Fig. 1. Images of ridge row

Fig. 2. Structure of Gaussian pyramid

Fig. 3. Gaussian difference algorithm

Fig. 4. Multi-scale feature image group of normalized ridge row

Fig. 5. Images of divided ridge row.(a) Distribution of feature matrix value of upper ridge row; (b) distribution of feature matrix value of middle ridge row; (c) segmentation of upper ridge row; (d)segmentation of middle ridge row

Fig. 6. Segmentation effect comparison of ridge row . (a) Original images; (b) MsSegN3 algorithm; (c) MsSegN6 algorithm; (d) PosOtsu algorithm; (e) KGFCM algorithm

Fig. 7. Number of eight connected domain in the segmentation results of each algorithm

Fig. 8. Algorithm running time with different values of N