JPH04248488A - Video signal processing circuit - Google Patents

Abstract

PURPOSE:To enable a video signal which highlights a discrimination between a background noise and an echo component to be displayed. CONSTITUTION:A data which is obtained by a sensor 2 of a sonar device and is digitized by a reception signal processing circuit 3 is stored at a data memory 4 of an N channel for each specified orientation interval, a stored data is read out for each specified distance interval, and an interval average value of an interval which is set at the orientation interval and the distance interval is obtained by an interval average value calculator 7. On the other hand, a maximum value and an average value over the distance interval for each orientation of the orientation interval are obtained by a maximum value detector 5 and a distance interval average value calculator 6, respectively. The interval average value is compared with the distance interval average value by a comparator 8, thus obtaining a Judgment result. Based on this judgment result, when the distance interval average value is larger than the interval average value, the maximum value is output from a selector 9 and is displayed on a display 10. On the other hand, when the interval average value is larger than the distance interval average value, the distance interval average value is outputted from the selector 9 and is displayed on the display 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing circuit, and more particularly to a video signal processing circuit that performs video processing to display a target video captured by a sonar device on a display screen of a display device.

0002

[Prior Art] As shown in FIG. 4, a conventional general sonar video signal processing circuit processes the reverberant sound of a target object 1 received by a sensor 2, performs various signal processing for improving the S/N, and determines the reception direction. The received signal processing circuit 3 subdivides the digital data in the azimuth direction by azimuth interpolation processing that interpolates between steps, and converts the digital data into received signal processing data, which is then input to the video signal processing circuit 13.
As video signal processing, predetermined azimuth steps (azimuth sections)
N-channel video signal processing channels 14 arranged in
-1, 14-2, . The maximum value detector 5 detects the maximum value for each divided azimuth of the azimuth step from the data stored in the memory 4, and displays the maximum value on the display 1.
0 and was displayed.

FIG. 5 is an explanatory diagram of conventional video signal settings. In FIG. 4, the azimuth section corresponds to the receiving direction of the N-channel video signal processing channel, the distance (time) corresponds to one search period, and the evaluation area 20, which is set together with the azimuth section, determines the movement and movement of the target. It is set in advance to have a sufficient spread for confirmation.

[0004] For the number of samples set by the azimuth interval and distance interval, the maximum value is detected for each azimuth in which the azimuth interval is subdivided, and this is displayed in the display area 3 of the display 10.
It was displayed as 0.

[0005] The number of samples shown in the evaluation area 20 is expressed as follows: L1, indicated by a black circle, is a sample group that includes the echo 21 and has approximately the same maximum value, and L3, indicated by a white circle, is a sample group centered on the low-bell background noise 22. , L2 indicated by an x mark is a sample group showing a level between the black circle and the white circle.

The results of the maximum value detection performed on the evaluation area 20 are shown in the display area 30 of the display 10, and the contents are shown enlarged in FIG.

By the way, the reason why such maximum value detection is performed and the maximum value is used as display data is that the number of samples in the distance (time) axis direction and the resolution of the display 10 in the distance direction are usually not one-to-one. There is no correspondence, and the resolution of the display 10 is coarser. For this reason, the received signal processing data for each distance section is stored for each subdivision of the azimuth section, and the display data is represented by the maximum value of the distance section, and the azimuth and distance position corresponding to this maximum value are stored. By setting the brightness level to .

[0008]

[Problems to be Solved by the Invention] The conventional video signal processing circuit described above detects the maximum value for each direction in the direction section and displays this on the display screen as a brightness level. Even if most of the stored received signal processing data has a weak signal level, if there is even one strong signal level, that value will be detected as the maximum value. For this reason, the brightness level on the display screen is also strongly expressed, and if the S/N is originally poor, there is a drawback that the S/N on the display screen is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a video signal processing circuit capable of displaying a screen that faithfully reflects the intensity of signal levels.

0010

[Means for Solving the Problems] The video signal processing circuit of the present invention includes N data memories for storing received signals acquired and digitized by a sonar device for each of N azimuth sections of a predetermined step; an interval average value calculator that cuts out the received signal stored in a data memory into a predetermined distance interval for each of the azimuth intervals and outputs the average value within an evaluation area specified by the azimuth interval and the distance interval as an interval average value; N distance interval average value calculators that output the average value over the distance interval as a distance interval average value for each direction in the evaluation area, and N maximum value detectors that calculate the maximum value of data over the distance interval. N comparators that compare the distance interval average value with the interval average value, and a comparison result of the comparator is such that the distance interval average value is larger than a predetermined setting value with respect to the interval average value. a selector that selects and outputs the maximum value within the distance interval when the value is lower than the set value, selects and outputs the average value of the distance interval when the value is lower than the set value, and outputs these selected outputs as images on a display device; Prepared and configured.

[0011] Furthermore, in the circuit of the present invention, the distance section is
The evaluation area set together with the azimuth section is set as a distance sufficient to ensure a range capable of expressing the movement of the target captured by the sonar device.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The configuration of the embodiment shown in FIG. 1 includes a sensor 2, a received signal processing circuit 3, a display 10, and a video signal processing circuit 12 that is directly related to the present invention.
In FIG. 1, a target object 1 is also shown.

The video signal processing circuit 12 has N video signal processing channels 11-I to 11-N, and an interval average that outputs the average value within the evaluation area indicated by the azimuth interval and the distance interval as the interval average value. It consists of a value calculator 7, and each video signal processing channel includes a data memory 4 that stores the received signal acquired and digitized by the sonar device for each of N azimuth sections of a predetermined step, and a reception signal stored in the data memory 4. A distance section average value calculator 6 that outputs the average value over the distance section for each direction in the evaluation area specified by the direction section and the distance section, which are obtained by cutting out the signal into a predetermined distance section for each direction section, as the distance section average value. , the maximum value detector 5 calculates the maximum value of data over the distance interval, the comparator 8 compares the distance interval average value with the interval average value, and the comparison result of the comparator 8 indicates that the distance interval average value is the interval average value. A selector 9 that selects and outputs the maximum value within the distance interval when the value is larger than a predetermined set value, and selects and outputs the average value of the distance interval when it is lower than the set value. It consists of

Next, the operation of this embodiment will be explained.

The received signal processing data of the digital data output from the received signal processing circuit 3 is provided to the video signal processing channels 11-I to 11-N for each azimuth section, and is stored in the data memory 4.

The data is extracted from the data memory 4 for each direction and for each distance section, and is supplied to a maximum value detector 5, a distance section average value calculator 6, and a section average value calculator 7.

The distance interval average value calculator 6 calculates the average value over the distance interval for each direction in the direction interval, and outputs this as the distance interval average value. This calculation formula is shown in the following formula (1).

[0019]

In equation (1), x(i) is a sample value for each direction in the direction section, and n is the number of samples over the distance section.

The maximum value detector 5 detects and outputs the maximum value of the sample values over the distance section for each direction.

The interval average value calculator 7 calculates the average value of all samples included in the evaluation area set by the azimuth interval and distance interval of each video signal processing channel,
Output as the interval average value. The formula for calculating this interval average value is shown by the following formula (2).

[0023]

In equation (2), x(i, j) represents a sample value determined corresponding to each direction in the direction interval and each unit distance in the distance range, and m represents each direction in the direction interval. is the number of samples corresponding to .

The comparator 8 compares the interval average value outputted by the interval average value calculator 7 and the distance interval average value outputted by the distance interval average value calculator 6. In this case, if the received signal processing data x (i, j) is dominated by background noise, the values indicated by each sample value will be dispersed within the evaluation area set by the azimuth interval and the distance interval, and equation (2) will be The interval average value shown and (1
) are almost equal.

On the other hand, when an echo component is included in the evaluation area, the average value of the interval becomes smaller than the average value of the distance interval of the direction containing many echo components. This is also clear from the fact that the echo components have a correlation between sample values.

The selector 9 selects whether the comparison result by the comparator 8 is
When the section average value is smaller than the distance section average value, it is determined that the echo component is strong, and the maximum value output by the maximum value detector 5 is selected and output. Furthermore, when the interval average value is larger than the distance interval average value, it is determined that the background noise component is emphasized and the distance interval average value is output. The outputs of these selectors 9 are displayed on a screen on a display 10.

FIG. 2 is an explanatory diagram of video signal settings in this embodiment. In this example, in a direction where many echoes 21 exist over a distance interval, L1 indicated by a black circle is indicated based on the results of the comparison and determination described above, and in a direction where background noise is predominant, even if L1 indicated by a black circle does not exist. indicates that L2 is shown as an average value even if Figure 3 is Figure 2
FIG. 2 is an enlarged diagram showing the video signal setting operation of FIG.

[0029] In this way, it is possible to display an image in which echoes and background noise are faithfully distinguished.

[0030]

Effects of the Invention As explained above, the present invention calculates the average value for each evaluation area set by the azimuth interval and the distance interval, and the distance interval average value over the distance interval in each direction of the azimuth interval, and then calculates the average value of both. By determining the appropriate brightness level to display on the display screen from the results of comparing the values,
This significantly improves the separation resolution by visual recognition of echoes and background noise in cases where the S/N ratio is poor, which was unclear on conventional display screens, and has the effect of significantly increasing target detection accuracy in sonar devices. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of video signal settings in the embodiment of FIG. 1;

FIG. 3 is a diagram showing an enlarged view of the contents of the video signal settings in FIG. 2;

FIG. 4 is a block diagram showing the configuration of a conventional video signal processing circuit.

FIG. 5 is an explanatory diagram of video signal settings in the video signal processing circuit of FIG. 4;

FIG. 6 is a diagram showing an enlarged view of the contents of the video signal settings in FIG. 4;

[Explanation of symbols]

1 Target object 2 Sensor 3 Received signal processing circuit 4 Data memory 5 Maximum value detector 6 Distance section average value calculator 7 Section average value calculator 8 Comparator 9 Selector 10 Display 11-I to 11-N Video signal processing channel 1
2, 13 Video signal processing circuit 14-I to 14-N Video signal processing channel 2
0 Evaluation area 21 Echo 22 Background noise 30 Display area

Claims (2)

[Claims] Claims 1: N data memories for storing received signals acquired and digitized by a sonar device for each of the N azimuth sections of a predetermined step; and a received signal stored in the data memories for each of the azimuth sections. an interval average value calculator that cuts out each predetermined distance interval and outputs the average value within the evaluation area specified by the azimuth interval and the distance interval as an interval average value; and an average value over the distance interval for each direction within the evaluation area. N distance interval average value calculators that output values as distance interval average values; N maximum value detectors that calculate the maximum value of data over the distance interval; N comparators to compare with, and if the comparison result of the comparator indicates that the average value of the distance interval is larger than a predetermined setting value with respect to the average value of the interval, the maximum value within the distance interval and a selector that selects and outputs the average value of the distance section when it is lower than the set value, and outputs these selected outputs as images on a display. 2. The distance interval is such that the evaluation area set together with the azimuth interval is set as a distance sufficient to ensure a range that can express the movement of the target to be captured by the sonar device. The video signal processing circuit according to claim 1.