JP2019141597A - Signal processing device and method, computer program, and recording medium - Google Patents

Abstract

To provide a signal processing device that displays time-series signals in a more easily viewable manner.SOLUTION: A signal processing device (13) includes: smoothing means (136) for performing a smoothing process for smoothing a temporal change of an image signal to the image signal on the basis of magnitude of the temporal change of the image signal for displaying characteristics of the time series signal on a display device (14); and output means (134) for outputting the smoothed image signal to the display means for displaying the display image indicated by the image signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a signal processing apparatus and method for processing a time series signal such as a respiratory sound signal, and a technical field of a computer program and a recording medium.

  A body sound such as a breathing sound is used as one of indices when a doctor diagnoses a pathological condition of the body. For this reason, a display device that displays characteristics of body sounds (in other words, visualizes body sounds) has been proposed in order to suitably assist diagnosis of medical conditions by medical personnel such as doctors. When the display device displays the characteristics of the body sound, the medical staff can recognize the body sound suitably or relatively easily.

  Patent Documents 1 and 2 are cited as prior art documents related to the present invention. In Patent Literature 1, when an electrocardiogram signal indicating a heart sound that is an example of a body sound is recorded, an electrocardiogram recording that records an envelope of the electrocardiogram signal as an electrocardiogram signal when the frequency of the electrocardiogram signal exceeds a specified value An apparatus is disclosed. In Patent Document 2, although it is not a display device that displays a body sound signal indicating a body sound, if the value of the input signal is smaller than the peak level being displayed, the peak level is reduced with time. Has been disclosed.

JP-A-5-154120 Japanese Patent Laid-Open No. 9-26332

  By the way, in order for a medical worker to diagnose a disease state, information on how the body sound changes may be useful. For example, if the change in characteristics per unit time (for example, signal intensity) is relatively small, the presence or absence of a slight change in the characteristics of the body sound and the tendency of the change can be useful information. In addition, for example, if the body sound has a relatively large change in characteristics per unit time, the tendency of the peak value (for example, the maximum value) of the characteristics of the body sound can be useful information.

  Therefore, from the viewpoint of suitably assisting the diagnosis of the medical condition by the medical staff, the display device displays a slight change in the characteristics of the body sound even when the characteristics of the body sound change relatively small. In addition, it is preferable to display the change in the characteristic of the biological sound in such a manner that the peak value of the characteristic can be identified even when the characteristic of the biological sound changes relatively greatly. For this reason, the display device is often designed to display a slight change in the characteristics of the body sound. Specifically, for example, a display device that displays the characteristics of a biological sound using a display image whose display mode greatly changes as the characteristic (for example, signal intensity) of the biological sound changes greatly can be given as an example.

  However, since such a display device can display a slight change in the characteristics of the body sound, when the characteristics of the body sound change relatively greatly, the display mode of the body sound characteristics ( For example, the display mode of the display image for visually specifying the characteristics is greatly changed. For example, a display device that displays a characteristic of a biological sound using a display image that increases as the characteristic (for example, signal strength) of the biological sound increases is taken as an example. Such a display device is designed to suitably change the size of the display image in accordance with a slight change in the characteristics of the body sound. However, such a display device has a technical problem that the size of the display image is greatly changed when the characteristic of the body sound changes relatively greatly. As a result, there is a technical problem that it becomes difficult for the medical staff who looks at the display device to recognize the characteristics of the biological sound when the characteristics of the biological sound change relatively greatly. This is because a large change in the display mode of the display image may be a kind of stimulus for medical staff who view the display device. For this reason, it is preferable that the display device does not change the display mode of the display image for displaying the characteristics of the biological sound excessively excessively even when the characteristics of the biological sound change relatively greatly. .

  In the technique disclosed in Patent Document 1, the ECG signal is smoothed by recording the envelope of the ECG signal. However, whether or not the envelope of the ECG signal is recorded is determined not by the signal strength of the ECG signal but by the frequency of the ECG signal. Therefore, just because the signal intensity of the electrocardiogram signal has changed relatively greatly, the envelope of the electrocardiogram signal is not always recorded. Therefore, a display device that displays the characteristics of an electrocardiogram signal using a display image whose display mode changes greatly as the signal intensity of the electrocardiogram signal increases, even if the technique disclosed in Patent Document 1 is adopted. It is not always possible to prevent a large change in the display mode of the display image due to a relatively large change in the signal intensity. Similarly, with the technique disclosed in Patent Document 2, the peak level of the input signal is only small. Therefore, when an input signal having a large signal strength is suddenly input, the signal strength of the input signal is displayed as it is. As a result, the display device that displays the characteristics of the input signal using a display image that increases as the signal strength of the input signal increases, even if the technique disclosed in Patent Document 2 is adopted, Therefore, it is not always possible to prevent a large change in the display mode of the display image due to a large change.

  Note that the same technical problem occurs when displaying characteristics of some time-series signal (arbitrary signal that can be specified by a waveform along the time axis), not limited to a body sound, on a display device.

  The present invention has been made in view of, for example, the conventional problems described above, and provides a signal processing apparatus and method, a computer program, and a recording medium capable of displaying the characteristics of a time-series signal in a more easily viewable manner, for example. The task is to do.

  In order to solve the above problems, the signal processing device smoothes the temporal change of the image signal based on the magnitude of the temporal change of the image signal for displaying the characteristics of the time-series signal on the display device. A smoothing unit that performs a smoothing process on the image signal; and an output unit that outputs the image signal subjected to the smoothing process to a display unit that displays a display image indicated by the image signal.

  In order to solve the above-described problem, a signal processing method smoothes a temporal change of the image signal based on the magnitude of the temporal change of the image signal for displaying the characteristics of the time-series signal on a display device. A smoothing step of performing a smoothing process on the image signal; and an output step of outputting the image signal subjected to the smoothing process to a display unit that displays a display image indicated by the image signal.

  In order to solve the above problems, a computer program is a computer program executed by a computer, and is based on the magnitude of temporal change of an image signal for displaying characteristics of a time-series signal on a display device. A smoothing step for smoothing the image signal with a smoothing process for smoothing temporal changes of the image signal, and a display for displaying the display signal indicated by the image signal for the image signal subjected to the smoothing process. And causing the computer to execute an output step of outputting to the means.

  In order to solve the above problems, a recording medium is a recording medium on which a computer program executed by a computer is recorded, and a temporal change of an image signal for displaying characteristics of a time-series signal on a display device. Based on the magnitude, a smoothing process for smoothing a temporal change of the image signal with respect to the image signal, and the image signal that has been subjected to the smoothing process, The computer program which makes the said computer perform the output process output to the display means which displays the display image to show is recorded.

It is a block diagram which shows the structure of the signal processing system of 1st Example. It is a flowchart which shows the flow of operation | movement of the signal processing system of 1st Example. It is the schematic which shows an example of the mounting | wearing aspect with respect to the biological body of a respiratory sound, and the graph which shows the waveform of a respiratory sound signal on a time axis. It is a classification chart which shows the kind of breathing sound. Five types of breathing sounds (alveolar breathing sounds, low-pitched continuous rales (sounding sounds), high-pitched continuous rales (flute sounds), fine intermittent rales (twisting sounds), and coarse intermittent rales It is a graph which shows the waveform of five types of signal components equivalent to (water bubble sound)) on a time axis. It is a schematic diagram which shows an example of the operation | movement which a signal memory | storage part memorize | stores a respiratory sound signal. It is a top view which shows an example of the display mode of each characteristic of two types of signal components which comprise a respiratory sound signal. It is a schematic diagram which shows an example of the operation | movement which a past image memory | storage part memorize | stores an image signal. A plane showing an example of a display mode of each characteristic of the two types of signal components when the smoothing process is performed, together with an example of a display mode of each characteristic of the two types of signal components when the smoothing process is not performed FIG. It is a block diagram which shows the structure of the signal processing system of 2nd Example. It is a top view which shows an example of the display mode of the characteristic of an atmospheric pressure signal. It is a top view which shows an example of the display mode of the characteristic of the atmospheric pressure signal at the time of performing a smoothing process with an example of the display mode of the characteristic of an atmospheric pressure signal when not performing the smoothing process.

  Hereinafter, embodiments of a signal processing apparatus and method, a computer program, and a recording medium will be described in order.

(Embodiment of signal processing apparatus)
<1>
The signal processing device according to the present embodiment performs a smoothing process for smoothing the temporal change of the image signal based on the magnitude of the temporal change of the image signal for displaying the characteristics of the time series signal on the display device. A smoothing unit that performs the image signal; and an output unit that outputs the image signal subjected to the smoothing process to a display unit that displays a display image indicated by the image signal.

  The signal processing device according to the present embodiment is a signal for displaying on a display device the characteristics of a time-series signal (that is, an arbitrary index that can specify the state of the time-series signal, for example, signal strength). Process. That is, the signal processing device of the present embodiment performs signal processing for displaying on the display device some display image (or display object) that can visually identify the characteristics of the time-series signal. The signal processing device may include a display device. Alternatively, the signal processing device may not include a display device. The display image is preferably a display image whose display mode changes according to the characteristics of the time-series signal. In other words, the display image is preferably a display image in which the display mode greatly changes as the characteristics of the time-series signal change greatly.

  The “time-series signal” here is a broad meaning meaning a signal composed of signal components along the time series or the time axis. Such a time series signal may be directly detected by the signal processing apparatus itself (that is, may be directly acquired). Alternatively, such a time-series signal may be detected by another device installed outside the signal processing device (that is, may be indirectly acquired by the signal processing device).

  In particular, the signal processing apparatus of the present embodiment includes at least a smoothing unit and an output unit in order to perform signal processing for displaying the characteristics of the time-series signal on the display device.

  The smoothing means is based on the magnitude of temporal change of an image signal for displaying the characteristics of the time series signal on the display device (that is, an image signal indicating a display image for visually specifying the characteristics of the time series signal). Thus, a smoothing process for smoothing the temporal change of the image signal is performed. That is, the smoothing means performs a smoothing process that smoothes the temporal change of the image signal in a manner that is determined based on the magnitude of the temporal change of the image signal.

  Here, since the image signal is a signal for displaying the characteristics of the time series signal on the display device, the image signal is also composed of a signal component along the time series or the time axis, like the time series signal. Signal. In other words, the image signal is an image signal indicating an image group configured by arranging a plurality of single display images along the time series or the time axis to visually specify the characteristics of the time series signal at a certain time point. Become. In other words, the image signal includes a plurality of image signals (in other words, signal components) indicating a single display image for visually specifying the characteristics of the time-series signal at a certain time point along the time-series or time axis. Thus, an image signal is formed. Accordingly, “temporal change of the image signal” means a change of the image signal over time (typically, a change in the characteristics of the image signal). In other words, “temporal change of the image signal” means a change of the image signal along the time axis. For example, the temporal change of the image signal may mean a change between at least two image signals for displaying the characteristics of the time-series signal at at least two different timings. In other words, for example, the temporal change of the image signal is one image signal for displaying the characteristics of the time series signal at one timing and the other image signal for displaying the characteristics of the time series signal at another timing. (For example, a change in one image signal based on another image signal).

  The temporal change of the image signal may be specified by a quantitative index. For example, the temporal change of an image signal is such that the change between one image signal and another image signal becomes larger (that is, the one image signal changes more greatly with respect to another image signal). It may be specified by a quantitative index so that the temporal change of the image signal becomes large.

  In consideration of the fact that the image signal is a signal for indicating some display image, a time change of the display image indicated by the image signal may be used in addition to or instead of the time change of the image signal. Good. In other words, the smoothing means performs the smoothing process for smoothing the temporal change of the image signal (or the temporal change of the display image indicated by the image signal) based on the temporal change of the display image indicated by the image signal. You may perform with respect to a signal (or the display image which an image signal shows).

  Further, the “smoothing process” for smoothing such “temporal change of the image signal” refers to the temporal change of the image signal (preferably the time per unit time) compared to before the smoothing process is performed. It may mean a process of reducing (in other words, gradual or smoothing). In other words, the “smoothing process” means a process of reducing the amount of change (preferably, the amount of change per unit time) of the image signal along the time axis as compared to before the smoothing process. May be. In other words, “smoothing process” means a process of reducing the temporal change of the image signal subjected to the smoothing process compared to the temporal change of the image signal before the smoothing process is performed. It may be. That is, in the present embodiment, the “smoothing process” does not mean a smoothing process (so-called noise removal process or the like) within a single display image indicated by a single image signal.

  The image signal smoothed by the smoothing means is output to the display device by the output means. As a result, the display device displays a display image indicated by the image signal that has been subjected to the smoothing process. That is, the display device can display the characteristics of the time-series signal by displaying the display image indicated by the image signal that has been subjected to the smoothing process.

  Here, considering that the image signal is a signal for displaying the characteristics of the time series signal, the temporal change of the image signal becomes relatively large when the characteristics of the time series signal change greatly. . For this reason, if the smoothing process is not performed on the image signal, the temporal change of the display image indicated by the image signal not subjected to the smoothing process also remains relatively large. Therefore, if the smoothing processing is not performed on the image signal, the display image (for example, the display mode of the display image) displayed by the display device is displayed when the characteristics of the time-series signal greatly change. There is a possibility that the change will be so large that it can be a stimulus for a user who views the apparatus. Such display of the display image is not always easy for the user to see.

  However, in the present embodiment, since the smoothing process is performed on the image signal, the image signal on which the smoothing process is performed is compared with the case where the smoothing process is not performed on the image signal. The time change of the display image indicated by becomes relatively small. For this reason, even if the characteristics of the time-series signal change greatly, the temporal change of the display image becomes relatively small. Therefore, in the present embodiment, a display image (for example, a display image displayed by the display device) is displayed even when the characteristics of the time-series signal are significantly changed compared to the case where the smoothing process is not performed on the image signal. The display mode of the display image) changes little to the extent that it can be a stimulus for the user. That is, in this embodiment, when it is not desired to excessively increase the temporal change of the display image (in other words, when it is not desired to change the display mode of the display image excessively large), the smoothing unit converts the image signal into the image signal. On the other hand, by performing the smoothing process, the temporal change of the display image can be made relatively small.

  For example, as described above, a case is assumed in which an image signal is generated so that a slight temporal change in characteristics of a time-series signal can be displayed. Specifically, for example, a case where an image signal for displaying a display image (typically, a figure) having a size proportional to the characteristic of the time-series signal (for example, signal strength) is generated. Suppose. In this case, when the characteristics of the time series signal change relatively greatly, if the smoothing process is not performed on the image signal, the size of the display image corresponding to the time series signal before the characteristics change significantly. In comparison with this, the size of the display image corresponding to the time-series signal after the characteristic is greatly changed becomes very large. As a result, the user looking at the display device needs to see a display image that changes in size relatively vigorously enough to be a stimulus for the user. Therefore, the user may not be able to properly recognize the display image. However, in the present embodiment, even when the characteristics of the time series signal change relatively greatly, since the smoothing process is performed on the image signal, the time series signal before the characteristics change significantly is changed. Compared with the corresponding display image, the size of the display image corresponding to the time-series signal after the characteristics are greatly changed is hardly or not at all. As a result, the user does not need to see a display image that changes in size relatively vigorously enough to be a stimulus for the user. Therefore, the user can preferably recognize the display image.

  As described above, according to the signal processing apparatus of the present embodiment, the characteristics of the time series signal are suitably displayed.

  The smoothing means applies a smoothing process to the display image for smoothing the temporal change of the display image based on the magnitude of the temporal change of the display image for visually specifying the characteristics of the time series signal. You may do it for. In this case, the output unit may output an image signal indicating the display image on which the smoothing process has been performed to a display device that displays the display image.

<2>
In another aspect of the signal processing apparatus according to the present embodiment, the smoothing unit performs the smoothing process so that the magnitude of the temporal change of the image signal is equal to or less than a predetermined threshold value.

  According to this aspect, the magnitude of the temporal change of the image signal is reduced by the smoothing process performed by the smoothing unit until the magnitude of the temporal change becomes equal to or less than the predetermined threshold value. Therefore, the various effects described above are favorably enjoyed.

  The smoothing means may perform the smoothing process so that the magnitude of temporal change of the display image is a predetermined threshold value or less.

<3>
In another aspect of the signal processing apparatus of the present embodiment, the smoothing means (i) performs the smoothing process when the magnitude of temporal change of the image signal is larger than a predetermined threshold, and (ii) When the magnitude of the temporal change of the image signal is not larger than a predetermined threshold value, the smoothing process is not performed.

  According to this aspect, the smoothing means only needs to perform the smoothing process when the magnitude of the temporal change of the image signal is larger than the predetermined threshold. In other words, the smoothing unit does not need to perform the smoothing process when the magnitude of the temporal change of the image signal is not larger than the predetermined threshold value. As a result, when the magnitude of the temporal change of the image signal is larger than the predetermined threshold, the smoothing means makes the magnitude of the temporal change of the image signal equal to or smaller than the predetermined threshold (in other words, the image signal Smoothing processing can be performed (until the magnitude of the temporal change is equal to or less than a predetermined threshold value). By the smoothing process performed by such a smoothing unit, the magnitude of the temporal change of the image signal is reduced until the magnitude of the temporal change becomes equal to or less than a predetermined threshold value. Therefore, the various effects described above are favorably enjoyed.

  When the smoothing process is performed even once on the image signal, the output means outputs the image signal on which the smoothing process has been performed (that is, as a result of performing the smoothing process, the time change is large). As described above, the image signal satisfying the condition that the length is equal to or less than the predetermined threshold value is output to the display device. On the other hand, if the smoothing process has not been performed once on the image signal, the output means can perform the smoothing process on the image signal (that is, even if the smoothing process is not performed) An image signal that satisfies a condition that the magnitude of the temporal change is equal to or less than a predetermined threshold value may be output to the display device.

  The smoothing means performs (i) the smoothing process when the temporal change in the display image is larger than a predetermined threshold, and (ii) the temporal change in the display image. Is not larger than the predetermined threshold value, the smoothing process may not be performed.

<4>
In another aspect of the signal processing apparatus of the present embodiment, the smoothing means includes one image signal for displaying the characteristics of the time-series signal at one timing and another timing before the one timing. Smoothing a temporal change between the one image signal and the other image signal based on a temporal change between the image signal and another image signal for displaying the characteristics of the time-series signal in Smoothing processing is performed on the one image signal.

  According to this aspect, the smoothing means temporally between two image signals (that is, one image signal and another image signal) for displaying the characteristics of the time-series signal at two successive timings. A smoothing process for smoothing the change can be performed. At this time, the smoothing means displays one image signal for displaying the characteristics of the time series signal at one timing and the characteristics of the time series signal at another timing located immediately before the one timing. It is preferable to perform a smoothing process for smoothing temporal changes between other image signals. As a result, the temporal change of one display image indicated by one image signal subjected to the smoothing process with respect to another display image is also reduced. Therefore, even if the display image displayed on the display device is switched from another display image to one display image, the display mode of the display image is almost excessively changed to such an extent that it can be a stimulus for the user. Or not at all. For this reason, the characteristics of the time-series signal greatly change during the period from another timing to the one timing (that is, from when another display image is displayed until the one display image is displayed). Even in such a case, the display image displayed by the display device (for example, the display mode of the display image) is hardly or completely changed so as to be a stimulus for the user. Therefore, the various effects described above are favorably enjoyed.

  In addition, the smoothing means includes one display image for visually specifying the characteristics of the time-series signal at one timing and the characteristics of the time-series signal at another timing before the one timing. The smoothing process for smoothing a temporal change between the one display image and the other display image based on a temporal change between the other display image visually specified. You may perform with respect to a display image.

<5>
As described above, in another aspect of the signal processing apparatus that performs the smoothing process for smoothing the temporal change between one image signal and the other image signal on the one image signal, the smoothing process includes: A process of setting a moving average of a predetermined number of the image signals that are continuous in time and including the one image signal to the new one image signal, and the smoothing means includes the one image signal and the one image signal. The predetermined number is set based on the magnitude of the temporal change between other image signals.

  According to this aspect, the smoothing means can smooth the image signal by calculating a moving average of a predetermined number of image signals continuous in time (that is, a moving average along the time axis). . In other words, the smoothing means smoothes the image signal by calculating a moving average of a predetermined number of image signals for displaying the characteristics of each time-series signal at a predetermined number of timings that are continuous in time. be able to. In other words, the smoothing means calculates a moving average of a predetermined number of image signals indicating a predetermined number of display images that visually specify the characteristics of each time-series signal at a predetermined number of timings that are continuous in time. Thus, the image signal can be smoothed. Specifically, the smoothing means calculates a moving average of a predetermined number of image signals that are temporally continuous (however, one image signal is included as, for example, the last or latest image signal in terms of time). Thus, one image signal can be smoothed. As a result, the characteristics of the time-series signal change greatly between the other timing and the one timing (that is, between the time when another display image is displayed and the time when one display image is displayed). Even in such a case, the display image displayed by the display device (for example, the display mode of the display image) is hardly or completely changed so as to be a stimulus for the user. Therefore, the various effects described above are favorably enjoyed.

  In addition, in this aspect, the smoothing means sets a predetermined number based on the magnitude of temporal change between one image signal and another image signal. Therefore, for example, the smoothing unit can set a predetermined number from the viewpoint of not excessively increasing a temporal change between one image signal and another image signal.

  The smoothing process newly adds a moving average of the predetermined number of the display images for visually specifying the characteristics of the time-series signal at a predetermined number of consecutive timings with the one timing as an end time. And the smoothing means sets the predetermined number based on a magnitude of temporal change between the one display image and the other display image. Also good.

<6>
In another aspect of the signal processing apparatus that sets a predetermined number based on the magnitude of temporal change between one image signal and another image signal as described above, the smoothing means includes the one image signal. The predetermined number is set so that the magnitude of temporal change between the image signal and the other image signal is equal to or less than a predetermined threshold.

  According to this aspect, the magnitude of the temporal change between one image signal and the other image signal by the smoothing process performed by the smoothing means is such that the magnitude of the temporal change is equal to or less than a predetermined threshold value. Becomes smaller. Therefore, the various effects described above are favorably enjoyed.

  The smoothing means may set the predetermined number so that the magnitude of the temporal change between the one display image and the other display image is not more than a predetermined threshold.

<7>
As described above, the smoothing means for setting a predetermined number based on the magnitude of the temporal change between one image signal and another image signal may be configured so that the one image signal and the other image signal are between The predetermined number is set so that the predetermined number increases when the magnitude of the temporal change in the number is greater than or equal to the predetermined threshold.

  According to this aspect, the magnitude of the temporal change between one image signal and the other image signal by the smoothing process performed by the smoothing means is such that the magnitude of the temporal change is equal to or less than a predetermined threshold value. Becomes smaller. This is because the number of parameters in calculating the moving average increases as the predetermined number increases, so that the time change between one image signal and another image signal increases as the predetermined number increases. This is because the size is likely to be small. Therefore, the various effects described above are favorably enjoyed.

  The smoothing means is configured to increase the predetermined number so that the predetermined number increases when the magnitude of temporal change between the one display image and the other display image is equal to or greater than the predetermined threshold. May be set.

<8>
In another aspect of the signal processing apparatus according to the present embodiment, the smoothing unit performs temporal processing of the partial image signal based on the magnitude of temporal change of the partial image signal of the image signal. The smoothing process for smoothing the change is performed on the partial image signal.

  According to this aspect, the smoothing means can perform the smoothing process on a part of the image signal in addition to or instead of performing the smoothing process on the entire image signal. As a result, even if there is a request for the smoothing means to selectively reduce a temporal change in a part of the display image indicated by the image signal, a temporal change in the part of the display image. The smoothing process can be performed so as to selectively reduce.

<9>
In another aspect of the signal processing apparatus of the present embodiment, the smoothing unit is based on the magnitude of temporal change of a part of the image signal indicating a part of the image portion of the display image indicated by the image signal. Then, the smoothing process for smoothing the temporal change of the partial image signal is performed on the partial image signal.

  According to this aspect, the smoothing means performs a temporal change of a part of the display image in addition to or instead of performing the smoothing process so as to reduce the overall temporal change of the display image indicated by the image signal. The smoothing process can be performed so as to reduce. As a result, the smoothing means selectively selects a temporal change in a part of the display image even when there is a request to selectively reduce a temporal change in a part of the display image. Smoothing processing can be performed to reduce the size.

<10>
In another aspect of the signal processing apparatus of the present embodiment, the signal processing apparatus further includes a conversion unit that converts a time-series signal input to the signal processing apparatus into the image signal.

  According to this aspect, the smoothing unit can perform the smoothing process on the image signal generated by the signal processing device itself (in other words, generated by the conversion unit included in the signal processing device).

(Embodiment of signal processing method)
<11>
The signal processing method according to the present embodiment performs a smoothing process for smoothing a temporal change of the image signal based on the magnitude of the temporal change of the image signal for displaying the characteristics of the time series signal on the display device. A smoothing step performed on the image signal; and an output step of outputting the image signal subjected to the smoothing process to a display unit that displays a display image indicated by the image signal.

  According to the signal processing method of the present embodiment, it is possible to suitably enjoy the same effects as the various effects enjoyed by the signal processing device of the present embodiment described above.

  Incidentally, in response to various aspects that can be adopted by the signal processing apparatus of the present embodiment described above, the signal processing method of the present embodiment may also adopt various aspects.

(Embodiment of computer program)
<12>
The computer program of the present embodiment is a computer program executed by a computer, and the time of the image signal is based on the magnitude of temporal change of the image signal for displaying the characteristics of the time series signal on the display device. A smoothing step for smoothing the image signal with respect to the image signal, and outputting the image signal subjected to the smoothing process to a display means for displaying a display image indicated by the image signal. Causing the computer to execute an output step.

  According to the computer program of the present embodiment, it is possible to suitably enjoy the same effects as the various effects enjoyed by the signal processing apparatus of the present embodiment described above.

  Incidentally, in response to various aspects that can be adopted by the signal processing apparatus of the present embodiment described above, the computer program of the present embodiment may also adopt various aspects.

(Embodiment of recording medium)
<13>
The recording medium of the present embodiment is a recording medium on which a computer program executed by a computer is recorded, and is based on the magnitude of temporal change of an image signal for displaying characteristics of a time-series signal on a display device. A smoothing step for performing smoothing processing on the image signal to smooth the temporal change of the image signal, and a display image indicated by the image signal for the image signal on which the smoothing processing has been performed. The computer program which makes the said computer perform the output process output to the display means to display is recorded.

  According to the recording medium of the present embodiment, it is possible to suitably enjoy the same effects as the various effects enjoyed by the signal processing apparatus of the present embodiment described above.

  Incidentally, in response to various aspects that can be adopted by the signal processing apparatus of the present embodiment described above, the recording medium of the present embodiment may also adopt various aspects.

  Such an operation and other advantages of the present embodiment will be further clarified from examples described below.

  As described above, the signal processing apparatus of this embodiment includes a smoothing unit and an output unit. The signal processing method of this embodiment includes a smoothing step and an output step. The computer program of this embodiment makes a computer perform a smoothing process and an output process. The recording medium of the present embodiment is a recording medium on which a computer program that causes a computer to execute a smoothing process and an output process is recorded. Therefore, the time series signal is displayed in a more easily viewable manner.

  Hereinafter, embodiments of a signal processing apparatus and method, a computer program, and a recording medium will be described with reference to the drawings.

(1) 1st Example First, the signal processing system 1 of 1st Example is demonstrated, referring FIGS. 1-9.

  In the first embodiment, a respiratory sound signal S indicating a respiratory sound is used as the time series signal. However, other biological sound signals different from the respiratory sound signal may be used as the time series signal. Examples of other biological sound signals include, for example, a heart sound signal indicating a heart sound, a pulsation sound signal indicating a sound caused by a pulsation (in other words, a pulse wave), and a sound caused by an activity state of an internal organ officer (for example, Examples include a visceral sound signal indicating intestinal sound due to intestinal movement), a blood flow sound signal indicating sound due to blood flow, and the like. Alternatively, as described in the second embodiment, any signal other than the biological sound signal (for example, the atmospheric pressure signal P shown in the second embodiment) may be used as the time series signal.

(1-1) Configuration of Signal Processing System 1 of First Example First, the configuration of the signal processing system 1 of the first example will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the signal processing system 1 of the first embodiment.

  As shown in FIG. 1, the signal processing system 1 of the first embodiment includes a respiratory sound sensor 11, a signal analysis device 12, a signal processing device 13, and a display device 14.

  The respiratory sound sensor 11 is attached to a living body and acquires a respiratory sound signal S by detecting the respiratory sound of the living body. The respiratory sound sensor 11 transmits the acquired respiratory sound signal S to the signal analysis device 12 via a wired or wireless communication line or a wired signal line.

  Such a respiratory sound sensor 11 is typically a microphone (for example, a coil-type microphone, a capacitor-type microphone, a piezoelectric microphone, or the like). However, as long as the respiratory sound sensor 11 can detect a respiratory sound, the respiratory sound sensor 11 may be any type of sensor.

  FIG. 1 shows an example in which the respiratory sound sensor 11 is arranged outside the signal processing device 13. However, the respiratory sound sensor 11 may be disposed inside the signal processing device 13.

  The signal analysis device 12 performs a predetermined analysis process on the respiratory sound signal S acquired by the respiratory sound sensor 11. In order to perform a predetermined analysis process on the respiratory sound signal, the signal analysis unit 12 includes an A / D (Analogue to Digital) conversion unit 121, a signal analysis unit 122, and a signal separation unit 123.

  The A / D conversion unit 121 performs A / D conversion processing on the respiratory sound signal S transmitted from the respiratory sound sensor 11. That is, the A / D converter 121 converts the respiratory sound signal S as an analog signal transmitted from the respiratory sound sensor 11 into a respiratory sound signal S as a digital signal.

  The signal analysis unit 122 performs a predetermined analysis process on the respiratory sound signal S on which the A / D conversion process has been performed. In the first embodiment, the predetermined analysis process includes an analysis process for separating the respiratory sound signal S into a plurality of types of signal components sk that can be distinguished from each other. In other words, the predetermined analysis process includes an analysis process for extracting at least one of a plurality of types of signal components sk that can be distinguished from each other from the respiratory sound signal S. In other words, the predetermined analysis process includes an analysis process for analyzing what kind of signal component sk is included in the respiratory sound signal S.

  Specifically, for example, the predetermined analysis processing includes analysis processing for separating the respiratory sound signal S into a signal component sk corresponding to a normal sound and a signal component sk corresponding to an abnormal sound different from the normal sound. You may go out. In other words, for example, the predetermined analysis process may include an analysis process for extracting from the respiratory sound signal S at least one of the signal component sk corresponding to the normal sound and the signal component sk corresponding to the abnormal sound. Good.

  Alternatively, for example, the predetermined analysis process may include an analysis process for separating the respiratory sound signal S into a plurality of types of signal components sk corresponding to a plurality of types of normal sounds that can be distinguished from each other. In other words, for example, the predetermined analysis process includes an analysis process for extracting at least one of a plurality of types of signal components sk corresponding to a plurality of types of normal sounds that can be distinguished from each other from the respiratory sound signal S. Also good.

  Alternatively, for example, the predetermined analysis process may include an analysis process for separating the respiratory sound signal S into a plurality of types of signal components sk corresponding to a plurality of types of abnormal sounds that can be distinguished from each other. In other words, for example, the predetermined analysis process includes an analysis process for extracting at least one of a plurality of types of signal components sk corresponding to a plurality of types of abnormal sounds that can be distinguished from each other from the respiratory sound signal S. Also good.

  The signal separation unit 123 separates the respiratory sound signal S into a plurality of types of signal components sk based on the analysis processing result by the signal analysis unit 122. The signal separation unit 123 further transmits each of the plurality of separated signal components sk to the signal processing device 13 via a wired or wireless communication line or a wired signal line.

  Note that the signal analysis device 12 may not include the signal analysis unit 122 and the signal separation unit 123. In this case, the signal analysis device 12 may transmit the respiratory sound signal S converted into a digital signal by the A / D conversion unit 121 to the signal processing device 13. In this case, the signal processing device 13 may perform predetermined signal processing on the respiratory sound signal S instead of performing predetermined signal processing on each of the plurality of types of signal components sk.

  Furthermore, the signal analysis unit 12 may not include the A / D conversion unit 121. In this case, the respiratory sound sensor 11 may transmit the acquired respiratory sound signal S to the signal processing device 13 via a wired or wireless communication line or a wired signal line.

  The example illustrated in FIG. 1 illustrates an example in which the signal analysis device 12 is disposed outside the signal processing device 13. However, at least a part of the signal analysis device 12 may be disposed inside the signal processing device 13.

  The signal processing device 13 visually determines the characteristics of each signal component sk for each of a plurality of types of signal components (that is, a plurality of types of signal components constituting the respiratory sound signal) sk transmitted from the signal analysis unit 12. Predetermined signal processing for generating a display image to be specified is performed. That is, the signal processing device 13 performs predetermined signal processing for each signal component sk.

  In order to perform predetermined signal processing on each of a plurality of types of signal components sk constituting the respiratory sound signal S, the signal processing device 13 includes a signal storage unit 131, an image generation unit 132, and a past image storage unit 133a. A comparison image storage unit 133b, an image difference determination unit 134, a smoothing parameter update unit 135, and a smoothing unit 136.

  The signal storage unit 131 temporarily stores a plurality of types of signal components sk transmitted from the signal analysis device 12. For this reason, the signal storage unit 131 may include a memory or a buffer. As will be described later, the signal storage unit 131 preferably stores a plurality of types of signal components sk constituting the respiratory sound signal S for a predetermined period.

  The image generation unit 132 generates an image signal D indicating a display image for visually specifying the characteristics of each signal component sk stored in the signal storage unit 131.

  The display image may be any display image as long as the characteristics of each signal component sk can be visually specified. For example, the display image may be a display image including text (for example, characters and numerical values) that visually specifies the characteristics of each signal component sk. Alternatively, for example, the display image may be a display image including a graphic (for example, a graph or a chart) that visually specifies the characteristics of each signal component sk. However, in the first embodiment, the display image preferably includes a display image whose display mode (for example, size, shape, color, luminance, etc.) changes according to the characteristics of each signal component sk. . Further, the display image preferably includes a display image whose display mode (for example, size, shape, color, luminance, etc.) changes greatly as the characteristics of each signal component sk change greatly. In other words, the display image preferably includes a display image whose display mode changes by an amount (a degree) corresponding to the magnitude of the temporal change in characteristics of each signal component sk.

  The past image storage unit 133a temporarily stores the image signal D generated by the image generation unit 132. For this reason, the past image storage unit 133a may include a memory or a buffer. As will be described later, the past image storage unit 133a generates a display image for visually specifying the characteristics of the image signal D for a predetermined period (that is, the characteristics of the plurality of types of signal components sk constituting the respiratory sound signal S). The image signal D) shown is preferably stored.

  The comparison image storage unit 133b temporarily stores the image signal D transmitted from the image difference determination unit 134 to the display device 14. The image signal D stored in the comparison image storage unit 133b is used for the determination operation in the image difference determination unit 134.

  The image difference determination unit 134 determines whether the latest image signal D generated by the image generation unit 132 or smoothed by the smoothing unit 136 and the past image signal D stored in the comparison image storage unit 133b. (That is, the temporal change between the latest image signal D and the past image signal D) is calculated. Further, the image difference determination unit 134 determines whether or not the difference between the latest image signal D and the past image signal D is larger than a predetermined threshold value.

  In addition, when it is determined that the difference between the latest image signal D and the past image signal D is not greater than a predetermined threshold, the image difference determination unit 134 uses a wired or wireless communication line or a wired The latest image signal D generated by the image generation unit 132 or smoothed by the smoothing unit 136 is transmitted to the display device 14 via the signal line. In this case, as described above, the image difference determination unit 134 also transmits the image signal D transmitted to the display device 14 to the comparison image storage unit 133b.

  The smoothing parameter updating unit 135 updates (in other words, sets) the smoothing parameter n that defines the mode of the smoothing process performed by the smoothing unit 136 based on the determination result in the image difference determination unit 134. Specifically, the smoothing parameter update unit 135 increments the smoothing parameter n by 1 each time it is determined that the difference between the latest image signal D and the past image signal D is greater than a predetermined threshold. .

  The smoothing unit 136 performs a smoothing process on the latest image signal D based on the determination result in the image difference determination unit 134. For example, each time the difference between the latest image signal D and the past image signal D is determined to be larger than a predetermined threshold, the smoothing unit 136 performs a smoothing parameter update unit on the latest image signal D. The smoothing process according to the smoothing parameter n updated by 135 is performed. In the first embodiment, the smoothing process for the latest image signal D is performed by moving the latest n image signals D that are temporally continuous (however, one of the image signals D becomes the latest image signal D). This is a process for calculating an average. The image signal D obtained as a result of the smoothing process is thereafter handled as the latest image signal D.

  Note that at least a part of the signal analysis device 12 and the signal processing device 13 (for example, the signal analysis unit 122, the signal separation unit 123, the image generation unit 132, the image difference determination unit 134, the smoothing parameter update unit, and the like) 135 and the smoothing unit 136) are processing blocks that are logically realized on a CPU (Central Processing Unit). However, at least a part of the signal analysis device 12 and the signal processing device 13 may be a processing circuit physically realized by a semiconductor chip or the like.

  The display device 14 displays the display image indicated by the latest image signal D transmitted from the signal processing device 13 (that is, the latest image signal D generated by the image generation unit 132 or smoothed by the smoothing unit 136). Is a display device. As a result, the display device 14 can display the characteristics of each signal component sk on the display screen of the display device 14.

  However, the display device 14 may display a display image indicated by the past image signal D stored in the image storage unit 133 in the signal processing device 13. In this case, the image storage unit 133 may transmit the past image signal D to the display device 14 via a wired or wireless communication line or a wired signal line.

  The example illustrated in FIG. 1 illustrates an example in which the display device 14 is disposed outside the signal processing device 13. However, at least a part of the display device 14 may be disposed inside the signal processing device 13.

(1-2) Operation of the Signal Processing System 1 of the First Example Next, the operation of the signal processing system 1 of the first example will be described with reference to FIGS. FIG. 2 is a flowchart showing the operation flow of the signal processing system 1 of the first embodiment. FIG. 3 is a schematic diagram showing an example of how the respiratory sound sensor 11 is attached to the living body, and a graph showing the waveform of the respiratory sound signal S on the time axis. FIG. 4 is a classification chart showing the types of breathing sounds. FIG. 5 shows five types of breathing sounds (alveolar breathing sounds, low-pitched continuous rales (similar sounds), high-pitched continuous rales (flute sounds), fine intermittent rales (haircut sounds), and rough sounds It is a graph which shows on the time-axis the waveform of five types of signal components sk corresponding to an intermittent ra sound (water bubble sound). FIG. 6 is a schematic diagram illustrating an example of an operation in which the signal storage unit 131 stores the respiratory sound signal S. FIG. 7 is a plan view showing an example of a display mode of each characteristic of the two types of signal components sk # 1 and sk # 2 constituting the respiratory sound signal S. FIG. FIG. 8 is a schematic diagram illustrating an example of an operation in which the past image storage unit 133a stores the image signal D. FIG. 9 illustrates an example of display characteristics of the two types of signal components sk # 1 and sk # 2 when the smoothing process is performed. The two types of signal components sk when the smoothing process is not performed. It is a top view shown with an example of the display mode of each characteristic of # 1 and sk # 2.

  As shown in FIG. 2, first, the respiratory sound sensor 11 acquires a respiratory sound signal S (step S11). Furthermore, the respiratory sound sensor 11 transmits the acquired respiratory sound signal S to the signal analysis device 12 (step S11).

  For example, as shown in FIG. 3A, the respiratory sound sensor 11 may be attached to the body surface of the living body (in the example shown in FIG. 3A, the body surface near the left chest). At this time, the mounting position of the respiratory sound sensor 11 may be fixed. Alternatively, considering that the position where the medical staff auscultates the auscultator is appropriately changed, the mounting position of the respiratory sound sensor 11 may be changed as needed during the acquisition of the respiratory sound signal S. Good. As a result, the respiratory sound sensor 11 acquires the respiratory sound signal S. At this time, the respiratory sound sensor 11 may periodically acquire the respiratory sound signal S according to a predetermined sampling frequency. That is, the respiratory sound sensor 11 may periodically acquire a sample value of the respiratory sound signal S. However, the respiratory sound sensor 11 may acquire the respiratory sound signal S aperiodically or continuously. As a result, the respiratory sound sensor 11 can acquire the respiratory sound signal S specified as a waveform on the time axis shown in FIG.

  In the following description, the sample value of the respiratory sound signal S acquired at the latest time t is referred to as a respiratory sound signal S (t). Similarly, a sample value of the respiratory sound signal S acquired at a past time tk (where k is an integer equal to or greater than 1) is referred to as a respiratory sound signal S (tk).

  As shown in FIG. 3B, considering that the respiration of the living body is a repetition of inspiration (that is, intake of air into the lung) and expiration (that is, exhalation of air from the lung), It can be said that the respiratory sound signal is a signal having periodicity. One cycle of the breathing sound signal is a period obtained by adding up the inspiratory period (that is, the period in which inspiration is performed) and the exhalation period (that is, the period in which exhalation is performed) following the inspiratory period. Needless to say, the period of the respiratory sound signal may vary with time.

  Following the respiratory sound signal S (t) from the respiratory sound sensor 11, the A / D converter 121 performs an A / D conversion process on the respiratory sound signal S (t) transmitted from the respiratory sound sensor 11. Thereafter, the signal analysis unit 122 performs a predetermined analysis process on the latest respiratory sound signal S (t) (or the respiratory sound signal S including the latest respiratory sound signal S (t)) (step S122). . That is, the signal analysis unit 122 performs an analysis process on the respiratory sound signal S to separate the respiratory sound signal S into a plurality of types of signal components sk.

  Here, the types of breathing sounds will be described with reference to FIG. As shown in FIG. 4, breathing sounds in a broad sense (that is, lung sounds) are classified into breathing sounds in a narrow sense and sub-noises that are examples of abnormal sounds. Narrowly defined respiratory sounds are classified into normal respiratory sounds, which are examples of normal sounds, and abnormal respiratory sounds, which are examples of abnormal sounds. Normal respiratory sounds are classified into alveolar respiratory sounds, bronchial respiratory sounds, bronchoalveolar respiratory sounds, and tracheal respiratory sounds. Abnormal breathing sounds are classified into breathing sounds caused by attenuation / disappearance, breathing sounds caused by enhancement, breathing sounds caused by exhaled breath, breathing sounds caused by bronchial breathing, and tracheal stenosis sounds. Is done. The sub-noise is classified into a ra sound and other sounds. The rales are classified into continuous rales and intermittent rales. The continuous rales are classified into low-pitched continuous rales (sounds), high-pitched continuous rales (flute sounds), and scwalks (inspiratory continuous rales). Intermittent rales are classified into fine intermittent rales (haircut sounds) and coarse intermittent rales (water bubbles). Other sounds are classified into pleural friction sounds and pulmonary vascular noise.

  In the first embodiment, the signal analysis unit 122 uses the respiratory sound signal S as a signal component (hereinafter referred to as “intermittent rar sound component sk # 1”) corresponding to the intermittent rar sound. Analysis processing is performed to separate the signal component corresponding to the breath sound (hereinafter referred to as “non-intermittent ra sound component sk # 2”). In other words, the signal analysis unit 122 performs an analysis process for extracting at least one of the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2 from the respiratory sound signal S. The first graph in FIG. 6 shows an example of a signal component corresponding to the alveolar respiratory sound that is a part of the non-intermittent ra sound component sk # 2. The second graph in FIG. 6 shows an example of signal components corresponding to analogy sounds that are part of the non-intermittent ra sound component sk # 2. The third graph in FIG. 6 illustrates an example of a signal component corresponding to a whistle voice that is a part of the non-intermittent ra sound component sk # 2. The fourth graph in FIG. 6 shows an example of a signal component corresponding to the haircut sound that is a part of the intermittent sound component sk # 1. The fifth graph in FIG. 6 illustrates an example of a signal component corresponding to a water bubble sound that is a part of the intermittent sound component sk # 1.

  The signal analysis unit 122 may separate the respiratory sound signal S into the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2 from the following viewpoints.

  Specifically, the non-intermittent ra sound component sk # 2 is a signal component that is temporally continuous (that is, continuous), while the intermittent racho component sk # 1 is temporally intermittent. There is a difference that it is a signal component. Therefore, the signal analysis unit 122 pays attention to such a difference in the distribution of the signal components on the time axis, so that the respiratory sound signal S is converted into the intermittent sound component sk # 1 and the non-intermittent sound component sk. It may be separated into # 2.

  Note that the above-described method relating to the analysis processing for separating the breathing sound signal S into two types of signal components (that is, the intermittent intermittent sound component sk # 1 and the intermittent intermittent sound component sk # 2) is merely an example. Therefore, the signal analysis unit 122 may execute analysis processing for separating the respiratory sound signal S into two types of signal components sk # 1 and sk # 2 by other methods. Note that a method for separating the respiratory sound signal S into a plurality of types of signal components sk (or extracting a specific type of signal components sk from the respiratory sound signal S) is disclosed in, for example, JP-T-2004-531309, 2005-66045 gazette, special table 2001-505085 gazette, special table 2007-508899 gazette, “Application to sparse representation of lung sound signal and intermittent sound separation, Sakai / Satomoto / Kiyasu / Miyahara, Nagasaki University National Studies Report 41, 76 "etc. Therefore, the signal analysis unit 122 may separate the respiratory sound signal S into a plurality of types of signal components sk using the methods disclosed in these documents.

  In addition to or instead of the analysis processing for separating the respiratory sound signal S into the above-described two types of signal components sk # 1 and sk # 2, the signal analysis unit 103 converts the respiratory sound signal S into an arbitrary plurality of types of signals. Analysis processing that separates into components sk (or extracts one or more arbitrary signal components sk from the respiratory sound signal S) may be executed.

  Note that the respiratory sound signal S to be analyzed by the signal analysis unit 122 typically includes a signal component corresponding to the alveolar respiratory sound that is a part of the non-intermittent raural component sk # 2. There is a high possibility of always including. This is because, as long as the living body is breathing, alveolar breathing sound, which is an example of normal sound, regardless of whether the breathing sound includes intermittent rarity, which is an example of abnormal sound, or not. Because it should be included. On the other hand, the respiratory sound signal S that is the target of the analysis processing by the signal analysis unit 122 may or may not include the intermittent sound component sk # 1. In any case, the signal analysis unit 122 executes the analysis process for separating the respiratory sound signal S into the above-described two types of signal components sk # 1 and sk # 2, thereby providing two types of signal components sk. Each of # 1 and sk # 2 can be acquired. For example, the signal analysis unit 122 can acquire the signal component sk included in the respiratory sound signal S by executing the analysis process, and can amplitude the signal component sk not included in the respiratory sound signal S. It can be acquired as a signal component sk whose level is zero.

  In parallel with the analysis processing performed by the signal analysis unit 122, the signal separation unit 123 converts the respiratory sound signal S into two types of signal components (that is, the intermittent sound component sk # 1 and the intermittent sound signal sk # 1). Separated into 2). Further, the signal separation unit 123 performs two separated signal components sk (that is, the intermittent sound component sk # 1 and the non-discontinuous sound component) via a wired or wireless communication line or a wired signal line. Each of sk # 2) is transmitted to the signal processing device 13.

  In parallel with the analysis processing performed by the signal analysis unit 122, the signal storage unit 131 transmits the respiratory sound signal S transmitted from the signal analysis device 12 (that is, the intermittent sound component sk # 1 constituting the respiratory sound signal S). And the intermittent sound component sk # 2) are temporarily stored (step S131).

  At this time, it is preferable that the signal storage unit 131 temporarily stores a predetermined number of sample values of the respiratory sound signal S that are temporally continuous. In the first embodiment, the signal storage unit 131 temporarily stores sample values of the latest 128 respiratory sound signals S. That is, the signal storage unit 131 temporarily stores sample values of 128 respiratory sound signals S that are temporally continuous including the latest respiratory sound signal S (t). In order to temporarily store the sample values of the latest 128 breathing sound signals S, the signal storage unit 131 preferably includes a ring buffer. However, the signal storage unit 131 may temporarily store an arbitrary number of sample values of the respiratory sound signal S.

  Furthermore, in the first embodiment, the signal storage unit 131 preferably stores the respiratory sound signal S for each signal component sk. That is, it is preferable that the signal storage unit 131 separately stores the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2 separately.

  As a result, as shown in FIG. 6, the signal storage unit 131 sets the sample value sk # 1 (t of the intermittent sound component sk # 1 constituting the respiratory sound signal S (t) acquired at the latest time t. ), A sample value sk # 1 (t-1) of the intermittent sound component sk # 1 constituting the respiratory sound signal S (t-1) acquired at time t-1, and time ( The sample value sk # 1 (t-127) of the intermittent sound component sk # 1 constituting the respiratory sound signal S (t-127) acquired at t-127) is temporarily stored. Similarly, the signal storage unit 131 includes the sample value sk # 2 (t) of the non-intermittent raural component sk # 2 constituting the respiratory sound signal S (t) acquired at the latest time t, and the time t−. Sampled values sk # 2 (t-1) of the non-intermittent ra sound sk # 2 constituting the respiratory sound signal S (t-1) acquired at 1, and acquired at time (t-127). The sample value sk # 2 (t-127) of the non-intermittent ra sound sk # 2 constituting the breathing sound signal S (t-127) is temporarily stored.

  In the following, the sample values of the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2 constituting the respiratory sound signal S (t) acquired at the latest time t are respectively shown as intermittent. These are referred to as the ra sound component sk # 1 (t) and the non-intermittent ra sound component sk # 2 (t). Similarly, sample values of the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2 (t) constituting the respiratory sound signal S (tk) acquired at the past time tk are obtained. These are respectively referred to as an intermittent sound component sk # 1 (tk) and a non-intermittent sound component sk # 1 (tk).

  Subsequently, each time the latest respiratory sound signal S (t) is stored in the signal storage unit 131 (in other words, every time the signal storage unit 131 stores a new respiratory sound signal S (t)), the smoothing parameter is updated. The unit 135 initializes the smoothing parameter n (step S135a). In other words, every time the intermittent sound sk # 1 (t) and the non-intermittent sound sk # 2 (t) are stored by the signal storage unit 131 (in other words, the signal storage unit 131 generates a new intermittent sound). The smoothing parameter updating unit 135 initializes the smoothing parameter n each time sk # 1 (t) and the non-intermittent ra sound sk # 2 (t) are stored. That is, every time the stored contents of the signal storage unit 131 are updated, the smoothing parameter update unit 135 initializes the smoothing parameter n. Here, the initialization of the smoothing parameter n means an operation of setting an initial value “1” to the smoothing parameter n.

  Further, every time the latest respiratory sound signal S (t) is stored in the signal storage unit 131, the image generation unit 132 generates an image signal D (t) corresponding to the latest respiratory sound signal S (t) ( Step S132). That is, the image generation unit 132 visually recognizes the characteristics of the intermittent sound component sk # 1 (t) and the non-intermittent sound component sk # 2 (t) that form the latest respiratory sound signal S (t). An image signal D (t) indicating a display image to be identified is generated (step S132). In the following description, an image signal D indicating a display image for visually specifying the characteristics of the two types of signal components sk constituting the respiratory sound signal S (t) acquired at the latest time t will be referred to as an image signal. This is referred to as D (t). Similarly, an image signal D indicating a display image for visually specifying the characteristics of each of the two types of signal components sk constituting the respiratory sound signal S (tk) acquired at the past time tk, This is referred to as an image signal D (tk).

  In the first embodiment, it is assumed that the characteristic of the signal component is the amplitude level of the signal component (that is, the characteristic indicating the signal strength). However, it goes without saying that the characteristic of the signal component may be a characteristic different from the amplitude level (in other words, an index (variable) capable of specifying the state of the signal component).

  In the first embodiment, the display image is a display image including a circular figure whose diameter increases as the amplitude level of each signal component increases. Specifically, as shown in FIG. 7, the display image is (i) a circular figure whose diameter increases as the amplitude level of the intermittent rar component sk # 1 increases (positioned on the left side in FIG. 7). And (ii) a circular figure whose diameter increases as the amplitude level of the non-intermittent sound component sk # 2 increases (see the circular figure located on the right side in FIG. 7). It is assumed that the display image includes In the display image illustrated in FIG. 7, the amplitude level of the intermittent intermittent sound component sk # 1 (t) is relatively large, while the amplitude level of the non-intermittent random sound component sk # 2 (t) is relatively small. It is shown that. However, as described above, the display image may be any display image as long as the characteristics of each signal component sk are visually specified. However, it is preferable that the display image includes a display image in which the display mode greatly changes as the characteristics of each signal component sk change greatly.

  Further, in the first example, the image generation unit 132 includes, as the image signal D (t), an image signal D1 (t) indicating a display image indicating the amplitude level of the intermittent rar sound component sk # 1 (t); It is assumed that the image signal D2 (t) indicating the display image indicating the amplitude level of the non-intermittent ra sound component sk # 2 (t) is generated independently. That is, the image generation unit 132 displays, as the image signal D (t), a display image that indicates the amplitude level of the intermittent sound component sk # 1 (t) (that is, a relatively left-side display image shown in FIG. 7). Image signal D1 (t) indicating the display image) and a display image indicating the amplitude level of the intermittent sound component sk # 2 (t) (that is, the display image on the right side of the display image shown in FIG. 7). The image signal D2 (t) indicating) is generated separately and independently. However, the image generation unit 132 is a single image indicating a single display image indicating the amplitude level of each of the intermittent sound component sk # 1 (t) and the non-intermittent sound component sk # 2 (t). A signal D (t) may be generated. That is, the image generation unit 132 may generate a single image signal D (t) obtained by superimposing the image signal D1 (t) and the image signal D2 (t).

  After the image generation unit 132 generates the image signal D (t), the past image storage unit 133a temporarily stores the image signal D (t) (step S133a). At this time, the past image storage unit 133a preferably temporarily stores a predetermined number of image signals D that are temporally continuous. In the first embodiment, the past image storage unit 133a temporarily stores the latest 128 image signals D1. That is, the past image storage unit 133a temporarily stores 128 temporally continuous image signals D1 including the image signal D1 (t) corresponding to the respiratory sound signal S (t). Specifically, as illustrated in FIG. 8, the past image storage unit 133a includes the image signal D1 (t) corresponding to the respiratory sound signal S (t) acquired at the latest time t, and the time t−1. Corresponding to the image signal D1 (t-1) corresponding to the acquired respiratory sound signal S (t-1), ..., the respiratory sound signal S (t-127) acquired at time (t-127) The image signal D1 (t-127) to be stored is temporarily stored. Similarly, in the first embodiment, it is assumed that the past image storage unit 133a temporarily stores the latest 128 image signals D2. That is, the past image storage unit 133a temporarily stores 128 temporally continuous image signals D2 including the image signal D2 (t) corresponding to the respiratory sound signal S (t) acquired at the latest time t. It shall be remembered. Specifically, as illustrated in FIG. 8, the past image storage unit 133a includes the image signal D2 (t) corresponding to the respiratory sound signal S (t) acquired at the latest time t and the time t−1. Corresponding to the image signal D2 (t-1) corresponding to the acquired respiratory sound signal S (t-1), ..., corresponding to the respiratory sound signal S (t-127) acquired at time (t-127) The image signal D2 (t-127) to be stored is temporarily stored. In order to temporarily store the latest 128 image signals D, the past image storage unit 133a preferably includes a ring buffer. However, the past image storage unit 133a may temporarily store an arbitrary number of image signals D.

  After the image generation unit 132 generates the image signal D (t), the image difference determination unit 134 compares the image signal D (t) corresponding to the respiratory sound signal S (t) acquired at the latest time t and the past. A difference between the image signal D (tk) corresponding to the respiratory sound signal S (tk) acquired at time tk is calculated (step S134a). That is, the image difference determination unit 134 determines the difference between the image signal D1 (t) and the image signal D1 (tk) and the difference between the image signal D2 (t) and the image signal D2 (tk). Is calculated. In the following description, each of the image signal D1 and the image signal D2 is collectively referred to as the image signal D to simplify the description. That is, in the following description, the operation for the image signal D means an operation for the image signal D1 and an operation for the image signal D2.

  In the first embodiment, the image difference determination unit 134 is acquired at the image signal D (t) corresponding to the respiratory sound signal S (t) acquired at the latest time t and the previous time t−1. It is assumed that the difference from the image signal D (t−1) corresponding to the respiratory sound signal S (t−1) and stored in the comparison image storage unit 133b is calculated. Since the image signal D (t−1) is stored in the comparison image storage unit 133b, the image difference determination unit 134 preferably acquires the image signal D (t−1) from the comparison image storage unit 133b. . On the other hand, the image difference determination unit 134 may acquire the image signal D (t) directly from the image generation unit 132 or the smoothing unit 136.

Specifically, for example, the image difference determination unit 134 displays the luminance value of the display image indicated by the image signal D (t) and the display image indicated by the image signal D (t−1) for each pixel constituting the display image. The difference between the luminance values is calculated. Further, the image difference determination unit 134 adds the calculated differences for each pixel over all the pixels. Furthermore, the image determination unit 134 divides the addition result (that is, a value obtained by adding the difference for each pixel over all the pixels) by the number of all the pixels. That is, the image difference determination unit 134 performs the calculation shown in Equation 1. However, the number of pixels in the horizontal direction (X direction) of the display image is w, the number of pixels in the vertical direction (Y direction) of the display image is h, and the coordinate position constituting the display image indicated by the image signal D (t) is The brightness value of the pixel at (x, y) is B _t (x, y), and the brightness value of the pixel at the coordinate position constituting the display image indicated by the image signal D (t−1) is (x, y). _Is B _t-1 (x, y).

  The image difference determination unit 134 handles the numerical value obtained as a result of the calculation shown in Formula 1 as the difference between the image signal D (t) and the image signal D (t−1).

  In the above example, the image difference determination unit 134 calculates the difference between the image signal D (t) and the image signal D (t−1) by paying attention to the luminance value of the display image indicated by the image signal D. ing. However, the image difference determination unit 134 pays attention to other characteristics (for example, hue, brightness, saturation, transparency, etc.) of the display image indicated by the image signal D, and the image signal D (t) and the image A difference from the signal D (t−1) may be calculated.

  Thereafter, the image difference determination unit 134 determines whether or not the difference between the image signal D (t) and the image signal D (t−1) is greater than a predetermined threshold (step S134b). An arbitrary value may be set as the predetermined threshold. In the first embodiment, for example, the predetermined threshold value is multiplied by a predetermined coefficient to the difference between the maximum luminance value that can be output by the display device 14 and the minimum luminance value that can be output by the display device 15. The value obtained in (1) may be set. Specifically, for example, the predetermined threshold value is (maximum luminance value that can be output by the display device 14−minimum value of luminance value that can be output by the display device 14) × predetermined coefficient (for example, 0.3). A value may be set.

  As a result of the determination in step S134b, when it is determined that the difference between the image signal D (t) and the image signal D (t-1) is larger than a predetermined threshold (that is, not lower than the predetermined threshold) (step S134b). : Yes), it is assumed that the temporal change between the display image indicated by the image signal D (t) and the display image indicated by the image signal D (t-1) is relatively large (or excessively large). . As a result, when the display image displayed on the display device 14 is switched from the display image indicated by the image signal D (t−1) to the display image indicated by the image signal D (t), a large change in the display image is displayed. There is a risk of excessive stimulation for a user (for example, a medical worker such as a doctor) watching the device 14.

  Therefore, in the first embodiment, when the difference between the image signal D (t) and the image signal D (t−1) is larger than a predetermined threshold, the image signal D (t) and the image signal D (t−1) ), The smoothing unit 136 performs a smoothing process on the image signal D (t).

  Specifically, first, the smoothing parameter update unit 135 increments the smoothing parameter n by 1 (step S135b). When the image signal D1 (t) and the image signal D2 (t) are generated separately and independently as the image signal D (t), smoothing processing is performed on the image signal D1 (t) as the smoothing parameter n. It is preferable to prepare separately the smoothing parameter n1 used when performing, and the smoothing parameter n2 used when performing the smoothing process with respect to the image signal D2 (t).

  Thereafter, the smoothing unit 136 performs a smoothing process on the image signal D (t) using the smoothing parameter n updated by the smoothing parameter update unit 135 (step S136). In the smoothing process in the first embodiment, a moving average (for example, a simple moving average) of the latest n image signals (that is, the image signal D (t−n + 1)) is newly calculated. It means an operation for setting the image signal D (t). That is, the smoothing unit 136 sets the image signal obtained as a result of the calculation shown in Equation 2 as a new image signal D (t). However, the smoothing process in the first embodiment is not limited to the operation of setting the moving average of the latest n image signals to the new image signal D (t), but the image signal D (t) and the image signal D ( Any processing that can reduce the difference from t-1) may be used.

  Note that since the last n image signals D (that is, the image signal D (t−n + 1) to the image signal D (t−n + 1) are stored in the past image storage unit 133a, the smoothing unit 136 includes the past image storage unit. It is preferable to obtain the image signal D (t−n + 1) from the latest n image signals D from 133a (that is, the image signal D (t)).

  Thereafter, while using the new image signal D (t) obtained as a result of the smoothing process instead of the image signal D (t) generated by the image generation unit 132, the image signal D (t) and the image The operations after step S134a are repeated until the difference from the signal D (t-1) becomes equal to or less than the predetermined threshold value.

  Since the parameter for calculating the moving average increases every time the smoothing parameter n is incremented, the image signal D (t) and the image signal D (t) are increased by incrementing the smoothing parameter n. The difference from -1) is likely to be small. However, considering that there is an upper limit (128 in the example shown in FIG. 8) in the number of image signals D stored in the past image storage unit 133a, the smoothing parameter update unit 135 sets the upper limit of the smoothing parameter n. It is preferable to increment the smoothing parameter n within a range not exceeding (for example, 128). If the smoothing parameter n exceeds the upper limit, even if the difference between the image signal D (t) and the image signal D (t-1) is not less than or equal to a predetermined threshold value, It is preferable to perform display processing according to the image signal D (t).

  On the other hand, as a result of the determination in step S134b, it is determined that the difference between the image signal D (t) and the image signal D (t-1) is not greater than the predetermined threshold (that is, less than the predetermined threshold). (Step S134b: No), the temporal change between the display image indicated by the image signal D (t) and the display image indicated by the image signal D (t-1) is relatively small (or not excessively large). ) Is assumed. As a result, even if the display image displayed on the display device 14 is switched from the display image indicated by the image signal D (t−1) to the display image indicated by the image signal D (t), excessive stimulation for the user. There is little fear of becoming.

  For this reason, when the difference between the image signal D (t) and the image signal D (t−1) is equal to or smaller than a predetermined threshold, the smoothing unit 136 performs a smoothing process on the image signal D (t). Not necessary.

  Thereafter, when the image difference determination unit 134 determines that the difference between the image signal D (t) and the image signal D (t−1) is not greater than a predetermined threshold (that is, less than or equal to the predetermined threshold), The image signal D (t) is transmitted to the display device 14. Thereafter, the display device 14 performs display processing based on the image signal D (t) (step S14). As a result, the display device 14 displays the amplitude level of each of the two types of signal components sk (that is, the intermittent sound component sk # 1 and the non-intermittent sound component sk # 2).

  In addition, when the image difference determination unit 134 determines that the difference between the image signal D (t) and the image signal D (t−1) is not larger than the predetermined threshold (that is, less than the predetermined threshold). The image signal D (t) is transmitted to the comparative image storage unit 133b. Thereafter, the comparative image storage unit 133b temporarily stores the image signal D (t). The image signal D (t) stored in the comparison image storage unit 133 is a past image signal D (t−) used in the determination operation by the image difference determination unit 134 after a new respiratory sound signal S (t) is acquired. 1).

  The operation described above is repeated until the respiratory sound sensor 11 does not acquire a new respiratory sound signal S (t) (or until the operation of the signal processing system 1 is completed) (step S15). When the respiratory sound sensor 11 acquires a new respiratory sound signal S (t) (step S11), the operation after step S122 is performed again for the new respiratory sound signal S (t).

  Here, a specific display mode of the display image will be described with reference to FIG. First, the respiratory sound signal S (t−1) acquired at time t−1 is an intermittent ra sound component sk # 1 (t−1) with an amplitude level of 11 dB and non-intermittent with an amplitude level of 32 dB. It is assumed that it includes a natural sound component sk # 2 (t-1). In this case, as illustrated in FIG. 9A, the image generation unit 132 (i) has a diameter (for example, a diameter of 11) corresponding to the amplitude level of the intermittent rato component sk # 1 (t−1) of 11 dB. ) And an image signal D1 (t−1) indicating a display image including a circular figure having a diameter, and (ii) a diameter corresponding to the amplitude level of the non-discontinuous rar sound component sk # 2 (t−1) of 32 dB (for example, And an image signal D2 (t-1) indicating a display image including a circular figure having a diameter of 32.

  Thereafter, the respiratory sound signal S (t−1) acquired at time t includes an intermittent ra sound component sk # 1 (t) having an amplitude level of 51 dB and an uninterrupted ra sound component having an amplitude level of 27 dB. It is assumed that sk # 2 (t) is included.

  In this case, if the smoothing process is not performed on the image signal D (t), as illustrated in FIG. 9B, the image generation unit 132 (i) an intermittent sound component sk # 1 of 51 dB. An image signal D1 (t) indicating a display image including a circular figure having a diameter corresponding to the amplitude level of (t) (for example, a diameter of 51), and (ii) a non-intermittent radian component sk # 2 of 27 dB An image signal D2 (t) including a circular figure having a diameter (for example, a diameter of 27) corresponding to the amplitude level of (t) is generated. However, the diameter of the circular figure specifying the amplitude level of the intermittent sound component sk # 1 (t) shown in FIG. 9 (b) is equal to the intermittent sound component sk # 1 (t) shown in FIG. 9 (a). Compared with the diameter of the circular figure which specifies the amplitude level of -1), it is greatly changed. Therefore, such a large change in the size of the display image (that is, a circular figure) may be an excessive stimulus for the user.

  However, in the first embodiment, the smoothing unit 136 can perform a smoothing process on the image signal D1 (t). Therefore, as shown in FIG. 9C, the diameter of the circular figure that specifies the amplitude level of the intermittent sound component sk # 1 (t) is (11 + 51) / 2 = 32. As a result, a display image (that is, a circular figure) that changes only to an extent that does not give excessive stimulation to the user is displayed.

  The same applies not only to the circular graphic that specifies the amplitude level of the intermittent sound component sk # 1, but also to the circular graphic that specifies the amplitude level of the non-intermittent sound component sk # 2. However, in the example shown in FIG. 9, the diameter of the circular figure specifying the amplitude level of the non-intermittent radian component sk # 2 (t) shown in FIG. 9 (b) is the non-intermittent shown in FIG. 9 (a). Since the amplitude level of the characteristic ra sound component sk # 2 (t-1) is not significantly changed compared to the diameter of the circular figure specifying the smoothing unit 136, the smoothing unit 136 performs the processing on the image signal D2 (t). Smoothing processing may not be performed.

  As described above, since the signal processing system 1 of the first embodiment can perform the smoothing process on the image signal D, it is compared with the case where the smoothing process is not performed on the image signal D. Thus, the temporal change of the display image displayed on the display device 14 becomes relatively small. For this reason, even when the characteristics of the respiratory sound signal S (or the intermittent rar sound component sk # 1 and the non-intermittent rar sound component Sk # 2 constituting the respiratory sound signal S) change significantly, the display image The temporal change of becomes relatively small. Therefore, the display mode of the display image displayed on the display device 14 even when the characteristics of the breathing sound signal S change significantly compared to the case where the smoothing process is not performed on the image signal D. There is little or no change in. That is, when it is not desired to change the display mode of the display image excessively large (in other words, when it is not desired to excessively increase the temporal change of the display image), the smoothing unit 136 generates the image signal D (t). By performing the smoothing process on the display image, an excessively large change in the display mode of the display image can be suitably prevented.

(2) Second Example Next, a signal processing system 2 of a second example will be described with reference to FIGS. 10 to 12. FIG. 10 is a block diagram showing the configuration of the signal processing system 2 of the second embodiment. FIG. 11 is a plan view showing an example of a display mode of the characteristics of the atmospheric pressure signal P. FIG. FIG. 12 is a plan view illustrating an example of a display mode of the characteristics of the atmospheric pressure signal P when the smoothing process is performed, together with an example of a display mode of the characteristics of the atmospheric pressure signal P when the smoothing process is not performed. In addition, about the component same as the component with which the signal processing system 1 of 1st Example is provided, the detailed description is irradiated by attaching | subjecting the same referential mark.

  As shown in FIG. 10, the signal processing system 2 according to the second embodiment does not include the respiratory sound sensor 11 but includes the atmospheric pressure sensor 21 as compared with the signal processing system 1 according to the first embodiment. It is different in that. Furthermore, the signal processing system 2 of the second embodiment is different from the signal processing system 1 of the first embodiment in that the signal analysis device 22 does not include the signal analysis unit 122 and the signal separation unit 123. Yes. Other configuration requirements of the signal processing system 2 of the second embodiment may be the same as other configuration requirements of the signal processing system 1 of the first embodiment.

  The atmospheric pressure sensor 21 acquires the atmospheric pressure signal P by detecting the atmospheric pressure value. The atmospheric pressure sensor 21 transmits the acquired atmospheric pressure signal P to the signal analysis device 22 via a wired or wireless communication line or a wired signal line.

  In the signal analysis device 22 to which the atmospheric pressure signal P is transmitted, the A / D conversion unit 121 performs A / D conversion processing on the atmospheric pressure signal P transmitted from the atmospheric pressure sensor 21. That is, the A / D converter 121 converts the atmospheric pressure signal P as an analog signal transmitted from the atmospheric pressure sensor 21 into an atmospheric pressure signal P as a digital signal. Thereafter, the A / D converter 121 transmits the atmospheric pressure signal P converted into a digital signal to the signal processing device 13.

  In the signal processing device 13 to which the atmospheric pressure signal P is transmitted, operation similar to that in the first embodiment is performed. However, in the second embodiment, the operations specially described below may be performed in a manner different from that of the first embodiment.

  First, in the second embodiment, the image generation unit 132 generates an image signal D (t) corresponding to the atmospheric pressure signal P (t) acquired at the latest time t. That is, in the second embodiment, the image generation unit 132 generates the image signal D (t) indicating the display image that visually identifies the characteristic of the atmospheric pressure signal P (t) acquired at the latest time t. In the second embodiment, it is assumed that the characteristic of the atmospheric pressure signal P is an amplitude level (that is, the magnitude of the atmospheric pressure value). However, it goes without saying that the characteristic of the atmospheric pressure signal P may be a characteristic different from the amplitude level (in other words, an index (variable) that can specify the state of the atmospheric pressure signal P). In the second embodiment, the display image is a display image whose hue changes according to the amplitude level (that is, the atmospheric pressure value) of the atmospheric pressure signal P as shown in FIG. Specifically, the display image shown in FIG. 11 indicates that the atmospheric pressure at the latest time t is approximately 1013.00 hPa. However, as described above, the display image may be any display image as long as the characteristics of the atmospheric pressure signal P are visually specified. However, it is preferable that the display image includes a display image whose display mode greatly changes as the characteristics of the atmospheric pressure signal P change greatly.

Furthermore, in the second embodiment, the image difference determination unit 134 displays the hue of the display image indicated by the image signal D (t) and the display image indicated by the image signal D (t−1) for each pixel constituting the display image. The difference between the hue is calculated. Further, the image difference determination unit 134 adds the calculated differences for each pixel over all the pixels. Furthermore, the image determination unit 134 divides the addition result (that is, a value obtained by adding the difference for each pixel over all the pixels) by the number of all the pixels. That is, the image difference determination unit 134 performs the calculation shown in Equation 3. However, the number of pixels in the direction (X direction) is w, the number of pixels in the vertical direction (Y direction) of the display image is h, and the coordinate position constituting the display image indicated by the image signal D (t) is (x, y ) Is set to H _t (x, y), and the hue of the pixel having the coordinate position (x, y) constituting the display image indicated by the image signal D (t−1) is set to H _t−1 ( x, y). In the second embodiment, the image difference determination unit 134 handles the numerical value obtained as a result of the calculation shown in Equation 3 as the difference between the image signal D (t) and the image signal D (t−1).

  Further, in the second embodiment, the maximum value of the hue that can be output by the display device 14 is displayed as the predetermined threshold value used when determining the difference between the image signal D (t) and the image signal D (t−1). A value obtained by multiplying the difference from the minimum hue value that can be output by the device 14 by a predetermined coefficient may be set. Specifically, for example, the predetermined threshold value is a value of (maximum hue value that can be output by the display device 14−minimum value of hue degree that can be output by the display device 14) × predetermined coefficient (for example, 0.3). May be set.

  Here, a specific display mode of the display image will be described with reference to FIG. First, it is assumed that the atmospheric pressure value indicated by the atmospheric pressure signal P (t−1) acquired at time t−1 is 1012.52 hPa. In this case, as shown in FIG. 12A, the image generation unit 132 generates an image signal D (t−1) indicating a display image having a hue corresponding to the atmospheric pressure value of 1012.52 hPa.

  Thereafter, it is assumed that the atmospheric pressure value indicated by the atmospheric pressure signal P (t−1) acquired at time t is 101.48 hPa. In this case, if smoothing processing is not performed on the image signal D (t), as shown in FIG. 12B, the image generation unit 132 displays a hue having a hue corresponding to an atmospheric pressure value of 1013.48 hPa. An image signal D (t) indicating an image is generated. However, the hue of the display image specifying the characteristic (atmospheric pressure value) of the atmospheric pressure signal P (t) shown in FIG. 12B is the characteristic (atmospheric pressure value) of the atmospheric pressure signal P (t−1) shown in FIG. ) Is greatly changed as compared with the hue of the display image for specifying. Therefore, such a large change in the hue of the display image may be an excessive stimulus for the user.

  However, in the first embodiment, the smoothing unit 136 can perform a smoothing process on the image signal D (t). Therefore, as shown in FIG. 12C, the display image for specifying the characteristic (atmospheric pressure value) of the atmospheric pressure signal P (t) corresponds to the atmospheric pressure value of (1012.52 + 1013.38) /2=1013.00 hPa. The display image has a hue. As a result, a display image that changes only to an extent that does not give excessive stimulation to the user is displayed.

  Even in the signal processing system 2 of the second embodiment, it is possible to suitably enjoy the same effects as the various effects that can be enjoyed by the signal processing system of the first embodiment described above.

  In addition, the present invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a signal processing apparatus and method, a computer program, and a recording accompanying such a change. The medium is also included in the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1, 2 Signal processing system 11 Respiration sound sensor 12 Signal analysis apparatus 13 Signal processing apparatus 132 Image generation part 134 Image difference determination part 135 Smoothing parameter update part 136 Smoothing part 14 Display apparatus 21 Barometric pressure sensor

Claims (1)

Smoothing for performing smoothing processing on the image signal for smoothing the temporal change of the image signal based on the magnitude of the temporal change of the image signal for displaying the characteristics of the time series signal on the display device Means,
An output unit that outputs the image signal subjected to the smoothing process to a display unit that displays a display image indicated by the image signal.