Abstract: A single-element ultrasonic sensor includes a single transducer element and transmits an ultrasonic wave on the basis of a pulse wave. An ultrasonic array sensor includes a plurality of transducer elements and receives an ultrasonic reflected wave. A pulsar supplies the pulse wave to the single element ultrasonic sensor. A receiver receives electric signals from the transducer elements included in the ultrasonic array sensor. An amplification and conversion unit amplifies the electric signals received from the transducer elements included in the ultrasonic array sensor, converts the electric signals into digital signals, and arranges the digital signals in a serial order so as to generate a serial digital signal. An image generator generates an image on the basis of the serial digital signal.

Abstract: A method for towing marine geophysical sensor streamers in a body of water includes moving a towing vessel at a selected speed along the surface of the body of water. At least one geophysical sensor streamer is towed by the vessel at a selected depth in the water. A velocity of the streamer in the water is measured at at least one position along the streamer. The selected speed of the towing vessel is adjusted if the measured velocity is outside of a selected range.

Abstract: The invention includes a method for reducing noise in migration of seismic data, particularly advantageous for imaging by simultaneous encoded source reverse-time migration (SS-RTM). One example embodiment includes the steps of obtaining a plurality of initial subsurface images; decomposing each of the initial subsurface images into components; identifying a set of components comprising one of (i) components having at least one substantially similar characteristic across the plurality of initial subsurface images, and (ii) components having substantially dissimilar characteristics across the plurality of initial subsurface images; and generating an enhanced subsurface image using the identified set of components. For SS-RTM, each of the initial subsurface images is generated by migrating several sources simultaneously using a unique random set of encoding functions. Another embodiment of the invention uses SS-RTM for velocity model building.