Structured Lighting for Full-Surface Papillary Imprint Fraud Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting fraudulent papillary impressions using optical properties are limited as they provide characterization only in specific small locations, making it possible for fraudsters to deceive detection by covering these areas with imitation fingerprints.
Innovation Solution
A method utilizing structured lighting that characterizes papillary impressions without emitting additional light signals, determining absorption and reduced diffusion coefficients through predictive models, allowing for comprehensive fraud detection across the entire fingerprint surface without increasing apparatus size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical characterization methods are used, then detection can be performed, but only in specific small locations making the system vulnerable to fraud
Solution Approach 1:
The lighting means are divided into multiple independently controllable lighting devices arranged in arrays, allowing selective activation of different regions. This segmentation enables the system to illuminate and characterize the entire fingerprint surface area while maintaining the precision of optical measurement by activating only necessary lighting segments at any given time.
Solution Approach 2:
The patent transitions from point-by-point or small-area characterization to full-surface characterization by utilizing two-dimensional arrays of lighting devices and detectors. This dimensional expansion allows simultaneous or sequential illumination of multiple locations across the entire fingerprint surface, overcoming the limitation of small characterization areas while preserving detection precision through maintained optical path geometry.
2Measurement precision
If multiple illumination wavelengths are used to characterize the papillary imprint, then fraud detection accuracy improves, but the device size and complexity increase
Solution Approach 1:
The lighting devices are designed to emit multiple wavelengths or have multiple wavelengths available, allowing a single lighting device to perform multiple characterization functions. This multi-functionality enables the system to obtain spectral information and tissue optical properties without requiring separate lighting devices for each wavelength, thereby maintaining fraud detection accuracy while reducing overall device complexity and size.
Solution Approach 2:
The system achieves multi-wavelength characterization by changing the operational parameters of existing lighting devices rather than adding multiple dedicated devices. By modulating the wavelength or spectral content of light sources and using structured lighting patterns, the system extracts multiple optical coefficients (absorption, reduced scattering, anisotropy) from a compact apparatus, avoiding the size increase that would result from multiple separate wavelength sources.
3Area of stationary object
If structured lighting with multiple lighting devices is implemented, then full surface characterization is achieved, but the lighting system complexity increases
Solution Approach 1:
The patent combines multiple lighting devices into integrated arrays that are closely coupled with the detector array. This merging of lighting and detection functions into a unified system reduces overall complexity by eliminating separate control and alignment systems. The lighting devices are positioned and controlled as an integrated unit, allowing full surface coverage while managing complexity through system integration rather than separate components.
Solution Approach 2:
The lighting devices are arranged and controlled to automatically provide structured illumination patterns without requiring complex external control mechanisms. Each lighting device can be independently activated based on detection needs, and the system self-regulates the illumination pattern to achieve full surface characterization. This self-service capability reduces the need for complex external control systems while maintaining comprehensive coverage.
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 provides consolidated fraud detection by characterizing the entire fingerprint surface, enhancing detection resolution and preventing deception by covering specific small areas with imitation fingerprints.
Implementation Method 1
characterize the papillary imprint by determining respective values of at least two optical coefficients, in particular an absorption coefficient μA and a reduced diffusion coefficient μS'
Implementation Method 2
The lighting means and the matrix optical sensor are superimposed, under the contact surface (106)... the lighting means provide lighting... and acquire an image of the papillary imprint
Data Source
Figure 1A~1D
Figure 2~3C
Figure 4~5
AI summary
The invention relates to a method for determining whether or not a papillary imprint consists of living human tissue, using a papillary imprint sensor (110) comprising, superposed, a contact surface (106), an optical matrix sensor (112), and lighting means (111) formed by a plurality of mutually parallel lighting devices (1110). The method according to the invention comprises the following steps: - illuminating the papillary imprint by the lighting means, the lighting devices together forming, on the contact surface, at least one uniform lighting figure along an axis which extends on both sides of a detection surface of the optical matrix detector, and acquiring an image by means of the optical matrix sensor, said steps being implemented at least once; - in each image, selecting pixels corresponding to the valleys of the imprint, or selecting pixels corresponding to the ridges of the imprint; and - from the selected pixels, extracting an optical feature defining the response to at least one illumination, of the material constituting the papillary imprint, and using said optical feature for determining the values of at least two characteristic optical coefficients of the imprint. An imprint can thus be characterised anywhere on the surface thereof.