JPH05228132A - X-ray image input system and light simulator used therefor - Google Patents

Abstract

PURPOSE:To detect a residual image characteristic of a TV camera simple substance without detaching a TV camera, and to facilitate the adjustment of the bias light quantity by providing a means for containing a light simulator, connecting the light simulator and an X-ray source in parallel, and selecting both of them. CONSTITUTION:The objecting system irradiates an object 5 to be photographed with X rays from an X-ray tube 4, converts it to a visible light by an X-ray image intensifier 6, A/D-converts an output signal of a TV camera 8, and thereafter, displays it on a television screen, and also, stores a digital image in an image data memory 1. In this case, this system is provided with a light simulator 21 for emitting the visible light by the same time sequence as irradiation of X rays by the X-ray tube 4, and consisting of a light controller 9, a visible light emitting part 10 and a first and a second storage means 11, 12. In such a state, by operating an operator image data memory 1, a connection selecting means 2 is controlled, so that it is switched in order to select one of the light simulator 21 and the X-ray tube 4, or both of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray image input device and a bias light amount supply control means (hereinafter referred to as a "light simulator") suitable for use in the same, and particularly to a television as the input means. An X-ray image suitable for use in a "real-time digital radiography device" (hereinafter referred to as "real-time DR device"), etc. that captures an X-ray image in real time using a camera device and performs image processing for diagnosis The present invention relates to an input device and a light simulator used therefor.

[0002]

2. Description of the Related Art For example, in an X-ray image input device used for a real-time DR device, an X-ray is applied to an object from an X-ray source.
The X-ray information transmitted by irradiating a subject is converted into light information by an X-ray image intensifier (hereinafter referred to as "X-ray II"), and imaged on a TV camera by an optical lens system.
The output current (video signal) from the television camera is converted into a digital image by an A / D converter and is stored in a storage device (hereinafter referred to as "image data memory") for processing, display,
I remember. In this type of X-ray image input device, the change in output current is delayed with respect to the change in incident light on the photocathode of the image pickup tube of the television camera, that is, the so-called “afterimage characteristic” is output from the television camera after photographing. A sufficient signal cannot be obtained in the first frame of the video signal. Then, in the first frame where this sufficient signal is not obtained,
When output as an image on the display device of the image data memory, a high-definition image cannot be obtained. On the other hand, for example, as disclosed in JP-A-61-242188 and JP-A-62-64187, a weak visible light called "bias light" is pulsed into a television camera before photographing. A method is known in which the rising of the first frame is improved by irradiating the photocathode of the image pickup tube in advance to obtain a high-definition image. In the above example, as a light source for the bias light described above, a light-emitting body such as an LED is set between the X-ray II of the X-ray image input device and the television camera, and is irradiated several times before X-ray irradiation. The rise of one frame is improved.

[0003]

However, as described above, in the method of irradiating the bias light in a pulsed form several times, the optimum bias light amount differs depending on each image pickup tube. Therefore, when the image pickup tube is changed, the bias light is changed. There is a possibility of irradiating a bias light with an excessive (or insufficient) amount of visible light, and it cannot be said that an optimum bias light is necessarily given. That is, there is a problem that the dynamic range is narrowed by irradiating an excessive amount of bias lights, and the rising of the first frame may be deteriorated by irradiating a bias light with insufficient light amount.
Further, conventionally, in order to obtain the optimum bias light amount corresponding to each of the above-mentioned image pickup tubes, the television camera is removed from the X-ray image input device, and the afterimage of the television camera alone (that is, each image pickup tube) There was the annoyance of having to investigate the characteristics. The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-described problems in the conventional technique and facilitate adjustment of a bias write amount suitable for use in a real-time DR device. An object is to provide an X-ray image input device and a light simulator suitable for use in this device.

[0004]

The above-mentioned object of the present invention is X
The subject is irradiated with X-rays from the radiation source, the X-ray information transmitted through the subject is converted into visible light by the X-ray image intensifier, and the image is formed on the television camera by the optical lens system.
An X-ray image input device provided with a storage device (image data memory) for converting an output signal of the television camera into a digital image by an A / D converter, performing image processing and displaying the image on a television screen, and storing the digital image. , Said X
A light simulator that is provided in parallel with the radiation source and emits visible light in the same time sequence as the irradiation of X-rays by the X-ray source; visible light emission by the light simulator and irradiation of X-rays by the X-ray source. It is achieved by an X-ray image input device characterized by having a connection switching means of.

[0005]

In the X-ray image input apparatus according to the present invention, a light simulator is built in, and the light simulator and X
When the light simulator is selected by connecting the radiation sources in parallel and providing means for selecting both, the light intensity and light emission time of the bias light and visible light described above are synchronized with the vertical synchronization signal by the light controller. The visible light of the same time sequence as that of the X-ray photography is controlled, and the visible light can be used to check the afterimage characteristic of the TV camera alone (that is, the image pickup tube) without removing the TV camera. Also, this characteristic is stored in the storage means,
Since the bias write amount is adjusted by extracting the corresponding information based on the set X-ray condition and the number of scanning lines,
Even if the image pickup tube is replaced, the optimum bias light can always be emitted.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a real time D showing an embodiment of the present invention.
FIG. 3 is a block configuration diagram of an R device (hereinafter, also simply referred to as “device”). The apparatus shown in the present embodiment includes an X-ray source section including an X-ray tube 4 and an X-ray controller 3 for controlling the X-ray tube 4, the above-mentioned X-ray II 6, an optical lens system 7 capable of switching an optical path by a mirror, and a television camera 8. And a bias light 13, 13 ', a detection unit, an image data memory (GDM) 1, a light simulator 21 characteristic of the present invention, and a connection selection unit 2. In addition, 5 is a subject. The image data memory 1 has a built-in A / D converter, converts the analog signal output from the TV camera 8 into a digital image, and stores it in a 4096 × 4096 × 16 bit memory.
It has the function of displaying on a screen of 2000 x 2000 pixels. Also,
The image data memory 1 has a built-in crystal oscillator and transmits a vertical synchronizing signal or the like which is a reference for image capturing. Further, as will be described later, a command by a pulse signal is output to the first storage means 11 and the second storage means 12 in the write simulator 21 and the connection selection means 2.

The light simulator 21 comprises a visible light emitting section 10, a light controller 9 for controlling the visible light emitting section 10, a first storage means 11 and a second storage means 12 which will be described later. The visible light emitting section 10 uses a total of 64 high-intensity green light emitting diodes, each of which is eight in length and width. In addition, a light controller 9 that controls the visible light emitting unit 10
Has various control functions as described later. The first storage means 11 and the second storage means 12 are ROMs.
Or a magnetic disk is common. Optical lens system 7
Has a rotatable mirror therein, and its angular position is configured so that either a or b in FIG. 1 can be selected. Further, the connection selection means 2 selects the mode (A mode) for selecting the light simulator 21, the X-ray controller 3 and the X-ray tube 4 by operating the image data memory 1 by the operator. It has a function to set one of the three modes of X-ray photography (B mode) and X-ray photography (C mode) in which both are selected and a bias light is also used during X-ray photography.

The light controller 9 for controlling the visible light emitting section 10 takes in the vertical synchronizing signal from the above-mentioned image data memory 1 and, in order to synchronize with the frame (cycle), (1) Bias light signal for improving the rising characteristics of the image pickup tube (2) Frame interval signal from the end of the bias light emission to visible light emission (3) Visible light of the same time sequence as the X-ray irradiation by the X-ray source Signal (4) Frame interval signal from visible light emission to video signal capture start signal (5) GDM capture start signal for capturing the signal output from the television camera 8 into the image data memory (GDM) 1 (6) It has a function of controlling a series of repeated signals of the above signals. Hereinafter, the operation of this embodiment configured as described above will be described.

In the device according to the present invention, when the television camera is set up, after replacement, or the like, the afterimage characteristic of the television camera is checked using the mode A and stored, and the bias light is used. Is characterized in that an appropriate bias light is applied based on the stored contents. Hereinafter, first, the A mode will be described. In the following description, as an example, a case will be described in which the light simulator is operated according to the sequence shown in FIG. 2A and the output signal of the television camera 8 corresponding thereto is measured. In the sequence shown in FIG. 2 (a), four frames of visible light are emitted at a predetermined level in synchronization with the vertical synchronization signal, and the output signal of the television camera 8 corresponding to this is measured. is doing. First,
The operator operates the above-mentioned image data memory 1 and selects the light simulator 21 by the function of the connection selection means 2. In this case, the angular position of the mirror inside the optical lens 7 is adjusted to the position of b.

First, as preliminary data, the visible light emitting section 1
From 0, the visible light with different brightness is radiated to the image pickup tube which is the measurement target, the output current value that finally reaches at that time is measured, and a graph showing the relationship between the brightness and the output current value is created.
An example of this is shown in FIG. Next, each output signal of the light controller 9 is set so as to realize the sequence shown in FIG. 2A, and the output signal of the television camera 8 is converted into a digital image and stored in the image data memory 1. The following processing is performed on the captured data by the software of the image data memory 1. First, the same region of interest is set, and the average value of the image data in the region is calculated corresponding to the passage of time within the first one frame. In addition,
Since this value is proportional to the output current of the TV camera 8,
It is also possible to take the output current value as it is. The above result is plotted against the time axis, and the time required for the average value (or output current value) to reach 90% of the finally reached value is obtained by the interpolation operation. Hereinafter, this time will be referred to as the "rise 90% response time".

Next, the above-mentioned "value finally reached" is converted into an output current value of the image pickup tube, this value is plotted on the horizontal axis, and "rise 90% response time" is plotted on the vertical axis. In the case of irradiating visible light with different brightness as described above,
By plotting "% response time", the graph shown in FIG. 4 can be obtained. In the graph shown in FIG. 4, the bias write amount is changed in three ways by applying the sequence shown in FIG. 2 (b) (with bias write) after the sequence shown in FIG. 2 (a) (without bias write). , Shows the measurement results when the bias write amount is changed in four ways. The result is the first storage means 11 described above.
Transfer to and store. Even when the number of scanning lines is changed, the same relationship is measured, and similarly, the first storage means 11 is also used.
Transfer to and store. It should be noted that the change of the scanning line is performed by the measurement target portion and is not essential for the present invention.

Next, the operator selects the above-mentioned B mode, that is, the X-ray imaging mode in which the X-ray controller 3 and the X-ray tube 4 are selected, and the X-ray I
A uniform X-ray is incident on I6, and the relationship between the incident X-ray dose and the corresponding output current (value at 100% rise) is determined. An example is shown in FIG. This result is
The data is transferred to the second storage means 12 and stored therein. Next, when the above-mentioned C mode, that is, the X-ray imaging mode in which the bias light is also used is selected and the object 5 is actually imaged, the operator operates the image data memory 1 to operate the light simulator. 21 and both the X-ray controller 3 and the X-ray source unit including the X-ray tube 4 are selected. The angular position of the mirror inside the optical lens 7 is adjusted to the position a. Next, with respect to the X-ray condition (X-ray dose) set by the operator in the X-ray controller 3 and the number of scanning lines set in the image data memory 1, refer to the data stored in the second storage means 12. Then, the output current value of the television camera 8 is obtained.

FIG. 4 is shown by referring to the data stored in the first storage means 11 based on the two pieces of information of the output current value of the television camera 8 and the number of scanning lines obtained above. It is possible to predict the 90% rise time of the image pickup tube for all four types of bias light. From this result, the bias write amount required to make the rise 90% response time less than a certain time can be selected from the above-mentioned four kinds of values. Based on this result, the write controller 9 sets the bias write condition, and X-ray irradiation is performed in this state. The sequence of X-ray irradiation in this case is the emission of “visible light” shown in FIG. 2 from the output surface of the X-ray II6 generated by the X-ray irradiation, and the “bias light” is the visible light emitting unit 1.
The bias lights 13 and 13 'having the same function as 0 emit light. According to the above-described embodiment, it is possible to obtain the effect of realizing the real-time DR device including the X-ray image input device that facilitates the adjustment of the bias light amount. More specifically, the afterimage characteristic of each image pickup tube can be examined even if the image pickup tube is changed, and the afterimage characteristic is stored in the first and second storage devices, so that it is optimal under the set X-ray condition. It is possible to obtain an effect that a high-definition image having a wide dynamic range can always be captured without wasting the first frame by adjusting an appropriate bias light amount.

Needless to say, the above-mentioned embodiment shows an example of the present invention, and the present invention should not be limited to this. For example, the sequence shown in FIG. 2 is shown as an example, and it is possible to use other sequences.

[0015]

As described above in detail, according to the present invention, an X-ray image input device suitable for use in a real-time DR device or the like, which facilitates adjustment of the bias light amount, and
This has the remarkable effect of realizing a light simulator suitable for use in this.

[0016]

[Brief description of drawings]

FIG. 1 is a block diagram of a real-time DR device showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a light emission sequence in an example.

FIG. 3 is a graph showing the relationship between luminance and output current value in the example.

FIG. 4 is a graph exemplifying a relationship between an output current and a 90% first frame rising time response time with a bias write amount as a parameter in an example.

FIG. 5 is a graph showing the relationship between the X-ray dose and the output current with the number of scanning lines as a parameter in the example.

[Explanation of symbols]

1: image data memory, 2: connection, selection means, 3: X-ray controller, 4: X-ray tube, 5: subject, 6: X-ray I
I, 7: optical lens, 8: television camera, 9: light controller, 10: visible light emitting unit, 11: first storage means, 12: second storage means, 21: light simulator,
13, 13 ': Bias light.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Ueda 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (3)

[Claims] 1. A subject is irradiated with X-rays from an X-ray source, X-ray information transmitted through the subject is converted into visible light by an X-ray image intensifier, and an image is formed on a television camera by an optical lens system. An X-ray image input device provided with a storage device (image data memory) for converting the output signal of the television camera into a digital image by an A / D converter, performing image processing to display the image on a television screen, and storing the digital image, An X provided by the X-ray source in parallel with the X-ray source.
An X-ray, comprising: a light simulator that emits visible light in the same time sequence as the irradiation of rays, and connection switching means for connecting visible light emission by the light simulator and X-ray irradiation by the X-ray source. Image input device. 2. The light simulator allows the X
At the same time that visible light is emitted in the same time sequence as the X-ray irradiation by the radiation source, an image capture signal is created and sent to the image data memory, and based on this, an output image signal output from the television camera is output. 2. The image data memory is configured to be loaded into the image data memory.
The described X-ray image input device. 3. A light simulator for use in the X-ray image input apparatus according to claim 1, comprising a visible light emitting section that emits visible light, a light controller that controls the visible light, and an image pickup tube of a television camera. A light simulator comprising a storage means for storing afterimage characteristics.