JPS58217926A - Automatic x-ray exposing device - Google Patents

Abstract

PURPOSE:To prevent the formation of a photograph with low density due to the influence of halation originated from a direct line part, gas image, etc., during photographing through fluoroscopy, by discriminating over-exposure with underexposure about each channel on the basis of a fixed level. CONSTITUTION:Only analog switches 12 corresponding to a visual field of natural lighting are turned on to irradiate an examined body with X-rays, and signals Ei proportional to input light corresponding to a visible image by X-ray fluoroscopic images to respective channels CH11A-CH11N of a multiple natural lighting part 11 are supplied to an over/under detecting circuit 19, supplying OR outputs corresponding to the respective channels to a latch circuit 23 except when the respective signals Ei are all over, all under, or partially over and the remainders are under. Respective outputs of the switches 12 corresponding to the latch output are summed up at a part 13 and supplied to a dividing circuit 14. The total number of channels CHi in operation is counted by a counter 24 and supplied to the circuit 14. The sum value of the signals Ei is divided by the total number of the channels in operation to obtain a mean value per channel, thus setting optimum fluoroscopy conditions at a part 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image intensifier (hereinafter [1, 1
This invention relates to an improvement in an automatic X-ray exposure device that automatically controls X@ exposure by collecting a portion of the output of the

FIG. 1 is a diagram showing the configuration of the conventional X-ray automatic exposure control device. In the figure, 1 is the X-ray tube, 2 is the subject, and 3 is the X-ray tube.
line film, 4 is I, 1. ．． 5 is an optical system, 6 is a phototimer, 7 is a television camera, 8 is a television monitor, 9 is an X-ray photography condition setting circuit, 10 is an X-ray high voltage generator, and the lighting field of the output of 1.1.4 above. A light source is installed inside the body to take in the light, and the phototimer 6 is operated based on the integrated value to determine the X-ray irradiation time corresponding to the subject 2. Thereby, the X-ray imaging condition setting circuit 9 automatically X-ray generator 1
X#j by controlling the X-ray irradiation time of 0'! X from %'l
The radiation dose is optimized.

In such conventional X-ray automatic exposure control devices, control is performed using the integrated light amount from the entire lighting field of the lighting device, so if a part of the lighting field is, for example, insufficient or excessive, In the former case, the X-rays generated from the X-ray tube 1 become stronger, and the entire irradiation field becomes overexposed. Moreover, in the latter case, the X-rays are weak, resulting in insufficient exposure.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and includes providing a lighting section consisting of a plurality of lighting devices within the lighting field of the output of the image intensifier, so that the output of each lighting device is means for detecting underexposure to X-rays and overexposure to X-rays; means for removing the output of the daylight under the condition of underexposure to X-rays and overexposure to X-rays based on the output of the means; and detecting underexposure to X-rays. An X-ray underexposure reference value setting means sets the reference value from the average output value of all daylighting devices, and an X-ray overexposure detection reference value is set using the fluoroscopy tube voltage when the fluoroscopy tube voltage becomes equal to or higher than the intermediate tube voltage. This is an X-ray exposure device that is equipped with an X-ray overexposure detection reference value setting means that sets an X-ray overexposure detection standard value using the average output value of all daylights when the tube voltage is lower than the tube voltage.
a halation signal detection means for detecting an output signal of a daylight when the light from the line part is incident; and a halation signal detection means for detecting an output signal of the daylight that corresponds to the detected halation signal when a halation signal is detected by the halation signal detection means; , said X
The present invention is provided with means for removing or reducing the input from the inputs of the line underexposure detection reference value setting means and the X# overexposure detection reference value setting means.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In addition, the same symbols are attached to the same parts in all figures. In addition, hereinafter, an exposure amount or an underexposure amount is referred to as "1 under", and an overexposure amount is referred to as "1 over".

FIG. 2 is a schematic diagram showing the configuration of one embodiment of the basic part of the automatic X-ray exposure apparatus of the present invention. In FIG. 2, 11 is 1. It is a multi-lighting part that takes in the output light of I and 4, and has multiple channels 11A to 11.
It is composed of N. Reference numeral 12 denotes an analog switch group, which is composed of a plurality of analog switches 128 to 12N. 16 is an adder circuit for adding the outputs from the analog switch group 12; 14 is a divider circuit for dividing the output from the adder circuit 13 by the number of channels and outputting an average value per channel; 15 is an output terminal, which is connected to the X-ray imaging condition setting circuit 9 shown in FIG.

16 is a lighting field, that is, the channels 11A to 11N.
17 is a circuit for generating a child signal R, 18 is a detection reference signal generating circuit for detecting the over and under conditions, and 19 is a terminal for the output of each of the channels 118 to 11N. This is an over/under detection circuit that detects whether it is over or under. 20 is a detection circuit for detecting that all outputs of all channels 11A to 11N are over, 21 is a detection circuit for detecting that all outputs of all channels 11A to 11N are under, and 22 is a detection circuit for all channels. 11A-11
A detection circuit for detecting that one part of N is over and the rest is under, 23 is a child circuit;
First, it is put into a hold state by the child signal R, and the output does not change during the hold state. 24 is a divider circuit for calculating the total number of operating channels% 25A~25
C is an analog switch, which is turned off when it is at the no-i (tl) level and turned on when it is at the low (L) level. 26
27 is a logical sum (OR) circuit, and 27 is an over setting signal generation circuit, which generates, for example, a signal at a level that indicates that the output of channel 11A is over. Reference numeral 28 denotes an under setting signal generation circuit, which generates a signal at a level such that the output of channel 11A is under, for example. 29 is a "1" signal generating circuit which generates a signal corresponding to "l" when representing the number of channels.

FIG. 3 is a diagram showing a specific configuration of the circuit of the multi-lighting section 11 shown in FIG. 2, in which 101 and 102 are photodiodes, and 111 and 112 are circuits that convert the output current of the photodiodes into voltage. .

FIG. 4 shows the over/under detection circuit 19 of FIG.
All channel over detection circuit 20. 3 is a diagram illustrating a specific configuration of a full-length, partial under-detection circuit 21 and a partial over-remaining total under-detection circuit 22. FIG. In the figure, 19
A is a comparator for over detection, and each comparator receives an electrical signal E1 corresponding to the X-ray exposure from each channel 11A to 11N and an over condition reference signal B.
.

is input and outputs a low (11) level signal where E i > E. 191"l is a comparator for under detection, each of which receives the electrical signal E1 and the under condition reference signal, and outputs a high (I) level signal when Ei<E-. 19C3 to 19C11 are logical sum (OR) circuits for detecting whether each channel is over or under, 20A, 21A, and 22A are switching switches for lighting field selection, respectively. Turn on all channels, and for 2-split shooting or 4-split shooting, turn on only the channels that are exposed to light on the output surface of r, 1.4.For unused channels, high B is a matching circuit, 30.31 is an inverter. , E ot is all channel over signal, Eo is one part over and remaining all under signal, Eos is all channel under signal, E f
14 is a signal for turning on the analog switch 25C.

FIG. 5 is a diagram showing a specific configuration of the child circuit 23 shown in FIG. In the figure, 25A and 23B are lighting field selection switches, and the a terminal side is set, and the b terminal side () and a (11) side) are reset. 230 is a switch for all channels, a low (L) level voltage is applied to the 11' terminal, and the L' terminal is a normal over/under detection terminal. The outputs of the OR circuits 19C0 to 190n shown in FIG. 4 are connected thereto.

Next, the operation of the embodiment shown in FIG. 2 will be explained.

First, switch 2 for lighting field selection shown in Fig. 5.
3■3 is connected to the a terminal side by the lighting field selection signal O8, and the analog switch 12 of the analog switch group 12 is connected.
Among A to 12N, only those corresponding to the lighting field are turned on. For example, in the case of single-panel operation, the analog switch 12A has a lighting field that corresponds to all channels.
~12N are all turned on. Next, X-rays are irradiated onto the subject 2, and each channel 11A of the multi-lighting unit 11 provided within the lighting field of the output fluorescent surface of 1.
Light corresponding to the visible image formed by the 11NK X-ray transmission image is input, and an electrical signal EI corresponding to the amount of light input to each channel 11A to IIN is output. Each output electrical signal E1 of each channel 11A to IIN is input to an over/under detection circuit 19 shown in FIG. 2 or 4, and it is detected whether each electrical signal is over or under. However, all electrical signals exceeded.

When all are under, some are over, and all are under, the outputs of the OR circuits 1961 to 19Cn corresponding to the respective channels 1' IA to 11N are input to the child circuit 23. For example, if the output of the OR circuit 1901 of channel 11A is at a high (H) level (that is, the output of channel 11A includes at least one of the over and under conditions), this Since the output of channel 23A is high (11), the analog switch 12A is in the OFF state, and there is no output of channel 11A, so the input to adder circuit 13 is do not have.

Furthermore, if the output of the OR circuit 19C7 of the channel 11B is at a low (L) level, this is input to the child circuit 26, so the output of the latch 23A becomes a low (L) level and the analog switch 12B is turned on ( ON) state, the analog output of the channel 11B is directly input to the adder circuit 13. Similarly, the outputs of other channels are also input to the adder circuit 13. In this way, the electrical signals Ei input to the adder circuit 16 are added to the divider circuit 1.
4 is input. On the other hand, a counting circuit 24 counts the total number of channels 11A to 11N activated by the output of the latch circuit 23, and a dividing circuit 14
Enter. The division circuit 14 divides the added value of the output electrical signal E1 by the total number of operating channels and outputs an average value for each channel. This output is sent to the X-ray imaging condition setting circuit 9 shown in FIG. 1 through the output terminal 15.
Optimal fluoroscopy and imaging conditions are set.

Next, when the logical sum circuits 19C1 to 190n of the over/under detection circuit 19 output a detection signal indicating that one part is over and the remaining parts are all under, the coincidence circuit 22 of the one part over and remaining part under detection circuit 22 is output. 3, a signal E 02 of one part over and the remaining part under is output. This outgoing word is Eox.

All channel onset switches 25C shown in FIG.
' terminal, switch for lighting field selection, 23
Analog switch 12A ~ via B, U, and Chi 23A
All analog switches corresponding to the 12N daylighting field are turned on. Then, an operation similar to the addition and division by 1 operation described above is performed.

Further, when the respective outputs of the over-detection comparators 19A of the over-under detection circuit 19 are all low, an all-channel over signal E is sent from the matching circuit 20B of the all-channel over detection circuit 20. , is output 3, and the analog switch 25A and OR circuit 26
The analog switches 250 are turned on via the respective analog switches 250 and 250.

As a result, the over setting signal generation circuit 27 and "1"
A signal of "1" is input from the signal generation circuit 29 to the counting circuit 24 and the addition circuit 13, and from the addition circuit 13 r I J
signal is output and removed from automatic exposure control.

At this time, the outputs of all the channels are the OR circuits 19C1 to 19 of the over/under detection circuit 19.
0n and is input to the latch circuit 26, turning off all analog switches 12A to 12N. Furthermore, when the outputs of the over/under detection circuit 190 and the under detection comparator 19B are all under, the matching circuit 21B of the all channel under detection circuit 21
An all-channel under signal Eos is output from , and the analog switch 250 is turned on via the analog switch 2513 and the OR circuit 26 . This results in
The under setting signal generation circuit 28 and the "l" signal generation circuit 29 also receive the "1" signal from the counting circuit 24 and the addition circuit 13.
The addition circuit 16 outputs a signal of "l" and is removed from automatic exposure control. At this time, as in the case of all channels over, the outputs of all channels under are inputted to the child circuit 23 through the OR circuits 19C+ to 190n of the over/under detection circuit 19, and all analog switches 12A to 190n are inputted. Turn off 12N.

In addition, in the device that implements the basic part of the automatic X-ray exposure device of the present invention shown in FIG. 2, in order to eliminate the influence of barium images, gas images, halation images, etc. in gastrointestinal imaging, It determines whether the level is over or under. For example, a barium image is an underlevel, gas image.

Halation images and the like are judged based on their overlevels, and the signals of channels corresponding to these are separated, and the signals of the remaining channels are used as an average value signal for each channel to determine automatic exposure for fluoroscopy and photography. This is, for example, the sixth
As shown in the figure, the last week's visual images are of three channels: ■,
When light is received in the multi-lighting field of view (2), the output signal EI of each channel is as shown in FIG. FIG. 7 is a diagram showing the level of the output signal Ei of each channel under optimal conditions, where LLO is over level and LU is under level. Based on these output signals Ei, for example, if exposure is determined by channel (2) for the gas image region, the entire image becomes too thin, and if exposure is determined by channel (2) for the barium image region, the entire image becomes too dark.

Therefore, if the light is received in channel ① of the area of the soft tissue image, the density will be just right. However, in order to select only this channel (2), it is sufficient to set the under level LU and over level LO shown in FIG. 7.

In the method of the implementation apparatus shown in FIG. 2, this point is not particularly mentioned, and over and under conditions of each channel are determined based on a fixed level. With this method, there is no problem when the exposure is stable, but in Example A, if the exposure condition is under, a situation like the one shown in Figure 8 will occur, and the situation will become stable and it may not be possible to reduce the exposure to the optimum condition. It happens. FIG. 8 is a diagram showing the signal level of each channel when the exposure condition is under, Lo is over level, LtJ
is below level.

Such a condition may occur even when the exposure conditions are over, and the barium may rise to meet the exposure conditions.

This state u, over level LO and 7inter level L
The closer the distance between U is, the more likely it is to occur. For this reason, in practice, the over level should be increased by 1.0,
This is to prevent this situation from occurring.

As a result, although the influence of the barium image can be well removed, the influence of the gas image and the halation image cannot be eliminated, and the image tends to become thinner.

Therefore, in order to solve the problems of the device implementing the basic part, the present invention provides means for setting the under level from the average output value of all channels, and means for setting the over level when the fluoroscopic tube voltage is equal to or higher than the intermediate tube voltage. Then, set the fluoroscopic tube voltage,
Equipped with a means to set the output from the average output value of all channels when the voltage falls below the intermediate tube voltage, ensuring optimal exposure is always achieved by reliably determining and excluding gas images, barium images, etc., regardless of the X-ray conditions or body position. It was made so that it could be obtained.

FIG. 9 is a diagram showing the configuration of one embodiment of the present invention, and it is shown that the over/under condition reference signal +E2 generated from the over/under detection reference signal generation circuit 18 of FIG. 2 is at a fixed level. From the average value of the output signals of all channels and the signal corresponding to the fluoroscopic tube voltage, the over level L is calculated.
This is a fortune telling that sets O and 77 Dar 1/Bell LU.

In FIG. 9, 30 is an average value circuit for the output signal E1 of all channels 11A to 11N, and each channel 11
The output signals E1 of A to 11N are respectively...
Aka1aR1~Rnh” (DR11*af*
It is composed of a first operational amplifier 60A. 61 is an overlevel setting circuit based on the average value of all channels, and a first potentiometer 61A.

Consists of a first variable resistor 31B, a second operational amplifier 510, a first potentiometer 31A and a first variable resistor 31B
is connected as a feedback circuit of the second operational amplifier 510. The first potentiometer 31A is for setting the amount of parallel movement of the overlevel curve, and the first variable resistor 61B is for setting the amount of inclination of the overlevel curve.

32 is an under level setting circuit based on the average value of all channels, and is composed of a second potentiometer 32A, a second variable resistor 32B, and a third operational amplifier 320. Third
It is connected as a feedback circuit for the operational amplifier 320. The second potentiometer 32A is for setting the amount of parallel movement of the under-level curve, and the second variable resistor 52B
is used to set the amount of slope of the underlevel curve. 66 is an FKV signal input terminal proportional to the fluoroscopic tube voltage;
64 is an overlevel setting circuit using an FKV signal corresponding to the fluoroscopic tube voltage, and a third potentiometer 64
A, third variable resistor 34B.

The third potentiometer 54A and the third variable resistor 34B are connected to the fourth operational amplifier 340.
40 is connected as a feedback circuit. The third potentiometer 34A is for setting the amount of parallel movement of the overlevel curve, and the third variable resistor 34B is for setting the amount of inclination of the overlevel curve. 35 is a load resistance r with a first diode 55A and a second diode 35.
I3 is an overlevel select circuit connected in parallel, and the input of the first diode 35A is the output signal of the overlevel setting circuit 31 based on the average value of all channels. The input of the second diode 35B is the output signal of the overlevel setting circuit 64 based on the fluoroscopic tube voltage, and the output of the second diode 653 and the first diode j
The larger output of the 5A outputs is output as the over condition reference signal El. 36 is an over condition reference signal output terminal, and 67 is an under condition reference signal output terminal.

Next, the operation of the embodiment shown in FIG. 9 will be explained.

In FIG. 9, the output signals of all channels 11A to 11N are averaged by an average value circuit 3o.

That is, when the input signal of the average value circuit 6o is V, ~Vn, the average value VA is obtained by the input resistors R3 to Rn and the feedback resistor 4 of the first operational amplifier 30A (by the following equation (1)).

1't R v1×zeR+v,×zeIt 10■n4/R-VA
(1) Next, the first button/g meter 31A of the overlevel setting circuit 31 sets the amount of parallel movement of the overlevel curve, and the first variable resistor 31B sets the amount of inclination of the overlevel curve. In addition, it corresponds to the tube voltage of fluoroscopy.
The third over level setting circuit 34 based on the KV signal
The amount of parallel movement of the overlevel curve is set by the potentiometer 34A, and the amount of inclination of the overlevel curve is set by the third variable resistor 34B. And all channels 1
Signal of average value VA of output signal E1 of 1A to 11N and FK
(2) The larger signal is output from the over-level select circuit 35 as the over-condition reference signal E1 based on the set parallel displacement amount and tilt amount, and is output from the over-condition reference signal output terminal 36.

On the other hand, the second potentiometer 32A of the underlevel setting port 132 sets the amount of parallel movement of the underlevel curve, and the second variable resistor 32B sets the amount of inclination of the underlevel curve. And all the channels 11A to 11N
The signal of the average value VA of the output signals is the under condition reference signal E based on the determined amount of parallel movement and amount of inclination.
The under condition reference signal is output from the under condition reference signal output terminal 37.

For example, in the case of the previous week's visual image as shown in Fig. 6, the output of each region is as follows in this embodiment: the gas image level ■, the soft tissue image level ■, and the barium image level as shown in Fig. 1O. ■It becomes. And all channels 11A to 11N
The average of the output signal E1 of .

Since the signal of value VA is similar to the output of each part, the overlevel L □,! m under level LIJ ha 1st
It is now possible to set it as shown in Figure 0.

On the other hand, when there is a large amount of barium coverage, for example when performing 4-part compression imaging, the overall average value signal VA will decrease, so the over level LO and under level LU will also decrease and the barium A situation may also occur where only the area around the statue is illuminated. Therefore, even if the average value VA signal decreases, it is possible to deal with the under level LtJ by changing the slope so that it does not decrease too much, but with the over level LO, even if the signal of the average value VA decreases, it is possible to deal with the over level LtJ.
Therefore, compression imaging with a large amount of barium coating utilizes the fact that the fluoroscopic tube voltage becomes high regardless of the thickness of the subject. That is, when the fluoroscopy tube voltage increases due to compression or the like, the overlevel L O set by the fluoroscopy tube voltage becomes the overlevel L set from the signal of the average value VA of the output signals Ei of all channels 11A to jlN.
By utilizing the fact that LO is higher than O, it is possible to prevent the overlevel LO from decreasing due to compression or the like. As a result, 2
For heavy contrast imaging, etc., by setting the over level LO and under level LUf set by the signal of the average value VA of the output signals E1 of all channels 11A-S-11N.
It becomes possible to reliably recognize barium images and gas images in response to various body positions and body thicknesses, and to make reliable judgments and remove their effects, thereby enabling optimal automatic exposure for fluoroscopy and photography. FIG. 11 shows the relationship between over-level and under-level with respect to the subject thickness.

In the method of the implementation apparatus shown in FIG. 9, the film density is often uniform in the case of general photography, but in certain body positions, such as the first oblique position in a three-dimensional image, the film does not pass through the subject.
X-rays that directly enter the input surface of 1.1.4 from the X-ray tube (
Hereinafter, we will simply refer to the part where the direct line (%) is incident, or
As shown in Fig. 12, when the gas image is very large, the average value of the lighting output level increases as shown in Fig. 13, and the output signal of channel Since the output signal of this channel ■ becomes very large, it is removed, but the output signal of the channel ■ located in the middle is judged to be effective because it is larger than the overlevel LO, and a part of the gas image is removed. There is a problem in that the density of the film obtained under the exposure conditions set by this lighting becomes low due to daylight.

The present invention further solves the above problems, and provides a halation signal detection means for detecting an output signal of a channel into which a gas image or a direct line part light is incident, and when a halation signal is detected by the halation signal detection means, means for removing or reducing the output signal of the channel corresponding to the detected halation signal from the input of the X-ray underexposure detection reference value setting means and the X-ray overexposure detection reference value setting means; Even if there is a direct line part, gas image, etc. in a part of the lighting field, the detection standard level should not change slightly, and the influence of the direct line part or gas image should be removed or reduced. It is something.

FIG. 14 is a diagram showing the configuration of one embodiment, and FIG.
This is an improved version of the average value circuit 60 of the X-ray underexposure detection reference value setting means and the X-ray overexposure detection reference value setting means shown in the figure.

In FIG. 14, 40 is a detection standard average value calculation circuit, and 40A and 40B are channels for halation detection provided in areas where halation is likely to occur.
This is a halation signal removal switch that is connected to the output of (2) and is used to prevent a halation signal from being input to the operational amplifier 400. 41 is a halation signal detection circuit, which includes a halation standard setter 41A, a first comparator 41B, a second comparator 410, and a latch circuit 4.
1N). 41g is a latch gate signal input terminal, SG, 8G, crawl, child circuit 411)
is the output signal of The signal SG+ is the first comparator 41
The signal is "1" when B is on, and "0" when it is off. Further, the signal SG is rlJ when the second comparator 41C is on, and is "0" when the second comparator 41C is off.

Next, the operation of this embodiment will be explained with reference to FIG.

``Mass, set the halation standard setting device 41A to the halation standard value. The first comparator 4113 and the second comparator 410 compare the ration reference value with the ration reference value, and if the signals of the channels ■ and ■ are larger than the ration reference value, the first comparator 41B and the second comparator 410 are turned on. , this on state is turned on in the child circuit 411).Here,
cormorant.

In the child circuit 411), the effects of signal noise, pull, etc. can be removed by varying the gate spacing. U, the detection reference average value calculation circuit 4 uses the output signals SG and SGt of the child circuit 41D.
0 no-ration signal removal switch, 40A and 40B
control. Signal SG.

When is r-IJ, the signal removal switch 40A is turned off, and the output signal of channel 2 is not input to the operational amplifier 400. Also, the signal SO.

When is "1", NO lane, N signal removal switch, CH40
I3 is turned off, and the output signal of channel R is not input to operational amplifier 400.

Here, if the output of the first comparator 41B is 31B and the output of the second comparator 410 is b, and the output is 11'' when on and 0 when off, then the output of the operational amplifier 400 (channel group 11 (output average value) VA can be expressed by the following equation (2).

(n-2)+a<+> In other words, the signals of channels other than the one in which the halation signal was detected are output from the operational amplifier 40C as an average value. The halation signal removal switches 40A and 40
When B is turned on, the output signals of channels ■ and ■ that are performing no-ration detection are averaged together, and when turned off, that output signal is excluded, so when no-ration detection is performed, the average The signal of this no-ration part is excluded from the value signal, and the influence of halation caused by the direct line part and the gas image is eliminated.

FIG. 15 shows another embodiment of the average value circuit of the present invention,
The output signals of channels ① and ① for halation detection shown in FIG. 14 are passed through buffer amplifiers 50A and 50B. ), the upper limit limiting circuits 51A and 5113 are configured to limit the signal level so that it does not exceed the standard signal level.
It is designed to reduce the effects of halation.

Note that the upper limit limiting circuits 51A and 5173 are resistors It
Although it is constructed using a diode, it may also be constructed using a transistor or the like, and any type of device may be used as long as it limits the signal level so that it does not exceed a certain level.

Of course, the present invention is not limited to the embodiments described above, and can be modified in various ways without changing the gist thereof.

As described above, according to the present invention, it is possible to prevent low-density photographs from being obtained due to the effects of halation caused by direct line portions, images, etc. during fluoroscopic photography.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional X-ray automatic exposure control device, FIG. 2 is a professional diagram showing the configuration of an embodiment of the basic part of the present invention, and FIG. FIG. 2 is a diagram showing a specific configuration of the circuit of the multi-lighting section, and FIG. 4 is the over/under detection circuit of FIG. 2. FIG. 5 shows the specific configuration of the all-channel over detection circuit, the all-channel under detection circuit, and the partial over-remaining all-under detection circuit. 6 to 8 are diagrams for explaining the principle of over/under detection reference signal generation according to the present invention, and FIG. 9 is an illustration of an over/under detection reference signal generation circuit according to the present invention. A diagram showing the configuration of an example,
FIG. 10 is a diagram showing the output, over level, and under level of each part in the case of the previous week's visual image according to the embodiment of FIG. 9, and FIG. Figures 12 and 12. 13 is a diagram for explaining the problem of the over/under detection reference signal generation circuit according to the present invention shown in FIG.
FIG. 4 is a diagram showing the configuration of one embodiment of the over/under detection reference signal generation circuit of the present invention, and FIG. 15 is a diagram showing the configuration of another embodiment of the over/under detection reference signal generation circuit of the present invention. It is a diagram. 40 Detection standard average value calculation circuit 40A, 40B Halation No. a removal switch 40Q
Operational amplifier 41 Halation signal detection circuit 41A Halation reference setter 41r3 First comparator 410 Second comparator 411] Latch circuit 411D Latch gate signal input terminals 50A, 50B
・Buffer amplifier srA, s1B Upper limit limit circuit agent Patent attorney Aki 1) Shu Ki

Claims (1)

[Claims] A means for providing a lighting unit consisting of a plurality of lighting devices within the lighting field of the output of the image intensifier, and detecting whether the output of each lighting device is underexposed to X-rays or overexposed to X-rays, and the means means for removing the output of the daylight under the conditions of X-ray underexposure and X-ray overexposure by the output of;
X-ray underexposure detection reference value setting means for setting an X-ray underexposure detection reference value from the average output value of all daylights; This is an X-ray exposure device equipped with an X-ray overexposure detection reference value setting means that sets an X-ray overexposure detection reference value that is set at A halation signal detection means detects the output signal of the lighting device into which the light enters, and the halation signal detection means detects the
- When the ration signal is detected, the output signal of the lighting device corresponding to the detected ration signal is input to the X-ray underexposure detection reference value setting means and the X-ray overexposure detection reference value setting means. 1. An automatic X-ray exposure device characterized by comprising means for removing or reducing and inputting an X-ray.