Sequential Light Source Subsets for Biometric Image Acquisition
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Solution Overview
Problem
Fingerprint authentication in electronic devices can be delayed by background processes and other tasks, necessitating a method to quickly and efficiently acquire biometric image data while minimizing interference.
Innovation Solution
An electronic device with a dielectric cover layer and optical image sensors, equipped with optical elements like pin-hole masks or microlenses, and a controller that operates subsets of light sources in a sequential and directional manner to acquire biometric image data, allowing for dynamic illumination patterns and improved image acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If all light sources are operated simultaneously to acquire biometric image data, then image acquisition speed is improved, but energy consumption and device complexity increase
Solution Approach 1:
The patent divides the light source array into multiple subsets that are operated sequentially rather than simultaneously. Each subset illuminates a specific region or pattern on the finger, allowing the sensor to capture multiple images that are later combined to form a complete biometric image. This segmentation reduces energy consumption while maintaining image acquisition capability.
Solution Approach 2:
The patent implements periodic activation of light source subsets, where different subsets are turned on in sequence at different time intervals. This periodic action allows the system to capture multiple frames over time, improving image quality and reducing noise while consuming less energy compared to continuous illumination of all light sources.
2Area of stationary object
If all light sources are operated simultaneously, then illumination coverage is improved, but heat generation and energy waste increase
Solution Approach 1:
The light source array is segmented into multiple subsets that cover different spatial regions or patterns. By activating subsets sequentially rather than simultaneously, the system achieves complete illumination coverage over time while reducing instantaneous energy consumption and heat generation.
Solution Approach 2:
The patent uses partial illumination by activating only the necessary subsets of light sources required for each imaging frame, rather than illuminating the entire area simultaneously. This partial action approach reduces energy waste while still capturing sufficient information for biometric recognition.
3Use of energy by moving object
If sequential operation of light source subsets is implemented, then energy efficiency is improved, but image acquisition time increases
Solution Approach 1:
The system uses rapid periodic activation of light source subsets, capturing multiple images in quick succession. These images are then processed and combined to form a complete biometric image. The periodic action is optimized to complete within acceptable timeframes for biometric authentication, balancing energy efficiency with speed requirements.
Solution Approach 2:
The patent performs preliminary processing of the multiple captured frames, combining them to form a complete image. This preliminary action of capturing multiple frames in advance allows the system to reduce noise and improve image quality while maintaining acceptable acquisition times.
4Measurement precision
If multiple passes with transverse directions are used, then three-dimensional geometric information is improved, but complexity of operation increases
Solution Approach 1:
The patent introduces a temporal dimension by performing multiple passes of light source subset activation in different spatial directions. The first pass captures geometric information in one direction, while the second transverse pass captures complementary information from a different angle. This multi-dimensional approach enhances the three-dimensional geometric information of the fingerprint while the controller manages the complexity through systematic coordination.
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 enables rapid and effective fingerprint authentication by enhancing the acquisition of three-dimensional geometric information, reducing latency, and improving the accuracy of fingerprint recognition.
Implementation Method 1
at least one optical image sensor below the dielectric cover layer
Implementation Method 2
The plurality of light sources may include a plurality of light emitting diodes (LEDs), for example
Data Source
AI summary
An electronic device may include a dielectric cover layer defining a finger sensing surface and at least one optical image sensor below the dielectric cover layer. The electronic device may also include at least one optical element associated with the at least one optical image sensor. Light sources may be below the dielectric layer and may be selectively operable in subsets of light sources. A controller may be configured to sequentially operate respective adjacent subsets of light sources while acquiring biometric image data from the at least one optical image sensor.