Abstract: A sonar depth sounder device and method for processing echo signals, reflected from objects within a body of water, utilizes a processor, a memory, a display, and a keypad connected to the processor. The receiver receives sonar signals indicative of ambient noise in an underwater environment. The processor receives an electrical signal representative of the ambient noise, and calculates a detection threshold. The detection threshold is calculated by multiplying a scaling factor times the variance of the signal indicative of the ambient noise, and adding that product to the mean of the signal indicative of the ambient noise in the underwater environment. A transmitter then excites a transducer which emits sonar pulses into a body of water, and a receiver receives reflected sonar echo signals. When the intensity of the reflected sonar echo signals is less than the detection threshold, the reflected echo signals are eliminated from processing.

Abstract: A method and an apparatus is disclosed for controlling electrical loads as a function of displacement detection of objects within a monitored zone by utilizing the non-Doppler shifted component of an electromagnetic, acoustic, microwave, infrared, or optical field. In the case of an ultrasonic field, a transmitter generates an ultrasonic transmission frequency into a zone to be monitored. Information is extracted from the spatial and temporal variation of the amplitude and/or phase of the total ultrasonic field at the original (i.e. non-Doppler shifted) frequency of transmission. At a detection stage, after filtering all Doppler returns, the signal received from each of a plurality of receivers/transducers, if not already digital, is digitized and passed to a gate array, microprocessor, or similar processing means where amplitude and/or phase changes are demodulated to control one or more electrical loads, for example, lighting, alarms, A/C according to an embedded algorithm within the processor.

Abstract: Hydrophone with two unsymmetrically connected sensitive elements. The hydrophone comprises a detection unit including a closed housing (1) delimited by two cups (2, 3) resting against each other, each one being provided with a flexible diaphragm (4) and at least two piezoelectric sensitive elements (6, 8) associated each with electrodes (7, 9), one outside the housing, the other inside the housing. The two sensitive elements are preferably different in size, notably with different diameters. Electrodes (7a, 9a) of the sensitive elements that are not in contact with cups (2, 3) are electrically interconnected and the electrodes in contact with cups (2, 3) are also electrically interconnected. Each detection unit is preferably included in a protective assembly (not shown). The hydrophone can be used for marine seismic monitoring or prospecting for example.

Abstract: A system is disclosed for locating swimmers who could be in danger of drowning, as determined by preset parameters such as the time duration that they remain at a depth where breathing is impossible. In this system, each individual swimmer wears a SONAR Swimmer Location Monitor (SSLM). This is a miniature electronic device that not only determines the extent of the swimmer's danger but also emits an ultrasonic alarm signal whenever such danger exists. At each occurrence, an alarm, which may be audible and/or visual, is sounded on the surface. Meanwhile the swimmer's location is tracked in real time from the signals received on a hydrophone array deployed along the perimeter of the swimming area. These signals are combined in a central processor and the computed real-time location is displayed graphically on a monitor to guide the guard personnel in rescue operations. The invention is intended for use in pools, beaches, water parks, and other swimming areas.

Abstract: A fluidborne projector of sound derived from an electro-mechanical noise source translates acoustical energy through a piston subjected to balanced pressures of gas and liquid to enabled dynamic displacement thereof. Such displacement of the piston to a static position is regulated by controlled pressurization of gas, mechanically limited to prevent damage from changing pressures exerted on the piston.

Abstract: This invention is a thermoacoustic sonar system for detecting a target that is located at or beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located above the water and a plurality of passive receivers that are located on or above the water. The laser produces a light beam whose amplitude is subsequently modulated or whose pulses are varied in time. A particle accelerator would produce a pulsed particle beam that varies in time. These modulated or varied pulses are focused or deflected to a small layer of water at the air/water interface so that the beam will be absorbed by the water causing the water to produce an acoustic signal that may propagate to a target where the acoustic signal will be reflected and possibly detected by one or more passive receivers.

Abstract: An ultrasound-signal radiating device comprises a piezoelectric substrate, a first input interdigital transducer, a second input interdigital transducer, an output interdigital transducer, a cap, an amplifier, and a modulator with an input terminal. All the interdigital transducers are formed on one end surface of the piezoelectric substrate. The cap is mounted on a surface part of the other end surface of the piezoelectric substrate. If an input electric signal is applied to the first input interdigital transducer, a non-leaky elastic wave is excited in the piezoelectric substrate owing to the existence of the cap. The non-leaky elastic wave is detected at the output interdigital transducer as a delayed electric signal, which is amplified via the amplifier. A signal part of an amplified electric signal is fed back to the first input interdigital transducer, again.

Abstract: Disclosed are methods for increasing the fail-safety characteristics of tracking systems for navigation receivers which receive signals from many satellites. In an exemplary embodiment of the present invention, an individual PLL circuit is used to track the phase of each satellite's carrier signal, and a vector common tracking loop is used to track the disturbances of the carrier phases which are caused by one or more common sources, such as the movement of the receiver's antenna(s) and/or the phase fluctuation of the receiver's main reference oscillator. The vector common tracking loop uses phase information from all of the satellites being tracked, and for this reason can be made more wide-band than each of the individual PLL circuits. The wider bandwidth of the vector common tracking loop provides higher dynamic properties and more safe tracking when faint and weakening satellite signals are present.

Abstract: The millimeter-wave zoom antenna for guiding a beamrider hypervelocity missile uses varying range information derived from the flight of the missile toward the target as control signals for the beam control computer to perform electronically the zooming and the nutation of the millimeter wave guidance beam that emits from a phased array antenna so as to maintain a constant energy density at the missile receiver regardless of the actual distance of the missile from the launch platform at any given time.

Abstract: A plurality of applications for a micro-machined ultrasonic transducer (MUT) including an improved MUT array containing optimized transmit MUT elements and optimized receive MUT elements, a MUT array in which staggered MUT elements increase the sensitivity of the array, and a MUT array for multiple plane scanning.

Abstract: The invention in its preferred embodiment is applied to a spherical assembly of rows of transducer elements arranged in a uniform distribution of elements in each circular row, each row being at a different latitude. The beamforming is accomplished in two steps. First, vertically oriented fan-shaped left and right half beams are formed by a portion of the transducers in each selected row within an elliptical array of transducers. Two adjacent left and right half beams are formed per row. These beams are angularly spaced by the included angle of two adjacent transducers of that row. By a process of interpolation of signals received from a signal source by the left half beams and the right half beams, respectively, resultant left and right half beams with a main response axis in the source azimuth direction are obtained.

Abstract: The invention relates to a method for sensing ultrasound images of an object (1). The method is characterized in that an ultra-sound head (3) is moved along the object so as to sense individual image subdomains (13) of said object (1). An evaluation subdomain (14) is analyzed in order to determine the extent of the object (1) or the spacing (&dgr;x) between the individual image subdomains (13). This evaluation subdomain (14) is sensed perpendicularly to the sensed image subdomains (13); that is, it represents a domain of the object (1) which overlaps at least two image subdomains (13). In this way, allocation within the individual image subdomains (13) can be determined by using the structures of the object (1) thus obtained. To this end, in particular a vertical column structure (11) of the object (1) (evaluation subdomain (14)) is analyzed, thus enabling allocation of a plurality of individual horizontal line structures (10), i.e.

Abstract: The vertical beamwidth of the received beam of a return signal of a sonar system is adaptively modified as a function of water depth, altitude and range. The received beam is also vertically steered as a function of altitude and is steered at least once prior to the adaptive modification of the beamwidth. The vertical aperture is thereafter grown as a function of range by increasing the number selected elements in the hydrophone array. This is achieved by dynamically controlling a vertical beamformer by controlling the number of elements selected and the vertical steering angle in response to sensors which provide, among other things, data as to water depth, altitude or sonar depth, platform dynamics, and sonar range/time.

Abstract: The invention relates to synthetic antenna sonars. It consists, in order to correct the effects of the spurious motions of the physical antenna (202) of this sonar, in simultaneously using an autofocussing by crosscorrelation of the recurrences, a measurement of the rotation of the physical antenna with a rate gyro, and a correction of this measurement of rotation on the basis of the measurement of the angle of elevation of the reception signal as obtained with the aid of an auxiliary antenna (203) perpendicular to the physical antenna. It makes it possible to obtain synthetic antenna sonars having excellent spatial resolution.

Abstract: The invention relates to an ultrasonic measuring apparatus for determining the geometrical position of a boundary between two materials in a first material from a reference place, more particularly for wall thickness or fault testing. To enable even very thin-walled materials to be measured, the measuring apparatus isolates the reflected ultrasonic signals from the ultrasonic mixed signal received by the receiver, which consists of the ultrasonic signal reflected at the boundary to the first material and the ultrasonic signal reflected at the boundary to the second material, so that the time of impingement of the reflected signal is clearly determined for the determination of propagation time.

Abstract: A fishing method and apparatus is provided comprising a lure module enhanced with circuitry that is capable of releasing hooks upon detection of a signal sent from a user operated, remote device enhanced with circuitry to send the signals causing hook release. The module may be provided as a lure, as a bait-holder, or as a shape-neutral module, while the signal-sending device may be a mounted or handheld device used for example in a boat. Upon determining that a irretrievable snag has occurred, the signal sending device is used to send an appropriate remote signal to the lure or module effecting hook-release rendering the lure or module free from obstruction and retrievable. The lure or module may be reset with replacement hooks for continued fishing.

Abstract: A transducer shell assembly and bimodal transducer are provided. The transducer shell assembly has a hollow split tube such that a gap extends along its length to define first and second opposing edges. A locking mechanism can lock the first and second opposing edges in a fixed relationship to fix the gap. In terms of the bimodal transducer, an electromechanical driver is coupled to an inside surface of the tube. A first frequency of operation is defined when the gap is fixed, while a second frequency of operation is defined when the first and second opposing edges are free to move with respect to one another.

Abstract: Apparatus for accelerating the onset of wear related damage on a circumferential cam surface including a structure for supporting a camshaft including the circumferential cam surface, a plurality of rollers having respective circumferential roller surfaces, and structures supporting the rollers at respective locations adjacent the structure for supporting the camshaft for positioning the circumferential roller surfaces for circumferential rotating contact with the circumferential cam surface. The apparatus includes a mechanism operable for rotating the camshaft with the circumferential cam surface and the circumferential roller surfaces in the circumferential rotating contact. The apparatus further includes a mechanism for variably biasing the respective rollers against the camshaft during the circumferential rotating contact simulative of actual operating conditions.

Abstract: A fiber optic probe apparatus useful for conducting Raman spectroscopy remotely over optical fibers with minimal interference from Raman scattering within said fibers which includes three elements. The first element is at least one transmitting optical fiber having a first end and a second end. The second element is at least one collecting optical fiber for collecting light from a sample positioned near the first end of the transmitting optical fiber, the collecting optical fiber having a first end and a second end, the first end of the collecting optical fiber being in closely spaced relationship with the first end of the transmitting optical fiber wherein the longitudinal axis of the first end of the collecting optical fiber converges with the longitudinal axis of the first end of the transmitting optical fiber at an angle of less than forty five degrees. The third element is at the heart of the invention.

Abstract: Systems and methods are provided for enhancing an image by removing defects or blemishes from the image. A user selects a region of one or more pixels to be altered or modified. Interpolation techniques are used to determine interpolated values for pixels in the selected region based on the values of pixels surrounding the selected region. Thereafter, a smoothing function determines new values for each pixel in the selected region based on the values of pixels adjacent to the pixel being smoothed. The smoothing function kernel is applied iteratively to the pixels in the selected region until the image is smoothed to a desired degree.