Illumination modelling in 3D sonar images

Summary form only given. Software has been developed to obtain a 3D perspective view of Pacific Ocean bottom terrain by merging side-looking sonar images with ocean bottom terrain elevation data (bathymetry). The observer can be positioned at various locations and see the terrain from different viewpoints. However, the side-looking sonar images published by the USGS are mosaic images manually compiled from the postprocessed raw data. Different pieces of the data may have different processing parameters, leading to difficulty of interpretation. The author has performed line-source illumination modeling for five areas of the Pacific Ocean. The reflectivity of a pixel in the image depends on the acoustic coefficient mismatch and the geometrical relationship between the incoming ray and the orientation of the surface. The synthesized image from the illumination of the model is due to geometric effect. It is displayed in a separate window side by side with the perspective view. The intent is to be able to identify the dominant geometrical effect in the perspective view so that interpretation of acoustic reflectance is better