Abstract: Ultrasonic imaging apparatus and method are shown which include electronic correction of focus defects produced by acoustic refractive index inhomogeneities within an object (14) being imaged. The region of interest (38) within which focus correction takes place is selected by the operator using control (42 or 84). The imaging system includes adjustable time delays (28-l through 28-c) through which return signals from transducers (10-l through 10-n) pass. Outputs from the delays are summed (30) and the resultant signal is envelope detected (32). The envelope detector output is prepared for display at display (36) by scan converter (34). The output from a focus correction delay control circuit (64) is used to control delay times of individual delays (28-l through 28-c) to provide for a delay profile across operative elements of transducer array (10), which delay profile includes delay profile components that correspond to low order terms of a series expansion, such as a Fourier series (FIG. 4).

Abstract: An ultrasonic inspection system and method having an audible signal output is shown which includes an ultrasonic transducer (10) for pulse insonification of an object (12) under control of pulser (14). Echo signals are converted to electrical signals at transducer (10) and the electrical signals are supplied to an A/D converter 30 through amplifiers (18) and (20). Signals from converter (30) are processed to provide for an A-scan of B-scan display at CRT (38). Digital ultrasonic return signals from A/D converter (30) are converted to an audio frequency signal at ultrasound-to-audio converter (50). The audio frequency signal from converter (50) is converted to analog signal form at D/A converter (54) and the analog audio signal is supplied to first and second variable gain amplifiers (58) and (60) the gain of one of which is ramped up while that of the other is simultaneously ramped down.

Abstract: An ultrasonic imaging system and method are shown which includes a transducer (10) for pulse insonification of an object (12) and for receiving echo signals from within the object. Echo signals are converted to electrical signals at the transducer (10) and the electrical signals are supplied to a signal processor (28). Processor (28) includes an envelope detector (38) and integrator (40) for integrating the detected output. Echo signals obtained from a first range zone (Z1) at the focal point (F) are processed by processor (28) and supplied to a hold circuit (50) to provide a reflection pixel signal value which is dependent upon reflectivity at the focal point. Echo signals obtained from a second range zone (Z2) opposite the focal point (F) also are processed by processor (28) and supplied to a hold circuit (52) to provide a transmission pixel signal value which is dependent upon attenuation of ultrasonic waves at the focal point (F).

Abstract: A reflex transmission ultrasonic imaging system and method are shown which include a transducer (10) for pulse insonification (14) of an object (12) and for receiving echo signals from within the object. Echo signals are converted to electrical signals at the transducer (10) and the electrical signals are supplied to a signal processor (38) through a switching matrix (20), delays (22), and transmit-receive switches (18). The signal processor includes a detector (46) and integrator (48) for integrating the detector output. Echo signals obtained from a range zone (BZ) opposite a focal point (F) are processed by processor (38) and supplied to hold circuit (60) to provide an image pixel signal value. A compensation pixel signal value for hold circuit (64) is obtained by repeating the transmitting-receiving operation using a beam which is unfocused at any point along the beam axis between the transducer (10) and backscatter zone (BZ).

Abstract: A reflex transmission ultrasonic imaging system and method are shown comprising an ultrasonic transducer array of either a two dimensional or linear type acoustically coupled to a subject. An ultrasonic energy beam is transmitted by the array into the subject to insonify an image plane, in the case of the two dimensional array, or a line in the image plane in the case of the linear transducer array. Electronic focusing is employed during the reception of echo signals for simultaneously focusing the transducer array at a plurality of focal points while echo signals are received from a range zone opposite the focal points. For the two dimensional array case, an array of focal points is provided in the focal plane, and in the linear array case a line of focal points in the focal plane is provided during reception.

Abstract: An ultrasonic imaging system and method are disclosed which include a transducer (10) for pulse insonification (16) of an object (14). Reflecting means (29) containing scatterers is acoustically coupled to object (14) opposite transducer (10). Echo signals received from within reflecting means (29) are converted to electrical signals at the transducer (10), which electrical signals are supplied to a signal processor (30) for processing the same. Echo signals obtained from a range zone (Z) within reflecting means (29) are integrated by integrator (42). The amplitude of echo signals from the range zone (Z) is strongly dependent upon attenuation at the focal point (F) whereby the integrator (42) output (60) also is strongly dependent upon attenuation at the focal point (F). The integrator (42) output (60) is supplied to a display (48) for use in establishing one pixel thereof. A C-scan display is provided by scanning the focal point (F) in a focal plane (22) substantially normal to the beam axis (20).

Abstract: An ultrasonic imaging system and method are disclosed which include a transducer (10) for pulse insonification (16) of an object (14) and for receiving echo signals from within the object. Echo signals are converted to electrical signals at the transducer (10) and the electrical signals are supplied to a signal processor (30) for processing the same. The signal processor (30) includes a detector (40) and integrator (42) for integrating the detector output.Echo signals obtained from a range zone (Z) which is opposite the focal point (F) from the transducer (10) are integrated by integrator (42).The amplitude of echo signals from range zone (Z) is strongly dependent upon attenuation at the focal point (F) whereby the integrator (42) output (60) also is dependent upon attenuation at the focal point (F). The integrator (42) output (60) is supplied to a display (48) for use in establishing one pixel thereof.

Abstract: Method and apparatus for obtaining quantitative velocity profile measurements and for displaying the same are disclosed. From such velocity measurements, instantaneous volume flow within a vessel across which the measurements are obtained is calculated. In one operating mode, a real-time display of quantitative velocity profiles is provided together with a scrolling display of a plurality of total instantaneous volume flow measurements. In another operating mode, velocity profiles obtained at corresponding points in successive cardiac cycles are averaged to obtain a plurality of average velocity profiles which are selectively displayed under operator control. In this mode of operation, a fixed display of total instantaneous volume flow measurements obtained over a period of time which includes at least one cardiac cycle is provided.

Abstract: An ultrasonic imaging system (50) has an array (52) of transducer elements (54-1 through 54-21) for receiving ultrasonic signals reflected from within an inhomogeneous object (16) being examined. The system (50) has a means (80, 84, 88, 94) connected to generate an image in response to the ultrasonic signals. A cross-correlator (70) is connected to compare the signals received by the transducer elements (54-1 through 54-21). An output addressing circuit (130) is connected to inhibit or otherwise modify gain of selected ones of the signals based on the comparison to reduce multipath ultrasonic wave interference, refraction or obstruction image distortion or degradation. A preferred ultrasonic imaging array (52) for this purpose and for time delay image distortion correction has a plurality of segmented, annular transducer elements (54-2 through 54-21). The elements (54-2 through 54-21) are formed as sectors of circles with substantially equal arc lengths.

Abstract: This ultrasonic imaging apparatus has an array (44, 52 or 100) of transducer elements (44, 50 or 104) for transmitting ultrasonic signals having a first predetermined center frequency (fc1) into an object (12) to be analyzed through use of the transmitted signals reflected from within the object. A means (150, 116-1 through 116-X and 120-1 through 120-X) is connected to transmit the ultrasonic signals from the array (44, 52 or 104) in a stepped array mode. A means (150, 116-1 through 116-X and 120-1 through 120-X) is connected to transmit the ultrasonic signals from the array (44, 52 or 104) in an angle scanning mode. There is a means (150, 128-1 through 128-X) for focusing the transmitted signals at a desired depth within the object (12). The reflected signals sensed by the apparatus have a second center frequency (fc2) less than the first center frequency (fc1) as a result of signal attenuation by the object (12).

Abstract: The ultrasound apparatus contains a focusing device such as a lens or lens system for focusing ultrasound waves. It also contains an ultrasound detector for receiving the focused ultrasound waves. The detector includes a number of elongated piezoelectric detector elements. The longitudinal axis of these elongated elements are curved. The focusing device is an astigmatic focusing device and has a first and a second focal plane. The ultrasound detector is positioned in one of these planes.

Abstract: The apparatus incorporates an ultrasonic wave-generating transducer for providing ultrasonic waves, a first and a second ultrasound window, a first guiding device for guiding the ultrasonic waves to the first window, an ultrasonic receiving transducer for transforming an acoustic image field received from the second window into electrical signals, and a second guiding device for guiding ultrasound transmitted through the second window to the receiving transducer. The ultrasound windows define an examination gap for insonifying a patient's organ positioned therein. The apparatus further incorporates a lens for focusing the acoustic image field received from the gap onto the receiving transducer. A mirror device, preferably a plane mirror, is associated with the second guiding device. This mirror deflects ultrasound energy that passes through the gap in a direction which is different from the main insonification direction in the gap.

Abstract: An ultrasonic transducer system for use with tissue is shown, which system includes a container of liquid acoustic coupling medium within which focused transducer means are located. Focusing of the transducer means may be effected acoustically, as by use of an acoustic lens, and/or electronically, as by use of a transducer array. The liquid medium container is closed at one end by a rigid acoustically transparent window, or diaphragm, for acoustically coupling to the skin and underlying tissue of the subject under investigation. The material of the liquid acoustic coupling medium is selected so that the velocity of propagation of acoustic waves therein is substantially less than the velocity of the acoustic waves within the tissue under investigation. By using a low speed-of-sound coupling medium a shorter propagation path may be employed than is required by prior art transducer arrangements in which the speed-of-sound in the tissue and coupling fluid is substantially the same.

Abstract: Endoscopic method and apparatus are provided for the simultaneous visual and ultrasonic imaging of internal body parts through use of a probe insertable into a body cavity. The probe includes a rectilinear transducer array acoustically coupled to the body through a cylindrical focusing lens having an outer face which conforms to the probe contour. The transducer array is included in a pulsed ultrasonic imaging system of the B-scan type. A tube, which includes a flexible portion adjacent the probe, connects the probe to a control housing containing manually operated control mechanism for bending the flexible tube portion. A control handle extends from the side of the housing for control of bending by the operator. The pulsed ultrasonic imaging system includes pulse generator and pulse receiver means connected to individual elements of the transducer array by coaxial cables extending through the tube.

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: Pulsed real-time B-scan ultrasonic method and apparatus are disclosed together with pulsed Doppler Ulrasonic method and apparatus. The B-scan apparatus includes a pulse operated transmitter and receiver operating at a first frequency, and the Doppler apparatus includes a pulse operated transmitter and receiver operating at a second frequency sufficiently far removed from the B-scan frequency to avoid interference therebetween. A synchronous pulse operation of the B-scan and Doppler systems is provided. The sysem includes a visual display means to which the receiver outputs are connected through a multiplexer operated to pass the B-scan receiver output to the visual display means whenever such B-scan output is present. The Doppler apparatus includes means for temporarily storing the Doppler receiver output, which stored Doppler signals subsequently are read out through the multiplexer to the visual display means between select lines of B-scan display.

Abstract: Focused ultrasonic transducer means of the zone plate type are shown for producing a focused ultrasonic wave field without the need for lenses, reflectors, a curved transducer or the like, which transducer means are adapted for ultrasonic nondestructive testing and inspection, ultrasonic examination in diagnostic medicine, sonic heat generation, aerosol formation, and the like. Such transducer means, of course, may be used as a focused ultrasonic transducer receiver as well as a transmitting transducer. The transducer includes a uniformly poled cylindrical shaped body of electromechanically responsive material, such as a piezoelectric crystal, with electrodes formed at opposite parallel faces thereof. A pair of central axially aligned circular electrodes of different size are located on the opposite body faces, together with concentric different size annular electrodes which surround the central electrodes.

Abstract: Combination Doppler and B-scan ultrasonic imaging apparatus is disclosed which includes visual display means for the simultaneous visual display of received ultrasonic Doppler and B-scan information. The apparatus includes first and second focused transducers associated with the Doppler and B-scan systems, which transducers are individually mounted for movement along parallel linear paths. The transducers each comprise a generally semi-cylindrical shaped body of piezoelectric material having opposite end faces upon which electrodes are disposed for connection to Doppler and B-scan transmitter and/or receiver units. The flat side walls of the piezoelectric bodies are positioned closely adjacent a mid-plane extending between the transducers, and means are provided for focusing the transducers at substantially the same depth for operation along a common focal region at, or adjacent, the mid-plane. One such focusing means includes acoustic lenses carried by the piezoelectric bodies.

Abstract: The ultrasonic imaging method and apparatus comprises an ultrasonic wave transducer supplied with recurrent multifrequency energy pulses for pulse insonification of an object under investigation with ultrasonic waves. Resultant echo waves from the object are directed onto the transducer for converting the same to electrical signals which are supplied to a signal processor which includes a variable bandpass filter. One or more of the filter characteristics are varied as a function of depth from which the echo signals are returned for enhanced resolution and signal-to-noise ratio of the received signal. Preferably, the filter is matched to the noise and signal spectra of the system. For A scan and B scan operations wherein reverberated acoustic pulses are derived from a range of depths a time variable filter is employed for time varying operation thereof.

Abstract: Composite acoustic lens assemblies which are adapted for use in a fluid medium and utilized for forming acoustic images with incident acoustic waves or focusing incident acoustic waves are constructed utilizing two or more lens elements with a fluid filler medium contained therebetween. In order to reduce the radius of curvature of the lens elements to such an extent that mode conversion at liquid/solid interfaces is substantially eliminated while providing the required image or focusing, the materials of the lens medium and the liquid medium between the lens elements are selected so that the velocity of propagation of acoustic waves in the medium, at least on one side of the composite acoustic lens is intermediate the velocity of propagation of acoustic waves in the media of the lens elements and the fluid filler.