In this study, a laser-MIG hybrid welding monitoring system was designed based on the LabVIEW environment and the accuracy of the monitoring system was verified via experiments. The conclusions are as follows:

1) The designed monitoring system was capable of monitoring plasma signals and had three functions: saving plasma signals in TDMS format, saving process parameters, and playback of data.

2) Binarization processing, morphological filters, HUBER linear fitting, and path-tracing-based bifurcation removal algorithms were used to locate the wire and workpiece successfully. Thus, we calculated the distance of laser transmission through the hybrid plasma.

3) The monitoring system extracted DLTP values from the plasma images and output them. Compared with the DLTP value obtained via the image analysis software, the accuracy of the DLTP value calculated by the system reached about 96.5%.