Fig. 4From: A practical person authentication system using second minor finger knuckles for door securityMCP joint detection and ROI extraction. a Input image f(n 1,n 2). b Edge image f e (n 1,n 2). c Region around fingers f ′(n 1,n 2). d Vertical projection V(n 2). e Valley detection between fingers. f MCP joint detection. g Extracted ROI image for each fingerBack to article page