Pipeline transportation, as it is low cost, steady supply and high efficiency, is widely used nowadays. However, pipelines
might be damaged by natural power or human activities. Thus, pipeline status monitoring, including transmogrification,
corrosion, flaw and crack, shows up more and more important. This paper presents a method using magnetic field
measurement system which based on AMR (anisotropy magnetic resistance) sensors array to imaging the pipe's bug.
Compared with single sensor, it can capture more all-around information about the magnetic field distribution on pipe
wall, and it can make the detection more veracity; Compared with the traditional pipeline pig, which based on Hall
elements, it provides greater sensitivity. A mechanical model of relationships between the pipe's bug and the magnetic
field distribution is given; In this AMR measurement system, the hardware includes arrangement sensors, Set/Reset
circuits, amplifiers, multiplexers, DSP device, data radio module and power supply; and software contains an autocalibration
algorithm, and a VC display program of the measured magnetic field. An experimental pipe bug is detected
and the magnetic field is discussed.