Automatic Search Algorithms for Near-Field Ferromagnetic Targets Based on Magnetic Anomaly Detection

Table 1

Comparisons of four automatic search algorithms.

Algorithm basis	Magnetic modulus anomaly (MMA)		Magnetic vector anomaly (MVA)
Algorithm types	Gradient search	Enhanced gradient search	Gradient search	Enhanced gradient search
Convergence of paths	Plane: partly converge; Space: all converge	Plane: partly converge; Space: all converge	Plane: all converge; Space: all converge	Plane: all converge; Space: all converge
Distance of convergent paths	Plane: longest; Space: longest	Plane: longer; Space: medium	Plane: shorter; Space: shortest	Plane: shortest; Space: medium
Distributions of convergent terminal points	Plane: certain points; Space: surface of target	Plane: certain points or around projection profiles; Space: surface of target	Plane: certain points; Space: surface of target	Plane: around projection profiles; Space: surface of target
Suitable applications	Preliminary detection	Search and tracking with low cost	Precise and efficient search and tracking	Plane boundary search and identification