JPH07148161A - Dental X-ray imager - Google Patents

Abstract

(57) [Abstract] [Objective] A cooperative operation of the X-ray irradiating means and the image processing means is realized to prevent erroneous X-ray irradiation during execution of the processing of the image processing means. The image processing device 4 includes a CPU 31, a ROM 32 for storing programs and data, a main memory 33 for storing image data and image processing parameters, and image data to be displayed on the monitor device 5. An image memory 34 for storing, a DA conversion circuit 35 for outputting to the external monitor device 5 or the video printer 6, and D
The MA controller 36, a clock signal generating circuit 38 for driving the image sensor 2 such as a CCD sensor, and the image sensor 2
And an AD conversion circuit 40 for converting the image signal SG from the digital signal into a digital signal, and an input for issuing a busy signal BUSY to the external X-ray controller 20 and receiving an exposure signal EXP from the X-ray controller 20. It is composed of an output circuit 45 and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an X-ray image of a diagnosis site or a treatment site in the oral cavity as an electric signal to detect CR.
The present invention relates to a dental X-ray image capturing apparatus for displaying an image on a T (cathode ray tube) or the like.

[0002]

2. Description of the Related Art Conventionally, in order to obtain an X-ray image of an intraoral region, a film system has been widely used in which a photosensitive recording material such as a silver salt film is used for X-ray photography and then development and fixing processes are carried out. Has been done.

However, this film system requires 1) about 2 minutes or more from the time of X-ray photography to the observation.
2) A developing device and a processing solution for developing and fixing are indispensable. 3) The X-ray sensitivity of silver salts is limited, and a constant X-ray dose is required to obtain a desired image density.
4) The image once fixed cannot be corrected. There are problems such as.

In order to solve such a problem, CCD
There has been proposed an X-ray image capturing apparatus which displays an image on a CRT (cathode ray tube) or the like after converting the X-ray image into an electric signal by using an image sensor such as (charge-coupled device). This X-ray image capturing apparatus is a so-called filmless system that does not use a photosensitive recording material such as a silver salt film, and can be observed in real time from 1) X-ray capturing. 2) No developing device or processing liquid is required. 3) Since the image sensor has high sensitivity, X
It is possible to reduce the radiation dose. 4) It becomes easy to perform various kinds of image processing on the detected X-ray image and to copy and store the image. It has features such as.

[0005]

In the conventional film method, the X-ray irradiation is ready when the X-ray film is positioned in the oral cavity of the patient, and the X-ray irradiation can be performed at any time from that time. become.

On the other hand, in the latter X-ray image capturing apparatus, in order to reduce the dark current of the image pickup device, the charges accumulated in the light receiving portion of the image pickup device (charge due to X-ray photon incidence, charge due to thermal excitation, etc.) are cycled. The so-called blank reading operation is performed to read out the data. Therefore, if X-ray imaging is performed during the period during which this operation is performed, there is a problem that a complete X-ray image cannot be obtained. In addition, during the period when the image processing unit is performing the predetermined image processing on the X-ray image of the previous photographing or the period when other processing is performed, a new X is added to the image sensor.
Even if the line irradiation is performed, the signal from the image sensor cannot be captured by the image processing means, resulting in a failure of X-ray imaging.

In order to solve the above-mentioned problems, an object of the present invention is to realize a cooperative operation between the X-ray irradiating means and the image processing means, so that the X-ray from the image pickup device may be due to some processing being performed by the image processing means. An object of the present invention is to provide a dental X-ray image capturing apparatus capable of preventing erroneous X-ray irradiation when an image cannot be captured.

[0008]

SUMMARY OF THE INVENTION The present invention comprises an X-ray irradiating means for irradiating an intraoral site of a subject with X-rays,
An image sensor for detecting an X-ray image of the intraoral region,
A dental X-ray image radiographing apparatus comprising: an image processing unit for reading an X-ray image detected by the image sensor and performing a predetermined image processing, wherein the image processing is performed during a processing period of the image processing unit. A dental signal characterized by transmitting a busy signal indicating that the means is processing to the X-ray irradiation means, and stopping the X-ray irradiation when the X-ray irradiation means receives the busy signal. It is an X-ray imaging apparatus.

In the present invention, the X-ray irradiating means includes an X-ray generator and an X-ray controller for generating an activation signal for activating the X-ray generator. It is characterized in that the activation signal is not generated when the busy signal is received.

Further, in the present invention, the X-ray irradiating means includes an X-ray tube for generating X-rays and a high voltage circuit for supplying a high voltage to the X-ray tube, and a high voltage is supplied based on a busy signal. It is characterized in that the supply of voltage is stopped.

[0011]

According to the present invention, during the processing period of the image processing means, the busy signal indicating that the image processing means is processing is sent to the X-ray irradiation means so that the X-ray irradiation means performs the image processing. It becomes possible to recognize the processing state of the means. Further, by stopping the X-ray irradiation when the X-ray irradiation means receives the busy signal, the operator mistakenly performs X-ray irradiation.
Even when the radiation irradiating means is activated, the subject is not irradiated with X-rays. Therefore, erroneous X-ray irradiation can be prevented.

Further, the X-ray irradiation means includes an X-ray generator.
An X-ray control device that generates a start signal for starting the X-ray generation device is provided, and when the X-ray control device receives a busy signal, the start signal is not generated, so that the generation of X-rays is ensured. Can be stopped.

Further, the X-ray irradiating means emits X-rays.
It is possible to reliably stop the generation of X-rays by providing a X-ray tube and a high voltage circuit for supplying a high voltage to the X-ray tube, and stopping the supply of the high voltage based on the busy signal. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the state of use of a dental X-ray imaging apparatus according to the present invention. The X-ray generator 10 is attached to the swivel arm 12 so as to be vertically swingable and horizontally rotatable, and the orientation of the X-ray irradiation tube 11 so that X-rays are emitted toward the intraoral site of the subject 1. Is adjusted.

On the other hand, the X-ray irradiation cylinder 11 with the intraoral region sandwiched therebetween.
The image pickup device 2 for detecting the X-ray intensity distribution that has passed through the intraoral site, that is, the X-ray image, is positioned at a position opposed to. In FIG. 1, the subject 1 itself holds the positioning member 2a fixed to the image pickup element 2 with his / her finger so that the image pickup surface of the image pickup element 2 faces the X-ray irradiation direction.

The image sensor 2 includes a scintillator plate made of a rare earth element compound for converting X-ray photons into visible light, and visible light emitted from the scintillator plate.
An optical fiber array that transmits the dimensional distribution as it is, a CCD array sensor that receives the visible light distribution transmitted by the optical fiber array, accumulates the charges generated, and sequentially reads the charges accumulated for a predetermined time and converts them into electrical signals. A lead plate for preventing the incidence of scattered X-rays is provided on the back surface of the CCD array sensor, and these are housed in a housing made of synthetic resin or the like. The X-ray image detected by the image sensor 2 is converted into an electric signal by the CCD array sensor, passes through the signal cable 3 and the image processing device 4
Entered in.

The image processing device 4 digitizes the signal from the image pickup device 2 and stores it in a memory, and then performs predetermined image processing to display it on a monitor device 5 such as a CRT (cathode ray tube) or a recording paper. To print a hard copy.

FIG. 2 is a block diagram showing the electrical construction of an embodiment of the present invention. The image processing device 4 includes a CPU (central processing unit) 31 for controlling the entire operation, and a CPU.
ROM (random access memory) 32 for storing programs and data necessary for 31 to operate,
A main storage memory 33 for storing image data and parameters necessary for calculation processing such as image processing, and an image memory 3 for storing image data to be displayed on the monitor device 5.
4 and the DA conversion circuit 35 for converting the image data stored in the image memory 34 into an analog video signal VD and outputting the analog video signal VD to the external monitor device 5 or the video printer 6.
And a DMA (Direct Memory Access) controller 36 for controlling data transfer between the circuits without involvement of the CPU 31, and a clock signal CK necessary for operating the image sensor 2 such as a CCD sensor. A clock signal generation circuit 38 and a preamplifier 39 for taking in and amplifying an image signal SG output from the image pickup element 2.
An AD conversion circuit 40 for converting the output of the preamplifier 39 from an analog signal to a digital signal, and an input / output circuit 41 for supplying data to an external printer 42.
And an input / output circuit 43 for taking in data from a keyboard 44 for data input, and an external X-ray controller 2
I / O circuit 45 for issuing a busy signal BUSY to 0 or receiving the exposure signal EXP from the X-ray controller 20, and a bus 37 for connecting these circuits to each other.
Etc.

In the image pickup device 2, the charge accumulated for a certain period of time is periodically read out as a dark current on the basis of the clock signal CK from the clock generation circuit 38, and thermal excitation or scattering X is performed.
It is kept so that extra charges due to lines and the like do not remain.

The X-ray controller 20 outputs a start signal TG to the X-ray generator 10 in response to an instruction from the exposure switch 21, and the X-ray generator 10 detects the tube voltage, the tube current, and the tube current based on the start signal TG. By applying a high voltage to the X-ray tube 13 under a predetermined X-ray exposure condition such as exposure time,
Generate X-rays.

Next, the overall operation of the image processing apparatus 4 will be described. When the exposure switch 21 of the X-ray controller 20 is pressed, the X-ray generator 10 emits X-rays for a predetermined time. When the X-rays reach the image sensor 2 through the subject 1a, charges corresponding to the X-ray image irradiated on the image sensor 2 are accumulated, and are output in time series as image signals SG after the end of X-ray exposure. It The image signal SG from the image pickup element 2 is input to the preamplifier 39 and amplified to a predetermined level, and the image signal SG of the next stage is received.
It is input to the D conversion circuit 40 and converted into a digital value.
At this time, the DMA controller 37 occupies the bus 37 and the image data output from the AD conversion circuit 40 is transferred to the bus 3
It is sequentially stored in a part of the main storage memory 33 via 7.

On the other hand, even when there is no X-ray exposure, the image sensor 2
The dark current of the AD conversion circuit 40 is read regularly.
Are converted into digital values by and are stored in a part of the main memory 33 as dark current data.

The image data and the dark current data stored in the main memory 33 are arithmetically processed by the CPU 31, for example, the dark current data is subtracted from the image data and stored again in a part of the main memory 33. By
Background noise can be eliminated from the image data, and high-quality image data can be obtained. In addition,
If the dark current noise can be ignored, the subtraction process may be omitted to shorten the entire processing time.

The image data stored in the main memory 33 is transferred to the image memory 34 by the DMA controller 37. The contents stored in the image memory 34 are DA
The DA converter circuit 35 reads out the digital value image data into an analog video signal VD and outputs the analog video signal VD to the monitor device 5 and the video printer 6, which are read out in time series by the conversion circuit 35. The X-ray image detected by the image sensor 2 is
A hard copy is displayed on the screen of the monitor device 5 or by the video printer 6. If necessary, the video signal VD can be recorded by a recording device such as a video tape recorder.

FIG. 3 is a flow chart showing the operation of one embodiment of the present invention. First, starting from step a1, in step a2, the CPU 31 determines whether or not the keyboard 44 has been operated to input a command instructing a specific process, and if there is no keyboard operation, the process proceeds to step a6. If there is a keyboard operation, the process proceeds to step a3, where the CPU 31 sets a busy signal BUSY and sets it to a high level. The busy signal BUSY is input to the X-ray controller 20, and when the busy signal BUSY is at a high level, the X-ray controller 20 determines that the image processing device 4 is not ready, and the X-ray generator 1
It operates so as not to generate the activation signal TG for 0.
Even if the exposure switch 21 is pressed in this state, the start signal TG
Is not generated, the X-ray generator 10 does not operate. Therefore, it is possible to reliably prevent erroneous X-ray exposure during the processing of the image processing apparatus 4.

Next, at step a4, the CPU 31 or the DMA controller 36 executes the process corresponding to the command input by the keyboard operation. When this process ends, next, in step a5, the CPU 3
1 lowers the busy signal BUSY and sets it to the low level, and then proceeds to step a6. When the busy signal BUSY is at the low level, the X-ray controller 20 determines that the image processing device 4 is ready and allows the generation of the activation signal TG. In this state, the exposure switch 21 is pressed. Then, the activation signal TG is output, and X-rays are generated from the X-ray tube 13 of the X-ray generator 10 under a predetermined X-ray irradiation condition.

At step a6, the CPU 31 determines whether or not the exposure signal EXP is input from the X-ray controller 20 to the image processing device 4. The exposure signal EXP notifies the image processing device 4 of the time when the X-ray exposure starts and the time when the X-ray exposure ends, and keeps a high level from the start of the exposure to the end of the exposure, for example. Keep low level for the rest of the period. In step a6, the exposure signal E
If no XP is input, the process returns to step a2. On the other hand, if the exposure signal EXP is input and is at a high level, for example, it means that the X-ray generator 10 is performing the X-ray exposure operation, and the process proceeds to the next step a7, where the X-ray exposure is performed. Waits until the exposure signal EXP is inverted to a low level, for example.

Upon completion of X-ray exposure, the next step a8
And the CPU 31
Sets a busy signal BUSY and sets it to a high level, the X-ray controller 20 operates so as not to generate the activation signal TG and inhibits X-ray exposure.

At the next step a9, the image signal SG of the subject 1a output from the image pickup device 2 is converted into the preamplifier 3
9. After being taken into the main storage memory 33 via the AD conversion circuit 40 and the bus 37, dark current data subtraction processing, negative / positive inversion, enlargement, vertical conversion, density conversion, color display, and other images as necessary Processing is executed by the CPU 31,
Image data for display is created. Next step a10
In, the image data created in the main memory 33 is transferred to the image memory 34 by the DMA controller 36, converted into the video signal VD via the DA conversion circuit 35, and displayed on the monitor device 5 or the like.

When the processing of the image processing device 4 is completed, the CPU 31 causes the busy signal BU in the next step a11.
After lowering SY and setting it to low level, step a2
Then, the presence / absence of the keyboard operation and the presence / absence of the exposure signal EXP are continuously determined.

When the image processing apparatus 4 is executing some kind of processing as described above, the fact that the processing is being performed is indicated by the X-ray control apparatus 2
By informing 0, the X-ray control device 20 can determine whether or not X-ray irradiation is possible, and thus it is possible to prevent X-ray imaging from being performed before the image processing device 4 is ready.

FIG. 4 is a block diagram showing the electrical construction of another embodiment of the present invention. This embodiment is similar to that of FIG. 2, but the busy signal B output from the image processing device 4 is used.
The difference is that USY is input to the X-ray generation permission device 50 and the X-ray generation permission device 50 directly opens and closes the high voltage circuit of the X-ray generation device 10 according to the level of the busy signal BUSY.

The X-ray generation permitting device 50 sends the busy signal BU
A photocoupler 51 to which the current loop 46 for transmitting SY is connected, and a relay 52 for opening and closing the high voltage circuit of the X-ray generator 10 are provided.

The X-ray generator 10 includes a filament wire 1
4, the power is supplied through the common line 15 and the high voltage line 16, the primary side of the filament transformer FT is connected between the filament line 14 and the common line 15, while the common line 15 and the high voltage line 16 are connected. The primary side of the high voltage transformer HT is connected between them, and the switch 52b of the relay 52 is provided in the middle of the high voltage line 16.
Intervenes. The secondary side of the filament transformer FT is connected to the filament 13b of the X-ray tube 13, while the secondary side of the high voltage transformer HT is connected between the anode target 13b of the X-ray tube 13 and the filament 13b. The high voltage circuit shown in FIG. 4 is a high voltage transformer HT and a filament transformer F.
Although the example of the pre-ignition method having two transformers of T is shown, the present invention is also applicable to the simultaneous ignition method in which one transformer has both functions.

Next, the overall operation will be described. When the image processing device 4 is executing some kind of processing, that is, when it is in a so-called busy state, almost no current flows in the current loop 46, and the photo coupler 51 of the photo coupler 51 is operated. The light emitting diode 51a is turned off, and the phototransistor 51b is turned off. The phototransistor 51b is a relay 52
If the phototransistor 51b is in the cut-off state, the relay 52a
Does not operate, the switch 52b is in the cutoff state, and the high voltage line 16 of the X-ray generator 10 is cut off. Even if the exposure switch 21 is pressed in this state, the X-ray control device 20 outputs the activation signal TG, and the operation of the X-ray generation device 10 is started, the high-voltage line 16 is cut off, so the X-rays are cut off. No voltage is applied to the tube 13 and no X-rays are generated.

On the other hand, when the image processing device 4 is not operating, that is, when it is in the so-called knot busy state, a predetermined current flows in the current loop 46, and the light emitting diode 51a.
Emits light, and the phototransistor 51b becomes conductive. When the phototransistor 51b becomes conductive, the relay 5
2 operates and the switch 52b becomes conductive, and the X-ray generator 10
The high voltage line 16 of is made conductive. When the exposure switch 21 is pressed in this state, the X-ray controller 20 outputs a start signal TG and the operation of the X-ray generator 10 is started.

The first ignition method will be described below as an example.
First, a predetermined filament current flows through the filament wire 14 to heat the filament 13a of the X-ray tube 13, and then a predetermined voltage is applied to the high voltage wire 16 so that the anode target 13b of the X-ray tube 13 has a predetermined voltage. Tube voltage is applied, a predetermined tube current flows for a predetermined exposure time, and X-rays are generated from the anode target 13b.

When the image processing apparatus 4 is executing some processing in this way, the high voltage supply to the X-ray tube 13 is forcibly stopped based on the busy signal BUSY indicating that the processing is being executed. This makes it possible to prevent X-ray photography from being performed before the image processing device 4 is ready.
It should be noted that this embodiment has an advantage that it can be realized by changing the connection of the high-voltage circuit to the existing X-ray device only a little, and therefore it is easy to cooperate with the X-ray image capturing device using the CCD sensor. Will be realized.

[0039]

As described in detail above, according to the present invention, even if the operator mistakenly activates the X-ray irradiation means during the processing period of the image processing means, the X-ray irradiation to the subject is performed. Since it is not performed, erroneous X-ray irradiation can be reliably prevented. Therefore, suppressing unnecessary X-ray exposure to the subject,
It is possible to execute reliable X-ray image capturing.

[Brief description of drawings]

FIG. 1 is a state of use of a dental X-ray image capturing apparatus according to the present invention.

FIG. 2 is a block diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 4 is a block diagram showing an electrical configuration of another embodiment of the present invention.

[Explanation of symbols]

 1, 1a Subject 2 Image sensor 2a Positioning member 4 Image processing device 5 Monitor device 6 Video printer 10 X-ray generator 11 X-ray irradiation cylinder 12 Universal arm 13 X-ray tube 20 X-ray controller 21 Exposure switch 31 CPU 33 Main memory 34 Image memory 35 DA conversion circuit 36 DMA controller 37 Bus 38 Clock signal generation circuit 39 Preamplifier 40 AD conversion circuit 50 X-ray generation permission circuit 51 Photocoupler 52 Relay

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Makino 680, Higashihaman-cho, Fushimi-ku, Kyoto City, Kyoto Prefecture Morita Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. An X-ray irradiator for irradiating an intraoral site of a subject with X-rays, an image sensor for detecting an X-ray image of the intraoral site, and an image sensor detected by the image sensor. In a dental X-ray image capturing apparatus including an image processing unit for reading an X-ray image and performing a predetermined image processing, the image processing unit is processing during the processing period of the image processing unit. A busy signal to the effect is sent to the X-ray irradiating means, and when the X-ray irradiating means receives the busy signal, X
A dental X-ray image capturing apparatus characterized by stopping the irradiation of rays. 2. The X-ray irradiation means includes an X-ray generator, and an X-ray controller that generates a start signal for starting the X-ray generator, and the X-ray controller outputs a busy signal. The dental X-ray imaging apparatus according to claim 1, wherein the activation signal is not generated during reception. 3. The X-ray irradiation means includes an X-ray tube for generating X-rays, and a high voltage circuit for supplying a high voltage to the X-ray tube, and supplies the high voltage based on a busy signal. The X-ray image capturing apparatus for dental use according to claim 1, wherein