SCANNING SYSTEM FOR YIELDING A THREE-DIMENSIONAL DISPLAY

• US 3,705,261 A
• Filed: 04/09/1970
• Issued: 12/05/1972
• Est. Priority Date: 04/09/1970
• Status: Expired due to Term

• Current Assignee: Lawrence W. Langley
• Original Assignee: Lawrence W. Langley
• Inventors: Langley, Lawrence W.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Leibowitz, Barry L.
• Application Number:
  US05/026,846
• Time in Patent Office: 971 Days
• Field of Search: 178/6.5,6.8 250/217CR 128/24A 340/5I 350/138
• US Class Current: 348/42
• CPC Class Codes: A61B 8/00 Diagnosis using ultrasonic, sonic or infrasonic waves imaging of objects using sonar G01S15/00
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/0618 synchronised with scanning, e.g. in real-time
• CPC Class Codes: G01S 7/20 Stereoscopic displays; Three-dimensional displays; Pseudo-three-dimensional displays

Abstract

A system for scanning an object and obtaining a threedimensional display of the features of the object is described. Internal discontinuities within the scanned object can be detected and visually displayed. The system includes a transmitting element which transmits energy to the object under investigation. The energy transmitted to the object can be of a form which will pass through the object, for example, ultrasonic waves to obtain a view of internal features. Energy passing through the object is reflected back to the surface through which it entered the object by discontinuities within the object. The reflected waves are received by the scanning device where they are divided into separate channels. The two channels individually process the received signals which are then used to actuate a read-out device such as an oscilloscope. The visual read-out from the oscilloscope is then photographed by use of a stereo camera and a three-dimensional picture is obtained.

Claims

1. A pulsed echo system for creating a three-dimensional representation from reflected signals comprising:

scanning means for transmitting at least one energy impulse to an object and receiving at least one reflected energy signal from the object, means coupled to said scanning means controlling the transmission of said energy impulse for establishing the reference time of transmission of said energy impulse, and means responsive to said energy impulse for displaying a segment of an image representing said object on a display plane, said display means including first and second display portions, and image position locating means coupled to said reference time means and responsive to the time of receipt of said received reflected energy signal for locating the position of the image segment displayed on each of said display portions relative to a reference position for said energy impulse, so that the rate of propogation of the energy impulse to and from the object is represented by the rate of change of location of the image segment on each of the display portions, said image position locating means locating said image segment in opposite directions from said reference signal position on each of said portions so that complementary visual representations which may be combined to form a threedimensional representation are displayed on said first and second display portions.

2. The system of claim 1, wherein said scanning means includes a directional piezoelectric crystal for transmitting a short pulse of ultrasonic energy and a plurality of receiving piezoelectric crystals equiangularly spaced with respect to said transmitting crystal for receiving reflected signals.

3. A system as claimed in claim 1, including means for sectoring said scanning means across the surface of said object, said display means including said first and second portions each of which displays all of said image segment, said image locating means coordinating the image segment display on said portions with the motion of said sectoring means so that the combination of said image on said portions represents three-dimensionally the reflections from said object.

4. The system of claim 1, wherein said energy impulses are ultrasonic and said scanning means comprises a single transducer which received reflected pulses during the intervals in which it is not transmitting pulses.

5. A system as claimed in claim 3, including means for recording the image segments representing reflected signals appearing on said first and second portions over a period of time to produce a record of said three-dimensional representation.

6. The system of claim 3 wherein said sectoring means includes stepping means for effecting horizontal movement of said scanning means, and rotating means for moving said scanning means in a vertical oscillating pattern, so that said object is scanned in sectors.

7. A system as claimed in claim 6, wherein said sectoring means is reversible so that scanning takes place in both horizontal directions of movement of the scanning means across the object.

8. The system of claim 2, wherein said impulses are ultrasonic, and wherein said rotating means mounts said sectoring means for rotation about an axis and includes constantly rotating means;

cam means coupled to said constantly rotating means said cam means including guide means;

follower means coupled with said guide means so that said follower oscillates as said cam means rotates; and

means coupling said follower to said scanning means so that scanning means moves in a vertical oscillating pattern.

9. A system as claimed in claim 6, wherein said display means comprise first and second cathode ray tubes whose screens comprise said first and second display portions, and said image locating means includes readout means including first and second potentiometers directly coupled to each of said stepping means and rotating means for effecting horizontal and vertical movement for developing a first signal output indicative of the horizontal sectoring motion of said scanning means, and for developing a second signal output indicative of the vertical sectoring motion of said scanning means, said first and second signal outputs being applied to first and second deflection assemblies of each of said cathode ray tubes to coordinate the movement of the scanning beams of said cathode ray tubes with the motion of said scanning means.

10. The system of claim 9, wherein said energy impulses are ultrasonic and said scanning means comprises a piezoelectric crystal having a diameter which is large in comparison to the wavelength of said ultrasonic energy.

11. The system of claim 3, wherein said energy impulses are ultrasonic and said scanning means comprises a a single transducer which receives reflected pulses during the intervals in which it is not transmitting pulses.

12. A system as claimed in claim 11, including means for recording the image segments representing reflected signals appearing on said first and second display portions over a period of time to produce a record of said three-dimensional representation.

13. The system of claim 3, wherein said reference time means include means for establishing a reference time for receipt of a reflection of said transmitted scanning signal from the surface of object based on the time of transmission of said signal.

14. A system as claimed in claim 13, wherein said energy impulses are ultrasonic.

15. A system as claimed in claim 14, wherein said display means comprise a programmed gain amplifier having an initial value of amplification and gain ramp generator means responsive to said reference time means for controllably increasing the gain applied by said programmed amplifier to said received reflected energy signal substantially in proportion to the interval between the time of receipt of said reference surface signal and the time receipt of said reflected energy signal so that the intensity of said image segment is substantially independent of reflection distance.

16. A system as claimed in claim 15, wherein said gain ramp means are responsive to Said reference time means detection of said surface reflected signal for initiating said increasing gain program, said gain ramp means restoring said programmed amplifier to said initial amplification value after a time interval long enough to allow for reflected signal return from the furthest part of said object.

17. A system as claimed in claim 16, wherein said display means comprise first and second cathode ray tubes whose screens comprise said first and second display portions and said image locating means comprise readout means for developing a first signal output indicative of the horizontal sectoring motion of said scanning means, and for developing a second signal output indicative of the vertical sectoring motion of said scanning means, said first and second signal outputs being applied to first and second deflection assemblies of each of said cathode ray tubes to coordinate the movement of the scanning beams of said cathode ray tubes with the motion of said scanning means.

18. The system of claim 17, wherein said scanning means is coupled to the intensity controls of said cathode ray tubes so that the intensity of the image segments on said cathode ray tubes screens increase in response to receipt of said received energy impulse.

19. A system as claimed in claim 16, including means for recording the image segments representing reflected energy impulses appearing on said first and second display portions over a period of time to produce a record of said three-dimensional representation.

20. A system as claimed in claim 10, wherein said system is ultrasonic and wherein said first and second display portions comprise the screens of first and second cathode ray tubes, each of said tubes including a scanning beam for displaying said image segments on said cathode ray tube screen and first and second voltage deflection assemblies, said image locating means comprising said deflection assemblies of said tube.

21. A system as claimed in claim 20, wherein said image locating means comprise readout means for developing a first signal output indicative of the horizontal sectoring motion of said scanning means, and for developing a second signal output indicative of the vertical sectoring motion of said scanning means, said first and second signal outputs being applied to the first and second deflection assemblies of said cathode ray tubes to coordinate the movement of the scanning beams of said cathode ray tubes with the motion of said scanning means.

22. A system as claimed in claim 21, wherein said image locating means includes a positive high frequency mini-scan sweep control voltage source cooperating with said first deflection assembly of said first cathode ray tube and a negative high frequency mini-scan sweep control voltage source cooperating with said first deflection assembly of said second cathode ray tube, a mini-scan sweep being initiated for each of said transmitted energy impulses, so that the location of the image segment displayed during a mini-scan sweep represents the depth within said object at which said energy impulse is reflected.

23. A system as claimed in claim 22, wherein said reference time means are coupled to said scanning means to establish a reference time for receipt of a reflection of said transmitted scanning signal from the surface of said object based on the time of transmission of said signal, and wherein said display means comprises a programmed gain amplifier having an initial value of amplification and gain ramp generator means responsive to said reference time means for controllably increasing the gain applied by said programmed amplifier to said received reflected energy signal substantially in proportion to the interval between the time of said reference surface signal and the time of receipt of said reflected energy signal so that the intensity of said image segments is substantially independent of reflection distance.

24. A system as claimed in claim 23, wherein said gain ramp means are responsive to said reference time means detection of said surface reflected signal for initiating said increasing gain program, said gain ramp means restoring said programmed amplifier to said initial amplification value after a time interval long enough to allow for signal return from the farthest part of said object.

25. The system of claim 22, wherein the output from said scanning means for receiving is applied to the intensity controls of said cathode ray tubes so that the intensity of the image segments on said cathode ray tubes screens increase in response to said reflected signals.

26. The system of claim 22, wherein said scanning means comprises a single transducer which receives reflected pulses during the intervals in which it is not transmitting pulses.

27. A system as claimed in claim 26, including means for recording the image segments representing reflected signals appearing on said first and second screens over a period of time to produce a record of said three-dimensional representation.

28. The system of claim 3, wherein said scanning means is a single transducer for transmitting short pulses of ultrasonic energy and receiving reflected pulses during the intervals in which it is not transmitting pulses.

29. The system of claim 28, wherein said transducer is a piezoelectric crystal.

30. The system of claim 29, including a pulse blocking circuit comprising pulse generation means and an oscillator, the frequency of said oscillator being such that the wavelength exceed the time required to receive the last reflected signal, the output of said oscillator actuating said pulse generator means, the transmitted output of said scanning means being dependent upon the output of said pulse generating means.

31. The system of claim 30, wherein said pulse generating means generates a start pulse which is about 1/10 microsecond in duration.