Adaptive Rolling Shutter IR Control for Facial Recognition
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Solution Overview
Problem
Facial recognition systems using rolling shutter image sensors face challenges with non-uniform illumination, leading to inaccurate identification and increased power consumption due to the need for global shutter's buffer storage, which is not present in rolling shutter systems.
Innovation Solution
Adaptive control of IR timing and exposure timing in rolling shutter image sensors by switching between two operation modes to ensure uniform illumination and reduce power consumption, utilizing a processor to manage IR illumination and exposure timing based on target average luminance intensity and IR intensity ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If rolling shutter is used to reduce power consumption, then power consumption is reduced, but illumination uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by making the IR illumination timing adaptive rather than fixed. The system dynamically adjusts the IR illumination window to coincide with the rolling shutter exposure periods, ensuring uniform illumination across all pixel rows while maintaining the power-saving benefits of rolling shutter operation.
Solution Approach 2:
The patent changes the timing parameters of IR illumination to match the rolling shutter exposure schedule. By adjusting when IR light is emitted to align with each row's exposure window, the system achieves uniform illumination without requiring global shutter operation, thus maintaining low power consumption.
2Use of energy by moving object
If rolling shutter is used to reduce power consumption, then power consumption is reduced, but identification accuracy deteriorates
Solution Approach 1:
The system dynamically synchronizes IR illumination with the rolling shutter exposure timing, ensuring that each pixel row receives consistent IR lighting during its exposure period. This dynamic timing adjustment maintains image quality and identification accuracy while preserving the power-saving advantages of rolling shutter operation.
Solution Approach 2:
The system uses feedback from the rolling shutter exposure timing information to adjust IR illumination scheduling. By monitoring when each row is exposed and adjusting IR light emission accordingly, the system ensures optimal image quality for facial recognition while maintaining energy efficiency.
3Illumination intensity
If global shutter is used to achieve uniform illumination, then illumination uniformity is improved, but power consumption increases
Solution Approach 1:
The patent segments the illumination approach by applying IR lighting separately to each row during its specific exposure window, rather than illuminating the entire scene simultaneously as in global shutter. This segmented timing approach achieves uniform illumination效果 while avoiding the continuous power consumption of global shutter operation.
Solution Approach 2:
The system uses periodic IR illumination pulses synchronized with each row's exposure period in the rolling shutter sequence. Instead of continuous illumination, brief periodic IR bursts are emitted at the precise moments when each row is exposed, achieving uniform illumination with minimal 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
Enhances signal-to-noise ratio (SNR) image quality while reducing power consumption, maintaining or improving image quality and accuracy in facial recognition processes.
Implementation Method 1
a rolling shutter image sensor and an IR emitter... control an exposure timing of the rolling shutter image sensor and an IR illumination timing of the object
Data Source
AI summary
A processing device comprises a memory configured to store data and a processor. The processor is configured to control an exposure timing of a rolling shutter image sensor and an IR illumination timing of an object, by an IR light emitter, by switching between a first operation mode and a second operation mode. In the first operation mode, a sequence of video frames, each having a plurality of pixel lines, comprises a frame in which each pixel line is exposed to IR light emitted by the IR light emitter; a frame which is partially exposed to the IR light and a frame in which no pixel line is exposed to the IR light. In the second operation mode, alternating video frames of the sequence comprise one of a frame in which each pixel line is exposed to the IR light and a frame in which no pixel line is exposed to the IR light.