Abstract: An ultrasonic diagnosing apparatus comprising a probe for radiating ultrasonic wave beams toward a target and converting ultrasonic echo data reflected from the target into electrical signals indicative of a tomogram of the target, an ultrasonic wave transmission and reception circuit for controlling the probe to radiate the ultrasonic wave beams in predetermined ultrasonic field patterns, a processor for processing the electrical signals in accordance with correlations among the ultrasonic echo data, which depend upon the ultrasonic field patterns to eliminate artifact components of the tomogram from the electrical signals, a display device for displaying the tomogram of the target in response to the output signal of the processor, and a system pulse generator for generating a system synchronizing pulse supplied to the transmission and reception circuit and processor.

Abstract: The apparatus comprises a cylindrical carrier (1) which is rotatable about a supporting shaft (5) and is provided with n transducers (3) regularly distributed around its periphery, a first display device (35) for the display of a circular sector scan ultrasonic image with m radial picture lines in the B-mode, and a second display device (37) for an M-mode display of an ultrasonic image which consists of images relating to a single selected picture line (k) of the former image relating to successive instants in time, the successive line images being arranged parallel to one another with the same interline spacing.

Abstract: An ultrasonic transducer arrangement having ultrasonic oscillators, with which electronic delay chains are associated, includes a matrix of column-like ultrasonic oscillators the end faces of which are each connected to control electrodes arranged in the planes of the flat sides of the matrix. On one flat side of the matrix, rows of the oscillators are each provided with a common control line and, on the opposite flat side of the matrix, the jointly controlled groups of ultrasonic oscillators each form a concentric arrangement. This test head can be used selectably as a focusing or as an angle test head and in addition, the focal point can also be displaced in depth.

Abstract: To detect motion of an object, a repetitive video signal representative of the object at successive points in time is generated. At least a portion of successive repetitions of the video signal is integrated. The successive integrations are compared with each other. The integrated portion is preferably selected to optimize motion detection for the size and extent of movement of the object.

Abstract: An electronically step scanned real time ultrasonic imaging system and method is disclosed. The system includes a transducer assembly having an array of elements, each with an axis of transmission along which it transmits its main ultrasonic energy when electrically stimulated. The elements are disposed in a curvilinear array, wherein their axes of transmission are approximately coplanar, but divergent in the common plane. This configuration provides a relatively large scanned area without need for either electronic or mechanical sector scanning techniques to steer the incident ultrasonic energy over a large angle.

Abstract: Ultrasonic equipment for examinations using section images comprises a scanning mechanism, which includes a wheel that can be driven to rotate and carries a plurality of focussing sound transducer heads having working ranges which cover only respective fractional parts of the depth of the section surface. Each sound transducer head is activated as the sound beam emitted by the sound transducer head moves in the section surface. The echoes received by the sound transducer heads are used to generate a section image. In order to improve the image quality, sound transducer heads having working ranges in different depths of the section surface are activated in succession. Pre-entry paths are associated with sound transducer heads for examining regions near the surface of the object to be examined. Selecting means are provided which ensure that only echo signals derived from echoes which have originated in the working range of an activated sound transducer head are used to generate the image.

Abstract: An ultrasound multi-electrode transducer together with electrical control means in which a central circular section and at least one annular peripheral section are successively electrically connected during transmit and receive functions so as to provide an increased focal zone.

Abstract: In an exemplary embodiment, an ultrasonic applicator for line-by-line ultrasonic scanning supplies echo signals to a device for displaying a layer image. The aim of the disclosure is to produce an imaging system which does not cause any coupling problems in any position of the application location; in addition, application should also be possible, in particular, in the chest area for obtaining subcostal sectional images. This aim is achieved by a line-by-line scanning applicator being also additionally pivotally or rotatably mounted, for the purpose of oscillation or rotation of the scanning surface, about such an oscillating-or rotating-axis, e.g. over a specifiable angular range and by a motor drive, with the applicator being firmly assigned to the selected application location during the angular movement.

Abstract: In an exemplary embodiment, an ultrasonic array has an installation for dynamic focusing at least in the transmitting mode. It is the object of the disclosure to avoid excessively great time loss, and yet to permit dynamic focusing also in the transmitting mode. This object is achieved in that, in the case of a specifiable number of depth regions (with a respective fixed focusing in each depth region) preferably associated with each scanning line of the ultrasonic scanning, the transmitting/receiving cycle for each fixed focusing is progressively introduced in such a manner that, for every depth region of each such scanning line, transmission is effected at such a time-point which immediately follows, for example, that time interval in which echo information was received from the chronologically prior-scanned depth region for such scanning line.

Abstract: In an ultrasonic diagnostic equipment which irradiates a subject with ultrasonic waves and receives reflected waves responsive thereto so as to provide a tomogram of the subject on the basis of the received signals, two tap-changing type phased arrays having different focal sections are alternately operated during a period of the reception of the reflected waves, and while one of the phased arrays is being operated, the tap changing of the other phased array for altering the focal section is made. In spite of reduced numbers of high-class switches and phased arrays used, spike noise due to the changes-over of switches during the dynamic focusing are prevented.

Abstract: A scanner includes a scan head having a linear array of transducers Xn, and a transmitter 106 which excites the transducers in response to transmit signals TRn from a reference generator 110 so that the transducers emit a plurality of successive bursts of ultrasonic energy, each burst producing a transmitted beam which is steered and focused along a radially-extending scan line. To effect received beam steering and focusing, received signals Sn from the transducers are supplied to a processor 112 along with associated in-phase binary reference signals bn(R) and quadrature binary reference signals bn(I). The received signal is multiplied by a reference signal and the product is integrated for a specific time duration whose time occurrence is used to steer and focus the beam.

Abstract: Focussing sound transducer head comprise at least one focussing sound transducer head for transmitting ultrasonic pulses to form a focussed sound beam having a relatively constricted depth zone, in which the sound beam is narrower than a sound beam that would be transmitted by a nonfocussing sound transducer head that is otherwise comparable to the sound transducer head which transmits said focussed sound beam, and for deriving echo signals from echoes generated in response to the pulses. A scanning mechanism moves the sound beam across a section surface in an object to be examined. Display controls are adapted to receive said echo signals and cause the echo signals to be displayed on a fluorescent screen at locations which are geometrically coordinated with the locations at which the corresponding echoes have originated in the section surface.

Abstract: An ultrasonic imaging system includes a linear array of transducers of which a group of successively arranged transducers is selected and successively shifted to the next by at least one transducer. The transducers of the selected group are successively activated at respective delay times to transmit a radial scan beam which appears to emanate from a hypothetical point source located behind the transducer array. A scan converter is provided for conversion of analog echo signals in sector scan format to digital echo data in raster format for visual display.

Abstract: In an exemplary embodiment, the transducer elements are arranged in rows and columns, the transducer elements bein contacted at both sides by oppositely disposed contact surfaces, and switches being associated with the contacts of the one contact surface as well as with the contacts of the other contact surface for the purpose of adjustment of preselectable transmitting and/or receiving surface of transducer elements during a transmitting/receiving cycle, in particular, for the purpose of dynamic focusing. It is an object of the disclosure to construct an ultrasonic array which can function with an optimally low outlay of switches and which if desired also permits a transition to continuously varied apertures.

Abstract: An ultrasonic imaging device comprises transducers distributed along a line and operable at a frequency f. A generator delivers electrical pulses to time delay means which provide, in response to each electrical pulse, a plurality of low level pulses delayed by increased time delays in a number lower than the number of transducers. The distribution of the time delays between the transducers is stored in memory means and corresponds to focusing at a point located at a predetermined distance from the line. A plurality of amplifiers are each associated with an individual one of the transducers and deliver an energizing pulse to the associated transducer in response to a particular one of the low level pulses appearing on an associated channel of a bus line which is selected by the memory.

Abstract: A sector scan ultrasonic imaging system comprises a source of a plurality of square wave pulse trains each being delayed by a unit quantization time with respect to adjacent trains, and a plurality of transmitter circuits corresponding to the elements of a transducer array. The duration of each square wave pulse is an integral multiple of the unit quantization time interval. Each transmitter circuit includes a read only memory in which a set of different digital delay time data is stored for the corresponding transducer element and is arranged to be retrieved in response to each angle increment of the ultrasonic beam transmitted from the array. Further included are a data selector for selecting a pulse train in response to a pulse train selection data retrieved from the memory and a programmable counter for counting the pulses of the selected train to generate an output in accordance with a pulse selection data retrieved from the memory.

Abstract: An electronic scanning ultrasonic diagnostic system comprising a probe having ultrasonic beam emitting surface, in which plural ultrasonic wave transducers are convexly arranged at equal distances, emitting desired sector scanning ultrasonic beams, a transmitting and receiving wave control circuit dividing transducers into optional and plural groups and repeatedly performing of transmitting and receiving action with ultrasonic directivities respectively different to each group, and supplying ultrasonic beam scanning signals to an image display section with an assumption that the respective extension lines of each sector scanning ultrasonic beams coincide with the center of the arc shape of the probe.

Abstract: An ultrasonic diagnosis apparatus is provided with a plurality of phased array transducer elements arranged in a row. The number of simultaneously driven transducer elements is changed in response to a rate pulse to increase the ultrasonic scanning line density without increasing the number of the transducer elements, while the position of the focal point is adjusted to maintain the minimum width position of the ultrasonic beam provided by the group of the simultaneously driven transducer elements substantially constant irrespective of the change of the number of the simultaneously driven transducer elements by controlling the phase of transmitted and received ultrasonic waves by means of delay elements.

Abstract: A focusing circuit for focusing an array of transducers of an ultrasound imaging system includes a variable delay line comprising a plurality of summing amplifiers and a plurality of variable delay elements provided between successive summing amplifiers. A plurality of switches is provided for respectively connecting the transducers to selected summing amplifiers. The amount of delay of each variable delay element is individually controlled so that the corresponding electrical signals derived from the transducers arrive in phase at the output end of the variable delay line.

Abstract: Reconstruction of two-dimensional distribution of attenuation coefficients or sound velocities in a cross-sectional plane of an object is achieved by carrying out a plurality of measurements of absorption or of flight time with ultrasound bursts directed by elementary transmitting probes along several different incidences in the sectional plane. Switching between successive measurements is carried out by electronic scanning, without movement of the individual probes. Focusing of the burst energy transmitted by a group of probes is achieved by applying a same electrical signal to the probes with appropriate delays. The secured signals are stored and, after completion of the scanning, they are combined for computation of the distribution.

Abstract: The invention involves a digital synthetic-focus, acoustic imaging system which is operative in real time and includes one or more electro-acoustic transducers arranged to receive broadband pulses from a pulse generator for excitation of acoustic pulses which are directed into the region under observation. Signals reflected from an object or discontinuity in the region are received by the same transducers, and after inverse filtering and nonlinear amplification are converted to digital signals. These digital signals are stored in separate high speed random access memory units for storage, but are subsequently time-equalized through use of a programmed focus memory unit prior to delivery to a digital adder and thence through a digital-to-analog converter for ultimate intensity modulation on a raster scanned display unit which provides the real time image.

Abstract: A method and apparatus are described for electronically scanning a spherily focused beam in a c-scan mode using a spiral path rather than a traditional raster scan pattern. Essential to the technique is an electronically simulated rotating ultrasonic prism operating according to the general electrical input equation V.sub.IN =V.sub.o exp (i.omega..sub.o t+iA cos .OMEGA.t). The technique allows use of a single delay line with simple connections and no requirements of multiple mixing.

Abstract: A processing circuit is connected to the output of a mosaic which consists of n first electrodes on a first principal surface of a TGS plate and 2p second electrodes on the second principal surface thereof. The circuit is constructed so that the output connections of the second electrodes are grouped in p resultant groups which are connected, via p paths which each comprise an amplifier and a variable delay line, to the inputs of a first adder. The output of the first adder is connected, via a network of (q-1) delay lines having a fixed delay time, to the inputs of q parallel variable delay lines which are connected in parallel and which are connected to the inputs of a second adder. The delay times thus realized are controlled so that a first ultrasonic lens and a second ultrasonic lens are successively formed.

Abstract: An imaging system, particularly useful for acoustic medical diagonsis of a human subject, utilizes an array of radiating elements or sonic transducers located side-by-side and positioned along the subject. Signals received by the transducer are applied to a pair of pattern generation circuits which weight the individual signals by factors of +1, -1 or 0. Graphs of the weighting factors as a function of transducer location have the likeness of cosinusoidal and sinusoidal Fresnel patterns, these patterns being produced by the two circuits. Upon reception of signals, the weighted signals of each pattern are summed together, multiplied by cosinusoidal and sinusoidal reference signals and then summed together to provide a radiation pattern which converges from the array to a focal point in front of the array while eliminating a diverging pattern from a virtual focus behind the array.

Abstract: An ultrasonic diagnostic method and apparatus are provided for probing the condition in a tissue of a living body by projecting an ultrasonic beam onto the living body from a vibrator array transducer probe consisting of a plurality of tiny ultrasonic vibrators. The apparatus executes two scanning actions, of which one is a normal linear scanning that drives the ultrasonic vibrators sequentially in the manner to cause a sequential parallel shift of the ultrasonic beam substantially perpendicular to the vibrator array, and the other of which is an inclined linear scanning that drives the ultrasonic vibrators at individually different timings while sequentially shifting the driven vibrators in the manner to cause sequential parallel shift of the ultrasonic beam having an angle of inclination against the vibrator array. The images obtained through the normal linear scanning and the inclined linear scanning are combined to form a composite high-resolution image.

Abstract: A scan converter is disclosed for use in a sector scan type ultrasound imaging system in which ultrasound echo signals return from targets along a plurality of radial scan lines distributed in a sector field with a substantially equal tangential angular increment with respect to a reference line. The scan converter comprises a sampling circuit which samples the echo signals at a speed inversely proportional to the cosine of the angle of deflection of the radial scan lines with respect to the reference line so that the sampled points align themselves in lateral lines perpendicular to the reference line. The sampled echo signals are converted into digital echo data and stored in a random access memory in the direction of its columns. The stored data are retrieved serially in the direction of the rows and fed into an interpolator for making interpolations between the successively retrieved echo data.

Abstract: An array of transducer segments is arranged in columns, each of which has a multiplicity of segments. The segments are wired to permit excitation by one or the other of two opposite phases of high-frequency signal, and groups of segments can be excited with the same phase to approximate the shape of an annular-ring phase-reversal zone plate. By changing the groupings of the elements that are similarly excited, the position of the focal region produced by the zone plate is translated in lateral position. A ferrite-core transformer is conveniently employed for both phase splitting and addition of the echo signals received by the device.

Abstract: Method and apparatus for pulsed ultrasonic imaging of a section of the interior of an object from reflections by internal discontinuities of recurrent transmitted pulses of ultrasonic energy, are provided. There is included a transducer array comprising a plurality of adjacent transducer elements for converting echo signals received from discontinuities within the object to equivalent electrical signals. Range gated signal processing means are provided for processing electrical signals from the transducer array reflected from discontinuities within any one of a plurality of range zones within the section to be imaged to provided range gated signals representative of segments of lines within the section to be imaged. The signal processing means includes electronic receiver beam focusing and scanning means for focusing the transducer array at the range zone at which the signals are range gated and for scanning the same.

Abstract: A real-time ultrasonic imaging system is disclosed which includes an array of transducers adapted for propagating ultrasonic energy into a body to be ultrasonically examined and for receiving reradiated energy from points within the body. A plurality of signal channels each includes a transmitter branch and a receiver branch associated with respective transmit and receive transducers, or both branches may share a single transducer. A transmitter branch activates a transducer to propagate the sonic energy and a receiver branch receives from the transducer electrical signals corresponding to the reradiated energy. Memory means in each receiver branch receive and store data indicative of the signal level passed to the channel by its associated transducer. Display means are provided for receiving the data from the memory means in each of the channels and for combining and processing such data to effect a real-time display of the bodily portion being examined.

Abstract: Beam deflection delay time data of (L.times.M) data bits are stored in a read-only memory from which each datum is retrieved successively when the ultrasound beam is deflected to a given angle and repeatedly accumulated in a digital adder through a latching circuit connected between the output and input of the adder, where L is the number of discrete steps of deflection angle and M is a binary number representing the total delay time of piezoelectric transducers. The successively latched data is distributed to respective programmable counters for presetting the count values thereof to store therein respective delay time data. High frequency count pulses are supplied to the counters after the latter has been preset for delivery of carry outputs to the associated piezoelectric transducers.

Abstract: Delay controllers are provided to delay pulses supplied to a plurality of electro-acoustic transducers.Each controller comprises a delay line provided with a plurality of taps and a switch for selectively changing the taps. There are further provided a measuring circuit for measuring amounts of delay time defined by the respective taps of the delay controllers; a CPU for controlling the operation of the measuring circuit and delay controllers. The CPU causes the measuring circuit to measure the amounts of delay time defined by the respective taps. Where the electro-acoustic transducers are electrically operated in accordance with the result of measurement, data for selecting any of the taps is stored in the RAM after proper compensation.

Abstract: In order to obviate the necessity for providing a complete channel of electronics for each transducer of an array incorporated into a real-time ultrasonic imaging system, all system transducers are disposed in apparent series with a single inductor as to direct current. Charging resistors permit each transducer to slowly capacitively charge to a predetermined voltage under static conditions. When a switching transistor disposed in series with a given transducer is placed in the conducting state, the transducer rapidly discharges and mechanically deflects to introduce an ultrasonic pulse into an object. While the switching transistor remains conductive, the inductor and transducer are in parallel circuit as to echo signals returning to the transducer. When the switching transistor is rendered non-conductive, the transducer again charges capacitively in anticipation of a succeeding cycle.

Abstract: An array of ultrasound transducers for pulsed sector-scan operation includes a plurality of transducer elements disposed on an arc of a circle and oriented to emit and receive ultrasound radiation in the direction of the center of the arc. A group of adjacent transducers within the array is active for each ultrasound pulse. The position of the group in the array is incrementally shifted along the arc, one transducer at a time, to effect scanning. The inherent focussing effect of a curved group of transducers is compensated with time delays or a negative lens to provide a parallel, sector-scanned radiation beam.

Abstract: Equipment is disclosed which serves to trace B-scan section displays of specimens and comprises a sound transducer head, which is oscillated by a scanning mechanism and projects sound beams, which scan the section to be displayed. The echoes which originate in response to these sound beams are displayed on a fluorescent screen at locations which are associated with the locations at which said echoes have originated. The sound transducer head comprises two sound transducers, the axes of which in the plane in which they are oscillated include an angle which is not in excess of the angular range of oscillation. As a result, the pitch with which the section to be displayed is scanned by ultrasonic beams is decreased and/or the angular velocity of the sound transducer head may be decreased.

Abstract: A method and device for determining the internal structure of a body by means of acoustic beams. Transit times and intensities of acoustic beams passing through the body in different spatial directions are measured to establish the refractive index distribution and the acoustic absorption coefficient distribution, respectively at the points of a point matrix associated with the body. The non-rectilinear course of the acoustic beams is taken into account in this respect. This results in reconstructed images of higher quality.

Abstract: An array of sonic transducers, useful for medical ultrasonic imaging, has individual sections thereof separately coupled for forming separate beams of sonic energy which converge, respectively, to separate foci along a common axis of the beams. The ratio of the diameter of the radiating aperture of the array relative to a wavelength of the sonic energy is chosen to provide a moderate degree of focusing so that the depth of field at one focus blends with the depth of field of the next focus. Thereby, there is formed a continuous region of substantially uniform intensity of sonic radiation along the common beam axis. Circuitry is provided for selecting one or more specific foci dependent on the bounds of a selected region to be insonified.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed which controllably phases the signals associated with an array of electromechanical transducer elements and thereby enables selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory system are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses and the clock rate.

Abstract: An exemplary embodiment comprises an ultrasonic applicator for line-by-line ultrasonic scanning and a picture tube, for example, a television monitor for the visible echo image. The echo lines developing from the ultrasonic applicator are alternately stored in alternating memories and read out to the picture tube. The reading-out ensues singly or multiply in such reading-out times as correspond to the line sweep time of the picture tube. An imaging apparatus is desired which, in addition to direct reproduction, also renders possible the reproduction of stored ultrasonic images given the smallest technical outlay while doing without extravagant image memories.

Abstract: A selectable delay system for coupling between a plurality of elements and an input/output terminal, the relative delays between the input/output terminal and the individual elements being selectable under operator control. A single delay line is employed to obtain up to three different effective delay configurations that can be used, for example, to obtain three different focuses in an ultrasonic imaging system.

Abstract: An ultrasonic cross-sectional imaging apparatus comprising an ultrasonic probe, memory means and display means. The probe emits ultrasonic waves in non-interlaced fashion and receives echo data in non-interlaced fashion. The non-interlaced echo data are written into the memory means, read out therefrom in interlaced fashion and displayed by the display means as an image in interlaced fashion.

Abstract: In an ultrasonic imaging system including an array of ultrasonic oscillators, ultrasonic beams are electronically scanned by sequentially selecting a plurality of oscillator sets for beam transmission and reception. For one transmission of ultrasonic waves, at least two receiver oscillator sets having at least some oscillators in common are simultaneously selected, and the respective outputs from the oscillators in the at least two receiver oscillator sets are phase-adjusted so that echoes received by the at least two receiver oscillator sets effectively correspond to echoes substantially emanating from at least two respective different points on a depth level distanced from the plane of the oscillator array by a predetermined depth, whereby at least two signals and hence at least two successive scan lines relating to the echoes from those respective different points are produced. As a result, improved line resolution and rapid line acquisition can be obtained.

Abstract: An ultrasonic diagnostic equipment of linear electric scanning type includes a plurality of pulse generators for supplying electric pulses to a plurality of ultrasonic transducers disposed on a plane, gate circuits for driving the pulse generator, a plurality of analogue switching circuits for selecting the reflected ultrasonic pulse signals received by the ultrasonic transducers, and a control circuit for controlling these pulse generators and switching circuits. The control circuit synchronizingly controls the operations of the gate circuits and analogue switching circuits in order to operate a given number of ultrasonic transducers of the plural of the ultrasonic transducers. The pulse generator and switching circuit are provided corresponding to each transducer.

Abstract: An apparatus for pulse-echo ultrasonic examination, particularly in medical diagnostic examination comprised of one or more transducer elements for transmitting divergent pulses of ultrasonic energy into the object under examination and a greater number of transducer elements providing a plurality of received beams for each pulse transmitted.

Abstract: Echo ranging flaw detecting, characterizing and studying apparatus in which the work is scanned simultaneously by acoustic energy focused at a point from an acoustic-lens transducer and by acoustic energy focused along a line along which it is propagated from a focused-arc transducer. The acoustical echos from the lens transducer are combined with an electrical analog of an acoustical reference wave to produce an acoustical interference pattern which is reconstructed into a holographic display or hologram by a laser beam. The echos from the focused-arc transducer produce a cathode-ray tube display or are stored in a memory.

Abstract: Apparatus for the ultrasonic examination of an object comprises:means for transmitting pulses of ultrasonic energy along a plurality of beams into the object and receiving echoes of the pulses reflected along the beams by acoustic impedance discontinuities within the object, the means directing the beams from a plurality of spaced positions in a single plane relative to the object and along a plurality of beam directions in the single plane at each spaced position;means for forming a first display of information representative of the position of acoustic impedance discontinuities within the object from the echoes received along the plurality of beams;means for selecting a point or region within the object intersected by at least one beam direction from different ones of the spaced positions; andmeans for determining the shift of echoes from the selected point or region received along the beam in each beam direction caused by divergences of the velocity of propagation of ultrasonic energy through the object in

Abstract: An instrument for viscoelastic measurement, particularly for breast palpation, uses a plurality of spaced elongated electret strips which are pressed into the body being examined by a pressure member which applies a given periodic or steady stress to the tissue beneath the electret strips. Electronic measuring means then interrogates the output voltage of each of the strips in turn and the output of each strip is displayed to produce a display characteristic which will show the presence of an inclusion in the breast tissue being examined.

Abstract: A method for producing cross-sectional images using an ultrasonic imaging unit operating on the pulse-echo principle, which unit includes a transducer system having a stationary elongated array of adjacent transducer elements with transverse electrode segments adjacent one another on one side of the array. Successively and cyclically selected groups of adjacent elements are energized to produce an ultrasonic beam as a result of pulsed signals being applied to the corresponding electrode segments.

Abstract: The non-invasive testing of soft body tissue is accomplished with the use of a beam of ultrasonic energy which may be focused at varying depths in a patient. The energy content of the ultrasound beam is varied as a function of depth of focus to thereby employ the minimum energy required for proper resolution at the chosen examination depth. Signals commensurate with echoes received by a transducer having an array of coaxial annular electrodes thereon are combined in a manner which results in a good signal-to-noise ratio and minimum attenuation thereby improving the quality of the information derived from the examination procedure.

Abstract: A lens assembly exhibiting a certain fixed relative aperture is comprised of a physical acoustic lens having a given physical aperture and a fixed relatively short focal length serially spaced from an electronic acoustic lens having any selected one of a plurality of different relatively long focal lengths and simultaneously controlling the physical aperture of the electronic acoustic lens such that the relative aperture of the assembly as a whole remains fixed regardless of the selected one of the long focal lengths. Such a lens assembly is suitable for use in a pulse-echo ultrasonic-imaging system for imaging a deep structure.

Abstract: A phased array ultrasonic imaging system is disclosed which combines aspects of both dynamic and pseudo-dynamic focusing. The system includes a linearly arranged array of side-by-side transducers adapted for propagating ultrasonic energy into a body to be ultrasonically examined and for receiving reradiated sonic energy from points within the body. A signal channel is connected to each of the transducers for activating same to propagate the sonic energy and for receiving electrical signals from the transducers (which correspond to the reradiated energy). Controllable delay means are provided in each of the channels for introducing linear phase shifts in the electrical signals proceeding in the channels during both transmission and reception to thereby azimuthally steer the transducer array. Means are further provided for processing the received signals proceeding through the channels and for combining same to effect a visual display of the bodily portion being examined.