JP2001061829A - Fluoroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluoroscope preventing such deficiency as blooming when excessive X-rays enter a part of the picture. SOLUTION: In this fluoroscope, an X-ray generating part 1 generates X-rays for irradiating a subject, an X-ray I.I.3 receives the X rays transmitted through the subject and detects an image signal corresponding to the transmitted X rays, and an image display device 9 displays the detected image signal. The incoming of excessive X rays to a part of the picture is prevented by controlling an X-ray high voltage generator 12 according to an exposure signal 641 from an automatic exposure control device 6, which detects whether the image signal exceeds a prescribed maximum value or not, when the X-ray high voltage generator 12 controls the quantity of X rays to be generated from the X-ray generating part 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluoroscope for irradiating a subject with X-rays, capturing an X-ray image transmitted through the subject, converting the image into a video signal, and displaying it as a moving image of a continuous frame. In particular, when excessive X-rays enter a part of the screen, the amount of charge exceeds the maximum value that can be stored by a CCD (Charged Couple Device), and overflowing charges flow into adjacent pixels, resulting in image damage such as blooming. The present invention relates to an X-ray fluoroscope for preventing a problem.

[0002]

2. Description of the Related Art In a conventional X-ray fluoroscope, a subject is irradiated with X-rays, an X-ray image transmitted through the subject is captured by a television camera, and an output signal of the television camera is converted into a video signal by a signal processor. Then, it is displayed on the display as a moving image of a continuous frame. The imaging device of this TV camera is C
CDs are often used. CCDs have a problem of blooming, and to prevent the blooming, an imaging device has adopted an anti-blooming structure. In this structure example, an overflow drain that absorbs overflow charges is provided adjacent to each pixel in many cases. For example, on page 94 of "Image Input Handbook" written by Yuji Kiuchi et al., Nikkan Kogyo Shimbun (published in 1992), a schematic structure diagram of a horizontal overflow drain, which is one type of overflow drain, is shown.

[0003]

However, even if an overflow drain is provided as in the above-mentioned prior art, if an amount of light several hundred times the normal signal level is received by a direct line or the like, the overflow drain is not provided. In some cases, blooming may occur beyond the limit of discharging electric charges from the device.

Therefore, in the conventional X-ray fluoroscopy apparatus, the reference voltage of the analog-to-digital converter included in the signal processor is set to the value of the digital image when the output characteristic of the analog image signal is in the linear region and the maximum output is obtained. The device was devised to set the signal to the maximum digital value, but the measures to prevent blooming were not sufficient.

A first object of the present invention is to provide an X-ray fluoroscopic apparatus capable of preventing a trouble such as blooming when excessive X-ray enters a part of a screen.

A second object of the present invention is to provide an X-ray fluoroscopic apparatus capable of reducing the influence on a display image in preventing the above-mentioned problem caused by excessive X-rays.

[0007] A third object of the present invention is to provide a method for quickly canceling a measure for preventing a malfunction when the excess X-rays causing the malfunction disappear, and restoring the image quality reduced by the influence of the measure. It is to provide a fluoroscope.

[0008]

The first and third objects are achieved by the following constitution.

(1) X generating X-rays for irradiating a subject
A ray generation unit, an X-ray detection unit that receives an X-ray transmitted through the subject, and detects a video signal corresponding to the transmitted X-ray, a unit that displays the detected video signal, and the X-ray generation unit X-ray fluoroscopy apparatus comprising: an X-ray dose control means for controlling an X-ray dose generated by the apparatus; and a means for detecting whether the video signal exceeds a preset maximum value. An X-ray fluoroscope, wherein the X-ray dose control means is controlled in accordance with a signal.

(2) X for generating X-rays for irradiating a subject
A line generating unit, means for converting the X-rays transmitted through the subject into an optical image, aperture means for adjusting the amount of light of the converted optical image, means for capturing the adjusted optical image, and the captured optical An X-ray fluoroscopic apparatus comprising: means for displaying an image; and aperture control means for controlling the aperture means, comprising: means for detecting whether or not the video signal exceeds a preset maximum value; An X-ray fluoroscope, wherein said diaphragm control means is controlled in accordance with an output signal of said means.

When the output signal of the detecting means exceeds the maximum value, the X-ray dose of the X-ray dose controlling means or the light amount passing through the diaphragm means by the diaphragm controlling means is set below a critical point at which blooming does not occur. Control so that

When the maximum value is not exceeded, the X-ray dose of the X-ray dose control means or the amount of light passing through the aperture means by the aperture control means is not controlled for blooming.

In addition, when the video is switched from the video exceeding the maximum value to the video not exceeding the maximum value, the control related to blooming is promptly released.

The second object is achieved by the following constitution.

(3) An X-ray fluoroscope according to the above (1), further comprising means for correcting a fluctuation amount generated in the video signal by an X-ray amount controlled according to an output signal of the detection means. apparatus.

(4) An X-ray fluoroscopic apparatus according to the above (2), further comprising means for correcting a fluctuation amount generated in the video signal by a light amount controlled according to an output signal of the detection means. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an X-ray fluoroscope according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the X-ray fluoroscope according to the present invention. An X-ray generated by an X-ray generation unit 1 including an X-ray tube 11 and an X-ray high-voltage device 12 is applied to a subject 2 such as a human body.
X-ray I.I.3, which is an X-ray image converter for converting a line image into an optical image, CCD 71, which is an imaging device for converting an optical image into an analog video signal, and an output image of X-ray I.I.3 An imaging optical system 4 for forming an image on the CCD 71;
In order to adjust the light quantity of the upper optical image, an image is picked up by an X-ray sensing means composed of an optical diaphragm 5 provided in the image pickup optical system 4 and converted into an analog video signal 711 of a continuous frame. The analog video signal 711 is processed into a digital video signal 721 by a signal processor 72, which is a signal processing means having an analog-to-digital converter, and includes a display gradation LUT 8 as a display gradation conversion means and a video display 9. It is displayed as a moving image by the displayed image display means. CCD 71 and signal processor 72 are usually CCD
It is grouped as a camera 7. Automatic exposure control device 6
Is a mirror 61 which is inserted in the middle of the imaging optical system 4 and takes out a part of the light beam for photometry, and a lens 62 which forms an image of the light beam for photometry.
A PMT 63 for measuring the amount of light at the center of the image forming unit;
Amplifier 64 for converting the output current signal of T63 into a voltage signal
And an exposure signal 6 corresponding to the brightness at the center of the image.
41 is transmitted to the X-ray high voltage device 12. X-ray high voltage device 1
2 increases / decreases the irradiation X-ray dose so that the exposure signal 641 becomes a constant value.

Further, in the first embodiment, the analog video signal 711 has a constant signal value larger than the analog signal value corresponding to the maximum value of the digital video signal 721 in the signal processor 72 as the signal processing means. Detecting means (not shown) comprising an analog comparator for detecting a value equal to or higher than a certain detection level is provided, and a detection signal
In order to reduce the X-ray dose and the amount of light transmitted through the optical stop 5 in accordance with 3, a fluoroscopy controller 10 which is both a dose control unit and a stop control unit is provided. When the fluoroscopy controller 10 sends a gain increase command 120 to the automatic exposure control device 6, the gain of the amplifier 64 of the automatic exposure control device 6 increases and the sensitivity of the entire automatic exposure control device 6 increases, and conversely, the gain increases. The dose corresponding to the exposure signal 641 that is feedback-controlled to a value decreases. When the fluoroscopy controller 10 sends the stop command 130 to the optical stop 5, the optical stop is stopped down, and the amount of transmitted light decreases. The fluoroscopy controller 10 issues a detection level setting command 1
10, a detection level to be compared with the analog video signal 711 by an analog comparator (not shown) in the signal processor 72 is set as shown in FIG. FIG. 2 shows the exposure amount of the CCD 71 and the analog video signal 71 in the first embodiment.
It is a relation of 1. The analog signal value corresponding to the maximum value of the digital video signal 721 is set to be equal to or less than the maximum output of the linear area in FIG. 2, but the detection level is the maximum output of the linear area and the maximum of the analog video signal 711 corresponding to the amount of light of the blooming generation level. During the output, the value is set to a value corresponding to the light amount of the blooming alert level. Also, the fluoroscopy controller 10
Has a role of changing the display gradation LUT 8 so as to correct a decrease in the amount of light on the CCD 71 as an imaging device due to the gain increase command 120 and the aperture command 130 by the gradation change command 140.

A CPU is incorporated in the fluoroscopy controller 10 and operates according to the flowchart of FIG. First, as one of the processes at the time of starting, a detection level setting signal 110 is transmitted by a process 1101, and the detection level is set as shown in FIG. Thereafter, the detection signal 73 is constantly monitored by repetition including the determination 1102, and upon receiving the detection signal 73, a measure for preventing blooming is taken immediately. That is, the process 110
3, the aperture command 130 is sent to the optical aperture 5, the gain increase signal 120 is sent to the automatic exposure controller 6, and the gradation change command 1
40 is transmitted to the display gradation LUT 8 to reduce the amount of light on the CCD 71 and reduce the signal level of the analog video signal 711 as a whole, while correcting the reduction in the signal level by changing the conversion curve of the display gradation LUT 8. I do. Once blooming or near blooming occurs,
Since the cause often does not disappear for a while, it is necessary to wait 1 minute in processing 1104 and then execute processing 11105 in processing 1105.
After canceling the treatment performed in step 03, the process returns to the monitoring of the detection signal 73 by repetition including the determination 1102.

FIG. 4 is a block diagram showing a second embodiment of the X-ray fluoroscope according to the present invention. The second embodiment is different from the first embodiment in that an analog-to-digital converter (not shown) in the signal processor 72 outputs a digital video signal 721.
Has two types of analog signal values corresponding to the maximum value of the first and second AD conversion levels, and the AD conversion level designation command 150 from the fluoroscopy controller 10.
Thus, the first AD conversion level can be changed to the second AD conversion level. Also in the second embodiment,
The comparator (not shown) in the signal processor 72 compares the analog video signal 711 with the detection level. If the detection level exceeds the detection level, the detection signal 73 is transmitted to the fluoroscopy controller 10, and the fluoroscopy controller 10 issues a gain increase command 120 and an aperture command 130. Is issued, but instead of issuing the gradation change command 140 to the display gradation LUT 8, an A / D conversion level designation command 150 is issued to the signal processor 72.

FIG. 5 shows a CCD 71 according to the second embodiment.
And the analog video signal 711. Normally, in order to effectively use the amount of light up to the saturation level for video, the maximum output of the analog video signal 711 in the linear region is set to the first AD conversion level. As shown in FIG. 5, the second AD conversion level is set in a linear region lower than the first AD conversion level.
The ratio to the conversion level is the same as the ratio of the decrease in the signal level of the analog video signal 711 caused by the decrease in the amount of light on the CCD 71 due to the gain increase command 120 and the aperture command 130. Has no effect on

FIG. 6 is a flowchart showing the operation of the fluoroscopy controller 10 according to the second embodiment. Compared to the flowchart showing the operation of the fluoroscopy controller 10 of the first embodiment in FIG.
01 is the same as the processing 1101 and the judgment 1202 is the same as the judgment 1102, but the processing 1203 is different from the processing 1103 and the transmission of the gradation change command 140 of (3) to the transmission of the AD conversion level change command 150. Process 1204 is the same as process 1104, but
The process 1205 is a process 1105 and the gradation change command 14 of (1).
The release of 0 has changed to the release of the AD conversion level change command 150.

FIG. 7 is a block diagram showing a third embodiment of the X-ray fluoroscope according to the present invention. The third embodiment is different from the first embodiment in that the detection level to be compared with the analog video signal 711 by a comparator (not shown) in the signal processor 72 is:
With the first detection level setting command 160 and the second detection level setting command 170 from the fluoroscopy controller 10, two types of detection can be set: the first detection level and the second detection level smaller than the first detection level. Usually, the first detection level is set, and the analog video signal 711 is monitored in comparison with the first detection level. When the analog video signal 711 exceeds the first detection level and the detection signal 73 is transmitted to the fluoroscopy controller 10, the fluoroscopy controller 10 issues a gain increase command 120 and an aperture command 130 and sends a gradation change command 140 to the display gradation LUT 8. Until the signal is emitted, the same as the first embodiment, but in the third embodiment, the detection level is further switched to the second detection level by the second detection level setting command 170, and the analog video signal 711 is newly generated by the second detection level. Be monitored. That is, the gain increase command 1
The analog image signal 711 is reduced from around the first detection level to around the second detection level due to a decrease in the amount of light on the CCD 71 due to 20 and the aperture command 130. When removed, the analog video signal 711 becomes lower than the second detection level. Therefore, the fluoroscopy controller 10 detects this by the detection signal 73, cancels the blooming prevention process by the gain increase command 120 and the aperture command 130, and cancels the corresponding floor. The key change command 140 is also released.

FIG. 8 shows a CCD 71 according to the third embodiment.
And the analog video signal 711. First
The detection level is set to a value corresponding to the amount of light at the blooming alert level, similarly to the detection levels in FIGS. Second
Although the detection level is set lower than this, the ratio of the second detection level to the first detection level is determined by the gain increase command 120.
And the ratio of the decrease in the signal level of the analog video signal 711 caused by the decrease in the amount of light on the CCD 71 due to the aperture command 130, so that the detection is performed until the cause of blooming such as a direct line is reliably removed. The signal 73 is kept output.

FIG. 9 is a flowchart showing the operation of the fluoroscopy controller 10 according to the third embodiment. First, the first detection level setting signal 160
And sets the detection level to the first detection level. Thereafter, the detection signal 7
3 is constantly monitored, and upon receiving the detection signal 73, measures are taken immediately to prevent blooming. That is, by the processing 1303, the aperture command 130 is transmitted to the optical aperture 5, the gain increase signal 120 is transmitted to the automatic exposure control device 6, and the gradation change command 140 is transmitted to the display gradation LUT 8, so that the light amount on the CCD 71 is reduced. While the signal level of the analog video signal 711 is reduced overall, the reduction of the signal level is corrected by changing the conversion curve of the display gradation LUT 8. Further processing 130
4, the second detection level setting signal 170 is transmitted, the detection level is set to the second detection level, and the judgment 13 is performed again.
05, the detection signal 73 is constantly monitored. When the detection signal 73 is no longer received, the processing performed in the processing 1103 is canceled in the processing 1306, and the detection level is set in the processing 1307 by the first detection level setting signal 160. After returning to one detection level, the process returns to monitoring of the detection signal 73 by repetition including the determination 1302.

In the third embodiment, once the cause of blooming such as direct rays is eliminated, the anti-blooming treatment is immediately canceled without waiting for at least one minute as in the first and second embodiments, By increasing the amount of transmitted light through the aperture, it is possible to recover from a decrease in image quality due to a blooming prevention measure. Conversely, when the cause of blooming such as a direct line cannot be easily removed, in the first and second embodiments, the blooming prevention measure is canceled once, the detection signal 73 is detected again, and then the blooming prevention measure is resumed. This process is performed at one-minute intervals, and there is a disadvantage that the image changes each time, and some blooming occurs. However, in the third embodiment, a direct line or the like is taken while performing a blooming prevention measure. There is no such inconvenience because the cause of the blooming is awaited.

It is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified. For example,
In the above-described embodiment, both the reduction of the X-ray dose generated by the X-ray generation unit 1 and the reduction of the optical aperture 5 are performed as a blooming prevention measure. And the signal level of the analog video signal 711 can be reduced, so that the purpose of preventing blooming is achieved. Further, only one of them has a simple configuration and control. However, if the signal level of the analog video signal 711 is lowered only by lowering the X-ray dose generated by the X-ray generator 1, the signal-to-noise ratio of the X-ray image itself incident on the X-ray II. Since it is reduced in proportion to the square root of the rate of reduction of the radiation dose, the image quality is greatly reduced. On the other hand, if the signal level of the analog video signal 711 is lowered only by stopping down the optical stop 5, the X-ray II is reduced.
There is no deterioration in the image quality of the X-ray image itself incident on
Since the decrease in the amount of light above the line 71 reduces the signal-to-noise ratio of the analog video signal 711 due to the noise of the CCD 71 itself, the signal-to-noise ratio of the X-ray image is compared with the signal-to-noise ratio of the analog video signal 711. Unnecessarily high. When the subject 2 is a human body, an unnecessarily high signal-to-noise ratio of an X-ray image is harmful due to unnecessary X-ray exposure. As described above, from both aspects of image quality deterioration and X-ray exposure, as shown in the above embodiment, the X-ray generation unit 1
It is desirable to both reduce the X-ray dose at which the laser beam is generated and to stop down the optical stop 5.

In the above embodiment, the fluoroscopy controller 10 sends a gain increase command 120 to the automatic exposure controller 6 to reduce the X-ray dose generated by the X-ray generator 1. However, when the X-ray high voltage device 12 can directly change the target value of the exposure signal 641 by external control, the fluoroscopy controller 10 issues a command to the X-ray high voltage device 12 directly. To change the target value, more fine-grained control is possible.

The first and third embodiments employ a method of changing the display gradation of the display gradation LUT 8 in order to correct the signal level drop of the analog video signal 711.
In the second embodiment, a method of changing an analog signal value corresponding to the maximum value of the digital video signal 721 by an analog-to-digital converter in the signal processor 72 is adopted. The former method has an advantage that the display gradation can be finely adjusted by changing the gradation conversion curve as compared with the latter method. However, in some cases, the fluctuation range of the digital video signal 721 cannot be used effectively, so Errors may be noticeable. Therefore, if the control method can be somewhat complicated,
By combining these two methods, a better display can be obtained. In order to cancel the anti-blooming treatment, the first and second embodiments employ a method of waiting for a certain period of time, and the third embodiment employs a method of waiting for the detection signal 73 to stop being received. However, in the configuration of the third embodiment, the flow of the operation of the fluoroscopy controller 10 can be changed so that a combination of these two methods is waited for a predetermined time and then the detection signal 73 is not received. By doing so, the release of the blooming prevention measure is delayed, but more stable control can be achieved.

According to the present invention, there is provided an X-ray generating unit for generating X-rays for irradiating a subject, and capturing an X-ray image transmitted through the subject and converting it into a digital video signal of a continuous frame.
An X-ray sensing unit configured to generate an analog video signal that monotonically increases in accordance with an incident X-ray dose; an X-ray imaging unit including a signal processing unit configured to process the analog video signal into a digital video signal; In an X-ray fluoroscopic apparatus comprising: a video display unit for displaying a signal; and a dose control unit for controlling an X-ray dose generated by the X-ray generation unit, the signal processing unit is configured so that the analog video signal is a maximum value of the digital video signal. Detecting means for detecting that the value is equal to or greater than a constant signal value larger than the analog signal value corresponding to the above, and wherein the dose control means reduces the X-ray dose in accordance with the detection signal of the detecting means. Accordingly, it is possible to prevent a problem such as blooming from occurring when excessive X-rays enter a part of the screen.

The present invention also provides an X-ray generation unit for generating X-rays for irradiating a subject, and an X-ray image capturing unit for capturing an X-ray image transmitted through the subject and converting the image into a digital video signal of a continuous frame. An X-ray image converter for converting an X-ray image into an optical image, an imaging device for converting an optical image into an analog video signal that monotonically increases according to the amount of light, and an output image of the X-ray image converter connected to an imaging device. X-ray sensing means comprising an imaging optical system for imaging, an optical diaphragm provided in the imaging optical system for adjusting the amount of optical image on the imaging device, and a digital video signal An X-ray imaging apparatus comprising a signal processing means for processing the image, an image display means for displaying the digital image signal, and an aperture control means for controlling the optical aperture, Signal processing means includes detection means for detecting that the analog video signal is a value equal to or greater than a constant signal value larger than the analog signal value corresponding to the maximum value of the digital video signal, and the aperture control means includes: Since the amount of light is reduced according to the detection signal of the means, it is possible to prevent a problem such as blooming from occurring when excessive X-rays enter a part of the screen.

Also, the present invention provides an X-ray generation unit for generating X-rays for irradiating a subject, and an incident X-ray for capturing an X-ray image transmitted through the subject and converting the image into a digital video signal of a continuous frame. X-ray sensing means for generating an analog video signal that monotonically increases in accordance with the dose, X-ray imaging means including signal processing means for processing the analog video signal into a digital video signal, and displaying the digital video signal An X-ray fluoroscopic apparatus comprising: a display gradation converting unit; a video display unit configured to include a video display unit; and a dose control unit configured to control an X-ray dose generated by the X-ray generation unit. The signal processing means includes detection means for detecting that the analog video signal has a value equal to or greater than a certain signal value larger than an analog signal value corresponding to the maximum value of the digital video signal, The control means reduces the X-ray dose according to the detection signal of the detection means, and the display gradation converting means corrects the X-ray dose reduction by the dose control means according to the detection signal of the detection means. Since the tone is changed, it is possible to prevent a problem such as blooming from occurring when excessive X-rays enter a part of the screen. Impact on the environment can be reduced.

Also, the present invention provides an X-ray generating unit for generating X-rays for irradiating a subject, and an X-ray generating unit for capturing an X-ray image transmitted through the subject and converting the image into a digital video signal of a continuous frame. An X-ray image converter for converting an X-ray image into an optical image, an imaging device for converting an optical image into an analog video signal that monotonically increases according to the amount of light, and an output image of the X-ray image converter connected to an imaging device. X-ray sensing means comprising an imaging optical system for imaging, an optical diaphragm provided in the imaging optical system for adjusting the amount of optical image on the imaging device, and a digital video signal X-ray imaging means comprising signal processing means for processing the image, display gradation conversion means for displaying the digital video signal, video display means comprising a video display, and the optical diaphragm System X consisting of a diaphragm control means for
In the fluoroscopic apparatus, the signal processing unit includes a detection unit that detects that an analog video signal is a value equal to or greater than a constant signal value larger than an analog signal value corresponding to the maximum value of the digital video signal, The control means reduces the light quantity according to the detection signal of the detection means, and the display gradation conversion means corrects the display gradation so as to correct the light quantity decrease by the aperture control means according to the detection signal of the detection means. Since the configuration is changed, it is possible to prevent a problem such as blooming from occurring when excessive X-rays enter a part of the screen. The effect can be reduced.

The present invention also provides an X-ray generating unit for generating X-rays for irradiating a subject, and an incident X-ray for capturing an X-ray image transmitted through the subject and converting the image into a digital video signal of a continuous frame. X-ray sensing means for generating an analog video signal that monotonically increases in accordance with the dose, X-ray imaging means including signal processing means for processing the analog video signal into a digital video signal, and displaying the digital video signal An X-ray fluoroscopic apparatus comprising: a display gradation converting unit; a video display unit configured to include a video display unit; and a dose control unit configured to control an X-ray dose generated by the X-ray generation unit. The signal processing means converts the analog signal value corresponding to the maximum value of the digital video signal into a first AD conversion level,
A second AD conversion level smaller than the first AD conversion level, and a detection means for detecting that the analog video signal has a value equal to or greater than a predetermined signal value larger than the first AD conversion level; Reduces the X-ray dose according to the detection signal of the detection means, and the signal processing means converts the analog signal value corresponding to the maximum value of the digital video signal from the first AD conversion level according to the detection signal. Since it is configured to change to the second AD conversion level,
When excessive X-rays enter a part of the screen, it is possible to prevent problems such as blooming from occurring, and to prevent the above-described problems caused by excessive X-rays, it is possible to reduce the influence on a display image.

The present invention also provides an X-ray generation unit for generating X-rays for irradiating a subject, and an X-ray image capturing unit for capturing an X-ray image transmitted through the subject and converting the image into a digital video signal of a continuous frame. An X-ray image converter for converting an X-ray image into an optical image, an imaging device for converting an optical image into an analog video signal that monotonically increases according to the amount of light, and an output image of the X-ray image converter connected to an imaging device. X-ray sensing means comprising an imaging optical system for imaging, an optical diaphragm provided in the imaging optical system for adjusting the amount of optical image on the imaging device, and a digital video signal X-ray imaging means comprising signal processing means for processing the image, display gradation conversion means for displaying the digital video signal, video display means comprising a video display, and the optical diaphragm System X consisting of a diaphragm control means for
In the fluoroscopy apparatus, the signal processing means converts an analog signal value corresponding to the maximum value of the digital video signal into a first AD signal.
A conversion level and a smaller second AD conversion level are switchable, and the analog video signal is the first AD conversion level.
A detecting means for detecting that the value is equal to or greater than a constant signal value larger than the AD conversion level, the aperture control means reduces the light amount according to a detection signal of the detecting means, and the signal processing means In accordance with the detection signal, the analog signal value corresponding to the maximum value of the digital video signal is set to 1A
Since the configuration is changed from the D conversion level to the second AD conversion level, it is possible to prevent a problem such as blooming from occurring when excessive X-rays enter a part of the screen, and to prevent the above-mentioned excessive X-rays. In preventing problems, the influence on the displayed image can be reduced.

An X-ray generation unit for generating X-rays for irradiating a subject, and an X-ray image transmitted through the subject, which is taken and converted into a digital video signal of a continuous frame. X to generate an increasing analog video signal
X-ray imaging means including a line sensing means, a signal processing means for processing the analog video signal into a digital video signal, an image display means for displaying the digital video signal, and an X-ray generated by the X-ray generation unit. In an X-ray fluoroscopic apparatus comprising a dose control unit for controlling a dose, the signal processing unit may be configured so that the analog video signal has two signal values larger than the analog signal value corresponding to the maximum value of the digital video signal. A detection level, and a detection means for detecting that the value is equal to or more than a second detection level smaller than the detection level, wherein the dose control means detects that the detection means detects an analog video signal having a first detection level or more. X-ray dose is reduced, and when the detecting means stops detecting an analog video signal of the second detection level or more in one frame, the X-ray dose is increased. As a result, it is possible to prevent problems such as blooming from occurring when excessive X-rays enter a part of the screen, and to promptly prevent problems when excessive X-rays that cause the problem disappear. The treatment can be canceled, and the image quality reduced by the influence of the treatment can be restored.

An X-ray generator for generating X-rays for irradiating a subject, and an X-ray image which has been transmitted through the subject and which converts the X-ray image into an optical image in order to convert the image into a digital video signal of a continuous frame. An X-ray image converter for converting, an imaging device for converting an optical image into an analog video signal that monotonically increases according to the amount of light, and an imaging optical system for forming an output image of the X-ray image converter on the imaging device. X-ray sensing means comprising an optical diaphragm provided in an imaging optical system for adjusting the amount of an optical image on an imaging device, and signal processing means for processing the analog video signal into a digital video signal X-ray imaging means, an image display means for displaying the digital video signal, and an X-ray fluoroscope comprising aperture control means for controlling the optical aperture, the signal processing means, Analog video signal is a large two signal values than the analog signal value corresponding to the maximum value of the digital video signal, a first detection level, smaller than this second
Detecting means for detecting that the value is equal to or higher than any one of the detection levels, wherein the aperture control means reduces the light amount when the detecting means detects an analog video signal equal to or higher than the first detection level; The means is the second in one frame
Since the amount of light is increased when an analog video signal higher than the detection level is not detected, problems such as blooming can be prevented when excessive X-rays enter a part of the screen. When the incidence of excessive X-rays causing the above is eliminated, the measures for preventing the failure can be promptly canceled, and the image quality reduced by the influence of the measures can be restored.

[0039]

The present invention has the effect of providing an X-ray fluoroscope which prevents problems such as blooming when excessive X-rays enter a part of the screen.

Further, in preventing the problem caused by the excessive X-rays, there is an effect of providing an X-ray fluoroscope in which the influence on a display image is reduced.

When the incidence of the excessive X-rays causing the failure is eliminated, the measures for preventing the failure are immediately released, and
There is an effect of providing an X-ray fluoroscope in which image quality reduced by the influence of the treatment is restored.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of an X-ray fluoroscopic apparatus according to the present invention.

FIG. 2 is a graph showing a relationship between an exposure amount of a CCD and an analog video signal in the first embodiment of the X-ray fluoroscope according to the present invention.

FIG. 3 is a flowchart showing the operation of the fluoroscopy controller of the first embodiment of the X-ray fluoroscopy apparatus of the present invention.

FIG. 4 is a block diagram of a second embodiment of the X-ray fluoroscopic apparatus according to the present invention.

FIG. 5 is a graph showing a relationship between an exposure amount of a CCD and an analog video signal in a second embodiment of the X-ray fluoroscope according to the present invention.

FIG. 6 is a flowchart showing the operation of the fluoroscopy controller of the second embodiment of the X-ray fluoroscopy apparatus of the present invention.

FIG. 7 is a block diagram of a third embodiment of the X-ray fluoroscopic apparatus according to the present invention.

FIG. 8 is a graph showing a relationship between an exposure amount of a CCD and an analog video signal in a third embodiment of the X-ray fluoroscope according to the present invention.

FIG. 9 is a flowchart showing the operation of the fluoroscopy controller of the third embodiment of the X-ray fluoroscopy apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray generator 2 Subject 3 X-ray II. 4 Imaging optical system 5 Optical aperture 6 Automatic exposure controller 7 CCD camera 8 Display gradation LUT 9 Image display 10 Transparent controller

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Claims (4)

[Claims] An X-ray generating unit for generating X-rays for irradiating a subject; X-rays transmitted through the subject are incident thereon;
An X-ray detector comprising: an X-ray detector that detects a video signal corresponding to a ray; a unit that displays the detected video signal; and an X-ray dose controller that controls an X-ray dose generated by the X-ray generator. An X-ray fluoroscope, comprising: means for detecting whether or not the video signal exceeds a preset maximum value, and controlling the X-ray dose control means in accordance with an output signal of the detection means. Fluoroscope. 2. The apparatus according to claim 1, further comprising a unit that corrects a variation amount generated in the image signal by an X-ray amount controlled according to an output signal of the detection unit.
A fluoroscope. 3. An X-ray generator for generating X-rays for irradiating a subject, means for converting X-rays transmitted through the subject into an optical image, and diaphragm means for adjusting the amount of light of the converted optical image; In an X-ray fluoroscopic apparatus including a unit that captures the adjusted optical image, a unit that displays the captured optical image, and a diaphragm control unit that controls the diaphragm unit, the image signal is set to a predetermined maximum. An X-ray fluoroscope, comprising: means for detecting whether the value exceeds a value, and controlling the aperture control means in accordance with an output signal of the detecting means. 4. The X-ray fluoroscopic apparatus according to claim 3, further comprising: means for correcting a fluctuation amount generated in said video signal by a light amount controlled according to an output signal of said detection means.