Camera Module Adaptive Optical Signal Power for TOF Safety
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Solution Overview
Problem
The time-of-flight (TOF) method for acquiring distance information faces challenges in ensuring object safety, particularly when measuring close or moving subjects, and requires improved power efficiency for short distance determinations.
Innovation Solution
A camera module that outputs a first optical signal with lower power and a second optical signal with higher power, where the control unit determines which signal to use based on the distance information, ensuring safety and efficiency by adjusting the output power and irradiance according to the object's proximity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high output power optical signal is used for TOF distance measurement, then accurate distance information can be acquired, but object safety cannot be secured when measuring close objects
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the output power of the optical signal based on the measured distance. When an object is detected at a close distance, the system reduces the optical signal power to safe levels while maintaining measurement capability. This resolves the contradiction by changing the power parameter adaptively rather than using fixed high power, thereby ensuring both measurement accuracy and object safety.
Solution Approach 2:
The system implements dynamics by making the optical signal output power variable rather than static. The control unit continuously monitors distance measurements and adjusts the signal power in real-time based on object proximity. This dynamic adjustment allows the system to maintain high power for distant objects (ensuring measurement accuracy) while automatically reducing power for close objects (ensuring safety).
2Measurement precision
If a high output power optical signal is continuously output for accurate distance measurement, then measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by outputting optical signals only when distance measurement is required, rather than continuously. The system uses a first optical signal for initial distance estimation and selectively activates a second high-power optical signal only when needed for improved accuracy at certain distances. This selective, partial usage of the measurement function reduces overall power consumption while maintaining measurement accuracy when necessary.
Solution Approach 2:
The system changes the power parameter dynamically based on measurement requirements. Instead of maintaining constant high power output, the control unit adjusts the optical signal power according to the detected distance and measurement needs. This parameter adaptation allows the system to consume minimal power during normal operation while achieving accurate measurements when required.
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 allows for accurate distance determination while ensuring object safety and reducing power consumption, particularly effective for short distances and reducing the risk of harm from high-intensity light exposure.
Implementation Method 1
distance information is information that indicates a spatial distance and refers to perspective information of a point with respect to another point in a two-dimensional image... a distance to an object is calculated using information about light that is emitted and reflected... a camera module which extracts distance information using a time-of-flight (TOF) method
Data Source
AI summary
Disclosed in the present invention is a camera module comprising: an optical output unit for outputting a first optical signal and a second optical signal to an object; a sensor for receiving a first reflected optical signal in which the first optical signal is reflected by the object; and a control unit for obtaining first distance information to the object by using the first optical signal and the first reflected optical signal, wherein an output of the first optical signal is smaller than an output of the second optical signal, and the control unit determines whether to output the second optical signal by using the first distance information.