Fingerprint Sensor Extrapolation for Non-Overlapping Position Detection

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Solution Overview

Problem

Existing fingerprint reading technologies require overlapping areas between partial images to detect the positional relationship, which is not feasible in all scenarios, especially when there is no overlap.

Innovation Solution

An image reading apparatus and method that includes a fingerprint sensor, prediction, extrapolation, and relative position detection sections to reconstruct the entire fingerprint image from partial images without overlapping areas by performing extrapolation and relative position detection using similarity and cross-correlation methods, and generating extended images to determine the positional relationship.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If overlapping areas between partial images are required to detect positional relationships, then the accuracy of position detection is improved, but the adaptability to different scanning scenarios deteriorates

Engineering Contradiction:
Improveposition detection accuracyVSAvoidadaptability to scanning scenarios
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces an extrapolation section that generates virtual overlapping areas by extrapolating image data from non-overlapping partial images. This intermediary mechanism creates the appearance of overlap without requiring actual physical overlap during scanning, thereby maintaining position detection accuracy while adapting to scenarios where overlap is not feasible.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary extrapolation of image data before position detection. By pre-calculating and extending image boundaries beyond the actual scanned areas, the system prepares virtual overlapping regions in advance, enabling accurate positional relationship detection even when the original partial images do not overlap.

Inventive Principle:
Principle #10Preliminary action

2Area of stationary object

If a small-size sensor face is used to fit small information devices, then the device size is reduced, but the ability to capture complete fingerprint images without multiple sweeps deteriorates

Engineering Contradiction:
Improvesensor face areaVSAvoidfingerprint image completeness
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent divides the fingerprint scanning process into multiple partial images captured sequentially by the small sensor face. Each partial image covers a specific region, and the system reconstructs the complete fingerprint by combining these segmented images with extrapolated boundary data, achieving complete fingerprint capture despite the limited sensor area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system extends the two-dimensional sensor face coverage into a three-dimensional temporal-spatial domain by capturing multiple partial images at different positions and times. Through extrapolation, it virtually expands the coverage area beyond the physical sensor boundaries, achieving complete fingerprint acquisition with a small sensor face.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2128817B1Image reading device, image reading program, and image reading method
Publication Date: 2019.04.03 FUJITSU LTD
  • EP2128817B1 patent drawingFigure 1
  • EP2128817B1 patent drawingFigure 2
  • EP2128817B1 patent drawingFigure 3

AI summary

Provided is an image reading apparatus including a fingerprint sensor 1 that acquires a plurality of first images obtained by successively reading the portions of a relatively moving object, an extrapolation section 3 that extrapolates the plurality of first images to generate a plurality of second images obtained by extending the image area of the first image, and a relative position detection section 4 that calculates the relative position between the plurality of images or the plurality of second images based on a plurality of images including at least the plurality of first images or the plurality of second images.