Pulsed Light Biometric Authentication via Time-Resolved Imaging
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Solution Overview
Problem
Current biometric authentication methods face challenges in accurately distinguishing between surface reflection components and internal scatter components, leading to potential false authentication rates and reduced security, especially when using conventional cameras that detect both components simultaneously.
Innovation Solution
The identifying device employs a light source that emits pulsed light with a controlled pulse duration to illuminate a user, allowing an image sensor to differentiate between surface reflection components and internal scatter components through time-resolved imaging, enhancing the signal-to-noise ratio and improving authentication accuracy by verifying the signals against stored biometric data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional cameras are used to detect reflected light for biometric authentication, then the device complexity is low, but the measurement precision is insufficient due to inability to distinguish surface reflection components from internal scatter components
Solution Approach 1:
The patent applies periodic action by using pulsed light illumination instead of continuous light. The light source emits light in periodic pulses with controlled duration (0.2 ns to 1 μs), allowing the system to capture time-resolved reflectance signals. This periodic illumination enables separation of surface reflection components (arriving earlier) from internal scatter components (arriving later), thereby improving authentication accuracy without requiring complex hardware modifications beyond the light source and timing control
Solution Approach 2:
The patent introduces a time dimension to the traditional spatial imaging approach. By measuring reflected light intensity as a function of time after pulsed illumination, the system creates a time-resolved reflectance profile. This temporal dimension allows differentiation between surface and subsurface tissue characteristics, enabling more precise biometric authentication while maintaining relatively simple device architecture
2Reliability
If both surface reflection components and internal scatter components are detected simultaneously, then the ease of operation is maintained, but the reliability is reduced due to false authentication rates
Solution Approach 1:
The patent applies segmentation by separating the detection of surface reflection components and internal scatter components through time-resolved measurement. By analyzing the temporal profile of reflected light, the system segments the total reflectance signal into distinct components: early-arriving surface reflections and later-arriving internal scatters. This segmentation enables independent verification of both surface and subsurface biometric features, improving authentication security while maintaining operational simplicity through automated temporal analysis
3Measurement precision
If pulsed light with very short duration is used to improve time resolution, then the measurement precision is improved, but the use of energy is reduced due to shorter illumination time
Solution Approach 1:
The patent applies parameter changes by systematically varying the pulse duration parameter within the range of 0.2 ns to 1 μs to optimize the balance between time resolution and signal intensity. Different pulse durations can be selected based on the specific application requirements: shorter pulses for higher time resolution when signal intensity is sufficient, and longer pulses when more illumination energy is needed. This parameter optimization allows the system to achieve adequate time resolution for component separation while maintaining sufficient signal strength for reliable detection
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 significantly reduces false acceptance and rejection rates by clearly detecting texture and vein patterns, providing a more secure authentication system that combines surface reflection and internal scatter component analysis for reliable identification.
Implementation Method 1
a portion of the body of a user is illuminated with light, and reflected light is observed to thereby obtain information for individual identification
Data Source
AI summary
An identifying device includes a light source, an image sensor, a memory that stores biometric data indicating a feature of a body of a user, and a processor. The processor causes the light source to emit pulsed light having a pulse duration of more than or equal to 0.2 ns and less than or equal to 1 μs to illuminate the user with the pulsed light, causes the image sensor to detect at least part of reflected pulsed light that returns from the user and to output a signal corresponding to two-dimensional distribution of an intensity of the at least part of the reflected pulsed light, and verifies the signal against the biometric data to identify the user.