Mosaicing ultrasonic volumes for visual simulation

The article addresses the problem of mosaicing a large volume from a set of small volumes acquired from a 3D ultrasound device. The formation of large volumes is necessary for an ultrasound visual simulator. Trainees using the simulator learn how to identify and diagnose a wide range of medical cases by operating a simulated ultrasound device on a mannequin, without any need for actual patients. The principle of the simulator is simple but apparently effective. In an offline preprocess, a volume buffer is generated from real ultrasound images. Slicing the volume buffer online then generates simulated images. Such images can be generated rapidly, including postprocessing enhancements, and can produce in most cases images indistinguishable from the real ultrasound images. The ultrasonic volume buffer has to be big enough and represent a large portion of the mannequin to permit the bound-free practice of a real-life diagnosis. Contemporary ultrasound devices don't provide the capability of obtaining the entire volume in a single acquisition. This implies that the volume buffer must be reconstructed from several subvolumes obtained from different viewpoints. The registration of monomodal data sets has been extensively investigated in medical applications where atlas data is used. The basic technique of a mosaicing operation aligns and registers two given volumes with a significant overlap into a single volume that smoothly combines the information from both. The type of registration technique that can be appropriately applied directly depends on the type of variation between the two volumes. Thus, designing a registration method requires knowing the type of variation exhibited by ultrasonic volumes.