Patent ID: 8444055

Claim:
A detection device comprising: a magnetic field generating unit that generates a magnetic field; a sensing unit that detects a change in the magnetic field by a magnetic substance excited by the generated magnetic field and that outputs a signal in response to the detected change in the magnetic field; an amplifying unit that amplifies the signal output from the sensing unit so as to output a waveform signal indicating a transient response waveform; a first calculating unit that calculates and outputs a first correlation coefficient between the transient response waveform and a first reference waveform indicating a transient response waveform which is preliminarily stored; a second calculating unit that calculates and outputs a second correlation coefficient between the transient response waveform and a second reference waveform indicating a transient response waveform which is preliminarily stored; a third calculating unit that calculates a value based on the first correlation coefficient and the second correlation coefficient; and a detecting unit that outputs a detection signal indicating that the magnetic substance is detected when the value calculated by the third calculating unit satisfies a predetermined condition.