THRESHOLD CIRCUIT FOR CONVERTING A VIDEO SIGNAL TO A BINARY VIDEO SIGNAL
First Claim
1. In a particulate measuring system wherein a video signal having sloping transitions is generated by scanning a represented sample with a television camera, a threshold circuit for converting said video signal to a binary video signal having sharply defined transitions corresponding substantially with the particle boundaries of the represented sample being scanned, comprising:
- a. adjustable threshold control circuit means for generating a first image intensity reference level signal;
b. an automatic threshold network for generating a second image intensity reference level signal;
c. first comparator circuit means connected to receive said video signal and said first and second image intensity reference level signals for comparing said video signal with either of said first or second image intensity reference level signals and including means for generating a first output signal whenever said video signal exceeds whichever one of said image intensity reference level signals with which it has been compared and a second output signal whenever said video signal does not, said first or second output signals being fed back to said automatic threshold network;
d. first circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the maximum value reached by said video signal between transitions of said otuput signals of said first comparator circuit means;
e. second circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the minimum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
f. signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said output signals of said first comparator circuit means;
g. signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said output signals of said first comparator circuit means;
h. second comparator circuit means connected to receive said delayed video signal, said first image intensity reference level signal and said weighted average signal for comparing said delayed video signal with said first image intensity reference level signal or said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which it has been compared and a second state whenever said delayed video signal does not; and
i. switching means for connecting said adjustable threshold control circuit means or said automatic threshold network to said first comparator circuit means and including means for connecting said adjustable threshold control circuit means or said signal summing network means to said second comparator circuit means.
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Accused Products
Abstract
In a particle measuring system wherein a particulate sample is measured by operating on and with a video signal derived from a television camera which scans the sample, a trimodel threshold circuit for converting the sloping transitions of the video signal to a binary video signal having sharply defined transitions which occur substantially at and generally coincide with the particle boundaries of the sample being scanned.
12 Citations
14 Claims
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1. In a particulate measuring system wherein a video signal having sloping transitions is generated by scanning a represented sample with a television camera, a threshold circuit for converting said video signal to a binary video signal having sharply defined transitions corresponding substantially with the particle boundaries of the represented sample being scanned, comprising:
- a. adjustable threshold control circuit means for generating a first image intensity reference level signal;
b. an automatic threshold network for generating a second image intensity reference level signal;
c. first comparator circuit means connected to receive said video signal and said first and second image intensity reference level signals for comparing said video signal with either of said first or second image intensity reference level signals and including means for generating a first output signal whenever said video signal exceeds whichever one of said image intensity reference level signals with which it has been compared and a second output signal whenever said video signal does not, said first or second output signals being fed back to said automatic threshold network;
d. first circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the maximum value reached by said video signal between transitions of said otuput signals of said first comparator circuit means;
e. second circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the minimum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
f. signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said output signals of said first comparator circuit means;
g. signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said output signals of said first comparator circuit means;
h. second comparator circuit means connected to receive said delayed video signal, said first image intensity reference level signal and said weighted average signal for comparing said delayed video signal with said first image intensity reference level signal or said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which it has been compared and a second state whenever said delayed video signal does not; and
i. switching means for connecting said adjustable threshold control circuit means or said automatic threshold network to said first comparator circuit means and including means for connecting said adjustable threshold control circuit means or said signal summing network means to said second comparator circuit means.
- a. adjustable threshold control circuit means for generating a first image intensity reference level signal;
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2. The threshold circuit, according to claim 1, which further comprises:
- a. logic circuit means connected to said second comparator circuit means for constantly maintaining said binary video signal in one of its two said states regardless of whether said represented particulate sample comprises '"'"''"'"''"'"''"'"'white'"'"''"'"''"'"''"'"' particles on a '"'"''"'"''"'"''"'"'black'"'"''"'"''"'"''"'"' background or vice versa; and
b. switching means for enabling or disenabling said logic circuit means as the relative color of said represented particulate sample and its background dictates.
- a. logic circuit means connected to said second comparator circuit means for constantly maintaining said binary video signal in one of its two said states regardless of whether said represented particulate sample comprises '"'"''"'"''"'"''"'"'white'"'"''"'"''"'"''"'"' particles on a '"'"''"'"''"'"''"'"'black'"'"''"'"''"'"''"'"' background or vice versa; and
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3. The threshold circuit, according to claim 2, wherein said adjustable threshold control circuit means comprises a manually adjustable potentiometer.
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4. The threshold circuit, according to claim 1, wherein said adjustable threshold control circuit means comprises a manually adjustable potentiometer.
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5. The threshold circuit, according to claim 4, which further comprises:
- a. amplifying circuit means for amplifying said video signal;
b. an impedance matching circuit connected between said amplifying means and said television camera for matching said camera and said threshold circuit; and
c. clamping circuit means connected to said amplifying means for clamping the bottom of the horizontal sync pulses of said amplified video signal to a fixed d.c. level before its introduction into the remainder of said threshold circuit.
- a. amplifying circuit means for amplifying said video signal;
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6. The threshold circuit, according to claim 1, which further comprises:
- a. amplifying circuit means for amplifying said video signal;
b. an impedance matching circuit connected between said amplifying means and said television camera for matching said camera and said threshold circuit; and
c. clamping circuit means connected to said amplifying means for clamping the bottom of the horizontal sync pulses of said amplified video signal to a fixed d.c. level before its introduction into the remainder of said threshold cIrcuit.
- a. amplifying circuit means for amplifying said video signal;
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7. The threshold circuit, according to claim 6, which further comprises:
- a. logic circuit means connected to said second comparator circuit means for constantly maintaining said binary video signal in one of its two said states regardless of whether said represented particulate sample comprises '"'"''"'"''"'"''"'"'white'"'"''"'"''"'"''"'"' particles on a '"'"''"'"''"'"''"'"'black'"'"''"'"''"'"''"'"' background or vice versa; and
b. switching means for enabling or disenabling said logic circuit means as the relative color of said represented particulate sample and its background dictates.
- a. logic circuit means connected to said second comparator circuit means for constantly maintaining said binary video signal in one of its two said states regardless of whether said represented particulate sample comprises '"'"''"'"''"'"''"'"'white'"'"''"'"''"'"''"'"' particles on a '"'"''"'"''"'"''"'"'black'"'"''"'"''"'"''"'"' background or vice versa; and
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8. The threshold circuit, according to claim 7, wherein said adjustable threshold control circuit means comprises a manually adjustable potentiometer.
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9. In a particulate measuring system wherein a video signal having sloping transitions is generated by scanning a represented sample with a television camera, a threshold circuit for converting said video signal to a binary video signal having sharply defined transitions corresponding substantially with the particle boundaries of the represented sample being scanned, comprising:
- adjustable threshold control circuit means for generating an image intensity reference level signal;
first comparator circuit means connected to receive said video signal and said image intensity reference level signal for comparing said video signal with said image intensity reference level signal and including means for generating a first output signal whenever said video signal exceeds said image intensity reference level signal with which it has been compared and a second output signal whenever said video signal does not;
first circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the maximum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
second circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the minimum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
output signals of said first signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said output signals of said first comparator circuit means;
signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said output signals of said first comparator circuit means; and
second comparator circuit means connected to receive said delayed video signal and said weighted average signal for comparing said delayed video signal with said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which it has been compared and a second state whenever said delayed video signal does not.
- adjustable threshold control circuit means for generating an image intensity reference level signal;
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10. The threshold circuit as defined in claim 9, wherein the second comparator circuit means is additionally connected to receive the image intensity reference level signal for comparing said delayed video signal with said image intensity reference level signal or said weighted average signal for the included means to generate a binary video signal having a first state whenever said delayed video signal exceeds a signal with which it has been compared and a second state whenever said delayed video signal does not.
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11. In a particulate measuring system wherein a video signal having sloping transitions is generated by scanning a represented sample with a television camera, a thresHold circuit for converting said video signal to a binary video signal having sharply defined transitions corresponding substantially with the particle boundaries of the represented sample being scanned, comprising:
- an automatic threshold network for generating an image intensity reference level signal;
first comparator circuit means connected to receive said video signal and said image intensity reference level signal for comparing said video signal with said image intensity reference level signal and including means for generating a first output signal whenever said video signal exceeds said image intensity reference level signal with which it has been compared and a second output signal whenever said video signal does not, said first or second output signals being fed back to said automatic threshold network;
first circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the maximum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
second circuit means responsive to said video signal and said output signals of said first comparator circuit means for determining and storing the minimum value reached by said video signal between transitions of said output signals of said first comparator circuit means;
signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said output signals of said first comparator circuit means;
signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said output signals of said first comparator circuit means; and
second comparator circuit means connected to receive said delayed video signal and said weighted average signal for comparing said delayed video signal with said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which it has been compared and a second state whenever said delayed video signal does not.
- an automatic threshold network for generating an image intensity reference level signal;
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12. In a system for measuring represented objects by generating a video signal having a profile as a function of the response of each represented object along each one of a plurality of scanning tracks across each represented object, the video signal profile having sloping transitions, a threshold device for generating a switch signal having transitions occurring as a function of the profile of each sloping transition of the video signal, comprising:
- network means including a filtering circuit and offset-voltage generator means for generating an offset-voltage signal, said network means receiving the video signal for generating through the filtering circuit a modified video signal as a function of the video signal and the offset-voltage signal, where the offset-voltage signal has a polarity determined by the state of a switch signal generated by a further included comparison means receiving the video signal and the modified video signal for generating the switch signal having one state if the value of the modified video signal exceeds the value of the video signal and having another state if the value of the modified video signal is less than the value of the video signal.
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13. In a system for measuring represented objects by generating a video signal having a profile as a function of the response of represented objects along scanning tracks across the represented objects, the video signal profile having sloping transitions, a threshold device for generating a switch signal having transitions occurring as a function of the profile of each sloping transition of the video signal, comprising:
- filtering means receiving the video signal to generate a filtered signal as a function of the video signal;
comparison means to generate a switch signal having a first condition if the filtered signal has a value which exceeds the video signal value by an amount at least equal to an offset signal and having a second condition otherwise, which offset signal is a function of the switch signal;
first circuit means responsive to said video signal and said switch signal for determining and storing the maximum value reached by said video signal between transitions of said switch signal;
second circuit means responsive to said video signal and said switch signal for determining and storing the minimum value reached by said video signal between transitions of said switch signal;
signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said switch signal;
signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said switch signal; and
first comparator circuit means connected to receive said delayed video signal and said weighted average signal for comparing said delayed video signal with said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which it has been compared and a second state whenever said delayed video signal does not.
- filtering means receiving the video signal to generate a filtered signal as a function of the video signal;
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14. In a system for measuring represented objects by generating a video signal having a profile as a function of the response of the represented object along scanning tracks across the represented objects, the video signal profile having sloping transitions, a threshold circuit for generating a switch signal having transitions occurring as a function of the profile of each sloping transition of the video signal, comprising:
- filtering means receiving the video signal to generate a filtered video signal;
switching means for receiving the filtered video signal to generate a switch signal having a first condition when the filtered video signal exceeds an offset signal and a second condition otherwise, which offset signal is a function of the switch signal;
first circuit means responsive to said video signal and said switch signal for determining and storing the maximum value reached by said video signal between transitions of said switch signal;
second circuit means responsive to said video signal and said switch signal for determining and storing the minimum value reached by said video signal between transitions of said switch signal;
signal summing network means connected to said first and second circuit means and responsive thereto for determining a predetermined weighted average of said maximum and minimum values of said video signal reached between transitions of said switch signal;
signal delay means receiving said video signal for delaying said video signal for a period of time equal to the time required by said first and second circuit means and said summing network to determine in concert the weighted average of said maximum and minimum values reached by said video signal between transitions of said switch signal; and
first comparator circuit means connected to receive said delayed video signal and said weighted average signal for comparing said delayed video signal with said weighted average signal and including means for generating a binary video signal having a first state whenever said delayed video signal exceeds the signal with which It has been compared and a second state whenever said delayed video signal does not.
- filtering means receiving the video signal to generate a filtered video signal;
Specification