JPH1073648A - Method and apparatus for display of acoustic signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load of an operator and to restrain the probability of an erroneous detection. SOLUTION: By a frequency analyzer 1, an underwater sound is frequency- analyzed, signal levels at respective frequencies are found, and a signal frequency whose signal level is at a prescribed level or higher out of the found signal levels is extracted. In a change-rate computing part 21, the time change rate of a frequency at the extracted signal frequency is computed at a prescribed time interval. The extracted signal frequency and the time change rate are stored in a frequency-change-rate storage part 31 together with the time in which the time change rate is computed. Then, on the basis of information stored in the storage part 31, signal frequency groups whose computed time change rate is equal to each other in the identical time are judged to be generated from an identical target, and the signal frequency groups are emphasized by a signal emphasis processing part 22 so as to be displayed on a display device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal display method and apparatus, and more particularly, to an audio signal display method and apparatus for displaying an audio signal emitted from a target existing in water.

[0002]

2. Description of the Related Art Conventionally, an acoustic signal display of this type includes a frequency analyzer 1 and a display 5 as shown in FIG.

The frequency analyzer 1 analyzes the frequency of a sound received by a wave receiving device (hereinafter referred to as underwater sound) dropped into water to determine a signal level for each signal frequency, and converts the determined signal level in advance. A signal frequency having a signal level higher than the threshold level is extracted by comparing with a set threshold level. The display device 5 displays a signal frequency output from the frequency analysis device and level information indicating a signal level of the signal frequency.

Next, the operation of this conventional acoustic signal display device will be described with reference to FIGS.

[0005] The sound received by the wave receiving device dropped into the water, ie, the underwater sound, is transmitted to an acoustic signal display device mounted on an aircraft or ship via a wireless line. The transmitted underwater sound is frequency-analyzed by the frequency analyzer 1, and a signal level for each frequency is obtained. Further, only the signal frequency having a signal level higher than a preset threshold level among the obtained signal levels is extracted, and the extracted signal frequency and its signal level (level information) are sent to the display device 5.

In the display device 5, the signal frequency and level information sent from the frequency analysis device 1 are displayed on a screen in time series as shown in FIG. In FIG. 7, the horizontal axis is the frequency axis, the vertical axis is the time axis, and the signal level is represented by display luminance. The display output in this type of format is generally called a gram. And
The output from the frequency analyzer 1 is displayed on a gram every moment from bottom to top in FIG.

At this time, if the target exists in the water and the target is at a certain level or higher and emits a signal of a specific frequency, the specific frequency portion is a high-luminance signal continuous in the time direction on the screen. Will be displayed as And
Since such a signal is normally displayed longer and longer than noise, the operator can recognize the presence of the target by referring to the display on the display device 5.

[0008]

However, in this conventional acoustic signal display device, when many receiving devices are dropped into water at the same time, one gram is displayed for each receiving device. , The operator needs to check many grams. Therefore, the load on the operator becomes enormous, and as a result, there is a problem that the probability of false detection increases.

[0009]

In order to solve the above problems, an acoustic signal display method according to the present invention determines the signal level of each frequency by analyzing the frequency of underwater sound, and determines a predetermined signal level among the determined signal levels. A signal frequency having a signal level equal to or higher than the signal frequency is extracted, and among the extracted signal frequencies, a signal frequency group having the same time rate of change in the frequency direction is determined to be generated from the same target, and this signal frequency group is determined. Are highlighted to distinguish them from other signal frequencies.

Further, the acoustic signal display device of the present invention analyzes the frequency of underwater sound to determine a signal level for each frequency, and extracts a signal frequency having a signal level higher than a predetermined level from the determined signal levels. The analyzer determines that a signal frequency group having the same time change rate in the frequency direction at the same time among the extracted signal frequencies is generated from the same target, and emphasizes the determined signal frequency group. It comprises a data processing device and a display device for displaying a signal frequency group emphasized by the data processing device.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An audio signal display method according to an embodiment of the present invention utilizes a target signal sound generation mechanism disclosed in "Principle of Underwater Sound" (Kyoritsu Shuppan). Here, the signal sound generation mechanism will be described. The target signal sound is mainly generated from a drive system such as an engine, a shaft and a propeller. If the number of rotations of the shaft per unit time becomes １ ／, the frequency of the signal generated from the shaft also becomes about 、, and the frequency of the signal generated from the propeller also becomes about １ ／. Further, the signal frequency generated from the motor rotating the shaft and the signal frequency generated from the gears are accordingly reduced. Thus, the signal frequency emitted by one target is
It changes while maintaining a certain relationship according to the target running state and the like.

Therefore, according to this mechanism, it is possible to determine that signal frequencies having the same time change are generated from the same target.

That is, in the acoustic signal display method according to the present embodiment, the received underwater sound is subjected to frequency analysis to determine a signal level for each frequency, and a signal level higher than a preset threshold level among the signal levels is obtained. Only the signal frequency of the level is extracted. Among the signal frequencies of the extracted high-level signals, signal frequency groups having the same time rate of change in the frequency direction are determined as being generated from the same target, and signal frequency groups having the same time rate of change are subjected to emphasis processing. Is displayed on the gram to be distinguished from other signal frequencies.

Next, an audio signal display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an audio signal processing device according to the present embodiment. The audio signal display device according to the present embodiment includes a frequency analysis device 1, a data processing device 2 operated by program control, information And a display device 4 for displaying the output of the data processing device 2.

The frequency analyzer 1 analyzes the frequency of underwater sound to determine a signal level for each frequency, and among the signal levels, a signal frequency having a signal level higher than a preset threshold level (hereinafter referred to as a high-level signal). Frequency).

The storage device 3 includes a frequency change rate storage unit 31. The frequency change rate storage unit 31 stores the high-level signal frequency calculated by the change rate calculation unit 21 and the time change rate thereof.

The data processing device 2 includes a change rate calculator 21 and a signal emphasis processor 22. Change rate calculator 21
Calculates the temporal change rate of the high-level signal frequency output from the frequency analysis device 1. The signal enhancement processing unit 22
Among the high-level signal frequencies extracted by the frequency analysis device 1, signal frequency groups having the same rate of change are subjected to an enhancement process such as coloring.

The display device 4 displays the high-level signal frequency subjected to the emphasis processing by the signal emphasis processing section 22.

Next, the operation of the acoustic signal processing apparatus according to the present embodiment will be described with reference to FIGS.

A wave receiving device dropped into water, for example, an underwater sound received by a buoy receives a frequency analysis device 1 via a radio line.
Sent to. The transmitted underwater sound is transmitted to the frequency analyzer 1
In the frequency analysis, the signal level for each frequency is obtained,
Further, only the signal frequency (high-level signal frequency) having a signal level higher than a preset threshold level is extracted from the obtained signal levels, and the extracted signal frequency is sent to the change rate calculator 21.

FIG. 2 is a flowchart showing a processing procedure in the change rate calculating section 21. The change rate calculating unit 21
When a high-level signal frequency is input from the frequency analyzer 1 (S101), the high-level signal frequency input this time is stored in the frequency change rate storage unit 31 in the previous process in order to track this high-level signal frequency. It is determined whether or not the high-level signal frequency is within a range of a minute frequency width ± α set in advance (S102). If the high-level signal frequency input this time is within this range, the high-level signal frequency is stored in the frequency change rate storage unit 3.
It is determined that the high-level signal frequency stored in 1 has changed with a change in the target running state or the like. Then, the high-level signal frequency input this time is stored in the corresponding item of the frequency change rate storage unit 31 (S10).
3). Here, the item in the frequency change rate storage unit 31 is a summary of the signal frequency being tracked and the progress of the change rate, and the frequency change rate storage unit 31 has the same number of signal frequencies that are being tracked. Item exists. As shown in FIG. 4, the storage structure of the frequency change rate storage unit 31 includes a field for storing a signal frequency, a field for storing a change rate, and a time for storing a time in one item. With fields.

Returning to FIG. 2, the explanation will be continued. In addition to the storage of the high-level signal frequency in the frequency change rate storage section 4, the high-level signal frequency stored in the frequency change rate storage section 31 in this process is also stored. The ratio of the high-level signal frequency stored at the first time of the item to the high-level signal frequency (the high-level signal frequency stored this time / the high-level signal frequency stored first at the item) is calculated as the rate of change, and this is calculated as the frequency change. The change rate of the corresponding item in the rate storage unit 31 is stored in a field to be stored (S104). Then, the time at which the change rate is calculated is similarly stored in the corresponding field of the frequency change rate storage unit 31 (S105).

On the other hand, in the process of S 102, the high-level signal frequency input to the change rate calculating section 21 falls within the range of width ± α with respect to the latest high-level signal frequency stored in the frequency change rate storing section 31. If it is determined that there is no
The high-level signal frequency is determined to be the signal frequency generated by the new target, a new item is created in the frequency change rate storage unit 31, and the signal frequency and the current time are stored (S106 and S107). The signal frequency stored in this new item will be tracked in subsequent processing.

The above processing is repeated until all the data sent from the wave receiving device at one time is executed (S1).
08).

The signal emphasis processing section 22 performs a process focusing on the change rate of the signal frequency in accordance with the procedure of the flowchart shown in FIG. That is, all data stored in the frequency change rate storage unit 31 is searched for each field having the same time, and the change rates at the same time obtained by the search are compared for each item. As a result of the comparison, it is determined that the signal frequency groups stored in the plurality of items having the same change rate at the same time are generated from the same target, and the time and the signal frequency group are extracted (S
201). Then, for the extracted signal frequency group,
In order to distinguish the signal frequency from other signal frequencies, an emphasis process such as different coloring is performed (S202), and transmitted to the display device 4 (S203).

The display device 4 displays the signal frequency and the like transmitted from the signal emphasis processing unit 22 on a gram in an image as shown in FIG. As shown in FIG. 5, as for the signals A and C, since the time change rates of the signal frequencies are substantially equal to each other, it is determined that the signals are generated by one target, and the signals are colored and the signals are displayed on the gram. Is displayed. On the other hand, the signals B, D, and E have substantially the same time rate of change in their signal frequencies, but differ from the time change rates of the signals A and C, and thus are different from the targets that issued the signals A and C. It is determined that the signal is generated by one target, and a signal different from the signals A and C is subjected to coloring processing and displayed on a gram.

In this embodiment, the emphasis processing for the signal frequency group is performed in the data processing device 2. However, this signal emphasis processing function may be provided on the display device 4 side.

The signal emphasizing process for the signal frequency group is not limited to the coloring process. The signal frequencies from different targets may be distinguished by adjusting the luminance level.

[0030]

As described above, according to the audio signal display method and apparatus according to the present invention, it is determined that one target emits a signal frequency having the same time change rate, and the signal frequency is determined. In order to differentiate the display from other signal frequencies, the operator pays attention only to the signal frequency of the signal on the gram. Can be extracted. Therefore, it is possible to reduce the load on the operator when simultaneously processing the sound received by many wave receiving devices, and as a result, it is possible to reduce the probability of false detection.

Further, in order to group high-level signal frequencies having the same rate of change over time and to display each of them with a different color, when two or more targets are present in the water, a gram on the gram is displayed. By focusing only on the colored signal frequencies, the presence of two or more targets can be easily recognized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of an audio signal display device according to the present invention.

FIG. 2 is a flowchart illustrating a processing procedure in a change rate calculating unit in FIG. 1;

FIG. 3 is a flowchart illustrating a processing procedure in a signal enhancement processing unit in FIG. 1;

FIG. 4 is a diagram showing a storage structure of a frequency change rate storage unit in FIG. 1;

FIG. 5 is a diagram illustrating an example of a gram displayed on the display device in FIG. 1;

FIG. 6 is a block diagram illustrating a configuration of a conventional acoustic signal display device.

FIG. 7 is a diagram showing a display example in a conventional acoustic signal display device.

[Description of Signs] 1 Frequency analysis device 2 Data processing device 21 Change rate calculation unit 22 Signal enhancement processing unit 3 Storage device 31 Frequency change rate storage unit 4 Display device

Claims (6)

[Claims] An underwater sound is subjected to frequency analysis to obtain a signal level for each frequency, a signal level having a signal level equal to or higher than a predetermined level is extracted from the obtained signal levels, and a frequency direction is extracted from the extracted signal frequencies. An audio signal characterized in that a signal frequency group having the same time rate of change is determined to be generated from the same target, and this signal frequency group is emphasized and displayed to distinguish it from other signal frequencies. Display method. 2. A step of frequency-analyzing the underwater sound to obtain a signal level for each frequency, extracting a signal frequency having a signal level equal to or higher than a predetermined level from the obtained signal levels, A step of determining signal frequency groups having the same time change rate in the frequency direction at the same time to be generated from the same target; and determining a signal frequency group determined to be a signal frequency generated from the same target. Displaying the signal in an emphasized manner. 3. A step of frequency-analyzing the underwater sound to obtain a signal level for each frequency; a step of extracting a signal frequency having a signal level equal to or higher than a predetermined level among the obtained signal levels; Calculating the time rate of change of the frequency of the extracted signal frequency; and determining signal frequency groups having the same time rate of change calculated at the same time as signal frequencies generated from the same target. A sound signal display method comprising: a step; and a step of highlighting and displaying a signal frequency group determined to be generated from the same target. 4. A frequency analyzer for frequency-analyzing the underwater sound to determine a signal level for each frequency, and extracting a signal frequency having a signal level equal to or higher than a predetermined level among the determined signal levels; A data processing device that determines that signal frequency groups having the same time change rate in the frequency direction at the same time are generated from the same target, and emphasizes the determined signal frequency group; and And a display device for displaying the signal frequency group emphasized in (1). 5. The data processing device, comprising: a change rate calculating unit that calculates a time change rate of the frequency of the signal frequency extracted by the frequency analysis device at predetermined time intervals; The signal frequency and the time change rate calculated by the change rate calculation unit,
The storage unit that stores the time change rate together with the calculated time, the signal frequency stored in the storage unit, based on the time change rate and the time, among the signal frequencies extracted by the frequency analysis device, the same The acoustic signal display device according to claim 4, further comprising: a determination unit that determines that signal frequency groups having the same time rate of change calculated at a time are generated from the same target. . 6. The data processing apparatus according to claim 1, further comprising means for coloring a group of signal frequencies determined to be generated from the same target in a color different from other signal frequencies. The acoustic signal display device according to claim 4.