Iris Recognition Device Noise Removal via Phase Synchronization
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Solution Overview
Problem
Iris recognition devices face challenges in removing noise, such as 'ghost' artifacts, generated by ambient light, which affects the accuracy of iris image processing and biometric authentication, particularly in environments with varying light conditions.
Innovation Solution
The use of a light source unit that transmits a modulated near-infrared light signal and a light source receiver that synchronizes the reflected signal with reference signals of different phases to generate sampling signals, allowing for the removal of noise offsets and calculation of iris image data, including distance information, thereby enhancing image quality and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ambient light is present during iris image capture, then the device can operate in various lighting conditions, but noise (ghost artifacts) is introduced into the iris image signal
Solution Approach 1:
The light source emits light in periodic pulses rather than continuous illumination. By controlling the timing and duration of light pulses, the system can distinguish between reflected light from the iris and ambient light, reducing ghost artifacts while maintaining operation in various lighting conditions
Solution Approach 2:
The system uses reference signals to create feedback mechanisms that allow the receiver to identify and remove offset components corresponding to ambient light noise. By comparing received signals with reference signals, the system can selectively eliminate ghost artifacts from the iris image data
2Measurement precision
If phase-based sampling signals are used to remove noise, then noise removal accuracy is improved, but device complexity increases
Solution Approach 1:
Reference signals are generated and synchronized with the light source pulses before the actual iris image capture. This preliminary setup of phase-based sampling signals allows the system to have predetermined timing references for distinguishing signal components, improving noise removal accuracy without requiring complex real-time processing
Solution Approach 2:
Phase-based sampling signals act as intermediaries between the light source and the receiver. These sampling signals provide a temporal framework that simplifies the correlation process, enabling accurate noise removal through phase comparison rather than requiring complex direct signal analysis
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 effectively removes ambient light-induced noise, improving the accuracy of iris image processing and biometric authentication by isolating the iris signal from ghost artifacts, leading to more reliable security applications, especially in mobile devices.
Implementation Method 1
a light source receiver configured to receive a reflected light signal of an image of the iris from the iris
Implementation Method 2
The light signal transmitted by the light source unit may include a near infrared ray (NIR)
Data Source
AI summary
An iris recognition device, a mobile device having the same, and a method of biometric authentication using the same are provided. The iris recognition device includes: a light source unit configured to transmit a light signal to an iris; and a light source receiver configured to receive a reflected light signal of an image of the iris from the iris, and remove an offset of the reflected light signal, corresponding to noise in the iris image, using a plurality of reference signals having different phases.