Digital image acquisition in the SEM is poised to take over conventional methods of image recording. Because a majority of researchers use Polaroid film which only records about 1,000 lines of information, the acquisition systems available today are capable of matching and possibly exceeding the resolution of this medium.

Several methods are available to accomplish the acquisition task, and they each have certain benefits and disadvantages. by far the simplest and least expensive is to digitize the video output from the SEM when available. Under some conditions the video output can be digitized directly. The advantage of this method is cost. A single frame video digitizer costs less than $200. The signal, however, is usually very noisy. Because the human eye “sees” at a slower rate than video, we normally are “seeing” a 10-20 frame average. When we choose one frame, the results are too noisy. Fortunately, for under $1,500, digitizers that average frames are available. With multiple frames, the results are often acceptable for some applications.