Patent ID: 8597177

Claim:
A probe shape detection apparatus comprising: a magnetic field sensing section adapted to sense a magnetic field generated when an alternating current signal is applied to an electromagnetic coil provided in a probe having flexibility; a movement speed calculation section adapted to calculate a movement speed of the electromagnetic coil; a coordinate computation section adapted to perform a computational operation to calculate three-dimensional coordinates which represent a position of the electromagnetic coil based on the magnetic field sensed by the magnetic field sensing section; a moving average coordinate calculation section adapted to calculate moving average coordinates within a predetermined period based on a plurality of sets of three-dimensional coordinates of the electromagnetic coil detected by the coordinate computation section within the predetermined period; a comparison section adapted to compare the movement speed calculated by the movement speed calculation section with a predetermined threshold; a coil coordinate setting section adapted to set the moving average coordinates as the three-dimensional coordinates of the electromagnetic coil when a comparison result produced by the comparison section indicates that the movement speed is lower than the predetermined threshold and set the three-dimensional coordinates calculated by the coordinate computation section as the three-dimensional coordinates of the electromagnetic coil when the comparison result indicates that the movement speed is higher than the predetermined threshold; and a signal processing section adapted to generate a video signal to display a shape of the probe, based on the three-dimensional coordinates of the electromagnetic coil set by the coil coordinate setting section.