60 Field procedure
Keep in mind the number of impulses which you have recorded per scanning path. This amount
should be entered later in the software program, when transferring the data to a PC, to receive
all measured data correctly from your measuring instrument!
There is no special rule for selecting the right number of impulses. But there are different aspects which
should be considered. These are some considerations
• the length of your measured area and
• the size of the objects you are searching for.
A preferable distance between two impulses is about 15 cm to 30 cm. The smaller the distance between
two impulses is, the more exactly the graphical representation will be. If you are looking for small
objects you have to select a smaller distance, for big objects you can increase the distance between the
impulses.
Figure 8.3 shows the effects of the distance and the number of impulses per scanning path for some
objects.
Figure 8.4 shows the difference between very few impulses (left side) and much more impulses (right
side) on the same length of scanning path. Therefor the second record (right side) shows much more
details and also smaller objects can be seen.
Do not hesitate to record more measurements with different numbers of impulses. For example you can
scan a large area before doing a second detailed precision measurement. Especially if searching for
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