JPS58105743A - X-ray image treating apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves irradiating a subject with X-rays, inputting the transmitted X-ray image into an image intensifier, photographing the resulting output image with a television camera, and recording the video signal. The present invention relates to an X-ray image processing device that performs image processing by converting from analog to digital.

Conventional X-ray fluoroscopic imaging equipment that includes an Yes, the X-ray irradiation dose is small. Therefore, the dynamic range of the input light amount of the TV camera is 10nA ~]0
It is as small as OnA.

When such a television camera is used to take a normal photographic image with a large amount of X-ray irradiation, the amount of input light to the television camera is 10 to 100 times higher than in the case of fluoroscopy, and the camera may become saturated. Therefore, a diaphragm device is used to limit the signal current so that it can be used within a range that does not saturate.

If the aperture of the aperture device is changed to prevent the signal current from always being saturated, the television camera can be used for inputs with a large dynamic range, but the difference between the input X-ray dose transmitted through the subject and the signal output The correspondence relationship becomes unclear. Therefore, it is not possible to perform quantitative evaluation by receiving the signal output, which causes inconvenience when processing such as subtraction.

SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray image processing apparatus that eliminates the above-mentioned drawbacks and is capable of quantitative input evaluation using a television camera even for inputs with a large dynamic range.

A feature of the present invention is that an aperture device is provided in the front stage of a television camera, and the aperture value of the aperture device corresponds to the peak value of the video signal by inputting and quantitatively evaluating the peak value of a predetermined video signal in two or more digital stages. The present invention includes an aperture value setting means for setting the aperture value, a means for controlling the automatic aperture device according to the aperture value setting, and a means for calibrating a video signal using the aperture value setting.

The present invention will be described in detail below along with examples.

FIG. 1 is a professional diagram showing the configuration of an embodiment of the present invention, in which 1 is an X-ray tube, 2 is a subject, 3 is an image intensifier, and 4 is an automatic aperture using a servo motor. A device, 5 is a television camera, 6 is a video signal peak value input from the television camera 5 by inputting and quantitatively evaluating the peak value of a predetermined video signal from 2 to 4 (represented by 2 bits). 7 is an analog-to-digital converter that converts the video signal into a digital signal, and 8 is a level conversion and logarithmic conversion table that pre-calibrates the digital video signal with the set aperture value. ROM (R, e
ad 0nly Memory ) or RAM (
The image information stored in this ROM or RAM 8 is read out and sent to an image processing unit CPU (not shown).

For example, as shown in FIG. 2, the automatic aperture device 4 has an aperture control port between the plus (+) voltage and the minus (-) voltage supplied from the power source CC of the lens control section 4A of the television camera 5. A tension meter 4B is provided, and its button/
The aperture control voltage is taken out from the contact point of the slider 4C of the Yonmeter 4B and inputted to the differential amplifier 4D.
The output of D automatically controls the aperture control motor 4E.

The aperture value setting circuit 6, for example, as shown in FIG. 3, holds the peak value of the video signal for one frame in a peak bold circuit 6A, and this peak value is set in advance, for example. The analog-to-digital converter 6B detects which stage of the digital stages of 0°1.2.3 the input corresponds to and quantitatively evaluates the input. Since this step value is inversely proportional to the aperture rate of the aperture device, this value is used as the set aperture value. Latch this set aperture value to 6C,
It is applied to the slider 4C of the aperture control button meter 4B shown in FIG. 2 through the digital-to-analog converter 6D. Also, since the set aperture value is temporarily stored in the Ciro C as a digital value, the set aperture value can be used for the R
It is configured to send to OM or RAM 8 to calibrate the digital video signal.

Next, the operation of this embodiment will be explained.

In Fig. 1, when an X-ray (1) is irradiated from an X-ray tube 1 in response to an X@irradiation start signal, the X-ray image that passes through a subject 2 (1-) enters an image intensifier 3, and this image intensifier is converted into light and output. This light output image is photographed by a television camera 5, and this video signal is input to an aperture value setting circuit 6 that controls the aperture of the automatic aperture device 4, and a peak hold circuit 6 shown in FIG.
The peak value of the video signal for one frame is held at A, and the analog-to-digital converter 6B detects which stage of preset digital stages this peak value corresponds to. For example, this detected value is "3"
If so, the set aperture value is "3" (actual aperture ratio is "l/
3). This set aperture value "3" is applied to the slider 4C of the aperture control potentiometer 4B shown in FIG. 2 via the digital-to-analog converter 6D. During measurement (during X-ray irradiation), the aperture rate of the aperture device 4 is fixed at this set aperture value. This enables constant evaluation of the input X-ray dose transmitted through the subject. Since the set aperture value "3" of the aperture device 4 is digitally represented, this set aperture value "3" is input to the rtOM or R, AM8, and the video signal from the television camera 5 is converted to an analog-to-digital converter. The digital video signal converted into a digital signal in step 7 is converted to a level calibrated with the set aperture value "3", logarithmically converted, and sent to the image processing unit CPU.

It should be noted that the aperture value setting circuit of the present invention is not limited to the above-mentioned embodiment, and can of course be modified without changing the gist of the present invention.

As explained above, according to the present invention, a television camera is used even for input with a large dynamic range, and an aperture device is provided in front of the television camera, and the peak value of the video signal for one frame is calculated. The aperture value of the aperture device that corresponds to the peak value of the video signal is set by quantitatively evaluating the input at two or more digital stages, and the video signal is calibrated using this set aperture value, allowing highly accurate input quantitative evaluation. Inspection is possible and good subtraction processing etc. can be performed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention in a professional manner, FIG. 2 is a diagram showing the configuration of an embodiment of the automatic diaphragm device of the present invention, and FIG. FIG. 2 is a diagram showing the configuration of an embodiment of an aperture value setting circuit. 1 X-ray tube 2 Subject 6 Image intensifier 4 Automatic aperture device 5 Television camera 6 Aperture value setting circuit 7 Analog-to-digital converter 8- ROM or FLAM Agent Patent attorney Aki 1) Collection Ki

Claims (1)

[Claims] Irradiate the subject with X-rays (7) The transmitted X-ray image is incident on an image intensifier, the output image obtained is photographed with a television camera, and the video signal is converted into an analog
In an X-ray image processing device that performs image processing through digital conversion, an aperture device is provided upstream of the television camera, and the peak value of a predetermined video signal is input and quantitatively evaluated in two or more digital stages. The present invention is characterized by comprising an aperture value setting means for setting an aperture value of the aperture device corresponding to the peak value of , a means for controlling the automatic aperture device according to the set aperture value, and a means for calibrating a video signal using the set aperture value. An X-ray image processing device.