KR101475044B1 - Noise eliminating system of Radition Detectot - Google Patents

Abstract

The present invention relates to a noise elimination system and method for an X-ray detector, and more particularly, to a noise elimination system and method for an X-ray detector, which includes a detector sensing unit for detecting an image signal in an X-ray detector panel, a noise filter for removing noise from the image signal input from the detector sensing unit, And an A / D conversion unit for A / D-converting the signal filtered by the noise filter unit.

According to the present invention, it is possible to provide a system and an elimination method that can efficiently remove radiation noise caused by X-ray irradiation, thereby improving the S / N ratio and amplifying the signal stably to easily obtain a desired distortion- .

X-ray detector, noise rejection, low pass filter

Description

[0001] The present invention relates to a noise eliminating system of a radiation detection signal,

The present invention relates to an X-ray detector, and more particularly, to a system and method for efficiently removing a radiation noise included in a detection signal generated by transmitting an X-ray, thereby ensuring a stable signal without distortion of the signal.

An X-ray detector is a device that reads an x-ray transmitted through a human body or an object and implements it as an image.

X-ray inspection methods widely used in medicine, engineering and the like are photographed using an X-ray detection film and subjected to a predetermined film printing step in order to know the result. However, there is a problem in that it takes a long time for the usability because the photograph can be recognized after a certain time after a certain time. Especially, when the film itself is damaged due to difficulty in storing and preserving the film after photographing, It has been difficult to confirm such a problem.

In order to solve the above problems, a detector for detecting an x-ray image using a TFT (Thin Film Transistor) has been researched / developed. The detector using the TFT can realize an advantage that the TFT can be used as a switching element and the result can be diagnosed in real time immediately after photographing of the X-ray. Currently, commercial X-ray signal detection methods can be divided into indirect method and direct method.

In an indirect method, a photodiode is formed on a TFT, a scintillator for converting an X-ray signal into a visible light is coated on the photodiode, and the X-ray signal converted into visible light by the scintillator is photo- And converts it into an electrical signal through a diode, stores it in the capacitor of the TFT, and then applies a readout signal to the gate electrode of the TFT to read the x-ray signal charged in the capacitor.

The direct method uses a TFT similar to the above indirect method, and a photoconductor (a-Se, Csl, PbO) sensitive to X-rays is formed on the TFT to convert an X-ray signal into an electrical signal, Is stored in the capacitor of the TFT, and a read signal is applied to the gate to read the X-ray signal charged in the capacitor.

As described above, the conventional detector using a TFT has a disadvantage in that it requires a large number of thin-film transistors per pixel in the panel in addition to the difficulty in manufacturing, which makes it difficult to increase the size, increase the cost, and decrease the sensitivity. In order to solve these drawbacks, a method of using a PDP as a detector as an alternative apparatus has recently been proposed. In other words, the PDP structure is adopted instead of the structure using the TFT, and the gas in the gas layer inside is ionized by the X-ray to generate electron and hole pairs. The electrons are also accelerated by the electric field to ionize the other gas, . The collected electrons use the principle that the electrical signals output to the lead-out device are converted into image data and outputted as an image to generate a radiation image.

In any case, the detection signal to be inputted is read as a video signal and has the same principle. However, the method has a difference in the method of reading the signal and the structure of implementing it.

Referring to FIG. 1, the conventional radiographic apparatus using X-ray is an implementation of the entire system disclosed in Korean Patent Publication No. 10-2005-0018620.

A conventional radiographic imaging apparatus includes an X-ray tube 1 (radiation irradiation means) for radiating X-rays toward a subject M and an FPD (radiation irradiation means) for detecting X- D converter (not shown) for digitizing and extracting an X-ray detection signal (radiation detection signal) at a predetermined sampling time interval? T from the FPD 2 (radiation detection means) and FPD (flat panel type X- A detection signal processing section 4 for generating an X-ray image based on the X-ray detection signal outputted from the A / D converter 3, And an image monitor 5 for displaying a line image. The X-ray irradiating control unit 6 controlled by the main control unit 14, the mechanism 7 for moving the X-ray tube, the mechanism 8 for moving the detector of the X-ray tube, A motion control unit 9, a memory unit 10, a time delay removing unit 11, an impulse response specifying unit 12, an operation unit 13, and the like.

The radiation imaging apparatus having such a complicated configuration radiates X-rays to the subject M and successively extracts X-ray detection signals corresponding to the X-ray detection signals at sampling intervals, And a time delay corrector 11 for eliminating the delay component to obtain a corrected radiation detection signal by removing the time delay component.

However, it is general to use a method of removing noise using software to remove the noise of the detection signal in the above-described X-ray detector of the TFT type or PDP type detector of the gas type or the radiography apparatus shown in Fig. Especially in this case, there is a problem that the A / D converted signal itself necessarily contains a lot of noise. In particular, in the case of such a software-based noise canceling method, since the comparison is made several times, there is a problem that the actually detected signal is distorted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an elimination system capable of efficiently removing noise contained in an original signal generated during X-ray irradiation, thereby improving the S / N ratio And to provide a method for removing noise of a radiation detection signal which can stably amplify a signal and easily obtain a desired distortion-free signal.

A second aspect of the present invention is a method for solving the above-mentioned problems, comprising a first step of inputting an original signal to an X-ray detector panel and a second step of filtering the input signal of radiation noise generated during X- A noise removal processing method of a radiation detection signal.

For a more specific implementation, the second step of the present invention comprises the steps of: a) firstly removing the radiation noise generated during X-ray irradiation at a low pass filter stage; b) Amplifying the original signal using an amplifier (Pre-AMP), and c) secondarily removing the amplified noise from the original signal amplified by the low pass filter .

In addition, it is preferable to adopt a scheme of re-amplifying the signal input channel through the multiplexer after amplification of the signal in the above-mentioned b).

In addition, it is preferable that the present invention further includes a third step of performing A / D conversion using the noise-removed signal after step 2).

According to an aspect of the present invention, there is provided a system for implementing a noise reduction processing method for a radiation detection signal, comprising: a detector sensing unit for detecting an image signal in an X-ray detector panel; And an A / D converting unit for A / D-converting the signal filtered by the noise filter unit. The noise cancellation system of the present invention can provide a noise canceling system for a radiation detection signal.

In particular, in order to realize the characteristic efficiency of the present invention, the noise signal filter unit includes a low pass filter for eliminating noise generated in an input video signal during X-ray irradiation and a low pass filter for removing the noise- A preamplifier (Pre-AMP) for amplifying a video signal, and a multiplexer (Mux) for reselecting an input channel of a video signal.

Also, it is possible to provide a system for removing noise of a radiation detection signal, wherein at least one or more noise signal filter units are formed.

According to the present invention, it is possible to provide a system and an elimination method that can efficiently remove radiation noise caused by X-ray irradiation, thereby improving the S / N ratio and amplifying the signal stably to easily obtain a desired distortion- .

Hereinafter, the configuration and operation according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 2, FIG. 2 is a block diagram illustrating a system for removing a noise of a radiation signal according to the present invention.

The noise removing system according to the present invention includes a detector sensing unit 200 for detecting an image signal in an X-ray detector sensor panel, a noise signal filtering unit 300 for removing and amplifying noise from the image signal input from the detector sensing unit 300 And an A / D conversion unit 400 for A / D-converting the signal filtered by the noise filter unit.

Of course, the power supply source for implementing the X-ray detection signal may be additionally implemented with the voltage generating device 100 and the display unit 500 finally implementing the image.

The noise signal filter unit 300 generates at least one or more low-pass filters (hereinafter, referred to as " low-pass filters ") for removing noise generated in the input video signal when an X- (Pre-AMP) 310 for amplifying a noise-removed signal to an original video signal, a multiplexer (Mux) 330 for reselecting an input channel of a video signal, And the like.

The principle of operation of the whole system will be described as follows.

First, a detection signal is generated by an X-ray detector in an X-ray detector. The detection signal is sensed by a detector sensing unit 200, which is an X-ray detector sensor panel, and a detection signal is input to a noise signal filtering unit 300 through an input terminal. The input detection signal includes the radiation noise generated when the X-ray is irradiated. The radiation noise included in the detection signal is filtered through the noise signal filter unit secondarily. Specifically, the radiation noise is primarily removed from the low-pass filter 320 stage. The preamplifier (Pre-AMP) 310 amplifies the removed signal from which the radiation noise has been removed, to the original detection signal. Thereafter, an input channel of each detection signal is selected through a multiplexer (Mux) 330, and when the signal of the selected channel is amplified again using a low-pass filter, the noise amplified together with the detection signal is removed once again (Secondary elimination), thereby detecting a signal without distortion. Finally, the A / D conversion is performed using the noise-free signal, and then the image is implemented through the display unit.

Referring to FIG. 4, the upper graph of FIG. 4 shows the detection signals from the X-ray detector. As can be seen from the waveform, it can be seen that the detection signal is smaller than noise. The lower graph shows the detection signal through the noise signal filter section which is the analog circuit section according to the present invention. As a result, it can be seen that the noise can be perfectly removed and the amplification can be performed efficiently and well, and a distortion-free detection signal can be obtained.

The present invention can provide a system and a method that can efficiently remove the radiation noise due to a large amount of radiated noise generated upon X-ray irradiation. This is superior to the conventional topology of analog circuits, and it is possible to realize excellent performance in terms of efficiency. In addition, since the impendence of the panel is rapidly changed during the X-ray irradiation, the function of compensating the impendence of the panel can be performed. Therefore, the advantage of stable signal amplification . In addition, the system according to the present invention as described above provides a system and a removal method that can effectively remove radiation noise generated upon X-ray irradiation, thereby improving the signal to noise ratio and improving the distortion- The signal can be easily obtained. (The signal to noise ratio is the ratio of the desired signal to the undesired signal. The larger the signal to noise ratio is, the better the detection signal is.)

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

FIG. 1 is a schematic diagram of an entire conventional radiographic apparatus.

Figures 2 and 3 illustrate a preferred embodiment of the system according to the invention.

Fig. 4 is a graph comparing noise removal effects according to the present invention. Fig.

Claims (7)

delete A preamplifier connected to the detector through a input channel to detect a video signal in an X-ray detector panel, a low-pass filter connected to the preamplifier, and a multiplexer connected to the low- A noise removal method in a removal system, A first step of the preamplifier receiving an original signal as the video signal from the detector sensing unit; And A second step of filtering the radiation noise included in the original signal occurring in the X-ray irradiation by the low-pass filter; Wherein the second step comprises: a) removing the radiation noise included in the signal output from the preamplifier in the low pass filter stage first; b) transmitting the signal filtered in step a) to the preamplifier (Pre-AMP) and amplifying the signal using the preamplifier; c) filtering the signal amplified by the preamplifier in the step b) through the low pass filter to remove the noise amplified together with the signal; And a noise suppression processing unit for suppressing noise in the radiation detection signal. The method of claim 2, The second step comprises: Further comprising the step of reselecting an input channel of the signal through the multiplexer after amplification of the signal in step b). The method of claim 2, Further comprising a third step of analog-to-digital (A / D) conversion of the detection signal in which the noise is removed in the second step in the second step. A detector sensing unit for detecting an image signal in the X-ray detector panel; A noise signal filter unit coupled to the detector sensing unit and configured to remove noise included in the original signal, which is generated when the X-ray is irradiated, and is input to the detector sensing unit; And An A / D converter for analog-to-digital (A / D) -converting the detection signal filtered by the noise signal filter; , ≪ / RTI & Wherein the noise signal filter unit comprises: A preamplifier coupled to the detector sensing unit, a low pass filter coupled to the preamplifier, and a multiplexer coupled to the low pass filter, Wherein the noise elimination circuit removes radiation noise included in a signal output from the preamplifier in the low pass filter stage, and transmits the filtered signal to the preamplifier to amplify the amplified signal again, Wherein the signal is filtered by the low-pass filter to remove the amplified noise together with the amplification of the signal. delete The method of claim 5, Wherein the noise signal filter unit is formed at least one or more according to the number of connection channels connected to the detector sensing unit.

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