Method and apparatus for visual imaging of ultrasonic echo signals utilizing a single transmitter

Claim 2

Apparatus for providing a visual display of ultrasonic echo signals reflected from an object and its acoustic heterogeneities comprising a single acoustic transmitter for generating a periodic pulsed ultrasonic frequency pressure wave signal in a liquid medium, means for directing the periodic ultrasonic signal at an object being examined, a plurality of closely spaced acoustic detectors arranged in a single row along an axis perpendicular to the centerline axis of the apparatus for simultaneously detecting ultrasonic echo signals reflected from the object in response to the periodic ultrasonic signals incident thereon and for converting the detected ultrasonic signals to equivalent electrical signals, acoustic image focussing means for imaging the ultrasonic echo signals onto said acoustic detectors, the centerline axis of the apparatus being defined by the centerline axis of said focussing means and the center of the row of detectors, a like plurality of amplifying means connected to outputs of associated said acoustic detectors for amplifying the electrical signals developed by said detectors, means in communication with outputs of said signal amplifying means for providing a visual display of the detected echo signals wherein each line of the visual display is associated with a corresponding acoustic detector, means having an output connected to an input of said acoustic transmitter for generating a periodic short duration electrical pulse which triggers the generation of the periodic pulsed ultrasonic signal from said transmitter and also establishes a periodic zero reference time of operation of said apparatus, and means having an input connected to an output of said periodic short duration electrical pulse generating means and an output connected to inputs of said signal amplifying means for simultaneously gating all of the signal amplifying means periodically on and off at desired time intervals corresponding to the range of the object from the transmitter and detectors and to the depth of field in the object being examined, each line of the visual display depicting the echo signals reflected from the object and its internal heterogeneities and detected by the associated acoustic detector within the depth of field defined by said gating means whereby the display represents a visualization in depth of a planar slice of the object wherein the slice lies in a plane defined by the centerline axis of the apparatus and the axis of the single row of detectors.

Claim 3

The apparatus set forth in claim 1 wherein said ultrasonic signal directing means consists of said acoustic transmitter being oriented such that the output thereof is directed toward the object being examined and is aligned with the centerline axis of the apparatus whereby the generated pulsed ultrasonic signal propagates directly from said acoustic transmitter to the object being examined.

Claim 4

The apparatus set forth in claim 1 wherein said acoustic image focussing means is of the reflective concave type and is aligned with the center of said row of detectors and with the centerline axis of signal propagation from said transmitter to the object, said ultrasonic signal directing means consists of said acoustic image focussing means and the output of said acoustic transmitter being directed toward said acoustic image focussing means and being aligned with the centerline axis of the apparatus whereby the generated pulsed ultrasonic signal propagates from said acoustic transmItter to said acoustic image focussing means and is reflected therefrom toward the object being examined.

Claim 5

The apparatus set forth in claim 2 wherein said acoustic image focussing means is of the reflective concave type and is aligned with the center of said row of detectors and with the centerline axis of signal propagation from said transmitter whereby the ultrasonic echo signals are reflected from said acoustic image focussing means for imaging onto said acoustic detectors.

Claim 6

The apparatus set forth in claim 1 wherein said acoustic image focussing means consists of a converging type acoustic lens positioned between said acoustic detectors and the object being examined and aligned with the centerline axis of signal propagation from said transmitter to the object.

Claim 7

The apparatus set forth in claim 1 wherein said acoustic image focussing means consists of a concave type acoustic reflector aligned with the centerline axis of signal propagation from said acoustic transmitter to the object, said acoustic detectors positioned between said acoustic reflector and the object being examined and spaced from said reflector beyond the focal point thereof.

Claim 8

The apparatus set forth in claim 1 and further comprising means connected between outputs of said amplifying means and an input of said visual display means for temporarily storing the amplified electrical signals, and means in communication with said gating means for periodically generating sequential signals which are applied to said signal storage means to provide periodic sequential read-out of the amplified electrical signals to said visual display means, said sequential signal generating means also controlling the scan timing of the visual display means for synchronization with the read-out of the stored amplified electrical signals whereby each serial scan depicts the echo signals detected only by an associated acoustic detector within the depth of field defined by said gating means.

Claim 9

The apparatus set forth in claim 7 wherein said visual display means is a cathode ray tube.

Claim 10

The apparatus set forth in claim 7 wherein said visual display means is a cathode ray tube provided with a single signal input connected to a common output of said signal storage means.

Claim 11

The apparatus set forth in claim 1 wherein said visual display means is a parallel input device having a like plurality of inputs connected respectively to separate outputs of said amplifying means whereby the outputs of said amplifying means are simultaneously applied to the plurality of inputs of said visual display means.

Claim 12

The apparatus set forth in claim 10 wherein said visual display means is a multi-input cathode ray tube wherein the sweep lines are simultaneously generated to thereby provide a more rapid display of the detected echo signals.

Claim 13

The apparatus set forth in claim 10 wherein said visual display means is a plasma display panel containing an array of rows and columns of gas discharge devices, the gas discharge devices being connected row-by-row respectively with the outputs of said amplifying means, and the columns being sequentially energized by signals generated in a range timing circuit triggered by said gating means.

Claim 14

The apparatus set forth in claim 10 wherein said visual display means is an array of rows and columns of liquid crystals, the crystals being connected row-by-row respectively with the outputs of said amplifying means, and the columns being sequentially energized by signals generated in a range timing circuit triggered by said gating means.

Claim 15

The apparatus set forth in claim 10 wherein said visual display means is an array of rows and columns of light emitting diodes, the diodes being connected row-by-row respectively with the outputs of said amplifying means, and the columns being sequentially energized by signals generated in a range timing circuit triggered by said gating means.

Claim 16

The apparatus set forth in claim 1 Wherein said acoustic transmitter, said acoustic detectors and the object being examined are immersed in the liquid medium.

Claim 17

The apparatus set forth in claim 1 wherein said plurality of acoustic detectors are of number in the range of 20 to 1,000.

Claim 18

The apparatus set forth in claim 1 wherein said acoustic transmitter is a piezoelectric transducer for converting electrical exciting waves into equivalent ultrasonic pressure waves in the liquid medium in which said transmitter, detectors and object being examined are positioned.

Claim 19

The apparatus set forth in claim 1 wherein said acoustic transmitter and detectors are each piezoelectric transducers, the minimum spacing between adjacent acoustic detectors is one half the wavelength of the ultrasonic signal in the liquid medium.

Claim 20

The apparatus set forth in claim 18 wherein said acoustic detectors are equally spaced apart.

Claim 21

The apparatus set forth in claim 3 wherein said row of acoustic detectors are spaced approximately mid-way between said acoustic image focussing means and the object being examined.

Claim 22

The apparatus set forth in claim 1 wherein the wavefront pattern of the periodic ultrasonic pressure wave signal generated by said single acoustic transmitter is sufficiently broad to illuminate the entire object being examined, and the repetition rate of the periodic short duration electrical pulses is at least 15 times a second and thereby is sufficiently rapid to provide a display of motion of the object being examined.

Claim 23

Apparatus for providing a visual display of an object undergoing motion and its internal acoustic heterogeneities by means of ultrasonic echo signals reflected therefrom and comprising a single acoustic transmitter for generating a periodic pulsed ultrasonic frequency pressure wave signal in a liquid medium at a repetition rate of at least 15 times a second, the wavefront pattern of the ultrasonic signal being sufficiently broad to be incident on the entire area of interest on the object being examined, a plurality of at least 20 closely spaced acoustic detectors arranged in a single row within the liquid medium along an axis perpendicular to the centerline axis of signal propagation from said transmitter, said detectors being simultaneously responsive for detecting ultrasonic echo signals periodically reflected from the object in response to the periodic generated ultrasonic signals incident thereon and for converting the detected ultrasonic echo signals to equivalent periodic electrical signals, each detector being sensitive to a broad ultrasonic pressure wavefront pattern to thereby receive multidirectional reflections from a particular echo producing region in the object being examined, a concave reflective acoustic image focussing means located within the liquid medium and aligned with the center of the row of detectors and with the centerline axis of signal propagation from said transmitter, said detectors located between said acoustic image focussing means and the object being examined, a like plurality of amplifiers connected to outputs of associated said acoustic detectors for amplifying the electrical signals developed by said detectors, means in communication with outputs of said amplifiers for providing a visual display of the detected ultrasonic echo signals, an electronic synchronizing generator for periodically generating a short duration electrical pulse which initiates the periodic operation of said ultrasonic transmitter and also establishes a periodic zero reference time of operation of said apparatus, and an electronic range gating pulse generator having an input connected to an output of said synchronizing generator and a first output connected to inputs of said amplifiers for simultaneously gating all of the amplifiers periodically on and off at the repetition rate of generation of the short duration electrical pulses, the gating on time corresponding to the raNge of the object being examined and the time interval between gating on and gating off corresponding to the depth of field in the object being examined to thereby obtain a time domain discrimination of the ultrasonic echo signals, a second output of said range gating pulse generator providing a periodic synchronizing signal to a scan synchronizing input of said visual display means, each scan line of the visual display depicting the echo signals detected by an associated acoustic detector within the depth of field defined by said range gating pulse generator whereby the display represents a moving visualization in depth of a planar slice of the object while it is undergoing motion wherein the slice lies in a plane defined by the centerline axis of signal propagation from said transmitter and the axis of the single row of detectors.

Claim 24

Apparatus for providing a visual display of an object undergoing motion and its internal acoustic heterogeneities by means of ultrasonic echo signals reflected therefrom and comprising a single acoustic transmitter for generating a periodic pulsed ultrasonic frequency pressure wave signal in a liquid medium at a repetition rate of at least 15 times a second, the wavefront pattern of the ultrasonic signal being sufficiently broad to be incident on the entire area of interest on the object being examined, a plurality of at least 20 closely spaced acoustic detectors arranged in a single row within the liquid medium along an axis perpendicular to the centerline axis of signal propagation from said transmitter, said detectors being simultaneously responsive for detecting ultrasonic echo signals periodically reflected from the object in response to the periodic generated ultrasonic signals incident thereon and for converting the detected ultrasonic echo signals to equivalent periodic electrical signals, each detector being sensitive to a broad ultrasonic pressure wavefront pattern to thereby receive multidirectional reflections from a particular echo producing region in the object being examined, a concave reflective acoustic image focussing means located within the liquid medium and aligned with the center of the row of detectors and with the centerline axis of signal propagation from said transmitter, said detectors located between said acoustic image focussing means and the object being examined, a like plurality of amplifiers connected to outputs of associated said acoustic detectors for amplifying the electrical signals developed by said detectors, means in communication with outputs of said amplifiers for providing a visual display of the detected ultrasonic echo signals, an electronic synchronizing generator for periodically generating a short duration electrical pulse which initiates the periodic operation of said ultrasonic transmitter and also establishes a periodic zero reference time of operation of said apparatus, and an electronic range gating pulse generator having an input connected to an output of said synchronizing generator and a first output connected to inputs of said amplifiers for simultaneously gating all of the amplifiers periodically on and off at the repetition rate of generation of the short duration electrical pulses, the gating on time corresponding to the raNge of the object being examined and the time interval between gating on and gating off corresponding to the depth of field in the object being examined to thereby obtain a time domain discrimination of the ultrasonic echo signals, a second output of said range gating pulse generator providing a periodic synchronizing signal to a scan synchronizing input of said visual display means, each scan line of the visual display depicting the echo signals detected by an associated acoustic detector within the depth of field defined by said range gating pulse generator whereby the display represents a moving visualization in depth of a planar slice of the object while it is undergoing motion wherein the slice lies in a plane defined by the centerline axis of signal propagation from said transmitter and the axis of the single row of detectors.

Claim 25

The apparatus set forth in claim 22 and further comprising memory means connected between outputs of all of said amplifiers and a single signal input of said visual display means for temporarily storing the amplified electrical signals, and means having an input connected to the second output of said range gating pulse generator and having a first output connected to inputs of said memory means for periodically generating sequential signals for sequentially reading out the memory means and thereby serially supplying the read out amplified electrical signals to the single signal input of said visual display means, and having a second output connected to the scan synchronizing input of said visual display means for synchronizing a line-by-line scan on said visual display means with the sequential readout of said memory means, said visual display means being a serial input device.

Claim 26

The apparatus set forth in claim 22 wherein said visual display means being a parallel input device having a like plurality of signal inputs connected to the outputs of associated said amplifiers, the periodic synchronizing signal from the second output of said range gating pulse generator providing a simultaneous synchronization of all the scan lines on said visual display means with the gating on of said amplifiers.

Claim 29

The method set forth in claim 25 and further comprising the steps of temporarily storing the amplified electrical signals prior to supplying them to the visual display device, and sequentially reading out the stored amplified electrical signals and serially supplying them to a single signal input of the visual display device which is of a serial input type, the periodic synchronizing signal supplied to the scan synchronizing input of the visual display device providing a synchronization of a line-by-line scan on the visual display device with the sequential reading out of the stored amplified electrical signals.

Claim 30

The method set forth in claim 25 wherein the step of supplying the amplified electrical signals to the visual display device consists of simultaneously supplying the outputs of the amplifiers to a plurality of signal inputs of the visual display device equal in number to the number of acoustic detectors in response to the gating on of the amplifiers, the periodic synchronizing signal supplied to the scan synchronizing input of the visual display device which is of a parallel input type provides a simultaneous synchronization of all the scan lines on the visual display with the gating on the amplifiers.

Claim 31

The method set forth in claim 25 and further comprising the steps of increasing the resolution of the display on the visual display device along a vertical direction corresponding to the axis of the single row of acoustic detectors by more closely spacing of adjacent detectors, the limit of spacing being half a wavelength of the ultrasonic pressure wave signal in the liquid medium, and increasing the resolution of the display along a horizontal direction corresponding to the depth of field in the object being examined by utilizing a higher frequency of the ultrasonic frequency of excitation of the acoustic transmitter, the ultrasonic frequency being in a range of 1 to 10 megahertz.