CN104306014B - A kind of digitlization update device of film type panorama gear division X-ray machine - Google Patents

Abstract

A digital upgrade device for a film-type panoramic dental X-ray machine belongs to the technical field of medical instrument digitization. It includes a cassette speed scanning device, a TDI CCD-based X-ray detector, an AD conversion and uploading device for video signals, a PC display platform and a power supply. Use the cassette speed scanning device to scan the motion of the existing film-type panoramic dental X-ray machine, and then transmit the scanned speed signal to the X-ray detector based on TDI CCD, and the processed motion signal drives the sensor The transfer of the internal charge of the TDI CCD; the signal output by the X-ray detector enters the video signal AD conversion and uploading device for analog-to-digital conversion of the signal and transmits it to the PC platform. The PC platform stores and displays the file after the analog-to-digital conversion. The digital upgrade device of the film-type panoramic dental X-ray machine provided by the present invention digitally upgrades the existing domestic film-type dental panoramic machine, which not only saves costs, but also cooperates with the existing domestic film-type dental panoramic machine manufacturers to provide technology support.

Description

A digital upgrade device for a film-type panoramic dental X-ray machine

technical field

The invention relates to a digital upgrading device of an X-ray machine, in particular to a digital upgrading device of a film type panoramic dental X-ray machine.

Background technique

Dental panoramic X-ray imaging equipment is widely used in hospital oral diagnosis and treatment. It can take pictures of the whole mouth of the human body and obtain tomographic images of teeth, periodontal tissues and their adjacent anatomical structures. According to different X-ray receivers, dental panoramic X-ray imaging equipment can be divided into film cassette type X-ray panoramic machine, IP plate imaging X-ray panoramic machine and charge-coupled device type X-ray panoramic machine. The film cassette type X-ray panoramic machine is the most traditional imaging method. It consists of an intensifying screen, a photosensitive film and a cassette. It needs to go through the steps of developing, fixing, washing and drying to obtain images. The operation is complicated and has certain chemical pollution; The IP plate imaging X-ray panoramic machine is an indirect imaging method, which needs to scan the IP plate through a laser scanner to obtain a digital image. Although it does not need to be processed to improve efficiency, the operation is still complicated, time-consuming, and the radiation dose is large; digitalization The X-ray panoramic machine can directly convert the received X-rays into image data, without chemical processing in the darkroom, with fast imaging speed, higher imaging resolution, and smaller radiation dose.

At present, domestic dental panoramic X-ray imaging equipment is in the stage of upgrading, and digital imaging is the development trend. Large, medium and small hospitals mainly adopt foreign import methods, while most small and medium-sized hospitals still use traditional film cassette X-ray panoramic machines. . The digital upgrading device for an X-ray machine provided by the present invention can digitally upgrade and transform existing domestic film cassette type X-ray panoramic machines or IP plate imaging X-ray panoramic machines, thereby greatly saving costs.

Contents of the invention

It is used to digitally upgrade the existing film-type panoramic dental X-ray machine in the hospital, and it is characterized in that it includes a cassette speed scanning device, an X-ray detector based on TDI CCD, an AD conversion and uploading device for video signals, a PC display platform and a power supply Power supply; use the film box speed scanning device to scan the motion of the existing film-type panoramic dental X-ray machine to scan the film box, and then transmit the speed signal obtained by scanning to the X-ray detector based on TDI CCD. The core chip CPLD is used for motion The signal is processed, and the specific processing method is realized through CPLD internal programming. The motion signal output by the grating ruler is a pulse signal, specifically, the mechanical film cassette outputs a pulse every time the grating scale passes 4um; the pixel of the CCD is 48*48um, that is, the internal charge transfer of the CCD passes through 48um at a time, so that only the film cassette Every time 48um is passed, a pulse is generated to trigger the charge transfer of the CCD, so that the movement of the film and the charge transfer of the CCD can be synchronized. The solution is to count the direct output signal of the grating ruler by 12 times, so that the trigger pulse of the grating ruler changes from a pulse of 4um to a pulse of 48um; secondly, since the movement of the film cassette uses a stepping motor, there will inevitably be jitter, In this way, the output signal of the grating ruler is disturbed by jitter, so the signal processing program part also has a debounce module. The processed motion signal drives the transfer of the internal charge of the sensor TDI CCD. For the motion signal of the cassette to drive the internal signal transfer of the CCD, it is necessary to retain the controllable input terminal of the transfer gate signal while the CPLD is programmed to generate the CCD drive signal. The CCD signal driver is such as the commonly used definite integral driver (Liu Youjun, Lu Jianrong, Liu Rongli, Yu Ran. TDI-CCD driver circuit with adjustable integration time: China, Utility Model Patent. 201120323369.8[p].2012.), film motion signal Control the vertical transfer of CCD charge to achieve the goal of complete matching between the motion mechanism and the TDI CCD charge transfer; after that, the effective teeth signal output by the X-ray detector enters the video signal AD conversion and uploading device for analog-to-digital conversion of the signal and transmits it to the PC platform. The PC platform stores and displays the bin file obtained after analog-to-digital conversion in bmp format; the power supply provides the required voltage for the digital upgrade device of the entire film-type panoramic dental X-ray machine.

The digital upgrade device of the film-type panoramic dental X-ray machine provided by the present invention meets the requirements of clinical diagnosis, and can digitally upgrade the existing domestic film or IP plate-type dental X-ray machine, and has the advantages of no pollution, fast imaging speed, and high image level. More abundant and other advantages, can be directly used in the improvement of film-type panoramic dental X-ray machines in small and medium-sized hospitals, which greatly saves costs.

Panoramic dental X-ray machine is designed based on the principle of curved surface tomography. Curved surface tomography is based on the anatomical characteristics of the dental and maxillofacial region, using the principles of tomography and slit photography to design a one-time exposure. The photographic method of projecting the entire mouth of teeth on a film (Han Fengtan, Zhu Xianfeng. Medical Imaging Equipment (2nd Edition) [M]. Beijing: People's Health Publishing House, 2010: 12-37), so It is required that the motion of the film-type panoramic X-ray machine cassette must match the rotation of the C-arm so that the imaging point is on the curve of the dental arch. Only in this way can the panorama of the dental cavity obtained be clear. The core of the digital upgrade mentioned in the present invention is to use TDI CCD as a photoelectric sensor, which can directly convert the received X-rays into electrical signals. This design requires that the speed of internal signal transfer of TDI CCD is consistent with the moving speed of the film. The device of the invention fully matches with the improved panoramic dental X-ray machine, so as to obtain clear digital images. Therefore, a grating ruler is used to scan the motion of the film, and then trigger the transfer of the internal signal of the TDI CCD, so that the charge transfer speed of the CCD is exactly the same as the motion speed of the film.

The period of the grating ruler output signal is the time to detect the movement of the object at 4um, that is, the film will output a complete pulse every time the 4um grating ruler passes through, and the mechanical movement may shake, so the directly obtained grating ruler signal must first be debounced. . Afterwards, the output signal of the grating scale should be counted 12 times according to the distance of 48um each transfer of the charge of the TDI CCD, so that the film will output a pulse signal every 48um, and the pulse signal is used to trigger the charge transfer of the internal signal of the TDI CCD. The movement of the film and the TDICCD is exactly the same; de-jittering and counting processing are realized through CPLD chip programming.

The invention digitally upgrades the existing film cassette type X-ray panoramic machine or IP plate imaging X-ray panoramic machine with the following advantages and beneficial effects: the digital upgrading device of the panoramic dental X-ray machine provided by the invention makes the X-ray exposure dose Small size, large exposure latitude, no need to imply chemical processing, no need for laser scanners, wide image dynamic range, etc. Moreover, the digital upgrade device for panoramic dental X-ray machines provided by the present invention can directly carry out digital upgrades to existing domestic film cassette X-ray panoramic machines or IP plate imaging X-ray panoramic machines, which greatly saves costs and makes The original film type and IP board can be recycled by dental panoramic X-ray machines, which is in line with the trend of medical digital imaging.

Description of drawings

Fig. 1 is a structural block diagram of a digital upgrading device for an X-ray machine provided by the present invention.

Fig. 2 is a simplified diagram of a film-type dental panoramic X-ray machine and a schematic diagram of a fixing method of a grating ruler.

Figure 3 is a schematic diagram of the grating ruler.

Figure 4 is a schematic diagram of an X-ray detector based on a TDI CCD.

Figure 5 is a signal processing circuit.

Fig. 6 is a schematic diagram of TDI CCD driving signals.

Figure 7 is a schematic diagram of the high-speed data acquisition card FCFR-USB9825.

In the figure: 1. Lifting carriage; 2. Rotating cross arm; 3. Cassette; 4. Position of grating ruler; 6. Magnetic grating strip; 7. Reading head; 8. X-ray source.

detailed description

The digital upgrade device of the film-type panoramic dental X-ray machine provided by the present invention includes a cassette speed scanning device, an X-ray detector based on TDI CCD, a video signal AD conversion and uploading device, a PC display platform and a power supply. The structural block diagram of the digital upgrade device of the film-type panoramic dental X-ray machine is shown in Figure 1. Including five parts, the film cassette speed scanning device, using the grating ruler as the core to scan the moving speed of the film cassette; the X-ray detection device based on TDI CCD, mainly using CPLD internal programming to realize: processing the grating ruler transmission speed signal, CCD drive timing, etc.; The video signal AD conversion and uploading device mainly completes the analog-to-digital conversion of the signal and the transmission of the upper computer; the PC display realizes the image display and storage of the computer; the power supply supplies power to each module.

The film box speed scanning device is mainly composed of a grating ruler, which scans the film movement of the film-type panoramic dental X-ray machine to obtain its speed signal. The specific implementation method is to use the grating ruler to fix it on the mechanical structure of the film-type panoramic dental X-ray machine The location of the cassette is shown in Figure 2. The grating ruler reading head is fixed on the C-shaped rotating arm, and the magnetic grid strip of the grating ruler is fixed at the position of the cassette so that it moves with the cassette. The grating ruler is shown in Figure 3. The reading head reads the motion of the film and outputs its speed signal U1, and the speed signal U1 is given to the X-ray detector based on TDI CCD.

Fig. 2 includes eight parts, lifting carriage 1, mainly used for the lifting of the mechanical structure; rotating cross arm 2, which is the C-shaped arm, carrying the X-ray generating and receiving device; film box 3, for the film type X-ray machine Film loading; position 4 of the grating ruler is the approximate installation position of the grating ruler; magnetic grating strip 6 is the magnetic grating strip of the grating ruler, which is marked with a scale on the film box and used for speed calculation; the reading head 7 is the grating A ruler reading head, the reading head scans the magnetic grating bar 6, and obtains a speed signal through the scale scanned per unit time; the X-ray generating source 8 is used to generate X-rays. The schematic diagram of the X-ray detector is shown in Figure 4. The core chip EMP7512 is programmed to generate the CCD drive signal, as shown in Figure 6. The drive signal required by the TDI-CCD includes eight vertical transfer clocks (denoted as P1AVa, P1BVa, P2AVa, P2BVa , P1AVb, P1BVb, P2AVb, P2BVb), eight horizontal transfer clocks (P1AHa, P1BHa, P2AHa, P2BHa, P1AHb, P1BHb, P2AHb, P2BHb), two reset pulses (denoted as RGa and RGb), two transfer gating signals (Denoted as TGa and TGb), and two summation gate signals (denoted as SGa and SGb), controlling the gate signal TG can control the charge transfer of the CCD. Afterwards, the output signal U1 of the grating ruler is processed through programming, and the processing includes 12-fold counting and debounce processing of common signals.

The X-ray detector also includes a TDI CCD output signal processing circuit, and the processing circuit is designed using the commonly used correlated double sampling principle (Zhang Lin, Li Yongxin, Hu Xueyou. Research on CCD video signal processing based on correlated double sampling technology[J]. Aerospace Measurement Technology, 2007,27(2):34-37.), used to remove reset noise from TDI CCD output signal. It is mainly composed of a piece of CDS-1402 and two potentiometers R1 and R2. The signal U2 is respectively connected to pins 3 and 4 of the CDS-1402; pins 1 and 9 of the CDS-1402 chip are respectively connected to a potentiometer R1 and R2 for compensation and adjustment of the input voltage. The 11 and 12 pins of the CDS-1402 are respectively connected to the SHP and SHD signals of the EPM7512, and the signal U2 is sampled and held to obtain the signal High and the signal low of the signal level information respectively carrying the TDI CCD output signal reference level information . Pins 7 and 8 of the CDS1402 chip are connected, and pin 6 is connected to pin 8 through the potentiometer R3, so that the two signals High and Low can be subtracted to obtain the output signal U3 that only carries the pixel signal amplitude information in the TDI CCD output signal , output to the next stage by 22 feet.

The video signal AD conversion and uploading device adopts the existing high-speed data acquisition card FCFR-USB9825 to perform AD conversion, FIFO storage, data USB upload and other functions on the CCD output signal; the X-ray detector output signal U3 is connected to the input terminal of the acquisition card, and the acquisition card The internal principle is shown in Figure 7. After the signal is collected and processed by the acquisition card, it is transmitted to the host computer through USB. The PC receives the data sent by the data acquisition card and is programmed to display the image and store it as a medical bmp file.

Claims (5)

1. A digital upgrading device for a film-type panoramic dental X-ray machine, which is used for digitally upgrading the existing hospital film-type panoramic dental X-ray machine, is characterized in that: it includes a film box speed scanning device, based on TDI CCD X-ray detector, video signal AD conversion and uploading device, PC display platform and power supply; scan the movement of the existing film-type panoramic dental X-ray machine with the film-type panoramic dental X-ray machine, and then transmit the speed signal obtained by scanning Entering the X-ray detector based on TDI CCD, its core chip CPLD processes the motion signal, and realizes through CPLD internal programming: the motion signal output by the grating ruler is a pulse signal, specifically, the film box outputs a 4um grating ruler every time Pulse; the CCD pixel is 48*48um, that is, the internal charge transfer of the CCD passes through 48um at a time, so that the film movement and the charge transfer of the CCD can be synchronized only if a pulse is generated every time the film box passes through 48um to trigger the CCD charge transfer once; The solution is to count the direct output signal of the grating ruler by 12 times, so that the trigger pulse of the grating ruler changes from a pulse of 4um to a pulse of 48um; secondly, since the movement of the film cassette uses a stepping motor, there will inevitably be jitter, In this way, the output signal of the grating ruler is disturbed by the jitter, so the signal processing program part also has a debounce module; the processed motion signal drives the transfer of the internal charge of the sensor TDI CCD, and the motion signal of the cassette drives the internal signal transfer of the CCD , it is necessary to retain the controllable input terminal of the transfer gating signal while the CPLD is programmed to generate the CCD drive signal, and the rest of the CCD signal drive is such as the definite integral driver. The film motion signal controls the vertical transfer of the CCD charge to achieve the movement mechanism and TDI CCD The purpose of complete charge transfer matching; after that, the effective tooth signal output by the X-ray detector enters the video signal AD conversion and uploading device for analog-to-digital conversion of the signal and transmits it to the PC display platform, and the PC display platform converts the bin file obtained after the analog-to-digital conversion Store and display in bmp format; the power supply provides the required voltage for the digital upgrade device of the entire film-type panoramic dental X-ray machine. 2. The digital upgrading device of the film-type panoramic dental X-ray machine as claimed in claim 1, characterized in that: the film box speed scanning device uses a grating ruler to scan the motion of the film, so that the film can be provided in real time The film motion speed signal of the X-ray machine, and trigger the charge transfer inside the TDI CCD through the motion signal, so that the whole system matches each other and a clear digital image is obtained; the magnetic grid strip is fixed on the film box of the X-ray machine, and the grating ruler The reading head is fixed on the C-arm of the X-ray machine, so that the film cassette drives the magnetic grid bar to move relative to the reading head, so that the grating ruler can scan the moving speed of the film cassette. 3. The digital upgrading device of the film type panoramic dental X-ray machine as claimed in claim 1, characterized in that: the motion signal obtained by the film cassette speed scanning device can be directly obtained because of the vibration of the film type mechanical movement. The motion signal will jitter, so the core chip CPLD of the X-ray detector behind the cassette speed scanning device is required to de-jitter the cassette motion signal through programming. The jitter processing is realized by CPLD chip programming. Solution. 4. The digital upgrading device of film type panoramic dental X-ray machine as claimed in claim 1, is characterized in that: the X-ray detector based on TDI CCD comprises the drive signal part of TDI CCD and the CCD output signal processing part, said The CCD pixel of the TDI CCD-based X-ray detector is 48*48um, so the CCD charge travels through 48um every time it is transferred, and the grating ruler in the film cassette speed scanning device gives a pulse every 4um, so that the film can To trigger CCD transfer once by moving 48um, 12 counts are required for the grating signal, that is, a transfer pulse is given to CCD every time the film travels 48um, and the counting is realized by CPLD chip programming. 5. The digital upgrading device of the film type panoramic dental X-ray machine as claimed in claim 1, characterized in that: the X-ray detector based on the TDI CCD can directly convert the received X-rays into electrical signals; Moreover, the design of the TDI CCD drive signal can make the charge transfer integration time of the TDI CCD controlled by the external mechanical motion pulse signal. The signal can be triggered externally, and an external control signal input port is reserved on the hardware circuit.