Optical Fingerprint Module Adaptive Exposure Control
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Solution Overview
Problem
Optical fingerprint devices struggle to obtain valid fingerprint image data in varying light environments, as bright environments lead to signal overload and dark environments result in indistinguishable ridge and valley intensities, hindering effective fingerprint identification.
Innovation Solution
A method and apparatus that dynamically adjust operating parameters, such as exposure time, based on light environment conditions by determining target light information through pixel value calculations, allowing for effective fingerprint image acquisition and identification without increasing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical fingerprint device uses fixed operating parameters for fingerprint image acquisition, then the device structure remains simple, but the fingerprint image quality deteriorates in bright or dark environments
Solution Approach 1:
The patent implements dynamic adjustment of operating parameters (exposure time, gain) based on real-time light environment detection. The system transitions from fixed parameters to adaptive parameters that automatically respond to changing lighting conditions, ensuring reliable fingerprint acquisition across diverse environments without requiring manual intervention or complex hardware modifications.
Solution Approach 2:
The patent changes physical operating parameters (exposure time, signal gain) according to light intensity conditions. By modifying these parameters dynamically based on environmental lighting, the system optimizes the balance between signal strength and noise reduction, achieving reliable fingerprint image acquisition in both bright and dark environments while maintaining relatively simple device architecture.
2Measurement precision
If the optical fingerprint device increases light intensity to improve image quality in dark environments, then the image quality improves, but the signal overload problem in bright environments worsens
Solution Approach 1:
The system dynamically adjusts light intensity parameters (exposure time, gain) based on real-time detection of ambient light conditions. In dark environments, the system increases light intensity to improve image quality; in bright environments, it reduces light intensity to prevent signal overload. This dynamic adaptation resolves the contradiction between image quality and signal overload by making the system responsive to environmental conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors light environment conditions and adjusts operating parameters accordingly. The detected light intensity information feeds back to the control system, which then modifies exposure time and gain settings to optimize fingerprint acquisition while avoiding signal overload, creating a closed-loop control system that balances image quality and signal integrity.
3Adaptability or versatility
If the optical fingerprint device uses automatic parameter adjustment to adapt to light environments, then the adaptability improves, but the processing time increases
Solution Approach 1:
The system performs preliminary detection of light environment conditions before fingerprint acquisition and pre-adjusts operating parameters accordingly. By detecting and responding to light changes in advance, the system minimizes the time required for parameter adjustment during actual fingerprint acquisition, achieving fast adaptation without significant time loss.
Solution Approach 2:
The patent implements rapid dynamic adjustment of operating parameters based on real-time light detection. The system uses efficient algorithms to quickly determine appropriate exposure time and gain settings, enabling the fingerprint device to adapt to changing light environments with minimal processing delay, thus maintaining high adaptability while limiting time loss.
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
Enables reliable fingerprint image acquisition and identification across different light environments by dynamically adjusting operating parameters, ensuring consistent results without the need for additional hardware, thus improving the usability of optical fingerprint devices in diverse lighting conditions.
Implementation Method 1
the optical fingerprint device constructs a fingerprint image by signal strengths of reflected light resulting from valleys and ridges of the finger
Implementation Method 2
the light source device is configured to provide a light source when the optical fingerprint module performs the fingerprint identification
Data Source
AI summary
Embodiments of the present disclosure relate to a method and an apparatus for acquiring a fingerprint image and a terminal device. The method includes determining target light information of a light environment of a to-be-identified fingerprint; determining a target operating parameter corresponding to the target light information according to a correspondence between light information and operating parameters; and acquiring a first fingerprint image of the to-be-identified fingerprint according to the target operating parameter. According to the method and the apparatus for acquiring the fingerprint image and the terminal device of the embodiments of the present disclosure, the operating parameter used for a time when the fingerprint image of the to-be-identified fingerprint is acquired can be dynamically adjusted according to different light environments, so that an intended result of using an optical fingerprint in different environments is achieved without increasing hardware cost.