JP2002014059A - Fluoroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluoroscope capable of automatically setting optimum X-ray conditions, even with respect to an unknown object to be transilluminated. SOLUTION: The fluoroscope forms a histogram of luminance data of each pixel for constituting an image, based on an output from an X-ray detector 3, regulates the tube voltage so that the mode of the histogram falls within a first luminance range, in a state in which the tube current and tube voltage of an X-ray source 1 are set to specified values, then regulates the tube current, so that the mode of the histogram falls within a second luminance range of the luminance larger than the first range, automatically sets the tube current a tube voltage as low as possible in the range for fully transmitting X-rays through the object W to be transilluminated and a tube current as large as possible in the range which does not exceeding a sensitivity limit of the detector 3, and automatically obtains an easy-to-view fluoroscopic image.

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 observing the internal state of a sample and the like.

[0002]

2. Description of the Related Art In an X-ray fluoroscope for observing the inside of a sample under non-destructive conditions, an X-ray detector generally comprising an image intensifier, a CCD camera and the like facing an X-ray source is generally used. The X-ray detector is provided, and the X-rays of the fluoroscopic object are incident on the X-ray detector by arranging or passing the fluoroscopic object therebetween. Then, the output of the X-ray detector is guided to the image processing means, and the output is displayed as the luminance data of the pixel, and the X-ray fluoroscopic image of the fluoroscopic object is displayed on the monitor screen.

Here, the tube current and tube voltage of the X-ray source are
It is correlated with the X-ray dose and the X-ray intensity output from the X-ray tube, and by changing these, the amount and intensity of the X-ray irradiated to the fluoroscopic object change. Utilizing this, in the conventional X-ray fluoroscope, the X-ray conditions, that is, the tube of the X-ray source, are set so that an optimum fluoroscopic image can be obtained for a fluoroscopic object having various materials and sizes. It is configured such that the current and the tube voltage can be adjusted manually.

[0004]

However, in the conventional X-ray fluoroscope, it is necessary to manually adjust the X-ray conditions in accordance with the material and size of the fluoroscopic object. When observing images, it is not only troublesome to make adjustments, but also it is difficult to evaluate whether or not the obtained fluoroscopic image is optimal, and there is an artificial difference in the adjustment results. There was a problem that also occurs.

The present invention has been made in view of such circumstances, and has as its object to provide an X-ray fluoroscopic apparatus capable of automatically setting an optimum X-ray condition even for an unknown fluoroscopic object. I have.

[0006]

In order to achieve the above object, an X-ray fluoroscope according to the present invention has an X-ray detector arranged opposite to an X-ray source and an output of the X-ray detector. An X-ray fluoroscopic apparatus having image processing means for displaying, on a monitor screen, an X-ray fluoroscopic image of a fluoroscopic object placed between the X-ray source and the X-ray detector as luminance data of a pixel,
A histogram creating means for creating a histogram of the luminance data of each pixel based on the output of the line detector; and a mode value in the histogram of the luminance data with the tube voltage and the tube current of the X-ray source set to specified values Means for setting the tube voltage so as to fall within a first brightness range set in advance, and after setting the tube voltage, the mode value in the histogram of the brightness data is equal to the first mode.
It is characterized by having a tube current setting means for setting the tube current so as to fall within a second luminance range where the luminance is larger than the luminance range (claim 1).

Here, in the present invention, it is preferable that the apparatus is provided with an attention area setting means for setting an area on the monitor screen where a histogram of the luminance data of the pixel is to be created.

According to the present invention, the tube voltage of the X-ray source mainly affects the screen brightness of the X-ray fluoroscopic image, and the tube current mainly affects both the contrast of the X-ray fluoroscopic image and the screen brightness. In order to obtain an easy-to-view X-ray fluoroscopic image, the tube voltage must be as small as possible in a range where X-rays can sufficiently penetrate the fluoroscopic object and as large as possible in a range not exceeding the sensitivity limit of the X-ray detector. In addition to taking into account that the setting may be made, the information on the brightness of the monitor screen is represented by the mode of the histogram of the brightness of each pixel constituting the image, so that the X-ray for obtaining the optimal X-ray fluoroscopic image can be obtained. The condition is to be set automatically.

That is, with the tube current and the tube voltage set to specified values, a histogram of the brightness of each pixel on the monitor screen is created, and the mode voltage is first changed by focusing on the mode brightness. Then, the luminance of the mode is set in a first luminance range having a relatively small luminance set in advance. In this state, the tube current is changed so that the mode luminance falls within the second luminance range where the luminance is higher than the first luminance range. Accordingly, X-rays having an intensity enough to transmit through the fluoroscopic object and having the lowest possible X-ray intensity, and having a dose as large as possible within a range not exceeding the sensitivity limit of the X-ray detector.
X-rays can be irradiated to the fluoroscopic object, and optimal X-ray conditions can be automatically set.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

An X-ray source 1 is arranged so as to emit X-rays upward, and a table 2 for mounting a fluoroscopic object W is provided above the X-ray source 1 and further above the X-ray source. The X-ray detector 3 is arranged with the sensitive surface facing downward. The X-ray detector 3 is a known detector combining, for example, an image intensifier and a CCD camera.

The X-ray source 1 is operated by a tube current and a tube voltage supplied from a power supply unit 11. The magnitudes of the tube current and the tube voltage from the power supply unit 11 are determined based on a command from a control unit 4 described later. Is controlled by the X-ray control circuit 12 which operates.

Each pixel output of the CCD camera of the X-ray detector 3 is taken into the control device 4 every moment. The control device 4
Although it is actually composed of a computer and its peripheral devices, FIG. 1 shows a block diagram for each of the main functions included in the program installed in the computer. Each pixel output is taken into the image processing unit 41.

The image processing section 41 creates an X-ray fluoroscopic image of the fluoroscopic object W using the output from the X-ray detector 3 and displays it on the display 5. At this time, in the image processing unit 41,
The luminance of each pixel is determined according to the output value of each pixel of the CCD camera of the X-ray detector 3 to form an image. The luminance data of each pixel is also sent to the histogram calculator 42. The histogram calculation unit 43 creates a histogram of the luminance data of each pixel forming the image on the display 5 and supplies the histogram to the X-ray condition setting unit 43.

The control device 4 also has an input section 44 for inputting various commands and settings.

The X-ray condition setting section 43 determines the optimum values of the tube current and the tube voltage of the X-ray source 1 according to the following procedure, and gives an operation command to the X-ray control circuit 12 described above. FIG. 2 is a flowchart showing a procedure for setting the tube current and the tube voltage by the X-ray condition setting unit 43.
The details will be described with reference to FIG.

The program for setting the X-ray conditions is started by giving a command from the input unit 44 with the fluoroscopic object W placed on the table 2.
X-rays are emitted by setting the tube current and the tube voltage of the X-ray source 1 to relatively low values set in advance, respectively.
The output from the line detector 3 is taken. In this state, the mode value Hm of the histogram of the luminance data of each pixel generated by the histogram calculation unit 41 is read, and the value Hm is compared with a _first luminance range B1 set in advance, and FIG. As exemplified in A), when the mode value Hm is smaller, that is, when the mode is larger, the tube voltage is increased by a specified amount, and when it is larger, that is, when it is bright, the tube voltage is reduced by a specified amount. repeatedly, the mode Hm as illustrated in FIG. 3 (B) placed in the first luminance range B _1.

Here, when the tube voltage of the X-ray source 1 is increased, the histogram of the luminance of each pixel from the X-ray detector 3 moves in a direction in which the luminance increases while the spread is constant.
When the tube voltage is decreased, the histogram moves in a direction in which the luminance decreases while the spread is constant. On the other hand, as will be described later, when the tube current is increased, the histogram increases in size and at the same time moves in a direction in which the luminance increases, and when the tube current is reduced, the histogram moves in a direction in which the spread decreases and the luminance decreases. I do. First luminance range B
₁ is generally set to a luminance region lower than the average luminance on an easily viewable screen, and as described above, since the initial tube current is set to a relatively low value, only the tube voltage is changed. the histogram of the mode value Hm in the state of matches in the first luminance range B in _1, X-rays are sufficiently transparent perspective object, and in a state of being set to as small as possible tube voltage.

Next, while keeping the tube voltage, gradually increasing the tube current, as illustrated in FIG. 3 (C), a histogram of the mode Hm is accommodated in the second luminance range B ₂ At this point, the setting of the tube current is completed. In the case where the mode value Hm exceeds a second brightness range B ₂ to too high a tube current,
Reduce tube current. The second luminance range B _2, rather than the first luminance range B ₁ described above is set to a high luminance region, it is set to the average luminance in general easy to see the screen.

According to the above setting operation of the X-ray conditions, the luminance of the screen of the display 5 can be easily seen under the lowest possible tube voltage while sufficiently transmitting the fluoroscopic object W, in other words, the X-ray detector. The tube current is set to be as large as possible within a range not exceeding the sensitivity limit of 3, and an X-ray fluoroscopic image having appropriate luminance and high contrast is automatically obtained.

Here, in the above setting operation, a histogram of the luminance of all the pixels of the screen of the display unit 5 is created, and an X-ray fluoroscopic image which is easy to see in the entire area of the screen (entire field of view) is obtained based on the histogram. An example of setting X-ray conditions that can
As illustrated in FIG. 4, a histogram of the luminance data of each pixel in the attention area A is created for an arbitrary attention area A on the screen of the display device 5, and the mode is used as described above using the mode value. By setting the tube voltage and the tube current in this way, it is possible to obtain a screen in which the area of interest A is easy to see. The setting of the attention area A can be performed by the input unit 44. This setting of the attention area A is particularly effective when the material of the see-through target object W is not uniform, for example, when seeing through a circuit board or the like. Although it is difficult to see the X-ray fluoroscopic image even if it is easy to see, the X-ray condition is automatically set by setting the connection part by the solder, and the whole screen becomes too bright. The internal state can be easily seen.

[0022]

As described above, according to the present invention, a histogram of the brightness of the pixels constituting the X-ray fluoroscopic image is created, and the most frequent histogram of the histogram is obtained while changing the tube voltage of the X-ray source. After automatically setting the tube voltage so that the value falls within the first luminance range, while changing the tube current, the mode value of the histogram within the second luminance range where the luminance is higher than the first luminance range is changed. The tube current is automatically set so as to be within the range, so that the tube voltage is as small as possible in a range where X-rays can sufficiently penetrate the fluoroscopic object, and as small as possible within a range not exceeding the sensitivity limit of the X-ray detector. The tube current is automatically set, and an easy-to-view X-ray fluoroscopic image is obtained. This reduces labor compared to the conventional manual setting, and always provides an objectively easy-to-view fluoroscopic image. Can be.

Further, when a region of interest is set and the same setting operation is performed in that region as in the invention according to claim 2, an internal defect in a solder connection portion or the like in the circuit board is obtained. Can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing the contents of a program for setting X-ray conditions installed in a control unit 4 according to the embodiment of the present invention.

3A and 3B are diagrams illustrating an example of a histogram of luminance data of a pixel. FIG. 3A illustrates an example of a histogram in an initial setting state, and FIG. 3B illustrates an example of a histogram after automatic setting of a tube voltage. C) shows an example of the histogram after the automatic setting of the tube current.

FIG. 4 is an explanatory diagram of an attention area A set on a screen of a display device 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray source 11 Power supply unit 12 X-ray control circuit 2 Table 3 X-ray detector 4 Control device 41 Image processing unit 42 Histogram calculation unit 43 X-ray condition setting unit 44 Input unit 5 Display W Display target W

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G001 AA01 BA11 CA01 DA01 DA02 DA09 GA09 GA11 HA13 JA02 JA20 KA03 LA11 MA05 2G088 EE29 FF02 GG19 LL26 4C092 AA01 AB04 AC08 AC16 CC03 CC12 CD02 CD03 CE01 CF24 CF42 CJ07 CJ25 DD06

Claims (2)

[Claims] An X-ray detector is disposed opposite to an X-ray source, and an output of the X-ray detector is placed between the X-ray source and the X-ray detector as luminance data of a pixel. In an X-ray fluoroscopic apparatus having an image processing means for displaying an X-ray fluoroscopic image of a fluoroscopic object on a monitor screen, a histogram creating means for creating a histogram of luminance data of each pixel based on an output of the X-ray detector; In a state where the tube voltage and the tube current of the X-ray source are set to specified values, the tube voltage is set so that the mode in the histogram of the brightness data falls within a first brightness range set in advance. And setting the tube current so that, after setting the tube voltage, the mode in the histogram of the luminance data falls within a second luminance range where the luminance is larger than the first luminance range. X-ray fluoroscopy apparatus characterized in that it comprises current setting means. 2. The apparatus according to claim 1, further comprising an attention area setting unit that sets an area on a monitor screen where a histogram of the luminance data of the pixel is to be created.
A fluoroscope.