Masquerading Detection via Feature Point Transformation
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Solution Overview
Problem
Existing masquerading detection systems require additional devices for authentication and are prone to false acceptance due to changes in lighting environments, as they rely on variations in luminance rather than feature point movement.
Innovation Solution
A masquerading detection system that uses an imaging unit to capture images from different angles, calculates feature point coordinates, associates these points, performs plane projective transformation, and determines masquerading based on the difference between transformed and original coordinates, eliminating the need for extra devices and being resistant to lighting changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional devices (illuminating lamp, distance detection device, three-dimensional information processing apparatus) are used to detect masquerading, then masquerading detection capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the masquerading detection function from complex additional devices and implements it using only the imaging device's captured images. By analyzing feature point coordinates and plane projective transformation from standard images, the system eliminates the need for illuminating lamps, distance detection devices, and three-dimensional information processing apparatus while maintaining detection capability.
Solution Approach 2:
The imaging device serves dual purposes: it not only captures images for authentication but also provides the data needed for masquerading detection through feature point coordinate analysis and plane projective transformation. The system uses the images themselves to detect masquerading, making the imaging device self-sufficient without requiring external additional devices.
2Reliability
If masquerading detection is based on luminance variation, then detection can be performed, but false acceptance increases due to lighting environment changes
Solution Approach 1:
The patent changes the detection parameter from luminance variation to feature point coordinate variation. By analyzing the positions of feature points and their transformations through plane projective transformation, the system creates a detection method that is invariant to lighting changes, as coordinate geometry relationships remain consistent regardless of illumination conditions.
3Reliability
If three-dimensional information processing is used to eliminate masquerading, then authentication security is improved, but processing complexity and time increase
Solution Approach 1:
The patent extracts the essential masquerading detection function from complex three-dimensional information processing. By using plane projective transformation on feature point coordinates from two images, the system achieves security detection without requiring full three-dimensional reconstruction, significantly reducing processing complexity and time while maintaining authentication security.
Data Source
AI summary
A masquerading detection system includes: an imaging unit (2) that obtains a first image by imaging an inspection object (12) from a first angle, and a second image by imaging the inspection object from a second angle which is different from the first angle; a unit (101) that detects first feature points from the first image, obtains first feature point coordinates of the detected feature points, detects second feature points from the second image, and obtains second feature point coordinates of the detected feature points; a unit (104) that obtains transformed coordinates by performing a plane projective transformation for the second feature point coordinates from the second image to the first image; and a unit (105) that determines that masquerading has been attempted when the difference between the transformed coordinates and the corresponding first feature point coordinates is equal to or smaller than a predetermined value.