Biometric Authentication Image Processing Thinning and Focus Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In biometric authentication systems, particularly for moving subjects, obtaining an in-focus image quickly is challenging due to the narrow depth of field, requiring high frame rates and efficient focus evaluation processes to maintain authentication accuracy within tight time constraints.
Innovation Solution
An image processing device and method that involves sequential image capture, thinning processes, first and second focus evaluations, and selection of in-focus frame candidates to rapidly identify suitable images for authentication, reducing the overall processing time by focusing on images within the focusing range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high frame rate capture is used to obtain in-focus images of moving subjects, then authentication speed is improved, but processing time and computational load increase
Solution Approach 1:
The patent segments the image processing task into multiple stages: initial capture phase, focus evaluation phase, and authentication phase. By dividing the continuous image stream into discrete evaluation intervals and processing only selected frames, the system reduces overall processing time while maintaining authentication speed.
Solution Approach 2:
The patent performs focus evaluation on only a subset of captured frames rather than all frames. By selecting specific frames for detailed evaluation based on preliminary assessment, the system reduces computational load and processing time while still ensuring authentication accuracy.
2Measurement precision
If focus evaluation is performed on all captured images, then authentication accuracy is improved, but processing time increases
Solution Approach 1:
The patent divides the image sequence into evaluation intervals and performs focus evaluation only on selected frames within each interval. This segmented approach maintains authentication accuracy by evaluating sufficient samples while reducing total evaluation time compared to processing every frame.
Solution Approach 2:
The patent performs preliminary focus evaluation on selected frames to identify candidates that meet focus criteria before proceeding to detailed authentication processing. This preliminary filtering action reduces the number of images requiring full authentication evaluation, thereby reducing total processing time while maintaining accuracy.
3Length of stationary object
If the depth of field is increased to capture moving subjects, then the focusing range is improved, but the resolution and clarity of the iris pattern deteriorate
Solution Approach 1:
The patent employs dynamic focus adjustment that tracks the moving subject's position. By continuously adapting the focus position to match the subject's movement within the focusing range, the system maintains high iris pattern resolution while accommodating a practical focusing range for walk-through authentication.
Data Source
AI summary
The image processing apparatus 10 includes image storage means 11 for sequentially storing images continuously captured in time, thinning means 12 for performing a thinning process for the images continuously captured in time, first image evaluation means 13 for performing first focus evaluation on the images after the thinning process is performed, selection means 14 for selecting a plurality of in-focus frame candidates from the images continuously captured in time, based on an evaluation result of the first focus evaluation, second image evaluation means 15 for reading the images of the in-focus frame candidates selected by the selection means 14 from the image storage means 11 and performing second focus evaluation on the read images, and matching image determination means 16 for selecting a matching image for an authentication process from the images of the in-focus frame candidates, based on an evaluation result of the second focus evaluation.