JP4700951B2 - Digital filter processing apparatus, digital filter processing method, digital filter processing program, and MRI system - Google Patents

Description

  The present invention has a plurality of buffers for sequentially and temporarily storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers, Digital filter processing apparatus, digital filter processing method, and digital filter processing program for performing filter arithmetic processing using filter coefficients, and capable of suppressing the influence of noise retroactively before noise generation without adding parts The present invention relates to a processing device, a digital filter processing method, and a digital filter processing program.

  Conventionally, it has a plurality of buffers for sequentially storing digital data digitally converted from an analog signal on which noise of a predetermined threshold or more is superimposed, and filter coefficients associated with the plurality of buffers, and the digital data and the filter coefficients There is known a digital filter processing apparatus that performs a filter calculation process using the. Such a digital filter processing apparatus is used in a data collection unit such as a magnetic resonance computer diagnostic apparatus (hereinafter, “magnetic resonance computer diagnostic apparatus” is referred to as “MRI”).

  In such MRI, sudden noise may be superimposed on the MRI RF signal due to external factors such as surrounding electronic devices. When noise exceeding a predetermined threshold is superimposed on the RF signal, the influence of noise affects not only the digital data on which the noise is superimposed but also the digital data before and after the noise. Moreover, the RF signal after noise detection can be easily removed by an analog filter or the like, but it is difficult to remove the RF signal before noise detection because it has already passed.

  For example, in the conventional MRI of Non-Patent Document 1, an analog signal after noise is detected is removed, and noise superimposed on digital data corresponding to a time delay after digital conversion is further removed to go back to before noise detection. Conventional techniques for suppressing noise are applied.

GEmedical literature, “Magnetic Resonance (MR) Technology”, [October 18, 2004 search], Internet <URL: www. gehealthcare. com / company / docs / mr3. pdf>

  However, the conventional MRI of Non-Patent Document 1 has a problem that it can only remove noise superimposed on the digital data corresponding to the time delay that happens to exist in the MRI data collection unit. Further, if a buffer is provided in the middle of the data collection unit, noise can be removed retroactively, but there is a problem that a new buffer needs to be added to remove noise.

  The present invention has been made in view of the above, and a digital filter processing device, a digital filter processing method, and a digital filter processing capable of suppressing the influence of noise retroactively before the occurrence of noise without adding any components The purpose is to provide a program.

  In order to solve the above-described problems and achieve the object, the invention according to the first aspect includes a plurality of buffers for sequentially and temporarily storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed. A digital filter processing device having a filter coefficient associated with the plurality of buffers and performing a filter calculation process using the digital data and the filter coefficient, and sequentially stored in the plurality of buffers sequentially Data rewriting means for rewriting digital data to predetermined data, and when noise exceeding the predetermined threshold is detected, the range of the range affected by the detected noise that is temporarily stored in the plurality of buffers sequentially. Digital filter control means for rewriting digital data to the predetermined data and performing the filter calculation process , Characterized by comprising a.

  According to the first aspect of the present invention, digital data sequentially temporarily stored in a plurality of buffers is rewritten to predetermined data, and when noise exceeding a predetermined threshold is detected, the digital data is sequentially temporarily stored in the plurality of buffers. The digital data in the range affected by the detected noise is rewritten to the specified data and controlled to perform the filter calculation process, so the noise can be traced back to before noise generation without adding parts. The influence of can be suppressed.

  The invention according to the second aspect further includes data reading means for reading the digital data temporarily stored in the buffer immediately before the digital data rewritten by the data rewriting means in the invention according to the first aspect. The digital filter control means reads the digital data in a range that is affected by the detected noise and is temporarily stored in the plurality of buffers sequentially when noise of the predetermined threshold value or more is detected. The digital data is rewritten, and control is performed so as to perform the filter calculation process.

  According to the second aspect of the invention, the digital data temporarily stored in the buffer immediately before the rewritten digital data is read, and when noise of a predetermined threshold value or more is detected, the plurality of buffers are sequentially temporarily stored. The stored digital data in the range affected by the detected noise is rewritten to the read digital data, and control is performed so that the filter calculation process is performed. The influence of noise can be suppressed retroactively.

  According to a third aspect of the present invention, there are provided a plurality of buffers for sequentially and temporarily storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing device for performing a filter operation process using the digital data and the filter coefficient, wherein the data replacement means replaces the digital data sequentially temporarily stored in the plurality of buffers with predetermined data And when noise equal to or greater than the predetermined threshold is detected, the digital data in a range that is temporarily stored in the plurality of buffers and affected by the detected noise is replaced with the predetermined data, And digital filter control means for controlling to perform the filter calculation process.

  According to the third aspect of the invention, when digital data sequentially stored temporarily in a plurality of buffers is replaced with predetermined data, and noise exceeding a predetermined threshold is detected, the data is temporarily stored in the plurality of buffers. The stored digital data in the range affected by the detected noise is replaced with the specified data, and control is performed so that the filter operation is performed. Thus, the influence of noise can be suppressed.

  The invention according to the fourth aspect further comprises data reading means for reading the digital data temporarily stored in the buffer immediately before the digital data replaced by the data replacement means in the invention according to the third aspect. The digital filter control means reads the digital data in a range that is affected by the detected noise and is temporarily stored in the plurality of buffers sequentially when noise of the predetermined threshold value or more is detected. Control is performed so as to perform the filter calculation processing in place of the digital data.

  According to the fourth aspect of the invention, the digital data temporarily stored in the buffer immediately before the replaced digital data is read, and when noise exceeding a predetermined threshold is detected, the data is temporarily stored in the plurality of buffers sequentially. The stored digital data in the range affected by the detected noise is replaced with the read digital data, and control is performed to perform the filter calculation process. The influence of noise can be suppressed retroactively.

  According to a fifth aspect of the present invention, there are provided a plurality of buffers for sequentially and temporarily storing digital data digitally converted from an analog signal on which noise equal to or greater than a predetermined threshold is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing device that performs a filter calculation process using the digital data and the filter coefficient, wherein the filter coefficient replacement replaces the filter coefficient associated with the plurality of buffers with a predetermined filter coefficient And a filter coefficient associated with a buffer that temporarily stores digital data in a range that is affected by the detected noise when noise exceeding the predetermined threshold is detected as the predetermined filter coefficient. And a digital filter control means for controlling to perform the filter calculation processing by replacing And wherein the door.

  According to the fifth aspect of the invention, the filter coefficient associated with a plurality of buffers is replaced with a predetermined filter coefficient, and when noise of a predetermined threshold value or more is detected, the influence of the detected noise Since the filter coefficient associated with the buffer that temporarily stores the digital data in the range covered by is replaced with a predetermined filter coefficient and control is performed to perform the filter calculation process, noise is added without adding components. The influence of noise can be suppressed retroactively.

  The invention according to a sixth aspect is the invention according to any one of the first to fifth aspects, wherein the plurality of buffers are a plurality of temporary storages for sequentially storing the digitally converted digital data. It is a shift register.

  According to the sixth aspect of the invention, the plurality of buffers are a plurality of shift registers that sequentially and temporarily store digitally converted digital data, so that the sampled digital data is temporarily and temporarily stored. However, filter calculation processing can be performed.

  Further, the invention according to a seventh aspect is the invention according to any one of the first to fifth aspects, wherein the filter operation processing includes the digital data sequentially and temporarily stored in the plurality of buffers. Each filter coefficient associated with a plurality of buffers is multiplied, and the sum of the multiplied products is obtained.

  According to the seventh aspect of the present invention, the filter operation processing multiplies the digital data sequentially temporarily stored in the plurality of buffers and the filter coefficients associated with the plurality of buffers, respectively, and sums the multiplied products. Therefore, the filter calculation process can be easily performed.

  The invention according to the eighth aspect is the invention according to any one of the first to seventh aspects, wherein the magnetic resonance computer diagnostic apparatus collects the received signals collected from the subject to be diagnosed. A filter calculation process is performed.

  According to the eighth aspect of the invention, since the magnetic resonance computer diagnostic apparatus performs the filter calculation process on the received signal collected from the subject to be diagnosed, the magnetic resonance computer diagnostic apparatus A diagnostic image in which the influence is suppressed can be generated.

  According to a ninth aspect of the present invention, there is provided a plurality of buffers that sequentially store digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing method for performing a filter calculation process using the digital data and the filter coefficient, wherein the digital rewriting process sequentially rewrites the digital data temporarily stored in the plurality of buffers with predetermined data And, when noise equal to or greater than the predetermined threshold is detected, the digital data in a range that is temporarily stored in the plurality of buffers and that is affected by the detected noise is rewritten to the predetermined data, and And a digital filter control step for controlling to perform filter calculation processing.

  According to the ninth aspect of the invention, digital data sequentially temporarily stored in a plurality of buffers is rewritten to predetermined data, and when noise exceeding a predetermined threshold value is detected, the digital data is sequentially temporarily stored in the plurality of buffers. The digital data in the range affected by the detected noise is rewritten to the specified data and controlled to perform the filter calculation process, so the noise can be traced back to before noise generation without adding parts. The influence of can be suppressed.

  The invention according to a tenth aspect further includes a data reading step of reading the digital data temporarily stored in the buffer immediately before the digital data rewritten by the data rewriting step in the invention according to the ninth aspect, In the digital filter control step, when noise equal to or higher than the predetermined threshold is detected, the digital data in the range that is affected by the detected noise, which is temporarily stored in the plurality of buffers sequentially, is read. Control is performed so as to perform the filter calculation processing by rewriting digital data.

  According to the tenth aspect of the invention, the digital data temporarily stored in the buffer immediately before the rewritten digital data is read, and when noise of a predetermined threshold value or more is detected, the buffer is sequentially temporarily stored in a plurality of buffers. The stored digital data in the range affected by the detected noise is rewritten to the read digital data, and control is performed so that the filter calculation process is performed. The influence of noise can be suppressed retroactively.

  According to an eleventh aspect of the present invention, there are provided a plurality of buffers for sequentially storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing method for performing a filter calculation process using the digital data and the filter coefficient, wherein the digital replacement process sequentially replaces the digital data temporarily stored in the plurality of buffers with predetermined data. And when noise equal to or greater than the predetermined threshold is detected, the digital data in a range that is temporarily stored in the plurality of buffers and affected by the detected noise is replaced with the predetermined data, And a digital filter control step for controlling to perform the filter calculation process.

  According to the eleventh aspect of the invention, digital data sequentially temporarily stored in a plurality of buffers is replaced with predetermined data, and when noise exceeding a predetermined threshold is detected, the data is temporarily stored in the plurality of buffers. The stored digital data in the range affected by the detected noise is replaced with the specified data, and control is performed so that the filter operation is performed. Thus, the influence of noise can be suppressed.

  The invention according to a twelfth aspect further includes a data reading step of reading the digital data temporarily stored in the buffer immediately before the digital data replaced by the data replacement step in the invention according to the eleventh aspect. The digital filter control step reads the digital data in a range that is affected by the detected noise, which is sequentially temporarily stored in the plurality of buffers, when noise of the predetermined threshold value or more is detected. Control is performed so as to perform the filter calculation processing in place of the digital data.

  According to the twelfth aspect of the present invention, the digital data temporarily stored in the buffer immediately before the replaced digital data is read, and when noise of a predetermined threshold value or more is detected, the buffer is sequentially temporarily stored in a plurality of buffers. The stored digital data in the range affected by the detected noise is replaced with the read digital data, and control is performed to perform the filter calculation process. The influence of noise can be suppressed retroactively.

  According to a thirteenth aspect of the present invention, there is provided a plurality of buffers that sequentially store digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing method for performing a filter calculation process using the digital data and the filter coefficient, wherein the filter coefficient replacement replaces the filter coefficient associated with the plurality of buffers with a predetermined filter coefficient A filter coefficient associated with a buffer that sequentially and temporarily stores digital data in a range affected by the detected noise when noise equal to or greater than the predetermined threshold is detected as the predetermined filter coefficient And a digital filter control step for controlling to perform the filter calculation processing by replacing And wherein the door.

  According to the thirteenth aspect of the invention, the filter coefficient associated with a plurality of buffers is replaced with a predetermined filter coefficient, and when noise of a predetermined threshold value or more is detected, the influence of the detected noise Since the filter coefficient associated with the buffer that temporarily stores the digital data in the range covered by is replaced with a predetermined filter coefficient and control is performed to perform the filter calculation process, noise is added without adding components. The influence of noise can be suppressed retroactively.

  According to a fourteenth aspect of the present invention, there is provided a plurality of buffers that sequentially store digital data digitally converted from an analog signal on which noise of a predetermined threshold value or higher is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing program for performing a filter calculation process using the digital data and the filter coefficient, and rewriting the digital data temporarily stored in the plurality of buffers sequentially with predetermined data And, when noise equal to or greater than the predetermined threshold is detected, the digital data in a range that is temporarily stored in the plurality of buffers and that is affected by the detected noise is rewritten to the predetermined data, and And causing a computer to execute a digital filter control procedure for controlling to perform filter arithmetic processing. And wherein the door.

  According to the fourteenth aspect of the invention, digital data sequentially temporarily stored in a plurality of buffers is rewritten to predetermined data, and when noise exceeding a predetermined threshold is detected, the digital data is sequentially temporarily stored in the plurality of buffers. The digital data in the range affected by the detected noise is rewritten to the specified data and controlled to perform the filter calculation process, so the noise can be traced back to before noise generation without adding parts. The influence of can be suppressed.

  The fifteenth aspect of the invention is the computer according to the fourteenth aspect of the invention, further comprising a data reading procedure for reading the digital data temporarily stored in the buffer immediately before the digital data rewritten by the data rewriting procedure. The digital filter control procedure executes digital data in a range that is affected by the detected noise, which is sequentially temporarily stored in the plurality of buffers when noise of the predetermined threshold value or more is detected. Control is performed to rewrite the read digital data and perform the filter calculation processing.

  According to the fifteenth aspect of the invention, the digital data temporarily stored in the buffer immediately before the rewritten digital data is read, and when noise of a predetermined threshold value or more is detected, the plurality of buffers are sequentially temporarily stored. The stored digital data in the range affected by the detected noise is rewritten to the read digital data, and control is performed so that the filter calculation process is performed. The influence of noise can be suppressed retroactively.

  According to a sixteenth aspect of the present invention, there are provided a plurality of buffers that sequentially store digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing program for performing a filter calculation process using the digital data and the filter coefficient, and replacing the digital data sequentially temporarily stored in the plurality of buffers with predetermined data And when noise equal to or greater than the predetermined threshold is detected, the digital data in a range that is temporarily stored in the plurality of buffers and affected by the detected noise is replaced with the predetermined data, And a digital filter control procedure for controlling to perform the filter calculation process. And wherein the door.

  According to the sixteenth aspect of the present invention, when digital data sequentially stored temporarily in a plurality of buffers is replaced with predetermined data, and noise exceeding a predetermined threshold is detected, the data is temporarily stored in the plurality of buffers. The stored digital data in the range affected by the detected noise is replaced with the specified data, and control is performed so that the filter operation is performed. Thus, the influence of noise can be suppressed.

  According to a seventeenth aspect, in the invention according to the sixteenth aspect, the computer further includes a data reading procedure for reading the digital data temporarily stored in the buffer immediately before the digital data replaced by the data replacement procedure. The digital filter control procedure executes digital data in a range that is affected by the detected noise, which is sequentially temporarily stored in the plurality of buffers when noise of the predetermined threshold value or more is detected. Control is performed so as to perform the filter calculation processing in place of the read digital data.

  According to the seventeenth aspect of the present invention, the digital data temporarily stored in the buffer immediately before the replaced digital data is read, and when noise of a predetermined threshold value or more is detected, the data is temporarily stored in a plurality of buffers. The stored digital data in the range affected by the detected noise is replaced with the read digital data, and control is performed to perform the filter calculation process. The influence of noise can be suppressed retroactively.

  According to an eighteenth aspect of the present invention, there are provided a plurality of buffers that sequentially store digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed, and filter coefficients associated with the plurality of buffers. A digital filter processing program for performing a filter calculation process using the digital data and the filter coefficient, wherein the filter coefficient replacement replaces the filter coefficient associated with the plurality of buffers with a predetermined filter coefficient When noise greater than or equal to the predetermined threshold is detected, a filter coefficient associated with a buffer that sequentially temporarily stores digital data in a range affected by the detected noise is used as the predetermined filter coefficient. A digital filter control procedure for replacing and controlling to perform the filter calculation process; And characterized by causing a computer to execute.

  According to the eighteenth aspect of the invention, the filter coefficient associated with the plurality of buffers is replaced with a predetermined filter coefficient, and when noise of a predetermined threshold value or more is detected, the influence of the detected noise Since the filter coefficient associated with the buffer that temporarily stores the digital data in the range covered by is replaced with a predetermined filter coefficient and control is performed to perform the filter calculation process, noise is added without adding components. The influence of noise can be suppressed retroactively.

  The digital filter processing apparatus according to the present invention rewrites digital data temporarily stored in a plurality of buffers sequentially to predetermined data, and when noise exceeding a predetermined threshold is detected, the digital data is sequentially stored temporarily in the plurality of buffers. Since the digital data in the range affected by the detected noise is rewritten to the specified data and the filter calculation process is performed, the influence of the noise is suppressed retroactively before noise generation without adding any parts. There is an effect that can be done.

Embodiments of a digital filter processing apparatus according to the present invention will be described below in detail with reference to the drawings. Here, the following four examples will be described. Note that the present invention is not limited to the embodiments.
(1) In the first embodiment, a case will be described in which noise is suppressed by rewriting digital data affected by noise temporarily stored in a buffer of a digital filter processing device with predetermined data.
(2) In the second embodiment, a case will be described in which noise is suppressed by rewriting digital data temporarily affected by noise stored in the buffer of the digital filter processing device with data immediately before the digital data.
(3) In the third embodiment, a case will be described in which noise is suppressed by replacing digital data affected by noise temporarily stored in the buffer of the digital filter processing device with predetermined data.
(4) In the fourth embodiment, a case will be described in which noise is suppressed by replacing a filter coefficient associated with a buffer of a digital filter processing device with a predetermined filter coefficient.

  In the first embodiment, a case will be described in which noise is suppressed by rewriting digital data affected by noise temporarily stored in a buffer of a digital filter processing device with predetermined data. In the first embodiment, (1-1) the outline and main features of a digital filter processing apparatus applied to the data collection unit of the MRI system, (1-2) the configuration of the MRI system, and (1-3) data collection The configuration of the image processing unit and the digital filter processing device, (1-4) data collection processing procedure, and (1-5) filter calculation processing procedure will be described.

(1-1) Outline and Main Features of Digital Filter Processing Device Applied to Data Collection Unit of MRI System First, referring to FIGS. 1 to 5, the data collection unit of the MRI system 10 according to the first embodiment An outline and main features of the digital filter processing device 240 applied to the digital camera 24 will be described. FIG. 1 is a functional block diagram illustrating the configuration of the MRI system 10 according to the first embodiment. FIG. 2 is a functional block diagram showing the configuration of the data collection unit 24 shown in FIG. FIG. 3 is a diagram illustrating an example of noise superimposed on the RF signal captured by the data collection unit illustrated in FIG. 2. FIG. 4 is a diagram showing an example in which the AD converter shown in FIG. 2 converts the RF signal shown in FIG. 3 into digital data. FIG. 5 is a diagram illustrating an example of digital data on which noise stored in a plurality of buffers of the digital filter processing device 240 illustrated in FIG. 2 is superimposed.

  As shown in FIG. 1, the MRI system 10 is a diagnostic system that acquires a tomographic image of the subject 40 by using nuclear magnetic resonance of hydrogen atoms constituting the subject 40. That is, the MRI system 10 irradiates the subject 40 with an electromagnetic wave having a constant frequency in a magnetic field having a constant intensity. And the RF signal radiated | emitted from the hydrogen nucleus is received by making the hydrogen nucleus which comprises the test object 40 resonate by the electromagnetic wave of the fixed frequency irradiated. Further, a tomographic image of the subject 40 is acquired by data processing of the received RF signal.

  As shown in FIG. 2, the data collection unit 24 is a data collection device that takes in an RF signal received from the subject 40 and outputs it to the data processing unit 31. The data collection unit 24 includes a noise detection circuit 241, an AD converter 242, an input A processing circuit 243, a detection processing circuit 244, a digital filter processing device 240, and an output processing circuit 248 are included.

  The noise detection circuit 241 is a circuit that detects noise equal to or higher than a predetermined threshold value superimposed on the RF signal Ei shown in FIG. 3, detects the noise, and notifies the digital filter processing device 240 of it. Further, the AD converter 242 converts the RF signal Ei shown in FIG. 3 into digital data shown in FIG. One circle in FIG. 4 indicates one digital data. Among these digital data, the digital data indicated by ◎ is the digital data on which the detected noise is superimposed, and the digital data indicated by ● is the digital data in the noise influence range.

  The input processing circuit 243 corrects the offset of the digital data that has been digitally converted. The detection processing circuit 244 converts the center frequency of the input digital data into baseband. In addition, the digital filter processing device 240 performs a filter calculation process on the detected digital data to reduce the high frequency component of the digital data from 80 MHz to 1 MHz.

  Further, the digital filter processing device 240 stores the digital data in 80 (N = 79) buffers as shown in FIG. 5 in order to reduce the high frequency component of the digital data from 80 MHz to 1/80. Perform filter calculation processing. In addition, among the digital data in FIG. 5, the digital data stored in the nth buffer is the digital data on which the detected noise is superimposed, and the m digital data before and after the noise are in the noise affected range. It is data.

  In addition, when the digital filter processing device 240 receives a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected, the digital filter processing device 240 is sequentially detected in the 80 buffers of the digital filter processing device 240 and detected. Since the digital data in the range affected by noise, that is, the maximum (2m + 1) digital data is rewritten to the predetermined data and the filter calculation processing is performed, it is possible to go back to before noise generation without adding parts. The influence of noise can be suppressed. The output processing circuit 248 takes the consistency of the interface of the digital data that has been subjected to the digital filter processing, and outputs it to the data processing unit 31.

(1-2) Configuration of MRI System Next, the configuration of the MRI system 10 according to the first embodiment will be described with reference to FIG.
As shown in FIG. 1, the MRI system 10 includes an MRI apparatus 20, an operator console 30, and a subject 40. The MRI apparatus 20 includes a magnet system 21, an RF drive unit 22, a gradient drive unit 23, a data collection unit 24, and a control unit 25.

  The magnet system 21 is a system composed of a permanent magnet or a normal electromagnet that forms a constant electrostatic field and a high-frequency magnetic field in a cylindrical internal space into which the subject 40 is carried. The RF drive unit 22 is a drive unit that generates a RF signal by giving a drive signal to the magnet system 21 based on an instruction from the control unit 25 described later, and excites hydrogen nuclei in the body of the subject 40. The subject 40 is a subject or a subject to be examined.

  The gradient driving unit 23 is a driving device that forms a gradient in the electrostatic field by giving a driving signal to the magnet system 21 based on an instruction from the control unit 25 described later. The data collection unit 24 is a data collection device that takes in an RF signal received by the magnet system 21 based on an instruction from the control unit 25 described later and outputs the RF signal to the data processing unit 31 described later. The control unit 25 is a control device that controls the entire MRI apparatus 20.

  The operator console 30 includes a data processing unit 31, an operation unit 32, and a display unit 33. The data processing unit 31 is a processing unit that processes the data input from the data collection unit 24 and generates tomographic image data of the subject 40. The operation unit 32 is an input device that inputs a user operation signal to the data processing unit 31 and is a keyboard or a mouse. The display unit 33 is an image display device that displays a tomographic image of the subject 40 and is an LCD (Liquid Crystal Display) or the like.

(1-3) Configuration of Data Collection Unit and Digital Filter Processing Device Next, the configuration of the data collection unit and the digital filter processing device will be described with reference to FIGS. FIG. 6 is a functional block diagram showing the configuration of the digital filter processing device 240 shown in FIG. 2 in more detail.

  As shown in FIG. 2, the data collection unit 24 includes a noise detection circuit 241, an AD converter 242, an input processing circuit 243, a detection processing circuit 244, a digital filter processing device 240, and an output processing circuit 248.

  The noise detection circuit 241 is a circuit that detects noise equal to or higher than a predetermined threshold superimposed on the RF signal. When noise equal to or higher than the predetermined threshold is detected, noise that is equal to or higher than the predetermined threshold is applied to the digital filter processing device 240 described later. Notify that it has been detected. The AD converter 242 is a converter that converts an RF signal from an analog signal to digital data, and outputs the converted digital data to the input processing circuit 243. Here, an example of the noise superimposed on the RF signal captured by the data collection unit 24 shown in FIG. 2 will be described with reference to FIG. Noise as shown in the figure is mixed and superimposed on a high-frequency RF signal due to external factors such as the operation of surrounding electronic devices.

  An example in which the AD converter 242 shown in FIG. 2 converts the RF signal shown in FIG. 3 into digital data will be described with reference to FIG. As shown in the figure, the AD converter 242 samples the RF signal from the RF signal at a time interval Δt, for example, 12.5 nsec if it is 80 MHz, and converts it into digital data. One circle in the figure corresponds to one digital data. Further, ◎ indicates digital data on which noise equal to or higher than a predetermined threshold detected by the noise detection circuit 241 is superimposed. Also, ● indicates digital data within the noise influence range.

  The input processing circuit 243 is a processing circuit that corrects the offset of the digital data output from the AD converter 242, and outputs the digital data with the offset corrected to the detection processing circuit 244. The detection processing circuit 244 is a circuit that performs detection processing for converting the center frequency of the digital data into baseband, and outputs the digital data subjected to the detection processing to the digital filter processing device 240.

  The digital filter processing device 240 is a processing device that performs filter calculation processing on digital data that has been subjected to detection processing. Specifically, the digital filter processing device 240 performs filter calculation processing that reduces the high-frequency component of the digital data from 80 MHz to 1 MHz. The output processing circuit 248 is a data interface circuit for outputting the digital data subjected to the filter calculation process to the data processing unit 31.

  Here, an example of digital data on which noise is superimposed and stored in a plurality of buffers of the digital filter processing device 240 shown in FIG. 2 will be described with reference to FIG. The digital filter processor 240 has (N + 1) shift registers 0 to N, and the (n + m) th to (nm) th buffers are affected by the noise shown in FIG. 4 (2m + 1). ) Pieces of digital data are stored.

  As described above, since (2m + 1) pieces of digital data are digital data influenced by the detected noise exceeding the predetermined threshold value, the digital data affected by the noise exceeding the predetermined threshold value is rewritten. Therefore, the influence of noise can be suppressed.

  Next, the configuration of the digital filter processing device 240 shown in FIG. 2 will be described in more detail with reference to FIG. As shown in the figure, the digital filter processing device 240 includes a digital filter circuit 245, a filter coefficient storage unit 246, and a digital filter control unit 247.

  Here, before describing the digital filter circuit 245, the filter calculation processing will be briefly described. In the filter calculation process, as shown in the following (Equation 1), the output data g (n) at a certain point in time is converted into current and past input data f (n), f (n + 1)..., F (n + N). Obtained by multiplying the filter coefficients h (0), h (1),.

なお、フィルタ係数ｈ（ｋ）は、インパルス応答とも呼ばれ、単位パルスをあるシステムに入力したときのそのシステムの出力を表している。

The filter coefficient h (k) is also called an impulse response and represents the output of the system when a unit pulse is input to the system.

  The digital filter circuit 245 is a circuit that performs the calculation of (Expression 1) described above, and includes shift registers 2451-0 to 2451 -N, multipliers 2452-0 to 2452 -N, and an adder 2453. The shift registers 2451-0 to 2451-N are buffers that temporarily store (N + 1) pieces of digital data sampled at a sampling interval of Δt, and include data rewriting units 2451a-0 to 2451a-N. The data rewriting units 2451a-0 to 2451a-N are rewriting units for rewriting digital data stored in the shift registers 2451-0 to 2451-N according to instructions from the digital control circuit 247.

  As described above, since the plurality of buffers are the shift registers 2451-0 to 2451-N that sequentially and temporarily store digitally converted digital data, the sampled digital data is temporarily and temporarily stored while being shifted. be able to.

  Multipliers 2452-0 to 2452 -N multiply the digital data temporarily stored in the shift registers 2451-0 to 2451 -N by filter coefficients h (0)... H (N). It is a vessel. The adder 2453 is an adder that adds (N + 1) products of the multipliers 2452-0 to 2452 -N.

  Thus, the digital filter circuit 245 multiplies the digital data sequentially temporarily stored in the shift registers 2451-0 to 2451-N and the filter coefficient associated with the shift registers 2451-0 to 2451-N, respectively. Since the sum is taken, the filter calculation process can be easily performed.

  The filter coefficient storage unit 246 is a storage unit that stores the filter coefficients h (0), h (1)... H (N). In addition, when noise of a predetermined threshold value or more is detected, the digital filter control unit 247 affects the detected noise that is sequentially temporarily stored in (N + 1) shift registers 2451-0 to 2451-N. This is a control unit that controls to perform the filter calculation process by rewriting the digital data in the affected range, that is, the (n−m) th to (n + m) th digital data shown in FIG. 5 with predetermined data. Thereby, the influence of noise superimposed on the RF signal can be suppressed.

  In addition, the digital filter control unit 247 specifies the influence range of the digital data affected by the noise as follows. That is, the time t when the noise detection circuit 241 detects noise equal to or higher than a predetermined threshold value superimposed on the RF signal is time t, the sampling interval at which the RF signal is digitally converted by the AD converter 242 is Δt, and the RF signal is detected by the AD converter 242 Τ is a time delay until the digital data converted from the digital signal is stored in the shift register 2451-0 of the digital filter circuit 245 via the input processing circuit 243 and the detection processing circuit 244. When the time delay τ is greater than or equal to m × Δt, the digital data affected by noise is not yet stored in the shift register.

  Therefore, when the delay time τ elapses and the digital data affected by noise is stored in the shift register 2451-0, the digital filter control unit 247 stores the digital data stored in the shift register 2451-0. The data rewriting unit 2451a-0 is controlled so as to be rewritten to predetermined data. Of course, after the time Δt, the next digital data affected by the noise is stored in the shift register 2451-0, so the digital filter control unit 247 controls the data rewriting unit 2451a-0 to sequentially rewrite the data. To do.

On the other hand, when the time delay τ is less than m × Δt, the digital data affected by the noise is stored in the shift registers 2451-0 to 2451-m ′. That is,
m ′ = int [(m × Δt−τ) / Δt] −1 (Formula 2)
However, int [] is an operator that makes the operation result in [] an integer.

  Therefore, the digital filter control unit 247 controls the data rewriting units 2451a-0 to 2451a-m ′ so as to rewrite the digital data stored in the shift registers 2451-0 to 2451-m ′ with predetermined data. Of course, after the time Δt, the next digital data affected by the noise is stored in the shift register 2451-0, so the digital filter control unit 247 controls the data rewriting unit 2451a-0 to sequentially rewrite the data. To do.

  Usually, when the sampling interval Δt and the delay time τ are constant and the noise influence range m is constant, m ′ is also constant. Since the case where the time delay τ is less than m × Δt is more general, the case where the time delay τ is less than m × Δt will be described below.

(1-4) Data Collection Processing Procedure Next, the data collection processing procedure of the data collection unit shown in FIG. 2 will be described with reference to FIG. FIG. 7 is a flowchart showing a data collection processing procedure of the data collection unit shown in FIG. As shown in the figure, first, the data collection unit 24 inputs an RF signal from the magnet system 21 of the MRI apparatus 20 (step S701). The noise detection circuit 241 notifies the digital filter processing device 240 when noise that is equal to or greater than a predetermined threshold is detected in the RF signal (step S702).

  Further, the AD converter 242 samples the RF signal at 80 MHz, converts the sampled RF signal into digital data, and outputs the digital data to the input processing circuit 243 (step S703). Then, the input processing circuit 243 corrects the offset of the digital data input from the AD converter 242 and outputs it to the detection processing circuit (step S704). Further, the detection processing circuit 244 performs detection processing for converting the center frequency of the digital data input from the input processing circuit 243 into baseband, and outputs the result to the digital filter processing device 240 (step S705).

  Then, the digital filter processing device 240 performs a filter calculation process on the digital data input from the detection processing circuit 244 to reduce the high frequency component of the digital data from 80 MHz to 1 MHz (step S706). In this case, if there is a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected in the RF signal, the noise is detected from the digital data within the noise-affected range, which is sequentially temporarily stored in the digital filter processing device 240. The filter calculation process is performed by removing the influence of.

  Further, the output processing circuit 248 processes the digital data input from the digital filter processing device 240 so as to match the data interface of the data processing device 31 (step S707), and outputs the digital data to the data processing unit 31 (step S707). Step S708).

  By performing the above-described series of processing, when the digital filter processing device 240 receives a notification from the noise detection circuit 241 that noise equal to or greater than a predetermined threshold value has been detected in the RF signal, the digital filter processing device 240 sequentially stores the digital filter processing device 240 sequentially. The filter operation is performed by removing the influence of noise from the digital data within the noise influence range, so it is possible to suppress the influence of noise retroactively before the occurrence of noise without adding parts. it can.

(1-5) Filter Calculation Processing Procedure Next, the filter calculation processing procedure shown in FIG. 7 and step S706 will be described in more detail with reference to FIG. FIG. 8 is a flowchart showing the filter operation processing procedure shown in FIG. 7, step S706 in more detail. As shown in the figure, first, the digital filter control unit 247 determines whether or not there is a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected (step S801).

  As a result, when there is a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected (Yes in step S801), the digital filter control unit 247 determines that the shift registers 2451-0 to 2451-m ′ ( Control is performed so that the digital data within the noise influence range stored in Equation 2 is rewritten to predetermined data (step S802). For example, control is performed so that digital data within the noise influence range is rewritten to 0 or any other data.

  On the other hand, if there is no notification from the noise detection circuit 241 that noise equal to or greater than the predetermined threshold has been detected (No at step S801), the digital filter control unit 247 advances the procedure to step S803.

  Then, the digital filter circuit 245 shifts the data in the shift registers 2451-0 to 2451-N as a whole (step S803), and stores the new data input from the detection processing circuit 244 in the first shift register 2451-0. (Step S804).

  Further, the digital filter control unit 247 determines whether or not the new data is data within the noise influence range (step S805). As a result, when the new data is not data within the noise influence range (No at Step S805), the digital filter control unit 247 performs filter calculation processing (Step S806), and outputs the filter calculation processing result to the output processing circuit. It controls to output to H.248 (step S807).

  On the other hand, when the new data is within the noise influence range (Yes at Step S805), the digital filter control unit 247 rewrites the data affected by the noise to predetermined data (Step S808), and performs the filter calculation. Processing is performed (step S809), and control is performed so as to output the filter calculation processing result to the output processing circuit 248 (step S810). Thereafter, the procedure from step S803 to step S810 is repeated.

  By performing the above-described series of processing, the digital filter control unit 247, when notified from the noise detection circuit 241 that noise equal to or greater than a predetermined threshold is detected in the RF signal, shift registers 2451-0 to 2451-N. The digital data within the detected noise influence range that is temporarily stored in the above is rewritten to predetermined data, for example, 0, and the filter calculation process is performed. The influence of noise can be suppressed retroactively.

  As described above, in the first embodiment, the data rewriting units 2451a-0 to 2451a-N rewrite the digital data sequentially temporarily stored in the shift registers 2451-0 to 2451-N into predetermined data, When noise equal to or greater than a predetermined threshold is detected, the control unit 247 sequentially stores digital data in a range that is temporarily stored in the shift registers 2451-0 to 2451-N and that is affected by the detected noise. Therefore, it is possible to suppress the influence of noise retroactively before the occurrence of noise without adding any parts.

  In the second embodiment, a case will be described in which noise is suppressed by rewriting digital data affected by noise temporarily stored in the buffer of the digital filter processing device 240a with data immediately before the digital data. Here, the configuration of the digital filter processing device 240a and the filter calculation processing procedure will be described. The configurations of the MRI system 10 and the data collection unit 24 of the second embodiment are exactly the same as those of the first embodiment. Further, the data collection processing procedure of the second embodiment is exactly the same as that of the first embodiment.

  First, the configuration of the digital filter processing apparatus 240a according to the second embodiment will be described with reference to FIG. FIG. 9 is a functional block diagram of the configuration of the digital filter processing apparatus 240a according to the second embodiment. The difference from the configuration of the digital filter processing apparatus 240 according to the first embodiment is the digital filter control unit 247a, and the others are completely the same, so the data reading unit 2471 will be described.

  When noise of a predetermined threshold value or more is detected, the digital filter control unit 247a generates digital data within a range that is temporarily stored in the shift registers 2451-0 to 2451-N and that is affected by the detected noise. Is a control unit that controls to perform the filter calculation process by rewriting the digital data immediately before the range in which the data is affected, and includes a data reading unit 2471. When the data reading unit 2471 receives a notification from the noise detection circuit 241 that noise equal to or greater than a predetermined threshold has been detected, the data reading unit 2471 uses the noise stored in the shift registers 2451-0 to 2451-m ′ (see Expression 2). This is a reading unit that reads and holds data immediately before the affected data from the shift register 2451- (m ′ + 1).

  Since the digital filter control unit 247a controls to perform the filter calculation process by replacing the data read from the shift register 2451- (m ′ + 1) with the data in the noise influence range, Without adding, the influence of noise can be suppressed retroactively before the occurrence of noise.

  Next, with reference to FIG. 10, the filter calculation processing procedure of the digital filter processing apparatus 240a shown in FIG. 9 will be described in detail. FIG. 10 is a flowchart showing in detail the filter calculation processing procedure of the digital filter processing apparatus 240a shown in FIG. Steps S1004 to S1011 of this procedure are the same as steps S803 to S810 in FIG. 8 of the first embodiment, and thus steps S1001 to S1003 will be described.

  As shown in the figure, the digital filter control unit 247a first determines whether or not there is a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected (step S1001). As a result, when there is a notification from the noise detection circuit 241 that noise equal to or greater than the predetermined threshold has been detected (Yes in step S1001), the digital filter control unit 247a displays the data immediately before the data affected by the noise, That is, it controls to read and hold the data of the shift register 2451- (m ′ + 1) (step S1002).

  Further, the digital filter control unit 247a controls to rewrite the data within the noise influence range stored in the shift registers 2451-0 to 2451-m ′ to the read / held data (step S1003). On the other hand, if there is no notification from the noise detection circuit 241 that noise equal to or greater than the predetermined threshold has been detected (No at step S1001), the digital filter control unit 247a advances the procedure to step S1004.

  By performing the above-described series of processing, when the digital filter control unit 247a receives a notification from the noise detection circuit 241 that noise equal to or greater than a predetermined threshold has been detected in the RF signal, the shift registers 2451-0 to 2451-N Because the filter operation is performed by rewriting the detected noise and the digital data within the noise influence range immediately before being affected by the noise, and without adding any parts. The influence of noise can be suppressed retroactively before the occurrence of noise.

  As described above, in the second embodiment, the data reading unit 2471 reads the digital data temporarily stored in the shift register immediately before the rewritten digital data, and the digital filter control unit 247a has a predetermined threshold value or more. When noise is detected, the digital data in the range affected by the detected noise, which is sequentially temporarily stored in the shift registers 2451-0 to 2451-N, is rewritten with the read digital data, and the filter operation processing is performed. Since control is performed so as to perform, it is possible to suppress the influence of noise retroactively before the occurrence of noise, without adding components.

  In the third embodiment, a case will be described in which noise is suppressed by replacing digital data affected by noise temporarily stored in the buffer of the digital filter processing device 240b with predetermined data. Here, the configuration of the digital filter processing device and the filter calculation processing procedure will be described. The configurations of the MRI system 10 and the data collection unit 24 of the third embodiment are exactly the same as those of the first embodiment. Further, the data collection processing procedure of the third embodiment is exactly the same as that of the first embodiment.

  First, the configuration of the digital filter processing apparatus 240b according to the third embodiment will be described with reference to FIG. FIG. 11 is a functional block diagram illustrating the configuration of the digital filter processing apparatus 240b according to the third embodiment. The difference from the configuration of the digital filter processing device 240 according to the first embodiment is the digital filter circuit 245b and the digital filter control unit 247b, and the others are exactly the same, and therefore the digital filter circuit 245b and the digital filter control circuit 247b will be described. .

  The digital filter circuit 245b includes shift registers 2451-0 to 2451-N, a multiplier 2452, an adder 2453, and a switch 2454. The shift registers 2451-0 to 2451-N are buffers that sequentially and temporarily store (N + 1) pieces of digital data sampled at a sampling interval of Δt.

  The multiplier 2452 is a multiplier that multiplies the digital data temporarily stored in the shift registers 2451-0 to 2451-N by filter coefficients h (0)... H (N). The digital data temporarily stored in 2451-0 to 2451-N is sequentially switched by the switch 2454 and read. The adder 2453 is an adder that adds (N + 1) products of the multiplier 2452.

  The digital filter control unit 247b, when noise of a predetermined threshold value or more is detected, is sequentially stored temporarily in a plurality of buffers, and is digital data in a range affected by the detected noise, that is, shown in FIG. This is a control unit that controls to perform filter calculation processing by replacing (n−m) th to (n + m) th digital data with predetermined data, and includes a data replacement unit 2472. The data replacement unit 2472 is a replacement unit that replaces the (n−m) th to (n + m) th digital data shown in FIG. 5 with predetermined data, for example, 0 in the multiplier 2452.

  Next, with reference to FIG. 12, the filter calculation processing procedure of the digital filter processing apparatus 240b shown in FIG. 11 will be described in detail. FIG. 12 is a flowchart showing in detail the filter calculation processing procedure of the digital filter processing apparatus 240b shown in FIG. Steps S1201 to S1210 of this procedure are the same as steps S801 to S810 in FIG. 8 of the first embodiment except for steps S1202 and S1208. Therefore, steps S1202 and S1208 will be described.

  Steps S1202 and S1208 are procedures in which data affected by noise stored in the shift register is replaced with predetermined data, for example, 0 by the multiplier 2452, and the digital filter circuit 245b is replaced with steps S1202 and S1208. A filter calculation process is performed on the predetermined data.

  By performing the above-described series of processing, when the digital filter control unit 247b receives notification from the noise detection circuit 241 that noise equal to or greater than a predetermined threshold has been detected in the RF signal, the shift registers 2451-0 to 2451-N Since the digital data that is temporarily stored in the range of the detected noise within the range of influence of the detected noise is replaced with predetermined data by the multiplier 2452 and the filter calculation processing is performed, the noise is not added. The influence of noise can be suppressed retroactively.

  As described above, in the third embodiment, the data replacement unit 2472 replaces digital data temporarily stored in the shift registers 2451-0 to 2451-N sequentially with predetermined data, and the digital filter control unit 247b When noise equal to or greater than a predetermined threshold is detected, digital data in a range that is temporarily stored in the shift registers 2451-0 to 2451-N and is affected by the detected noise is replaced with predetermined data, Since the control is performed so as to perform the filter calculation process, it is possible to suppress the influence of noise retroactively before the occurrence of noise without adding components.

  In the fourth embodiment, a case where noise is suppressed by replacing a filter coefficient associated with a buffer of a digital filter processing device with a predetermined filter coefficient will be described. Here, the configuration of the digital filter processing device and the filter calculation processing procedure will be described. The configurations of the MRI system 10 and the data collection unit 24 of the fourth embodiment are exactly the same as those of the first embodiment. Further, the data collection processing procedure of the fourth embodiment is exactly the same as that of the first embodiment.

  First, the configuration of a digital filter processing apparatus 240c according to the fourth embodiment will be described with reference to FIG. FIG. 13 is a functional block diagram of the configuration of the digital filter processing apparatus 240c according to the fourth embodiment. The difference from the configuration of the digital filter processing apparatus 240 according to the first embodiment is the digital filter circuit 245c and the digital filter control unit 247c, and the others are exactly the same, and therefore the digital filter circuit 245c and the digital filter control unit 247c will be described. .

  The digital filter circuit 245c includes shift registers 2451-0 to 2451-N, a multiplier 2452, an adder 2453, and a switch 2454. The shift registers 2451-0 to 2451-N are buffers that sequentially and temporarily store (N + 1) pieces of digital data sampled at a sampling interval of Δt.

  The multiplier 2452 is a multiplier that multiplies the digital data temporarily stored in the shift registers 2451-0 to 2451-N by filter coefficients h (0)... H (N). The digital data temporarily stored in 2451-0 to 2451-N is sequentially switched by the switch 2454 and read. The adder 2453 is an adder that adds (N + 1) products of the multiplier 2452.

  The digital filter control unit 247c performs digital data in a range that is affected by the detected noise when noise of a predetermined threshold or more is detected, that is, (nm) th to (n + m) shown in FIG. This is a control unit that controls to perform filter calculation processing by replacing the filter coefficient associated with the register that sequentially stores the first digital data with a predetermined filter coefficient, and has a filter coefficient replacement unit 2473. The filter coefficient replacement unit 2473 is a replacement unit that replaces the filter coefficient associated with the (n−m) th to (n + m) th registers shown in FIG. 5 with a predetermined filter coefficient, for example, 0 in the multiplier 2452. is there.

  Next, the filter calculation processing procedure shown in FIG. 13 will be described in detail with reference to FIG. FIG. 14 is a flowchart showing in detail the filter calculation processing procedure shown in FIG. Steps S1401 to S1410 of this procedure are the same as steps S801 to S810 in FIG. 8 of the first embodiment except for steps S1402 and S1408. Therefore, steps S1402 and S1408 will be described.

  Steps S1402 and S1408 are procedures in which a multiplier 2452 replaces a filter coefficient associated with a shift register storing data affected by noise with a predetermined filter coefficient, for example, 0, and the digital filter circuit 245c Filter calculation processing is performed using the predetermined filter coefficients replaced in step S1402 and step S1408.

  By performing the above-described series of processing, when the digital filter control unit 247c receives a notification from the noise detection circuit 241 that noise of a predetermined threshold value or more has been detected in the RF signal, the digital filter control unit 247c falls within the range of influence of the detected noise. The filter coefficient associated with the shift register that primarily stores digital data sequentially is replaced with a predetermined filter coefficient by the multiplier 2452, and the filter calculation process is performed. Therefore, noise is generated without adding components. The influence of noise can be suppressed retroactively.

  As described above, in the fourth embodiment, the filter coefficient replacement unit 2473 replaces the filter coefficients associated with the registers 2451-0 to 2451-N with predetermined filter coefficients, and the digital filter control unit 247c When noise greater than a predetermined threshold is detected, the filter coefficient associated with the buffer that temporarily stores the digital data in the range that is affected by the detected noise is replaced with the predetermined filter coefficient to perform filter operation Since control is performed so as to perform processing, it is possible to suppress the influence of noise retroactively before noise generation without adding components.

  By the way, in the third embodiment, the data replacement unit 2472 replaces digital data in a range that is affected by the detected noise, which is temporarily stored in the shift registers 2451-0 to 2451-N, with predetermined data. However, the present invention is not limited to this, and the data replacement unit reads the digital data temporarily stored in the shift register immediately before the digital data replaced by the data reading unit. The present invention can be applied to the case where digital data in a range that is temporarily stored in the range affected by detected noise is replaced with read digital data.

  As described above, the digital filter processing apparatus according to the present invention is useful for a digital data processing apparatus, and is particularly suitable for MRI.

1 is a functional block diagram illustrating a configuration of an MRI system according to a first embodiment. It is a functional block diagram which shows the structure of the data collection part shown in FIG. It is a figure which shows an example of the noise superimposed on the RF signal taken in by the data acquisition part shown in FIG. FIG. 4 is a diagram illustrating an example in which the AD converter illustrated in FIG. 2 converts the RF signal illustrated in FIG. 3 into digital data. It is a figure which shows an example of the digital data on which the noise memorize | stored in the some buffer of the digital filter processing apparatus shown in FIG. 2 was superimposed. It is a functional block diagram which shows the structure of the digital filter processing apparatus shown in FIG. 2 in further detail. It is a flowchart which shows the data collection process procedure of the data collection part shown in FIG. It is a flowchart which shows the filter calculation process procedure shown in FIG. 7 in detail. FIG. 6 is a functional block diagram illustrating a configuration of a digital filter processing apparatus according to a second embodiment. 10 is a flowchart showing in detail a filter calculation processing procedure shown in FIG. 9. FIG. 9 is a functional block diagram illustrating a configuration of a digital filter processing apparatus according to a third embodiment. It is a flowchart which shows the filter calculation process procedure shown in FIG. 11 in detail. FIG. 10 is a functional block diagram illustrating a configuration of a digital filter processing device according to a fourth embodiment. It is a flowchart which shows the filter calculation process procedure shown in FIG. 13 in detail.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 MRI system 20 MRI apparatus 21 Magnet system 22 RF drive part 23 Gradient drive part 24 Data collection part 241 Noise detection circuit 242 AD converter 243 Input processing circuit 244 Detection processing circuit 240, 240a, 240b, 240c Digital filter processing apparatus 245, 245b, 245c Digital filter circuit 2451 Shift register 2451a Data rewriting unit 2452 Multiplier 2453 Adder 2454 Switch 246 Filter coefficient storage unit 247, 247a, 247b, 247c Digital filter control unit 2471 Data reading unit 2472 Data substitution unit 2473 Filter coefficient substitution unit 248 Output processing circuit 25 Control unit 30 Operator console 31 Data processing unit 32 Operation unit 33 Display unit 40 Subject

Claims (7)

A plurality of buffers for sequentially storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed; and filter coefficients associated with the plurality of buffers, the digital data and the filter A digital filter processing device that performs filter calculation processing using a coefficient,
Filter coefficient replacement means for replacing filter coefficients associated with the plurality of buffers with predetermined filter coefficients;
When noise equal to or greater than the predetermined threshold is detected, a filter coefficient associated with a buffer that sequentially temporarily stores digital data in a range affected by the detected noise is replaced with the predetermined filter coefficient. Digital filter control means for controlling to perform the filter calculation process;
A digital filter processing apparatus comprising:   2. The digital filter processing apparatus according to claim 1, wherein the plurality of buffers are a plurality of shift registers that sequentially and temporarily store the digital data that has been converted into digital data.   The filter operation processing is characterized in that digital data sequentially and temporarily stored in the plurality of buffers are multiplied by filter coefficients associated with the plurality of buffers, respectively, and a sum of the multiplied products is obtained. The digital filter processing apparatus according to claim 1 or 2.   The digital filter processing apparatus according to any one of claims 1 to 3, wherein the MRI system performs a filter calculation process on a received signal collected from a subject to be diagnosed. A plurality of buffers for sequentially storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed; and filter coefficients associated with the plurality of buffers, the digital data and the filter A digital filter processing method for performing filter calculation processing using a coefficient,
A filter coefficient replacement step of replacing filter coefficients associated with the plurality of buffers with predetermined filter coefficients;
When noise equal to or greater than the predetermined threshold is detected, a filter coefficient associated with a buffer that sequentially temporarily stores digital data in a range affected by the detected noise is replaced with the predetermined filter coefficient. A digital filter control step for controlling to perform the filter calculation process;
A digital filter processing method. A plurality of buffers for sequentially storing digital data digitally converted from an analog signal on which noise of a predetermined threshold value or more is superimposed; and filter coefficients associated with the plurality of buffers, the digital data and the filter A digital filter processing program for performing filter calculation processing using a coefficient,
A filter coefficient replacement procedure for replacing filter coefficients associated with the plurality of buffers with predetermined filter coefficients;
When noise equal to or greater than the predetermined threshold is detected, a filter coefficient associated with a buffer that sequentially temporarily stores digital data in a range affected by the detected noise is replaced with the predetermined filter coefficient. , A digital filter control procedure for controlling to perform the filter calculation process;
A digital filter processing program for causing a computer to execute.   A digital filter processing apparatus according to any one of claims 1 to 4 is provided, or the digital filter processing method according to claim 5 or the digital filter processing program according to claim 6 is executed. MRI system.

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