Time-of-flight sensor for display brightness control
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Solution Overview
Problem
Existing methods for controlling display brightness, such as using cameras, consume excessive power and compromise user confidentiality, as they require continuous operation even when the user is not present.
Innovation Solution
A system utilizing a microcontroller with a neural network and a time-of-flight sensor to estimate user direction and attention, adjusting display brightness based on measured distance, signal, and standard deviation values, without the need for continuous camera operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a camera is used to monitor user orientation for brightness control, then the display can automatically adjust brightness based on user attention, but the power consumption increases due to continuous camera operation
Solution Approach 1:
The patent replaces the camera-based optical detection system with a time-of-flight sensor that uses electromagnetic radiation (light pulses) to detect user presence and orientation. This substitution enables automated brightness control while consuming significantly less power, as the time-of-flight sensor can operate in lower power modes compared to continuous camera operation.
Solution Approach 2:
Instead of continuous monitoring, the system uses periodic captures by the time-of-flight sensor to detect user orientation changes. The sensor takes measurements at specific intervals rather than continuously, reducing power consumption while still enabling automatic brightness adjustment when the user returns to the display.
2Extent of automation
If a camera is used to detect user orientation, then brightness control can be implemented, but user confidentiality is compromised
Solution Approach 1:
The patent substitutes the camera system with a time-of-flight sensor that detects user presence and orientation through distance measurements and signal intensity variations. This replacement maintains the automated brightness control functionality while eliminating the confidentiality issues associated with camera-based user monitoring, as the time-of-flight sensor provides distance and orientation data without capturing visual images.
3Use of energy by moving object
If the display brightness is reduced to save power, then energy consumption decreases, but the display becomes less useful when the user is not directly in front of it
Solution Approach 1:
The system continuously receives feedback from the time-of-flight sensor about user presence and orientation, and automatically adjusts display brightness based on this feedback. When the user returns to the display, the sensor detects the change and triggers brightness increase, ensuring the display remains adaptable and useful without requiring manual intervention or continuous high 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
This solution reduces power consumption and maintains user confidentiality by using a time-of-flight sensor to accurately control display brightness based on user attention and orientation, while minimizing energy expenditure.
Implementation Method 1
a time-of-flight sensor coupled to the microcontroller, and configured to perform a first capture of an image scene comprising a user, the sensor comprising a plurality of pixels, the first capture comprising the measurement, for each pixel, of a distance from the user of the system
Implementation Method 2
the first capture comprising the measurement, for each pixel, of a distance from the user of the system, and of a signal value corresponding to a number of photons returning towards the sensor per unit of time
Data Source
AI summary
The present disclosure relates to a system includes a microcontroller including a neural network, a time-of-flight sensor including a plurality of pixels and configured to perform a capture of a scene comprising a user, the capture comprising, for each pixel, the measurement of a distance from the user and of a signal value. The sensor is further configured to calculate a value of a standard deviation associated with the distance value, and a value of a standard deviation associated with the signal value and a confidence value. The sensor is further configured to provide the values to the neural network. The neural network is configured to generate, based on the values, an estimate of a direction associated with the user. The system further includes a display, the microcontroller is configured to control the display, or another circuit, based on the estimate.