The scan showed double image

1.Possible cause analysis of failure:Do not know how to adjust the reverse clearance.
2.Solution:Draw a 20×20 box and set the Scan Interval value to 1 in Scan Parameters.Adjust the output power and start scanning.Use a ruler to measure the line from the scanning surface,(left+right-),and fill the measured number into the software settings.Tick scan(reverse gap) in General Settings.