Radar screen image
I believe the answer is:
blip
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">radar screen image</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for blip that I've seen before include "Signal on a radar screen" , "Momentary deviation" , "Unexpected and minor temporary deviation" , "Temporary setback - short high-pitched sound" , "Small mark - unforeseen deviation" .)