One of the easiest methods to identify these regions is by using the color images in the Vectrino Profiler software. To enable this, click on the last icon in the toolbar (it looks like a clock hovering above x-y axes) and select “Enable Imaging”. This will turn the right-hand side of the window (in the default layout) into four color images of the profile data.
Weak spots are usually easiest to identify at first in the Amplitude or SNR plots. Look for a band of higher amplitude that stays fairly constant through time. See the figure below:
With correlation it is a little harder to distinguish weak spot interference from general de-correlation due to a poor configuration. Here is the same weak spot as above but shown in the correlation data:
Finally, the same weak spot in the velocity data:
Once you become proficient at identifying weak spots, the signature in the velocity data is fairly obvious. But it is best to examine all three (or four if you also include SNR) data streams to identify a weak spot. The velocity data in this case also shows phase wrapping as the velocity sign changes in what is a unidirectional flow.
This is just one example, but it shows the most common signature of a weak spot in Amplitude (and SNR), correlation and velocity. Unfortunately, there is no way to correct for weak spots in post processing. A couple of tips on how to eliminate weak spots before recording are described in a different FAQ.