X-ray image brightness stabilizer

Claim 2

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, and having a cine camera for taking pictures of the visible image, the camera having shutter means with alternately open and closed periods, a control for stabilizing brightness of the visible image comprising: a. a light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. first integrator means selectively responsive to said first signal for providing a second signal proportional to brightness of the visible image integrated over each shutter open period; c. analog means selectively responsive to said first signal for providing a third signal proportional thereto; d. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; e. comparator means selectively connectable to receive one of said second and third signals and coupled to said circuit means for comparing said one signal with said constant level reference signal proportional to a desired image brightness level to provide a comparison signal proportional to a difference between said one signal and said reference signal; and, f. output means for receiving said comparison signal and providing to the X-ray source filamEnt energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 3

The system of claim 1, wherein said output means comprises second integrator means.

Claim 4

The system of claim 1, wherein said control signal is provided continuously.

Claim 5

The system of claim 1, wherein said output means comprises second integrator means, and said control signal is provided continuously.

Claim 6

The system of claim 4, further including discharge means for discharging said first integrator means intermittently in synchronism with operation of the shutter means.

Claim 7

The system of claim 4, further including switch means for enabling said comparator means continuously when said comparator means is connected to receive said third signal and gating means for enabling said comparator means intermittently in synchronism with operation of the shutter means when said comparator means is connected to receive said second signal.

Claim 8

The system of claim 6, wherein said gating means disables said comparator means during each shutter open period, and enables said comparator means during at least a portion of each shutter closed period, when said comparator is connected to receive said second signal.

Claim 9

The system of claim 7, further including discharge means for discharging said first integrator means intermittently in synchronism with operation of the shutter means.

Claim 10

The system of claim 8, wherein said first integrator means is discharged while said comparator means is disabled.

Claim 11

The system of claim 6, further including discharge means for discharging said first integrator means intermittently in synchronism with operation of the shutter means.

Claim 12

The system of claim 1, further including switch means for enabling said comparator means continuously when said comparator means is connected to receive said third signal and gating means for enabling said comparator means intermittently in synchronism with operation of the shutter means when said comparator means is connected to receive said second signal.

Claim 13

The system of claim 11, wherein said gating means disables said comparator means during each shutter open period, when said comparator is connected to receive said second signal.

Claim 14

The system of claim 12, wherein said gating means also enables said comparator means during at least a portion of each shutter closed period, when said comparator is connected to receive said second signal.

Claim 15

The system of claim 13, further including discharge means for discharging said integrator means intermittently in synchronism with operation of the shutter means.

Claim 16

The system of claim 14, wherein said integrator means is discharged while said comparator means is disabled.

Claim 17

The system of claim 11, further including discharge means for discharging said integrator means intermittently in synchronism with operation of the shutter means.

Claim 18

The system of claim 1, further including discharge means for discharging said integrator means intermittently in synchronism with operation of the shutter means.

Claim 19

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, and having a cine camera for taking pictures of the visible image, the camera having shutter means with alternately open and closed periods, a control for stabilizing brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. first integrator means responsive to said first signal for providing a second signal proportional to brightness of the visible image integrated oveR each shutter open period; c. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; d. comparator means connected to receive said second signal and coupled to said circuit means for comparing said second signal with said constant level reference signal to provide a comparison signal proportional to a difference between said second signal and said reference signal; e. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 20

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, and having a cine camera for taking pictures of the visible image, the camera having shutter means with alternately open and closed periods, a control for stabilizing brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. first integrator means responsive to said first signal for providing a second signal proportional to brightness of the visible image integrated oveR each shutter open period; c. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; d. comparator means connected to receive said second signal and coupled to said circuit means for comparing said second signal with said constant level reference signal to provide a comparison signal proportional to a difference between said second signal and said reference signal; e. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 21

The system of claim 18, wherein said output means comprises second integrator means, and said control signal is provided continuously.

Claim 22

The system of claim 19, further including gating means for enabling said comparator means intermittently in synchronism with operation of the shutter means.

Claim 23

The system of claim 20, wherein said gating means disables said comparator means during each shutter open period.

Claim 24

The system of claim 21, wherein said gating means also enables said comparator means during at least a portion of each shutter closed period.

Claim 25

The system of claim 22, further including discharge means for discharging said first integrator means intermittently in synchronism with operation of the shutter means.

Claim 26

The system of claim 23, wherein said first integrator means is discharged while said comparator is disabled.

Claim 27

The system of claim 19, further including discharge means for discharging said first integrator means intermittently in synchronism with operation of the shutter means.

Claim 28

The system of claim 18, further including gating means for enabling said comparator means intermittently in synchronism with operation of the shutter means.

Claim 29

The system of claim 26, wherein said gating means disables said comparator means during each shutter open period.

Claim 30

The system of claim 27, wherein said gating means also enables said comparator means during at least a portion of each shutter closed period.

Claim 31

The system of claim 28, further including discharge means for discharging said integrator means intermittently in synchronism with operation of the shutter means.

Claim 32

The system of claim 29, wherein said integrator means is discharged while said comparator is disabled.

Claim 33

The system of claim 18, further including discharge means for discharging said integrator means intermittently in synchronism with operation of the shutter means.

Claim 34

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, a control for stabilizing brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. analog means responsive to said first signal for providing a second signal proportional thereto; c. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; d. comparator means connected to receive said second signal and coupled to said circuit means for comparing said second signal with said constant level reference signal to provide a comparison signal proportional to a difference between said second signal and said reference signal; and, e. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 35

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, a control for stabilizing brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. analog means responsive to said first signal for providing a second signal proportional thereto; c. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; d. comparator means connected to receive said second signal and coupled to said circuit means for comparing said second signal with said constant level reference signal to provide a comparison signal proportional to a difference between said second signal and said reference signal; and, e. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 36

The system of claim 32, wherein said first, second and comparison signals are continuously provided.

Claim 37

The system of claim 32, wherein said first, second, comparision and control signals are continuously provided.

Claim 38

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, and having a cine camera having shutter means with alternately open and closed periods and providing shutter signals indicative of the open and closed periods, a control for stabilizing a brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. integrator means selectively connectable to receive said first signal for providing a second signal proportional to the brightness of the visible image integrated over each shutter open period; c. analog means selectively connectable to receive said first signal for providing a third signal proportional thereto; d. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; e. comparator means selectively connectable to receive one of said second and third signals and coupled to said circuit means for comparing said one signal with said constant level reference signal to provide a comparison signal proportional to a difference between said one signal and said reference signal; f. first switch means having a first position for connecting said integrator means to receive said first signal and said comparator means to receive said second signal, and having a second position for connecting said analog means to receive said first signal and said comparator means to receive said third signal; g. comparator gating means connected to receive the shutter signals and provide comparator gating signals to said comparator means to disable said comparator means in response to said shutter signals; h. second switch means for connecting and disconnecting said comparator gating means and said comparator means; i. discharge means connected to discharge said integrator means in response to discharge gating signals; j. discharge gating means connected to receive the shutter signals and provide said discharge gating signals to said discharge means in response to said shutter signals; and, k. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 39

In an X-ray system having an X-ray source with a filament connected to an energizing and control circuit, the X-ray source providing X-rays to a subject to be X-rayed and to an image intensifier positioned behind the subject relative to the X-ray source for converting an X-ray image of the subject into a visible image, and having a cine camera having shutter means with alternately open and closed periods and providing shutter signals indicative of the open and closed periods, a control for stabilizing a brightness of the visible image comprising: a. light-responsive means located adjacent the image intensifier for providing a first signal proportional to instantaneous brightness of the visible image; b. integrator means selectively connectable to receive said first signal for providing a second signal proportional to the brightness of the visible image integrated over each shutter open period; c. analog means selectively connectable to receive said first signal for providing a third signal proportional thereto; d. circuit means for developing a constant level reference signal having a value representative of a desired image brightness level; e. comparator means selectively connectable to receive one of said second and third signals and coupled to said circuit means for comparing said one signal with said constant level reference signal to provide a comparison signal proportional to a difference between said one signal and said reference signal; f. first switch means having a first position for connecting said integrator means to receive said first signal and said comparator means to receive said second signal, and having a second position for connecting said analog means to receive said first signal and said comparator means to receive said third signal; g. comparator gating means connected to receive the shutter signals and provide comparator gating signals to said comparator means to disable said comparator means in response to said shutter signals; h. second switch means for connecting and disconnecting said comparator gating means and said comparator means; i. discharge means connected to discharge said integrator means in response to discharge gating signals; j. discharge gating means connected to receive the shutter signals and provide said discharge gating signals to said discharge means in response to said shutter signals; and, k. output means for receiving said comparison signal and providing to the X-ray source filament energizing and control circuit a control signal that varies in proportion to said comparison signal to thereby produce a visible image having a constant brightness.

Claim 40

The system of claim 35, wherein said output means comprises second integrator means and said control signal is provided continuously.

Claim 41

The system of claim 36, wherein said comparator gating means comprises a monostable multivibrator for providing comparator gating signals for disabling said comparator means during each shutter open period and enabling said comparator during at least a portion of each shutter closed period.

Claim 42

The system of claim 36, wherein said discharge gating means comprises a monostable multivibrator for providing said discharge gating signals to said discharge means while said comparator means is disabled.

Claim 43

The system of claim 36, wherein said comparator gating means provides comparator gating signals for disabling said comparator means during each shutter open period and enabling said comparator during at least a portion of each shutter closed period and wherein said discharge gating means provides said discharge gating signals to said discharge means while said comparator means is disabled.

Claim 44

The system of claim 39, wherein said comparatoR gating means and said discharge gating means each comprise a monostable multivibrator.

Claim 45

The system of claim 35, wherein said comparator gating means provides comparator gating signals for disabling said comparator means during each shutter open period and enabling said comparator during at least a portion of each shutter closed period.

Claim 46

The system of claim 41, wherein said comparator gating means comprises a monostable multivibrator.

Claim 47

The system of claim 35, wherein said discharge gating means provides said discharge gating signals to said discharge means while said comparator means is disabled.

Claim 48

The system of claim 43, wherein said discharge gating means comprises a monostable multivibrator.

Claim 49

The system of claim 35, wherein said comparator gating means provides comparator gating signals for disabling said comparator means during each shutter open period and enabling said comparator during at least a portion of each shutter closed period and wherein said discharge gating means provides said discharge gating signals to said discharge means while said comparator means is disabled.

Claim 50

The system of claim 45, wherein said comparator gating means and said discharge gating means each comprise a monostable multivibrator.

Claim 51

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, an imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; variable reference signal circuit means for developing a reference signal which may be varied, but upon being set remains at a constant level, the value of said reference signal being representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference between the brightness of said visible image and a selected image brightness level; and, output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness.

Claim 52

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, an imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; variable reference signal circuit means for developing a reference signal which may be varied, but upon being set remains at a constant level, the value of said reference signal being representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference between the brightness of said visible image and a selected image brightness level; and, output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness.

Claim 53

An apparatus as defined in claim 47 wherein said X-ray source has a filament element and said X-ray source control circuit includes filament circuit means for energizing a said filament element in accordance with the value of a said control signal to thereby maintain a said visible image at a constant brightness.

Claim 54

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, an imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; reference circuit means for developing a constant level reference signal having a predetermined value with respect to ground representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference betweeN the brightness of said visible image and a selected image brightness level; output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness; a camera disposed to view a said visible image and having a shutter means, and shutter circuit means for opening said shutter means for predetermined time intervals; and, integrator circuit means for receiving a said first signal for providing an integrated signal having a value proportional to the value of the instantaneous brightness of the visible image integrated over each predetermined time interval, and said comparator circuit means being coupled to said integrator circuit means to receive a said integrated signal.

Claim 55

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, an imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; reference circuit means for developing a constant level reference signal having a predetermined value with respect to ground representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference betweeN the brightness of said visible image and a selected image brightness level; output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness; a camera disposed to view a said visible image and having a shutter means, and shutter circuit means for opening said shutter means for predetermined time intervals; and, integrator circuit means for receiving a said first signal for providing an integrated signal having a value proportional to the value of the instantaneous brightness of the visible image integrated over each predetermined time interval, and said comparator circuit means being coupled to said integrator circuit means to receive a said integrated signal.

Claim 60

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; reference circuit means for developing a constant level reference signal having a predetermined value with respect to ground representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference between the brightness of said visible image and a selected image brightness level; output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness; said imaging means comprises an image intensifier; and, said control system includes analog circuit means coupled to said light responsiVe means for providing an analog signal having a value proportional to the value of a said first signal, and said comparator circuit means is coupled to said analog circuit means to receive a said analog signal.

Claim 61

In an X-ray system having an X-ray source, an X-ray source control circuit for varying a signal applied to said X-ray source, imaging means positioned to receive at least a portion of the X-rays emitted by the X-ray source for converting the received X-rays into a visible image, and a control system for stabilizing the brightness of a said visible image and comprising: light responsive means disposed to receive light energy emitting from said imaging means for providing a first signal having a value representative of the brightness of a said visible image; reference circuit means for developing a constant level reference signal having a predetermined value with respect to ground representative of a selected image brightness level; comparator circuit means connected to said light responsive means and to said reference circuit means for comparing said first signal with said constant level reference signal to provide an error signal representative of a difference between the brightness of said visible image and a selected image brightness level; output means coupled to said comparator circuit means for applying to the X-ray source control circuit a control signal which varies in accordance with said error signal to thereby produce a visible image having a constant selected image brightness; said imaging means comprises an image intensifier; and, said control system includes analog circuit means coupled to said light responsiVe means for providing an analog signal having a value proportional to the value of a said first signal, and said comparator circuit means is coupled to said analog circuit means to receive a said analog signal.

Claim 62

An apparatus as defined in claim 52 wherein said light responsive means includes circuit means for providing a said first signal having a value which is proportional to the instantaneous brightness of a said visible image.