Abstract: A method of tracking a known object is presented, wherein a sonar image of an object which is distorted by an artifact associated with sonar imaging is compared with an image generated from a model of the object, and at least one of the two images is modified to reduce differences between them.

Abstract: A portion of a line from a line laying vessel to a touchdown support point on or near to the seabed is imaged with a 3 dimensional sonar imaging system to produce coordinates of a series of touchdown points using a time sequence of sonar images, and the time series of touchdown points is recorded.

Abstract: Reflected sonar signals arising from one or more possible unknown objects are distinguished according to a first criterion, and possible shapes each having a defined unique associated point are assigned each of the possible unknown objects. Then the three dimensional points are tracked by the sonar system.

Abstract: Beamformed sonar data is compressed before communicating the data to a storage step or to a further processing step. At lease some of the beams of the compressed beamformed data have values for at least two different ranges.

Abstract: In a sonar system using a large array multielement sonar detector to detect reflected signals sent out by a sonar ping generator, the sent out sonar ping generator sends out varying frequency sonar signals during each ping, where the frequency is neither monotonically increasing or monotonically decreasing.

Abstract: In a sonar system using a large array multielement sonar detector, the raw phase and intensity data is reduced to less than three bits per channel per slice for each of the detectors in the multielement array before the raw data is transmitted to a beamformer for transforming the data to information about the spatial positions of objects reflecting the sonar signals.

Abstract: An object is measured to record the relative surface coordinates. Then, a portion of the object “the front side” immersed in a fluid is imaged by directing a sonar pulse at the object and recording sonar signals reflected from the object with a sonar imaging array. Then, the recorded relative surface coordinates are iteratively fit to coordinates calculated from the sonar image. Thereafter, the coordinates of the surface of the “backside” of the object that is not observable in the sonar image are known, and a computer generated image of the backside is stitched to sonar image so that the object can be viewed from a plurality of viewpoints separated from the sonar imaging array.

Abstract: An object is measured to record the relative surface coordinates. Then, a portion of the object “the front side” immersed in a fluid is imaged by directing a sonar pulse at the object and recording sonar signals reflected from the object with a sonar imaging array. Then, the recorded relative surface coordinates are iteratively fit to coordinates calculated from the sonar image. Thereafter, the coordinates of the surface of the “backside” of the object that is not observable in the sonar image are known, and a computer generated image of the backside is stitched to sonar image so that the object can be viewed from a plurality of viewpoints separated from the sonar imaging array.

Abstract: An object is measured to record the relative surface coordinates. Then, a portion of the object “the front side” immersed in a fluid is imaged by directing a sonar pulse at the object and recording sonar signals reflected from the object with a sonar imaging array. Then, the recorded relative surface coordinates are iteratively fit to coordinates calculated from the sonar image. Thereafter, the coordinates of the surface of the “backside” of the object that is not observable in the sonar image are known, and a computer generated image of the backside is stitched to sonar image so that the object can be viewed from a plurality of viewpoints separated from the sonar imaging array.

Abstract: Sonar imaging data obtained by sending multiple sonar pings towards an object is reduced by assigning values measured by each sonar ping to bins, where each bin is fixed in World Space, and calculating the opacity of each bin to produce an image of the object. A normal vector associated with each bin is used to calculate the light reflected from a model constructed from the data. The most preferred normal vector is calculated from the vector sum of normals calculated from each ping.

Abstract: Sonar imaging data is reduced by assigning partially reflective and/or opaque two dimensional areas for each data point to a series of planes. The reflectivity and/or transmission of light from the areas is calculated and used to construct an image.

Abstract: Sonar three dimensional data are represented by a two dimensional image. Pixels of the two dimensional image are emphasized if the if the three dimensional data associated with the pixel differ by more than a criterion from the three dimensional data associated with neighboring pixels.

Abstract: Objects which are to be inspected by sonar imaging when they are submerged are coated with or formed with a surface which is a non-specular sonar reflector.

Abstract: A method of automatically performing a patch test for a sonar system is disclosed, where data from a plurality of overlapping 3D sonar scans of a surface as the platform is moved are used to compensate for biases in mounting the sonar system on the platform.

Abstract: Data recorded by directing a single sonar beam pulse towards a surface, and recording the reflected sonar signals with a large plurality of detectors, is used to generate a mathematical representation of the surface. The mathematical representation of the surface is chosen to fit the recorded data according to a criterion such as a least squares fit of a plane to the recorded data points. A mathematical representation of on object is built up from a number of non-overlapping mathematical objects such as triangles, each triangle joined to adjoining triangles to form a continuous surface in three dimensions. Images of such mathematical representations are then presented to the observer.

Abstract: A container for containing underwater sensors such as sonar transceivers, sonar imaging devices, optical imaging devices, etc, electronic equipment and a cooling liquid for cooling the electronic equipment is connected to a second, variable volume container which acts both as a heat exchanger and as a pressure compensator for compensating the pressure difference between the cooling fluid and the surrounding water or other fluid.

Abstract: A method of automatically performing a patch test for a sonar system is disclosed, where data from a plurality of overlapping 3D sonar scans of a surface as the platform is moved are used to compensate for biases in mounting the sonar system on the platform.

Abstract: Data recorded by directing a single sonar beam pulse towards a surface, and recording the reflected sonar signals with a large plurality of detectors, is used to generate a mathematical representation of the surface. The mathematical representation of the surface is chosen to fit the recorded data according to a criterion such as a least squares fit of a plane to the recorded data points. A mathematical representation of on object is built up from a number of non-overlapping mathematical objects such as triangles, each triangle joined to adjoining triangles to form a continuous surface in three dimensions. Images of such mathematical representations are then presented to the observer.