In electronic scanning, the scanning movement of electron beam from left to right is called line scanning or horizontal scanning, and the scanning movement of electron beam from top to bottom is called frame scanning or vertical scanning.
The scanning speed of the two is completely different. The speed of line scanning is faster than that of frame scanning. For the scanned image with 1000 lines, the speed ratio is 1000.
Scanning electron microscope (SEM) is a large analytical instrument, which is widely used to observe the morphology and composition of the surface ultrastructure of various solid substances.