US3711642A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuitry for displaying isodensity lines in an image
Assignee: US Philips Corp
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Filing: 1968-09-25
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Granted: 1973-01-16
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Expires: 1988-09-25
Abstract
Abstract A device for displaying isodensity lines of a radiation image on a CRT includes a radiation detector that provides a video signal that varies with the scanned radiation. A selector responsive to the video signal supplies first and second output signals. The first output signal is limited to a range between a given minimum and a given maximum value of the input signal and the second output signal is limited to a minimum value equal to the given maximum value of the input signal. The two output signals are subtractively combined and the resultant signal is applied to the control electrode of the CRT to vary the beam intensity.
Inventors
- 👤 M Jatteau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:49
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/30; H04N5/33
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
193 words
A device for displaying isodensity lines of a radiation image on the screen of a display tube comprising, a radiation detector for collecting the radiation from the various parts of the object to be examined and generating a signal that varies therewith, a plurality of amplifying stages to which the output signal of said detector is applied, a display tube having a display screen and a control electrode for varying the intensity of the image on the screen, a selector in cascade with the amplifying stages for selecting the signal variations corresponding to the isodensity line to be displayed, said selector comprising a first limiting member supplying a first output signal the minimum value of which lies at a given lower signal level ni and the maximum value of which lies at a given upper signal level ns of the input signal and a second limiting member supplying a second output signal the minimum value of which lies at the given upper signal level ns of the input signal, and means for subtractively combining the two output signals of the selector and applying the resultant signal to said control-electrode of the display tube.
Claim 2
Independent Claim
193 words
A device for displaying isodensity lines of a radiation image on the screen of a display tube comprising, a radiation detector for collecting the radiation from the various parts of the object to be examined and generating a signal that varies therewith, a plurality of amplifying stages to which the output signal of said detector is applied, a display tube having a display screen and a control electrode for varying the intensity of the image on the screen, a selector in cascade with the amplifying stages for selecting the signal variations corresponding to the isodensity line to be displayed, said selector comprising a first limiting member supplying a first output signal the minimum value of which lies at a given lower signal level ni and the maximum value of which lies at a given upper signal level ns of the input signal and a second limiting member supplying a second output signal the minimum value of which lies at the given upper signal level ns of the input signal, and means for subtractively combining the two output signals of the selector and applying the resultant signal to said control-electrode of the display tube.
Claim 3
Dependent Claim
179 words
A device as claimed in claim 1 wherein the first limiting member of the selector includes a first diode and a second diode, a first input resistor, means for applying the input signal to the selector through said first input resistor to similar electrodes of the two diodes, means for biassing the other electrode of the first diode through an output impedance at the given lower level ni, means directly biassing the other electrode of the second diode at the given upper level ns, a first selector output terminal connected to said first diode other electrode, the second limiting member including a third diode, a second input resistor, means for applying the selector input signal through said second input resistor to a first electrode of the third diode which is identical with the similar electrodes of the first and second diodes of the first limiting member, means for biassing the other electrode of said third diode through an output impedance at the given upper level ns, and a second selector output terminal connected to said third diode other electrode.
Claim 4
Dependent Claim
186 words
A device as claimed in claim 2 characterized in that the output impedance of the first limiting member compriSes two resistors, means connecting one end of each of said two resistors to the other electrode of the first diode, a source of direct voltage for supplying the bias voltage for the given lower signal level ni, means connecting the other end of one resistor to one terminal and the other end of the other resistor to the other terminal of said direct-voltage source, the output impedance of the second limiting member comprising two further resistors, means connecting one end of each of said two further resistors to the other electrode of the third diode, a second source of direct voltage for supplying the bias voltage for the given upper signal level ns, means connecting the other end of one resistor of said two further resistors to one terminal and the other end of the other resistor to the other terminal of said second direct voltage source, and means directly connecting said one terminal of the second direct-voltage source to the other electrode of the second diode.
Claim 5
Dependent Claim
32 words
A device as claimed in claim 1 characterized in that the total gain of the amplifying stages preceding the selector is controllable to produce a variable amplitude output signal from the selector.
Claim 6
Dependent Claim
22 words
A device as claimed in claim 1 further comprising at least one diode clipper connected to prevent saturation of the amplifying stages.
Claim 7
Dependent Claim
107 words
A device as claimed in claim 1 wherein said display tube is a cathode ray tube having electron beam deflection means, said device further comprising means for scanning the object field and sequentially supplying the scanned radiation to the detector, means for adjusting the bias level of the detector, means for controlling the tube deflection means in synchronism with the scanning means, a non-saturable amplifier and a variable attenuator connected in cascade between the detector and the amplifying stages, a clipper stage preceding each amplifying stage to prevent saturation thereof, a signal inverter connected in parallel with the selector, and a switch for rendering said inverter inactive.
Claim 8
Dependent Claim
50 words
A device as claimed in claim 6 wherein said detector includes a photoconductive cell and said bias adjusting means comprises a Wheatstone bridge having a variable resistor in one branch and said cell in a second branch, and a source of voltage connected to the input terminals of the bridge.
Claim 9
Independent Claim
187 words
A device for displaying a radiation image on the screen of a display tube with emphasis on a selected radiation concentration level comprising,radiation sensitive scanning means for generating a video signal that varies with the radiation scanned, means connected to said scanning means for amplifying said signal, a selector having an input coupled to the output of the amplifying means and first and second output terminals, said selector including first and second limiting means connected between the input terminal and said first and second output terminals and arranged to develop first and second output signals at said first and second output terminals, respectively, the first output signal being limited to a range of signal values between a given minimum value and a given maximum value of the selector input signal and the second output signal being limited to a minimum value equal to said given maximum value of the input signal, and means for substractively combining said first and second output signals and supplying the resultant signal to a control electrode of the display tube thereby to vary the intensity of the image on the tube screen.
Claim 10
Independent Claim
187 words
A device for displaying a radiation image on the screen of a display tube with emphasis on a selected radiation concentration level comprising,radiation sensitive scanning means for generating a video signal that varies with the radiation scanned, means connected to said scanning means for amplifying said signal, a selector having an input coupled to the output of the amplifying means and first and second output terminals, said selector including first and second limiting means connected between the input terminal and said first and second output terminals and arranged to develop first and second output signals at said first and second output terminals, respectively, the first output signal being limited to a range of signal values between a given minimum value and a given maximum value of the selector input signal and the second output signal being limited to a minimum value equal to said given maximum value of the input signal, and means for substractively combining said first and second output signals and supplying the resultant signal to a control electrode of the display tube thereby to vary the intensity of the image on the tube screen.
Claim 11
Dependent Claim
94 words
A device as claimed in claim 8 wherein said display tube is a cathode ray tube having electron beam deflection means, said device further comprising means for controlling the tube deflection means in synchronism with the scanning means, an amplifier connected to the output of said scanning means, and a switch for selectively connecting said amplifier to said combining means whereby the video signal is combined with said first and second output signals and supplied to the control electrode of the display tube for simulTaneously displaying the video signal and the selected radiation level.
Claim 12
Dependent Claim
58 words
A device as claimed in claim 9 wherein said combining means comprises an adding circuit having a first input connected to the first output terminal of the selector and a second input, and an inverter amplifier and a switch connected in series between the second output terminal of the selector and the second input of the adding circuit.
Claim 13
Dependent Claim
31 words
A device as claimed in claim 9 further comprising a source of variable bias voltage connected to the video signal generating means for adjusting the DC level of said video signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |