Fingerprint Acquisition System Addressing Optimization
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Solution Overview
Problem
Current row addressing devices in fingerprint acquisition systems, particularly those using TFT technology, have limited speed due to the time required to propagate the selection token across the matrix, leading to prolonged fingerprint recognition times, which can exceed the threshold of user-perceived latency.
Innovation Solution
A fingerprint acquisition system with an integrated line addressing system that includes an additional shift register with fewer stages than the primary shift register, allowing for localized activation of detection cells near the contact point, reducing the need for token propagation across the entire matrix and thus minimizing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the selection token propagates across the entire matrix from the first line, then all rows can be addressed systematically, but the fingerprint recognition time becomes excessively long due to the need to traverse all M rows
Solution Approach 1:
The patent divides the matrix addressing into two segments: an initial segment addressed by the additional shift register (covering a subset of rows where the fingerprint is located) and a remaining segment addressed by the main shift register. This segmentation allows the system to address only the relevant portion of the matrix first, significantly reducing the time to locate and process the fingerprint data.
Solution Approach 2:
The additional shift register performs preliminary addressing of the detection matrix by directly activating the subset of rows where the fingerprint contact is detected. This preliminary action occurs before the main shift register needs to propagate the selection token through all M rows, thereby eliminating the time wasted on addressing empty or irrelevant rows.
2Speed
If an additional shift register is added to enable localized addressing, then the scanning speed improves, but the device complexity and number of control signals increase
Solution Approach 1:
The patent applies local quality by creating a specialized additional shift register with fewer stages that is optimized specifically for addressing the subset of rows where fingerprint contact is detected. This local addressing unit has different characteristics (fewer stages, targeted row coverage) compared to the main shift register, allowing it to operate faster for the specific task of locating and initializing the fingerprint region without requiring a complete redesign of the entire addressing system.
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 the time required for fingerprint recognition by enabling the system to begin scanning at the desired location with minimal additional control signals, thereby improving user experience by reducing latency.
Implementation Method 1
Each detection cell P(i,j) is composed of a light sensor D(i,j), generally a photodiode, which generates charges in proportion to the light energy received and stores them in its capacitor
Data Source
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AI summary
The invention relates to a system for recognizing digital fingerprints, comprising a tactile surface, configured to provide an item of location information (InfoLoc) on at least one contact point (PCO) of a finger with a digital fingerprint in contact with the tactile surface, characterized in that the system comprises: - a TFT panel, arranged under the tactile surface, comprising a detection matrix comprising M lines, at least some of which comprise cells (P(i,j)) for detecting an image that represents the digital fingerprint, an addressing line system being integrated into the matrix and configured to activate, line after line, the detection cells (P(i,j)) of a corresponding line, along a direction of scanning the lines, - a calculation device (CALC) configured to receive the item of location information (InfoLoc) and to control the addressing system for addressing the matrix using an addressing zone (ZA) regrouping a subset of lines among the M lines of the matrix, and determined according to the item of location information (InfoLoc).