JP2003204562A - Signal monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal monitoring system capable of efficiently monitoring a signal with some extent of monitoring accuracy. <P>SOLUTION: The signal monitoring system derives a value d(u) corresponding to the difference between a first value obtained by extracting a component of a first signal V(x, y, z, t) to derive the variance and a second value obtained by extracting a component of a second signal U(x, y, z, t) to derive the variance, and outputs a warning signal when the value d(u) exceeds a threshold TH. Then by properly deciding the threshold TH, whether or not the second signal U(x, y, z, t) is deteriorated can be continuously monitored with respect to the first signal V(x, y, z, t) non-negligibly deteriorated and required action such as processing stop is taken when it is determined that the second signal is deteriorated with respect to the first signal non-negligibly deteriorated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal monitoring system, and more particularly to a signal monitoring system suitable for monitoring digital video / audio signals.

[0002]

2. Description of the Related Art With recent improvements in video processing technology, high-quality video such as high-definition television broadcasting has come to be broadcast. Here, the video signal relating to the high-definition broadcasting will be transmitted to each home through the network of satellite broadcasting or cable TV. However, while the video signal is being transmitted, signal deterioration may occur due to various causes. If such signal deterioration occurs, it is likely to be recognized as image blurring, noise, and the like, and the image quality is degraded depending on the degree of appearance.

[0003]

Therefore, it becomes necessary to monitor the deterioration of the video signal. In the past, a video signal was taken out by a transmission source and a transmission destination, and an observer monitored the video formed based on the video signal. However, a problem of the monitoring work performed via the monitor is that the concentration of the human is easily interrupted in a short time as a characteristic of human beings, and there is a demand for mechanization of this.

Since the video signal is a kind of data, it can be said that a method of mechanically monitoring the data can be used. As a data check method in the related art, there is a method using a checksum, for example. this is,
Calculate the total value of data in advance, send the data and the total value at the time of data transmission, calculate the total of the received data on the receiving side, and compare with the total value calculated on the transmitting side Is. If there is an error in the value of the transmitted data, the total value does not match, so the error can be detected.

However, in the case of a video signal, etc., in addition to the two-dimensional or three-dimensional coordinates as a component of the video signal,
Since it becomes four-dimensional data including the time component, the amount of signal becomes enormous. Therefore, it is extracted at the transmission source and the transmission destination.
It can also be said that the sum of the two signals cannot exactly match each other. On the other hand, in the case of a video signal, even if noise occurs in a momentary video, it may be ignored from the overall viewpoint. Therefore, it can be said that the checksum for checking only whether or not the total sum is different is not suitable for checking the video signal.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a signal monitoring system capable of efficiently monitoring a signal with a certain level of monitoring accuracy.

[0007]

A signal monitoring system according to the present invention according to claim 1 is a monitoring system for monitoring a second signal obtained by subjecting a first signal to a predetermined process. The first value obtained by extracting the component of the first signal and performing the statistical processing, and the second value obtained by extracting the component of the second signal and performing the statistical processing.
Index value obtained based on the value of
When (u)) exceeds the threshold, an alarm signal is output. Therefore, by appropriately setting the threshold, the second
It is possible to continuously monitor whether or not the signal of No. 1 has deteriorated to a level that cannot be ignored with respect to the first signal, and if it is determined that the signal has deteriorated to a level that cannot be ignored, it is necessary to stop processing. You can take action. Here, the “predetermined processing” may be processing such as signal transmission, compression, and expansion.

The present invention will be described. FIG. 1 is a schematic diagram of a signal before and after processing (considering an example having a value for each three-dimensional coordinate value such as a virtual video signal, but a normal video signal when z = 0). In FIG. 1, a predetermined (first) signal before three-dimensional coordinates (x, y, z) at time t is V (x, y, z, t),
The (second) signal after the predetermined processing at the three-dimensional coordinates (x, y, z) at time t is U (x, y, z, t). As a specific example, V (x, y,
When a video signal z, t) is transmitted (an example of a predetermined process), the monitor in Osaka corresponds to U (x,
This corresponds to the case where a video signal of y, z, t) is received.

Here, if a video signal is transmitted over a long distance, various problems such as signal loss and noise may occur. Therefore, V (x, y, z, t) = U is not always required.
There is a fact that it cannot be (x, y, z, t). However, on the assumption that the signals V (x, y, z, t) are different, what value the signal U (x, y, z, t) is in the allowable range becomes a big problem. .

However, like the checksum of the prior art, each component of V (x, y, z, t) and U (x, y,
In the method of comparing the total sums of the respective components of z, t), the calculation time is enormous, and it is practically impossible that they are exactly the same, so it can be said that it is inappropriate as an inspection method. On the other hand, in the present invention, the concept of statistical processing (for example, variance) is used, and for example, variance calculation can be performed relatively easily, so that quickness of inspection can be ensured, and if variance is smaller than a threshold value, processing can be performed. Even if noise is generated in the subsequent signal, it can be ignored (there is no discomfort for the human eye)
Therefore, the process can be treated as normal.

According to the first aspect of the invention, the first value obtained by extracting the component of the first signal and subjecting it to statistical processing is separate from the transmission of the first signal. In addition, there is a problem that it is necessary to obtain it through a public line or the Internet, which is troublesome and increases equipment costs. On the other hand, the signal monitoring system according to the second aspect of the present invention is obtained by performing a predetermined process on the first signal accompanied by the data (for example, binary data) corresponding to the first value. A signal monitoring system for monitoring a second signal, comprising: a second value obtained by extracting a component of the second signal and performing statistical processing; and the first value corresponding to the data. Based on the above, an alarm signal is output, so that the first value can be obtained from the data attached to the first signal even when the first signal is transmitted to a remote place as a process. Because you can
The comparison with the second value is easy.

According to the signal monitoring system of the present invention as set forth in claim 3, the first value is a value obtained by extracting a component of the first signal and performing statistical processing, It is preferable to output the alarm signal when an index value (for example, d (u) described below) obtained based on the first value and the second value exceeds a threshold value.

According to the signal monitoring system of the present invention described in claim 4, it is preferable that the statistical processing is distributed. With respect to the “dispersion” used as an example of the statistical processing of the present invention described above, the dispersion value A is represented by the following (Equation 1).

[Equation 1] The average value ave. Used here. V can be expressed by the following equation (2).

[Equation 2] Therefore, the signal value V (x, y, z, t) before the predetermined processing
Then, a variance value is obtained for each of the signal values U (x, y, z, t) after the predetermined processing, and a value (d (u) described later) that reflects the difference is compared with a threshold value (TH described later). By doing so, it is possible to determine whether or not the signal is normal.

According to the signal monitoring system of the fifth aspect of the present invention, it is preferable that the component of the signal can be represented by three-dimensional coordinates and time, for example, since it can be applied to a virtual video signal, but it is not limited to this. Instead, it can be applied to a two-dimensional still image.

According to the sixth aspect of the signal monitoring system of the present invention, it is preferable that the threshold value can be changed because it is possible to obtain a threshold value that does not cause discomfort for human eyes.

According to the signal monitoring system of the present invention as defined in claim 7, when the threshold value is changed according to the state of the second signal, more accurate monitoring can be performed.
“To change according to the state of the second signal” means, for example, when the curve C shown in FIG. 4 is taken as an example, u> A and u ≦ A
In this case, the value of the threshold (TH) is changed depending on.

According to another aspect of the signal monitoring system of the present invention, the first signal and the second signal are output from the same signal source, and the second signal is
Monitoring downstream of the first signal is preferred because errors can be detected by transmission.

According to a ninth aspect of the signal monitoring system of the present invention, the first value and the second value are the first value.
The processing speed can be remarkably improved by extracting the signals of the above-mentioned second signal and the signals constituting a specific small area in one frame. For example, the central area of one frame is
Since it is considered that a main subject such as a person is present, it is preferable to accurately detect the occurrence of image blurring. On the other hand, the peripheral area often becomes the background, so even if some image blurring occurs From the fact that it often does not occur, by setting the specific small area as the central area, the processing speed can be improved without substantially reducing the monitoring accuracy. However, it is also possible to set a plurality of the specific small areas and individually change the threshold level or the like (for example, make the central area strict and the peripheral area lenient) or take an average value. To be

According to a tenth aspect of the signal monitoring system of the present invention, an unsteady state of the image is detected based on the first value or the second value, and the unsteady state of the image is detected. When the alarm signal is output, the output of the alarm signal is prohibited. Therefore, in the unsteady state of the image in which the first value or the second value becomes unstable, the alarm is not issued, so that more accurate monitoring can be performed. Is possible. The “unsteady state of the image” refers to a state in which a spatiotemporal signal can greatly change, such as a scene change or an outline of an object.

According to the signal monitoring system of the present invention as set forth in claim 11, in the signal monitoring system for monitoring the video signal, the component of the video signal in the temporally preceding frame is extracted and statistically processed. The difference between the obtained statistic value (for example, variance value) and the statistic value (for example, variance value) obtained by extracting the component of the video signal in the frame that follows in time and subjecting it to statistical processing is When the value is below the first predetermined value, it is determined that the screen is frozen and an alarm signal is output, so that an inappropriate image can be quickly detected.

According to a twelfth aspect of the signal monitoring system of the present invention, in the signal monitoring system for monitoring the video signal, the components of the video signal are extracted and statistically processed for each frame displayed within a predetermined time. If the sum of the statistical values (for example, the variance value) obtained by applying is less than the second predetermined value, it is determined that the screen is in a blackout state and an alarm signal is output, which is inappropriate. Images can be detected quickly.

According to a thirteenth aspect of the signal monitoring system of the present invention, the statistical value is extracted from each of the signals constituting a specific small area in each frame of the video signal. The same effect as that of the invention described in 9 is obtained.

According to the signal monitoring system of the present invention as set forth in claim 14, an unsteady state of the image is detected based on the statistical value, and when the unsteady state of the image is detected, the alarm signal When the output is prohibited, the same operational effect as the invention according to claim 10 is obtained.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiments. FIG. 2 is a conceptual diagram showing the transmission system according to the present embodiment. In FIG. 2, when a video signal including an audio signal and a video signal is transmitted from a transmission source 10 such as a broadcasting station in Tokyo to a transmission destination 30 such as a satellite station in Osaka via a relay station 20. think of. Various types of transmission of such video signals can be considered such as satellite communication and optical fiber. Video signals output from the transmission source 10, the relay station 20, and the transmission destination 30 are input to the monitoring device 100, which is a signal monitoring system. The signal output from each monitoring device 100 is the terminal 20.
0, and is input to the central processing terminal 300 which is another signal monitoring system via the network.

FIG. 3 is a block diagram showing the configuration of the monitoring device 100. The left and right audio signals AL and AR are input to the audio input units 101 and 102, the signals output from the audio input units 101 and 102 are input to the delay units 103 and 104, respectively, and the results calculated by the calculation unit 105 are output to the output unit 10.
6, 107 are output.

On the other hand, the video signal VD is supplied to the video input section 1
The signal inputted to the frame 08 and outputted from it is inputted to the frame memories 109, 110 and 111. The frame memory 109 stores the current frame, the frame memory 110 stores the previous frame, and the frame memory 111 stores the previous frame.

The output signals from the frame memories 109, 110 and 111 are input to the MC calculation unit 112, and the results are output via the output units 113, 115 and 116. On the other hand, the output signal from the frame memory 110 is input to the video level calculation unit 119 and the CZC calculation unit 120. The calculation result of the video level calculation unit 119 is output via the output units 113, 114 and 116, and the calculation result of the CZC calculation unit 120 is output via the output units 117 and 118. Output signals from these output units are output from the monitoring device 100. Based on the output signal from the monitoring device 100, each terminal 200 can display the monitoring result on the display and can issue an alarm if necessary.

By the way, there is a defect in the video signal that cannot be monitored by each monitoring device 100 alone. It is the degradation of the video signal due to its transmission as a process. The degree of deterioration due to transmission can be known only by comparing the video signal of the transmission source and the video signal of the transmission destination.

In this embodiment, deterioration in transmission is obtained as follows. The monitoring device 100, to which the video signals output from the transmission source 10, the relay station 20, and the transmission destination 30 are input, calculates the variance value A shown in the equation (1), and sends the variance values to the central processing terminal 300. Send. The central processing terminal 300 receives the variance value A (first value) based on the video signal (first signal) output from the transmission source 10 and the video signal (second signal) output from the relay station 20. Based on the variance value A (second value), the difference is judged to be normal if it is below the threshold value, and if it is above the threshold value.
When it is determined that a transmission error has occurred between the transmission source 10 and the relay station 20, an alarm signal is output and an alarm (alarm display or alarm sound) is issued. On the other hand, the central processing terminal 300
Is the video signal (first signal) output from the relay station 20.
Based on the variance value A (first value) and the variance value A (second signal) based on the video signal (second signal) output from the transmission destination 30.
Value), and if the difference is below the threshold value, it is judged to be normal, and if it is above the threshold value, it is judged that a transmission error has occurred between the relay station 20 and the transmission destination 30. , It outputs an alarm signal and issues an alarm. However, the central processing terminal 300 uses the variance value A (first value) based on the video signal (first signal) output from the transmission source 10 and the video signal (second signal) output from the transmission destination 30. ) Based on the variance value A (second value), and if the difference is below the threshold value, it is determined to be normal, and if it is above the threshold value,
It is also possible to judge that a transmission abnormality has occurred between the transmission source 10 and the transmission destination 30 and output an alarm signal to issue an alarm.

Now, how to obtain the threshold value will be considered.
First, the transmission source video signal V (x, y, z, t) [simplified as V] and the transmission destination video signal U (x, y, z, t)
Find the deviation from [simplify to U]. Such deviation av
e. D (x, y, z, t) [ave. Simplify to D]
When expressed by, the relationship between them is expressed by the following equation (3).

[Equation 3]

The formula (3) can be expressed as the formula (4) as follows.

[Equation 4] Where A is the average value of V as a given value, u
Is a mean value of U but a variable amount, and R is a correlation coefficient between V and U.

In the equation (4), (ave.D)
^{Since 2} is represented by u and R, the expression (4) is partially differentiated by u to obtain the expression (5).

[Equation 5] Here, when R is represented by the general formula shown in (Equation 6),

[Equation 6] Expression (5) can be expressed in the form of expression (7). When a, b, and c are set to appropriate values, a curve C shown by a solid line in FIG. 4 is obtained.

[Equation 7]

FIG. 4 is a graph in which the vertical axis represents d (u) and the horizontal axis represents A. According to the curve C, there is a minimum value in d (u), and when it has the minimum value, that is, when it becomes zero, the clearest audio signal or video signal with the least noise is obtained. The larger the value of d (u), the more the video signal is deteriorated. Here, the cases are divided, and if u ≦ A, d (u) = A ² −u ² (8) is applied, while if u> A, d (u) = u ² −A ² Apply (9).

Therefore, in the present embodiment, the central processing terminal 300 sets the value TH as the threshold value, can judge that the video signal is normal when TH ≧ d (u), and gives an alarm when TH <d (u). It will output a signal. The threshold value TH may be set to a maximum value that does not cause discomfort when the image actually displayed on the monitor is judged by human eyes. This is because if the threshold value TH is lowered too much, there is a problem that an alarm is immediately issued even if the deterioration is a little.

It should be noted that, since the problem that occurs in the image is different between u> A and u ≦ A, it is also effective to use different thresholds. For example, when u> A, the threshold TH1 is used, and when u ≦ A, the threshold TH2 is used.
By monitoring using (<TH1), it is possible to monitor in accordance with the actual situation.

In the above example, for example, the video signal output from the transmission source 10 is used as the first signal, and the video signal input to the relay station 20 or the transmission destination 30 is used as the second signal. The first value, the second value) is calculated, the difference is calculated, and this is compared with the threshold value.
The dispersion value of this signal needs to be centrally obtained through, for example, a telephone line or the Internet, which is troublesome and requires facility cost. The following embodiments can solve such a problem.

FIG. 5 is a diagram for explaining the concept of the second embodiment. In FIG. 5, based on video raw data (first signal) output from a signal source such as a camera,
The variance value A (first value) is obtained through the statistical processing described above. Then, the first value is converted into binary data and attached to and integrated with the first signal.

FIG. 6 is a schematic diagram showing the entire video signal. According to a general video format, as shown in the figure, video raw data S1 (first signal) is stored in a state of being sandwiched by overhead data S2 and S3, and is transmitted as needed. Processing is performed. Here, the overhead data S2 and S3 are signals used for controlling the video, but the empty bits (Auxiliary)
A general-purpose bit called Bit) is included, and the general-purpose bit can be arbitrarily used by the user. Therefore, in the present embodiment, the dispersion value A (first value) is converted into binary data and embedded in the general-purpose bit to be integrated with the first signal. The video raw data sandwiched between the overhead data S2 and S3 may be data for one frame or data for a plurality of frames.

FIG. 7 is a schematic diagram showing signal processing.
It is assumed that the first signal and the first value integrated as described above are transmitted from the transmission source 10 to the relay station 20 in the process 1, for example. As a result, the first signal, which is the video raw data, changes to the second signal, but the first value in the overhead data accompanying it remains unchanged.

Subsequently, it is assumed that the second signal and the first value are transmitted from the relay station 20 to the transmission destination 30 in the process 2, for example. In this case as well, the second signal changes to the third signal, but the first value in the overhead data associated therewith remains unchanged. Even if the processes 1 and 2 are the compression / decompression process, the dubbing process, etc., the overhead data is maintained unchanged.

FIG. 8 is a schematic diagram of processing performed in the monitoring device 100. For example, in the case of judging the quality of the image at the time when the second signal is input from the relay station 20, FIG.
As shown in (a), the monitoring device 100 extracts the second signal from the entire input signal, obtains the variance value A (second value) through the above-described statistical processing, and outputs the overhead data. The first value is taken out. After that, by comparing the second value with the first value and comparing the difference with the threshold value, the degree of deterioration of the second signal can be checked as in the above-described embodiment.

Further, when judging whether the image is good or bad at the time when the third signal (the second signal in the invention) is inputted from the transmission destination 30, as shown in FIG. ,
The third signal is extracted from the entire input signal, the variance value A (second value) is obtained through the statistical processing described above, and the first value is extracted from the overhead data. After that, by comparing the second value with the first value and comparing the difference with the threshold value, the degree of deterioration of the third signal can be checked. Note that, regardless of the above example, it is of course possible to perform the process 2 after integrating the second value with the second signal.

According to the present embodiment, after the processing (second
Value) obtained by performing the statistical processing from the unprocessed (first) signal is attached to the signal in the invariant state. There is an advantage that the video signal can be easily checked even at the point of time, and therefore the central processing terminal 300 and the like are unnecessary.

FIG. 9 is a diagram for explaining another embodiment of the present invention. In the present embodiment, the dispersion value is not obtained for the entire video signal of one frame, but the dispersion value is obtained for a specific small area in order to improve the processing speed. This will be described more specifically. In FIG. 9, peripheral areas 201 to 204 at four corners and a central area 2 on a screen corresponding to one frame of an image.
Consider the case where 05 is set as a specific small area. In such a case, the monitoring device 100 of FIG.
04 and the video signal corresponding to the central area 205, respectively, by d _i (u) by dispersion as described above.
(I = 1 to 5) is calculated.

Further, the obtained d _i (u) (i = 1 to 5)
Is compared with the threshold value TH and the like as shown in FIG. 4, it is possible to determine the suitability of the image. In such a case, since the main subject often exists in the central area 205, d
_The thresholds with which ₅ (u) are compared are d ₁ (u) to d ₄ (u).
Is preferably set lower than the threshold to be compared. This means that the suitability of the image of the central region 205 is strictly determined, and the suitability of the image of the peripheral regions 201 to 204, which is often the background, is loosely determined. Not limited to this embodiment, the average value of d _i (u) (i = 1 to 5) may be obtained and compared with the threshold value, and the peripheral regions 201 to 204 are ignored and only the central region 205 is concerned. It is also possible to compare d ₅ (u) with a threshold. The setting of the specific small area is arbitrary on the screen. According to the above, the processing speed can be improved without substantially lowering the monitoring accuracy of the video signal.

By the way, as an example of the image defect, the screen may freeze (keep displaying only a specific frame). However, the screen freeze cannot be detected by the processing according to the above-described embodiment. On the other hand, the monitoring apparatus 100 according to another embodiment can detect the image freeze by the following processing.

More specifically, the variance value as a statistical value is calculated for each frame, and then the difference value and the first predetermined value are compared. In the following embodiments, the variance of the video signal at time t is represented as σ _b ² (t) for the sake of convenience, but this variance is the same as A obtained by the above-described mathematical expression 1.

The monitoring device 100, at a predetermined time T,
With respect to the entire video signal or a specific small area, the difference between the variance values of a certain frame and the next frame is calculated, the total sum of the differences is calculated, and this is compared with Th _N (first predetermined value). This relationship is shown in equation (8). With Th _N set to a small value that is not affected by noise,
Since the expression (8) is satisfied means that there is no screen change, the monitoring device 100 outputs an alarm signal as if the screen freeze occurred.

However, in the case of a video image of a flash of a lighthouse in a night view, if the variance difference is obtained in a relatively long time, there is a possibility that the equation (8) will be satisfied. Therefore,
Only when the formula (9) is satisfied at the same time, the monitoring device 10
It is desirable that 0 output an alarm signal. This is because if the light of the lighthouse is momentarily inserted in a dark night view, the equation (9) is not satisfied at that time.

[Equation 8]

[Equation 9]

On the other hand, for example, in the case of a defect that the luminance of the image changes periodically, it can be determined by the equations (10) and (11). The amount of change between frames (frames) is positive
/ If it is changing with a minus, according to the equation (10),
The values are offset and become smaller than THN '. At this time, the formula (11) needs to be established for the same reason as the formula (9).

[Equation 10]

[Equation 11]

Further, as another example of the image defect, the screen may be blacked out (keep displaying a completely black screen). Monitoring device 1 according to another embodiment
00, the blackout of the image can be detected by the following processing.

More specifically, the monitoring apparatus 100 calculates a variance value for each frame for the entire video signal or a specific small area at a predetermined time B, obtains a sum of the variance values, and calculates the sum as Th _b (second (Predetermined value of)). This relationship is shown in equation (12). When Th _b is set to a small value that is not affected by noise, the expression (12) is satisfied, which means that the brightness of the screen is extremely low for a predetermined time B. If the out has occurred, the monitoring device 100 outputs an alarm signal.

[Equation 12]

In the above embodiments, the monitoring is performed on the assumption that the same scene continues in the video, for example. However, when a scene change occurs, the variance value before and after the scene change is significantly different, and therefore the monitoring device 100 may erroneously output an alarm signal. Even when a small area including the contour of an object (such as the boundary between a mountain and the sky) is monitored, the image to be monitored may differ greatly due to image blurring, etc. May significantly change and the monitoring device 100 may erroneously output an alarm signal. Such a state is called an image non-steady state. In the following embodiments, the monitoring accuracy is improved by detecting a scene change or the like based on the variance value and not outputting an alarm signal in that case.

FIG. 10 is a diagram for explaining the operation of this embodiment. In the present embodiment, the variance calculated for the n-th field (specific small area) of the fields 1 to N is used, but the variance calculated for all fields may be used.

When the square of the variance of each frame is plotted in time series, a graph as shown in FIG. 10 is obtained. In such a case, the square of the variance greatly changes between time t−1 and time t, so it can be seen that a scene change has occurred. When this is expressed by an equation, Th = (| σ ² (n, t−3) −σ ² (n, t−2) |
+ | Σ ² (n, t-2) -σ ² (n, t-1) |) / 2 and | σ ² (n, t) -σ ² (n, t-1) | ≧ α × Th
In the case of (α is, for example, 1.5), the alarm device 100 can determine that a scene change has occurred between the time t−1 and the time t, so that the alarm signal is not output regardless of the variance value. Take action.
Note that n may be a plurality, Th may be an average value of three or more frames, and α is not limited to 1.5 and may be another value.

Although the present invention has been described above with reference to the embodiments, the present invention should not be construed as being limited to the above embodiments, and it goes without saying that appropriate modifications and improvements are possible. is there. For example, the statistical processing of the present invention is not limited to distribution. The signal to which the present invention can be applied is not limited to the video signal.

Further, in the present embodiment, the value obtained by performing the statistical processing from the signal before processing is inserted into the empty bit of the overhead data in the general video format, but the present invention is not limited to this. Instead, a video format may be newly created in which a dedicated bit for inserting such a value is provided.

[0058]

According to the present invention, it is possible to provide a signal monitoring system capable of efficiently monitoring a signal with a certain level of monitoring accuracy.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the concept of signals before and after processing.

FIG. 2 is a conceptual diagram showing a transmission system according to the present embodiment.

FIG. 3 is a block diagram showing a configuration of a monitoring device 100.

FIG. 4 is a graph in which the vertical axis represents d (u) and the horizontal axis represents A.

FIG. 5 is a diagram for explaining the concept of the second embodiment.

FIG. 6 is a schematic diagram showing an entire video signal.

FIG. 7 is a schematic diagram showing signal processing.

FIG. 8 is a schematic diagram of processing performed in the monitoring device.

FIG. 9 is a diagram for explaining another embodiment of the present invention, showing a screen of one frame.

FIG. 10 is a diagram for explaining the operation of the present embodiment, and is a graph below the plot of the square of the variance in time series.

[Explanation of symbols]

10 Transfer source 20 relay stations 30 transfer destination 100 monitoring device 200 monitoring terminals 300 Central processing terminal

Claims (14)

[Claims] 1. A signal monitoring system for monitoring a second signal obtained by subjecting a first signal to a predetermined process, which is obtained by extracting a component of the first signal and subjecting it to statistical processing. An alarm signal is output when the index value obtained based on the first value and the second value obtained by extracting the component of the second signal and performing the statistical processing exceeds the threshold value. A signal monitoring system characterized by: 2. A signal monitoring system for monitoring a second signal obtained by performing a predetermined process on a first signal accompanied by data corresponding to a first value, said second signal comprising: A signal monitoring system, which outputs an alarm signal based on a second value obtained by extracting a component of a signal and performing statistical processing and the first value corresponding to the data. . 3. The first value is a value obtained by extracting a component of the first signal and subjecting it to statistical processing, and based on the first value and the second value. The signal monitoring system according to claim 2, wherein the alarm signal is output when the obtained index value exceeds a threshold value. 4. The signal monitoring system according to claim 1, wherein the statistical processing is dispersion. 5. The signal monitoring system according to claim 1, wherein the signal component can be represented by three-dimensional coordinates and time. 6. The signal monitoring system according to claim 1, wherein the threshold value can be changed. 7. The signal monitoring system according to claim 6, wherein the threshold value is changed according to a state of the second signal. 8. The first signal and the second signal are output from the same signal source, and the second signal is monitored downstream of the first signal. The signal monitoring system according to any one of claims 1 to 7, which is characterized. 9. The first value and the second value are respectively extracted from the signals forming a specific small area in one frame of the first signal and the second signal. The signal monitoring system according to any one of claims 1 to 8, which is characterized. 10. An unsteady state of an image is detected based on the first value or the second value, and when the unsteady state of the image is detected, the output of the alarm signal is prohibited. The signal monitoring system according to any one of claims 1 to 9, characterized in that: 11. A signal monitoring system for monitoring a video signal, wherein a statistical value obtained by extracting a video signal component in a frame preceding in time and subjecting it to statistical processing, and a statistical value following the statistical value. If the difference from the statistical value obtained by extracting the component of the video signal in the frame and performing the statistical processing is less than the first predetermined value, it is determined that the screen is frozen and an alarm is issued. A signal monitoring system characterized by outputting a signal. 12. A signal monitoring system for monitoring a video signal, wherein a sum of statistical values obtained by extracting a video signal component for each frame displayed within a predetermined time and performing statistical processing is a second value. Is less than the predetermined value, the signal monitoring system determines that the screen is in a blackout state and outputs an alarm signal. 13. The statistical value of the video signal,
13. The signal monitoring system according to claim 11 or 12, wherein each signal is extracted from a signal forming a specific small area in each frame. 14. The non-steady state of the image is detected based on the statistical value, and when the non-steady state of the image is detected, the output of the alarm signal is prohibited. 13. The signal monitoring system according to any one of 13.