Fig. 3

(a) Principle of sensor (b) u-shaped sensor (c) sensor shell (d) the logic process of multi-frequency electromagnetic non-destructive testing system (e) hardware (f) software (g) engineering application.

(a) Principle of sensor (b) u-shaped sensor (c) sensor shell (d) the logic process of multi-frequency electromagnetic non-destructive testing system (e) hardware (f) software (g) engineering application.