To clearly monitor an arc beam, molten pool, grooves and a torch by taking in a groove image at a first shutter speed when the arc is off, executing addition for each pixel of the two-dimensional array, showing it in a monitor and taking in the pixel at a second shutter speed for conversion processing at the time of welding.
Before the start of welding, a power source 5 for driving a light source is turned on by a signal from an external interface 21, and the shutter speed of the control circuit 6 of a two-dimensional light receiving means is set at a first speed, so that the image of a groove is taken in. This image is added successively for each pixel of the same coordinate of the two-dimensional array (X, Y) between plural sheets of image. The final image data thus added are data-converted and outputted to a monitor TV for display. During the welding, the power source 5 for driving the light source is turned off, and the shutter speed of the control circuit 6 of the two-dimensional light receiving means is set at a second speed, so that the image of a groove is taken in. This image data are converted and outputted to the monitor TV for display.
SAITO NOBORU
HANEDA MITSUAKI
WADA TAKESHI
OI YASUKATA
