To evaluate the resolution of individual sonar images in field conditions without specific targets, a statistical sampling of the imagery is taken and analyzed. Large quantities of resolution measurements are made on point-objects identified in the imagery. The measurements are compared to improve fidelity and generate statistically significant results. The image is broken into segments for analysis to identify variation in resolution across the image. The mean value of point-target resolution per segment can be determined for the imagery. A segment with an insufficient number of measurements required to determine a statistically significant value for resolution is rejected. The image resolution can be determined as the mean or median value of the segment measurements for the entire image.

A forward scanning sonar system including at least a sonar transducer and a support structure having the at least a sonar transducer mounted thereto, the at least a sonar transducer being configured such that, while during scanning operation the sonar transducer is moved along a forward moving direction, a fan-shaped beam of the sonar transducer is forming a plane oriented forwardly downwardly such that the fan-shaped beam forms a scan line oriented at a scan angle to the forward moving direction with the scan angle being greater than 0 and smaller than /2 and such that the scan line intersects the forward direction at a point ahead of the sonar transducer.

An echo measuring apparatus has: a transmission signal forming unit for forming a transmission signal by a pseudo noise sequence signal; a transmitting unit for transmitting the transmission signal as an ultrasonic wave into the water; a receiving unit for receiving an echo of the ultrasonic wave; and a correlator for discriminating the echo corresponding to the transmission signal by executing a correlating process to the echo by the pseudo noise sequence signal and measuring a distance to a measurement target on the basis of a time difference between the transmission signal and the echo, wherein assuming that a velocity of a sound wave in the water is equal to Vu and the distance to the measurement target is equal to D, a period of the transmission signal includes a case where it is equal to or less than (2D/Vu).

A compensation filter is operable to receive a received signal in response to a transmitted signal, the received signal having a time duration. The compensation filter is operable to generate a compensated signal. The compensation filter changes shape of an associated transfer function during the time duration of the received signal to result in the compensated signal having an improved spectral flatness throughout the time duration of the received signal. The compensation filter can be used in a sonar system. A method, which can be used in a sonar system, uses the compensation filter.

Provided are method, system, and computer program product for imaging an underwater environment. The method may include receiving sonar returns and converting the sound energy of the sonar returns into sonar return data, and generating first beam data associated with a first beam having at least one first main lobe oriented in a first direction. Generating the first beam data may include: forming the sonar return data in the first direction; applying a first predetermined window to the sonar return data to define a first weighted return data; applying a second predetermined window to the sonar return data to define a second weighted return data; comparing a first power of the first weighted return data to a second power of the second weighted return data; and defining, when the first power is less than the second power, the first beam data based upon the first weighted return data.

A master-slave compatible PDC system, comprising a master sensor, at least one slave sensor, which comprises an ultrasonic IC, a boost drive module, and a second ultrasonic transducer; the CPU module drives the first ultrasonic transducer via the master drive module, the first ultrasonic transducer amplifies and transmits echoed signals to a A/D conversion module of the CPU module via a master amplifier module, the CPU module drives the ultrasonic IC of the corresponding slave sensor via a slave drive module, the ultrasonic IC drives the second ultrasonic transducer via the boost drive module, and the second ultrasonic transducer feeds back the echoed signal to the A/D conversion module of the CPU module via the ultrasonic IC. In the Invention, the ultrasonic IC is employed for each slave sensor, enabling a farther detection distance and stronger anti-interference capability of the whole system.

Techniques are disclosed for systems and methods to provide three dimensional volume rendering of volume data for use when operating mobile structures. A three dimensional volume rendering system includes a logic device configured to communicate with a user interface and receive volume data from a volume data source. The logic device is configured to render a three dimensional representation of the volume data, generate, within the 3D representation, a two dimensional grid having several vertices, adjust vertical coordinates of the several vertices based on the volume data, and render the adjusted 2D grid as a 3D surface.

A plurality of control points are defined having a known spatial relationship relative to an array of transducers. An amplitude is assigned to each control point. A matrix is produced containing elements which represent, for each of the control points, the effect that producing a modeled acoustic field having the assigned amplitude with a particular phase at the control point has on the consequential amplitude and phase of the modeled acoustic field at the other control points. Eigenvectors of the matrix are determined, each eigenvector representing a set of phases and relative amplitudes of the modeled acoustic field at the control points. One of the sets is selected and the transducer array is operated to cause one or more of the transducers to output an acoustic wave each having an initial amplitude and phase such that the phases and amplitudes of the resultant acoustic field at the control points correspond to the phases and relative amplitudes of the selected set.

A survey system including a multibeam echo sounder having a single projector array and a single hydrophone array constructs a multi-component message for ensonifying multiple fans and deconstructs a corresponding message echo for use in analyzing the returns from each fan.

A detection system to check the position of a pipeline in a bed of a body of water and extending along a predetermined route; the system comprising a device, which is configured to be moved in a moving direction and along the predetermined route and comprises a support, which mainly extends transversely to the moving direction, a quantity of acoustic wave sources, which are mounted on the support and are configured to transmit acoustic waves through the body of water and the bed of the body of water, and a quantity of acoustic wave receivers, which are located along the support and are configured to receive reflected acoustic waves and emit reception signals related to the reflected acoustic waves; and a processing unit comprising an acquisition unit, which is configured to receive, from the outside, at least one datum selected within a group of known or expected data comprising: the known value of the cross-section of the pipeline, an expected value of the trenching height of the pipeline, the known shape of the pipeline, the expected bathymetric profile of the bed of the body of water, and an expected value of the position of the pipeline; the processing unit being configured to calculate a parameter related to the position of the pipeline in the bed of the body of water on the basis of the reception signals and of said at least one datum selected within the group of data.