Abstract: A portable acoustic impedance measuring device 10 is provided for measuring the impedance properties of a panel 12. The device 10 includes a horn section 14 having a flexible plate 18. The plate 18 can assume the curvature of the duct panel 12. The horn section 14 is supported adjacent the panel's surface by a spindle shaft 28 which spans or bridges the inside diameter of the duct 12. The curvature of the plate 18 may be locked to hold the curvature of any of a variety of different panels having various sizes and shapes.

Abstract: Improvements in a full resolution image A are effected with an economical use of computer processing equipment and time by determining a field of improvement functions derived from processing a coarse representation of the original full resolution image. The coarse representation B is subjected to lightness field analysis to obtain an improved coarse image C, from which a coarse improvement field D is extracted by subtracting the original coarse representation. To obtain a full resolution improvement field E, the coarse improvement function is smoothly expanded by interpolation to the dimensions of the full resolution image. By modifying the original full resolution image field A with the values of the full resolution improvement field E, an improved full resolution image is obtained.

Abstract: An automatic underwater acoustic impedance measuring apparatus is instrumented with transducers whose outputs are led to a computer for the automatic measurement of acoustic impedance. One hydrophone is positioned so that is senses the incident and reflected signals to compute reflection factor. A second hydrophone is positioned at the face of the sample material so that is senses the incident and reflected waves from which it is possible to compute the phase angle. Acoustic impedance is obtained from the phase angle and reflection factor, computed and printed out in real time and automatically swept through a frequency range of interest.

Abstract: The disclosed scanning acoustic microscope comprises a solid lens body consisting of two sections of materials having different sound propagation characteristics but matching acoustic impedances. A lens is formed by the interface of said two sections and has a focal point coinciding with the apex of a sharply pointed tip formed at the free surface of one of said sections. The tip and the specimen to be investigated are immersed in a coupling medium having a relatively high acoustic absorption coefficient. The lens body carries an acoustic transducer on its surface remote from the tip for sending plane sound waves through the lens and tip onto the specimen. Acoustic waves reflected from the specimen are also received by this transducer. Acoustic waves transmitted through the specimen optionally may be received by a transducer arranged on the opposite side of the specimen. By appropriate processing of the received signals, high-resolution (10 nm) images of the specimen can be obtained.

Abstract: The invention is an apparatus which allows selective testing of aircraft or other vehicular components without requiring disassembly of the vehicle or components. The invention consists of a broad-band noise source 11, a guide 12 to direct the acoustic energy, soft sealing insulation 17 to seal the guide to the noise source and to the vehicle component, and noise measurement microphones 13, 14, both outside the vehicle at the acoustic guide output and inside the vehicle to receive attenuated sound. By directing acoustic energy only to selected components of a vehicle via the acoustic guide, it is possible to test a specific component, such as a door or window, without picking up extraneous noise which may be transmitted to the vehicle interior through other components or structure. This effect is achieved because no acoustic energy strikes the vehicle exterior except at the selected component.

Abstract: Apparatus for adjustably mounting ultrasonic testing devices around a rod end weld for providing water path adjustment to maintain predetermined focal depths of the testing devices, such as transducers. The apparatus enables the transducers to be adjustably radially located with respect to the rod end weld to be tested in order to establish a desirable ultrasonic beam normality. The apparatus provides for the remote actuation thereof.

Abstract: A two-dimensional image read-out device comprising a photoconducting layer, a plurality of X stripe electrodes applied on one surface of the photoconducting layer and arranged parallel with each other, and a plurality of Y electrodes applied on the other surface of the photoconducting layer and arranged parallel with each other in a direction perpendicular to the X electrodes. Both the X and Y electrodes are made of electrically conductive material, and the X or Y electrodes through which light from an image enters are made of transparent or translucent material. The light-entering side of the two-dimensional image read-out device is covered with an opaque material which allows the passage of light only through the picture elements which are formed at the intersections of the X and Y electrodes.

Abstract: An ultrasonic testing device of the type comprising a fixed hub with at least one ultrasonic transducer as well as an annular rolling means mounted for rotation on said hub and surrounding said transducer, this latter being mounted on the hub through a support whose external face opposite said transducer defines with the inner face of said rolling means a rotational sliding slit, the coupling between said support and said rolling means being provided by an ultrasonic liquid present in said slit, wherein a spongy resilient element is provided imbibed with said coupling liquid, said element being housed in a recess in said hub and being applied resiliently against the inner face of said rolling means.

Abstract: The reading of the presence or absence of a pencil or similar mark at various locations on a sheet of paper is accomplished by an optical Mark-Reader comprised of a completely solid state sensing mechanism with no moving parts. The Optical Mark Reader (OMR) contains a matrix of light sensitive transistors with their geometry and logic circuits capable of being tailored for a plurality of answer sheets. The internal logic circuits enable certain sections of the page to be read, generate a delay time while the data is being gathered, tell the host computer when the data is complete, and resets the OMR operator control system for successive page readings. Finally, the internal logic circuits and output bus of the OMR takes the "raw" data from the answer sheets and presents information on an output bus in a format allowing any computer (even a micro-computer) to be the host computer.

Abstract: A misregistration correction system that corrects for artifacts generated by the movement of a subject being imaged during the interval between temporally separated images. The system reduces the effects of secondary characteristics on the determination of a vector between a point on a first image and a point on a second image, which vector delineates the motion of the subject.

Abstract: A voxel of a scene is central to a neighborhood of twelve voxels disposed at corners of a tetradecahedron. A signal representation of a processed image of the central voxel is provided in response to a comparison of a signal representation of the central voxel and the neighborhood to a signal representation of an array of voxels.

Abstract: Apparatus for the determination of the location and/or distance traveled by a piston in a cylinder. This apparatus can easily be integrated into shock absorbers, vibration dampers and pneumatic springs, and exhibits a high degree of insensitivity to at least electrical interference, therefore being particularly well-suited for operation under unfavorable ambient conditions. As a result of the use of the most modern semiconductor technology and a suitable geometric arrangement, a very good resolution can be achieved, along with an automatic recognition of the direction of piston travel. Such an apparatus has a number of semiconductor elements; in one embodiment, in a beam fastened inside the cylinder or, in another embodiment, in the hollow piston rod. These semiconductor elements are arranged so that, over the axial length of the piston stroke, the distances between two neighboring semiconductor elements correspond to a specified measurement value resolution.

Abstract: In an ultrasonic transducer, frequency characteristics of phase detecting signal and frequency characteristics of transducer drive current are searched, resonant point with current dipping is found on the characteristics, the zero cross point corresponding to the current dipping is decided as the fundamental resonant point, and then PLL follow oscillation is performed. In such constitution, even if there exist many sub resonant frequency points near the fundamental resonant frequency, the PLL follow oscillation can be performed stably.

Abstract: The image is divided into regions of a given number of pixels. The original image is scaled down by a given factor. Each region of pixels is then enlarged in order to overlap its neighboring region. The enlarged regions are then sequentially written down in a scaled down version, in overlapped relationship, with each region oriented a given degree with respect to its neighboring region. The end result is a rotated image that has the same size as the original image with no gaps between neighboring oriented regions. This method applies to any arbitrary angle, as well as, to images defined as an arbitrary number of bits per pixel.

Abstract: Apparatus for testing a printed wiring board comprising means for optically scanning a board to be tested in two orthogonal, X-Y axes such that for each scan in the Y direction it scans a narrow strip of the board of predetermined width, w in the X direction. The optical scanning means is arranged to provide n.m discrete signals for each scan in the Y direction, wherein n is a predetermined number of signals representative of characteristics of the board across the width w of the strip (typically 1000) and m is a number dependent upon the dimension of the board to be scanned in the Y direction. Processing means is provided for processing the signals in groups of n'.times.m' where n' is less than or equal to n and m' is less than or equal to m (typically n' and m' are 40) to provide signals representative of the characteristics of the board along said strip and for storing said signals.

Abstract: A stress relaxation characteristic of an elastomeric material such as rubber and other elastomers under pressure is established by determining the ratio of the difference between two forces acting on a test sample before and after the test sample is stored under compression, to the force acting on the test sample before the sample is stored under compression. First the sample is subjected to an initial deformation, whereby its initial thickness is reduced by 23-27%. Subsequent deformations then amount to not more than 0.05 mm. In order to achieve these quantitatively very small subsequent deformations, the sample is permitted to expand rather than being subjected to additional compressions. Maintaining the exact magnitude of these subsequent deformations in the form of expansions as well as carrying out accurate force measurements is much simpler than causing additional compressive deformations and measuring the respective forces.

Abstract: A structure to provide increased surface area on the head of a shaker used for vibrational testing. The structure includes a base plate for attachment to the head of the shaker and a larger expanded head connected thereto by a frustoconical structure surrounding a cylindrical structure surrounding a spoke structure, all designed to increase the vibrational frequency at which undesired vibratory modes appear in the surface of the expanded head which otherwise can provide nonuniform vibration loading to the items attached thereto during testing. The structure also includes improved means for attachment to the shaker.

Abstract: An instrument for analyzing the size and charge of aerosol particles employs a dual beam laser Doppler velocimeter to track the motion of a particle while subjecting the particle to a sinusoidal acoustic field and to a pulsed, high voltage electric field. The particle transmitting through the crossed beams of the laser Doppler velocimeter moves with an oscillatory motion due to the acoustic field and, if the particle is charged, it has a horizontal drift parallel to the electric field during the electric pulse. The phase lag of the particle's motion with respect to the acoustic field is measured to determine the aerodynamic diameter of the particle and the velocity and the direction of the drift relative to the polarity of the applied high voltage electric field is used to determine the magnitude and polarity of the electric charge of the particle.

Abstract: A method and apparatus for measurement of time required for an ultrasonic tone burst to traverse a medium from a transmitter to a receiver is disclosed. Two transducers separated by a distance through which a medium flows alternatively act as a transmitter and then a receiver of ultrasonic signals. After a signal has been emitted from the first ultrasonic transducer, the second transducer is electronically checked for receipt of the ultrasonic signal. That checking is done at certain time intervals, preferably 4 microseconds, over a selected period of time. Samples are taken over each time interval. For each sample time slot the presence and strength of an output signal is measured. An address in a memory is selected which corresponds to each sampling time slot. Each input sample is stored in memory at an address which corresponds to the time slot at which the input sample was taken.

Abstract: Apparatus for measuring tensile strength of hair samples in which the test is controlled automatically to provide the average value of a plurality of hair samples. The apparatus is digitally controlled to provide a rapid testing cycle time. Tension is applied by a pivoted arm, and rotated by a solenoid that is controlled digitally to provide substantially constant velocity to the arm. A strain gage secured to the arm measures the force extended by the arm in tensioning the hair sample.