1. A device for recognizing a swimmer in water comprising, an electro-optical sensor providing a video display for viewing a target in water, first means for measuring the contrast of said target and assigning a first probability factor that said target is not a swimmer and measuring the width of said target and assigning a second probability factor that said target is not a swimmer, second means for encoding an area containing a target when said first means determines that said target has a probability of being a swimmer, said encoded target area being a portion of said video display, memory means for retaining said encoded target area, means providing reference scenes characteristic of a swimmer, and classification means for comparing said encoded target area with said reference scenes for determining whether said target is a swimmer.