On processing and registration of forward-scan acoustic video imagery

Producing high-resolution underwater imagery in range of visibility conditions is a capability of critical demand for a number of applications. New generation of forward-scan acoustic video cameras, becoming available for commercial applications in recent years, produce images with considerably more target details than optical systems in turbid waters. Previous computer processing of sonar imagery has dominantly involved target segmentation, classification and recognition by exploiting 2D visual cues from texture, or object/shadow shape in a single frame. Processing of video is becoming more and more important because of various applications that involve target tracking, object identification in search and inspection, self localization and mapping, among many other applications. This paper addresses the image registration problem for acoustic video, and the preprocessing steps to be applied to the raw video from a DID-SON acoustic camera for image calibration, filtering and enhancement to achieve reliable results.