Abstract: Method and apparatus for measurement of ice thickness employing ultra-sonic pulse echo technique, wherein an ultra-sonic pulse is emitted from a transducer at the ice-accreting surface of a structure, the pulse is reflected at the periphery of the accreted ice and the reflection is detected. The time delay is calibrated and related to ice thickness and accretion rate.

Abstract: An automatic technique and an apparatus for digitizing of line graphics, letters, etc., which includes the following steps: The image information is obtained from scanning the master and is stored in digital form and thereafter converted into vector data. The vector image is subjected to a shape recognition program and image elements, such as straight lines, sharp and rounded corners, narrow, average and shallow curves, turning points and tangential points are identified. The image elements are subjected to a spline fit. From the spline curve, as many coordinate pairs are calculated as are needed for an adequate description for the contour line, and, following the rules for the IKARUS concept, a digitized version of the contour is generated.

Abstract: A method is disclosed for changing the horizontal and vertical resolution of an image while the image is in digitized and compressed form, where the image is first scanned and digitized to be represented as a number of discrete picture elements (pixels) and then the digitized image data is compressed. To change the resolution of an image and thereby be able to display it in smaller or larger form, the compressed image data is first analyzed and the data for certain scan lines is replicated or eliminated to respectively increase or decrease the vertical resolution of the image by a selected vertical resolution change factor. Then the compressed image data with scan lines replicated or eliminated is further processed using a selected horizontal resolution change factor to increase or decrease the horizontal resolution by respectively increasing or decreasing the number of pixels representing each scan line. The image data may also be processed so that windowing on the image may be performed.

Abstract: A pulsating sound wave beam is transmitted into an object using an array-type ultrasonic wave transducer which consists of a plurality of elements; the reflected sound waves are received using said transducer while electronically focusing the reflected sound waves depending upon an estimated speed of sound in the object, and the beam width of sound waves is measured repeatedly near a particular reflector while successively changing the estimated speed of sound. The estimated speed of sound of when the beam width is minimal is the mean speed of sound of the object in practice, and the beam width at that moment serves as an indication of acoustical homogeneity of the object.

Abstract: A driver bar assembly for coupling together a shaker head 12 and a slip plate 34 carrying a test piece 60 to be vibration tested, the assembly comprising a driver bar 14 having a laterally extended locus of intersection (L-L, P-P) with the slip plate in the slip plate plane of test movement, and fastener means comprising a rigid pin 50 extending laterally within the locus of intersection in slip plate and bar interconnecting relation for transmission of shaker head vibration to the slip plate through the pin.

Abstract: A gated peak detector capable of operating at frequencies of the order of 50 Mhz. and with pulse repetition rates of the order of 10,000 pulses per second includes high speed positive and negative peak detectors driving corresponding sample and hold circuits, the outputs of which are combined in a differential amplifier, the output of which is digitized to provide an output digital signal corresponding to the peak-to-peak value of the input waveform. An automatic polarity selector circuit sums the outputs from the sample and hold circuits, compares the sum to a reference voltage, and controls switches connected to the outputs of the sample and hold circuits and to the input of an analog sample and hold circuit which provides an analog output signal corresponding to the larger of the detected peak values.

Abstract: In a matcher mechanism for verifying a match of a set of subject points having positional parameters against a set of reference points having positional parameters, the improvement of employing a set of Group tables derived from the difference table. Each line entry on the difference table constitutes a lead entry of a separate Group table. The Group table are overlapping subsets of the entries on the difference table. The members of the Group table are limited to only one line entry representing each reference point. That line entry is the one which is closest to the lead entry on the difference plane. In addition, all line entries within a Group are limited to those that are within a predetermined window on the difference plane around the lead line entry for the group. A quality score is determined for each of the Group tables based on a weighted proximity value between each pair of line entries in the Group involved.

Abstract: A method of anticipating defects in the operation of a machine, especially a rotary machine in which high-frequency and low-frequency ranges of a body-wave spectrum in a solid part of the machine are detected and respective auto-spectral density functions G.sub.11 and G.sub.22 are formed, the cross spectral density function G.sub.12 being formed from the measurements as well. The magnitude .gamma..sup.2 =G.sub.12.sup.2 /G.sub.11 .multidot.G.sub.22 is formed and the defect is anticipated by an increase in the value of .gamma..sup.2.

Abstract: An ultrasonic wheel probe of the type having a wheel-shaped container with an annular outer surface for rotating about an axis of rotation and rolling upon a specimen to be tested is provided with a plurality of transducers for transmitting and receiving ultrasonic acoustic energy, respectively. In accordance with the invention, an acoustic barrier is interposed between the transmitting and receiving transducers, and immersed in the coupling fluid, so as to isolate the transmitting and receiving transducers from one another. With this arrangement, echoes emanating from the interface, or surface, of the specimen being tested are prevented from reaching the receiving transducer. By eliminating the interface echo the only echoes received are from the back wall of the specimen under test or from anomalies within the specimen, thereby permitting testing from the front surface to the back wall of the specimen.

Abstract: The invention relates to an apparatus for dynamically determining the local weight per unit area of sheet-like material, for example, paper, in which the sheet-like material is exposed to sound waves from a sound transmitter. The portion of sound transmitted and/or reflected by the sheet-like material is measured by aid of a receiver and the weight per unit area determined from the measuring signal. In order to avoid disturbances of the measuring signal due to superimposed sound waves and in order to obtain high local resolution even in the case of quickly moving material to be measured, the transmitter, material to be measured and possibly the receiver as well are arranged on a slant relative to each other in such a way that the portions of sound reflected on these elements are faded out of the path of rays between the transmitter and the receiver. Means are additionally provided to prevent the faded out portions of sound from returning to the path of rays between the transmitter and the receiver.

Abstract: An ultrasonic probe for inspecting a weld between a cylinder (C) and a pipe (P) is caused to move in a holder at the end of an arm (11) pivoted at a point on the axis (Z) of the pipe so that the line (12) of transmission from probe penetrates the weld and, when projected beyond the weld, intersects the axis (Z) of the pipe (P) for all positions of the arm.

Abstract: A simple and shock-resistant device to measure angular acceleration about a predefined axis without using any spinning or vibrating mass. The device comprises a weight having a shape symmetrical with respect to an axis which becomes the aforementioned predefined axis, a stress transducer such as a piezoelectric element which is attached to the weight so as to have sensitivity to shear stress in a circumferential direction about the aforementioned axis, and a base member to which the assembly of the weight and the transducer is fixed such that at least a major portion of the weight is spaced from the base member. For example, the weight is a generally circular metal plate and the transducer is a ring-shaped element of a piezoelectric ceramic material having electrode films on the annular surfaces.

Abstract: A pattern recognition apparatus makes use of both optical templation and nal correlation techniques by using liquid crystal panels, CCD type cameras, video storage techniques, inter alia, to detect and identify electronic signal patterns transmitted thereto. The apparatus is also configured to detect pattern changes and image object movement.

Abstract: For carrying out several mutually complementary microscopic examinations, beams of different types or frequencies, for example light beams or acoustic beams, are focused simultaneously or successively on an object and recorded or visibly displayed in a known manner. The object is maintained stationary and is scanned in a grid pattern in two mutually perpendicular directions by at least one of the beams. A pillar arrangement is provided to receive different microscopic instruments which may be selectively pivoted by means of a rotary mounting plate into and out of a locked, exactly reproducible observation position. The instruments may be released for rotation out of the observation position independently of any vertical coarse-fine focusing displacement. Underneath a stationary object holder further microscopic instruments, such as an inverted optical microscope, may be mounted in such a manner that their height may be adjusted.

Abstract: An ice detector of the vibrating element type comprises a tube that vibrates along its longitudinal axis, and is driven by an excitation coil at the natural frequency of the tube is sealed by a diaphragm which has a surface exposed to an air stream in which icing is to be sensed. The exposed diaphragm surface is deflectable during vibration of the tube at a flexible support portion of the diaphragm. As ice accumulates on the exposed surface of the flexible support the spring rate or flexibility of the flexible support changes, thereby changing the natural frequency of the vibration of the tube section. The changes in the natural frequency are sensed to determine that ice is accumulating. The diaphragm is of low mass, and small so that stiffness of small amounts of ice significantly changes the spring constant of the flexible support and the diaphragm is shaped to conform to adjacent aerodynamic surfaces.

Abstract: An accelerometer system (FIG. 2) suitable for measuring low-frequency accelerations in inertial systems is also able to measure high-frequency vibrational accelerations which give rise to e.g. sculling effects in inertial platform arrangements employing three such accelerometer systems. The system comprises a low-frequency inertial quality force feedback accelerometer 10' and a high-frequency, e.g. piezo-electric, accelerometer 46. The output of h.f. accelerometer 46 is summed at 48 with the feedback signal from transducer 32' in the l.f. accelerometer feedback loop, the faster response of the h.f. accelerometer providing most of the feedback to balance the l.f. loop without significant displacement of mass 11'. Up to several hundred Hz the displacement of mass 11' and the feedback component from transducer 32' is only to overcome the error in the h.f. accelerometer signals and at higher frequencies the response of the h.f.

Abstract: In the ultrasonic testing of a casting for defects an ultrasonic probe is mounted in a tank of water and scans across a surface of the casting which faces downwards just below the surface of the water. A pantograph linkage interconnects the probe with a pointer that is movable by an operator over a facsimile of the surface scanned by the probe. The interconnection is such that each position of the probe is represented by a corresponding position of the pointer and as the pointer is moved over the facsimile of the surface the probe scans the surface of the casting. The water ensures that there is good acoustic coupling between the probe and casting and the pantograph linkage reduces the skill and concentration required by the operator. Conveniently, only anomalous signals arising from defects are passed on from the probe to the operator.

Abstract: Welds in plastic pipe are tested by compressing the welded portion in a generally radial direction.

Abstract: A system for recognizing the content of a communication in symbolic language and composed of plural glyphs arranged in a predetermined order, each glyph being the smallest (lowest) informational unit of the language. The system includes a device for inputting a stream of data indicative of the plural glyphs, such as formed in a page of text. That stream is input into a storage means. The stored data is horizontally segmented into discrete lines of text and is then vertically segmented into individual glyphs. Each individual glyph is assigned a unique identifier, whereby all substantially identical glyphs are represented by the same identifier. The identifiers are arranged in a sequence corresponding to the sequence in which the glyphs appeared in the communication, thus representing glyph "words".

Abstract: There is described an apparatus for determining the behaviour of powder of granular material under stress, comprising, at least one flexible boundary arranged to abut one face of a sample of the powder or granular material, means to apply stress to the sample through the flexible boundary, a detector to detect the position of the flexible boundary as the sample is stressed, and a control to adjust the position of the flexible boundary. The detector may comprise an electrical circuit, advantageously a make and break circuit. There is also described an apparatus for determining the behavior of powder or granular material under stress, comprising at least one flexible boundary arranged to abut one face of a sample of the powder or granular material, means to apply stress to the sample through the flexible boundary, and adjusting members attached to the flexible boundary to cause it to strain as the sample strains under the applied stress.