Abstract
It is important to estimate the distribution of intensity of a magnetic field for application of magnetic method to industrial nondestructive evaluation(NDE). This paper introduces the development of a system(Magnetic camera) that can measure the distribution of intensity of a magnetic field quantitatively in a short time without spatially restricted device like an automation movement device. Magnetic camera consists of magnetic source, sensor head, magnetic lens, A/D converter, data processor, monitor, and each part corresponds to light source, CCD sensor, optical lens, processor, video recorder and monitor in digital video camera relatively. Leakage magnetic flux near the crack on the magnetized specimen could be amplified by 3-dimensional magnetic fluid and zoom in and out of measurement area. The distribution of a magnetic field could be measured quantitatively at same interval with constant lift-off by the 2-dimensional arrayed magnetic sensors. In addition, multiple A/D converters were introduced in order to input the intensity of a magnetic field from sensor head to computer at high speed. Advantages of magnetic camera are demonstrated using a slit on plate specimen and modified steel reinforcement in concrete.
