object enters the capturing target space
Solution Approach 1:
Before entering power saving mode, the device performs preliminary detection using the light receiving unit to confirm no objects are present in the measurement space. This preliminary action ensures that when the device transitions to power saving mode, it can still detect object entry when objects appear, as the light receiving unit remains operational enough to detect changes and trigger a return to normal mode
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 enables effective power-saving operations while maintaining the ability to detect moving objects, reducing overall power consumption and improving the device's ability to transition between active and sleep states.
Implementation Method 1
a pixel having a photoelectric conversion element which generates a charge according to a light incident from the space
Implementation Method 2
a time of flight (hereinafter, referred to as 'TOF') type distance image capturing device has been implemented that uses a known speed of light and measures a distance between a measuring instrument and an object based on a flight time of light in space
Data Source
AI summary
A distance image processing unit executes either the normal mode or a power saving mode having lower power consumption than the normal mode, in the power saving mode, accumulates the charge in the charge accumulation unit at a frequency which is the same as that in the normal mode or smaller than that in the normal mode, determines whether or not a moving object is present in the space, and releases the power saving mode as satisfying a return condition in a case where the moving object is present in the space, and determines whether a moving object is present in the space according to the amount of charge accumulated in each of the charge accumulation units in the normal mode, and shifts to the power saving mode in a case where determining that the moving object is not present in the space.