JPH043266Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a scanning sonar image display device, and in particular, it displays fish school distribution in color on a color cathode ray tube display based on ultrasonic reception signals. This relates to improvements in equipment.

(Prior art) A device that emits cone-shaped ultrasonic waves from an ultrasonic transducer attached to the bottom of a boat, electrically processes the received signals, and displays the fish school distribution on a color cathode ray tube is well known. It is. Usually, this type of device is equipped with a device that controls the cone projection angle of the ultrasonic waves, and scans and projects the ultrasonic waves over a wide range from a narrow area to a wide area to obtain a fish school distribution image. FIG. 3 shows a conventional scanning sonar image display device, in which echoes of ultrasonic waves emitted from an ultrasonic transducer (not shown) are received by the ultrasonic transducer. The received signal is detected as a spiral detection signal by the detection device 1 based on the spiral scanning signal from the spiral scanning signal generator 11.

That is, this detection device 1 detects received signals in a polar coordinate system by spiral scanning. This spiral detection signal is then converted from an analog signal to a digital signal by the A/D converter 2, and this converted spiral detection signal is output to the image storage circuit 3.

On the other hand, the spiral scanning signal from the spiral scanning signal generator 11 is
It is output to the Y coordinate conversion circuit 4, and this X-Y
The coordinate conversion circuit 4 converts the spiral detection signal sent to the image storage circuit 3 into a pixel signal in the X-Y coordinate system. Therefore, the image storage circuit 3 stores pixel signals converted into the X-Y coordinate system. Note that one unit of this pixel signal corresponds to one pixel of the color cathode ray tube display 5.

On the other hand, a readout scanning signal is outputted from the raster scanning signal generator 10 to the image storage circuit 3, and a writing scanning signal is outputted to the color cathode ray tube display 5. This read scanning signal and writing scanning signal are synchronized,
The pixels of the image storage circuit 3 are scanned in the X direction by the readout scanning signal to read out the memory signal of each pixel, and this readout signal is sequentially written to the corresponding position of the color cathode ray tube display 5 specified by the writing scanning signal. It will be shown.

The color cathode ray tube display 5 is composed of an array of m pixels horizontally and n pixels vertically, and the total number of pixels of the cathode ray tube is m×n.

Further, the color cathode ray tube display 5 is provided with a well-known coloring means, and each pixel is colored in accordance with the fish distribution information included in the pixel signal, that is, the information on the signal strength. be exposed.

Therefore, when the density of the fish school is high (high brightness), for example, a red color is assigned, and as the density of the fish school becomes thinner, colors such as orange, yellow, green, blue, etc. are assigned. It is now possible to understand the distribution of fish schools by viewing the color image displayed on a color cathode ray tube.

(Problem to be solved by the invention) The color cathode ray tube in this type of device is
As shown in the figure, when configured with m x n pixels, for example when m = 256 and n = 192, the color cathode ray tube display will be circular, so the radius of this circle is the maximum detection distance of the school of fish ( range).

Therefore, in this case, even if the Y-axis is used to the maximum, the number of pixels is only 96. Therefore, for example, if the scanning frequency of scanning sonar is 1KHz,
(1ms), and if the maximum detection distance of a school of fish is 1000m, the number of spiral scanning lines will be approximately 1333 (at the time of underwater sound speed of 1500m/s).

In this case, as mentioned above, there are only 96 pixels on the Y axis of the color cathode ray tube, so as shown in Figure 5, approximately 14 pixels (6 in the figure) The spiral scanning line of the polar coordinate system (book) will pass through it.

That is, 14 pieces of information are sent to one pixel. However, as is well known, each pixel can only store one piece of information, so each time the spiral scanning lines pass, the stored information is updated to new information, so 14 spiral scanning lines pass. After that, only the information of the last spiral scan line will be stored, and the information of the past 13 scan lines will disappear.

In the above example, one pixel corresponds to a distance of approximately 10 m (1000 m/96), and as a result, information can only be obtained every 10 m, so the information density between each pixel becomes extremely coarse.
There is a problem that schools of small fish cannot be displayed.

Furthermore, as described above, even though one pixel is supplied with information from a plurality of spiral scanning lines, the information stored in that pixel 12 is based on the information of the scanning line that last passes through that pixel 12. Limited. As a result, even if other scanning lines passing through this pixel 12 carry fish school information, when the last scanning line carries fish school unconfirmed information, only the fish school unconfirmed information is ultimately stored in that pixel 12. The Rukoto. For this reason, pixels 12 that display fish school information and pixels 12 that display unconfirmed fish school information are mixed on the color cathode ray tube, and the entire screen is displayed as a simulated color pattern, making the screen difficult to see and showing the distribution of fish schools. There was a problem that it could not be displayed accurately.

The present invention was developed in order to solve the above-mentioned conventional problems, and its purpose is to create a scanning sonar image that can accurately and easily display the color distribution of fish schools in accordance with the density of fish schools. The purpose of this invention is to provide a display device.

(Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, the present invention includes a detection device that detects a received signal of a scanning sonar in a polar coordinate system by spiral scanning, and a spiral detection signal in a polar coordinate system detected by the detection device in an X-Y manner.
A scanning sonar pixel display device comprising a conversion means for converting into a coordinate system pixel signal, and a pixel storage circuit for storing the pixel signal converted by the conversion means and outputting the pixel signal to a color cathode ray tube display as appropriate. , a peak is provided between the detection device and the image storage circuit, for selectively holding a peak value signal among a plurality of spiral detection signals in a polar coordinate system included in each pixel in the X-Y coordinate system as a pixel signal for that pixel. It is characterized by the provision of a hold circuit.

(Operation) In the present invention having the above configuration, the reception signal of the scanning sonar is detected by the detection device as a spiral detection signal in a polar coordinate system. This spiral detection signal is then converted into a pixel signal in the X-Y coordinate system and stored in the image storage circuit. At this time, the peak hold circuit converts the spiral detection signal into a pixel signal in the The school of fish information, for example, the strength of each signal is compared, and the peak value is selected and held as the pixel signal for that pixel.

Then, the peak value signal selected and held by this peak hold circuit is stored in the image storage circuit as a pixel signal in the X-Y coordinate system. Then, the pixel signal of each pixel is colored based on the peak value stored by the image storage circuit, and a color image is displayed on the color cathode ray tube. In this case, in the present invention, the image is displayed based on the signal of the peak value, so the undulations of the signal strength of adjacent pixels on the color cathode ray tube are reduced, the color image does not look like a fake, and the school of fish is displayed. Natural color change display will be performed corresponding to the density.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. In the description of this embodiment, the same members as in the conventional example are given the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows the block configuration of the scanning sonar image display device of the present invention. A feature of this embodiment is that a peak hold circuit 6 is provided between the A/D converter 2 and the image storage circuit 3. This peak hold circuit 6
The details are shown in FIG _.
( ₁ = 1 to N, the number of N needs to be the same as the number of spiral scanning lines that cross the pixels 12) are connected in series. This signal storage circuit _M1 is
Information on each pixel 12 in the coordinate system, that is, information carried by a plurality of spiral scanning lines _S1 in the polar coordinate system passing through the pixel 12, as shown in FIG. 5, is sequentially stored.

For example, in the case shown in FIG. 5, the information carried by the scanning line _S1 that first passes through the corresponding pixel 12 is first stored in the signal storage circuit _M1 . Next, when this pixel 12 is crossed by a second scan line _S2 , the information carried by that second scan line _S2 is stored in the signal storage circuit _M1 , and the information carried by the previously stored M ₁ information is pushed out and moved to signal storage circuit _M2 .
In this way, the signal storage circuit _M1 can store N pieces of information carried by N spiral scanning lines. Then, a total of N+1 pieces of information stored in each signal storage circuit _M1 and information supplied from the A/D converter 2 at the end are output to the selector circuit 7.

A range command is outputted to this selector circuit 7 from a range data setting circuit 8, and is used to set the number of information to be extracted from each signal storage circuit _M1 and A/D converter 2. In other words, as mentioned above, the number of spiral scanning lines that pass through one pixel can be calculated by setting the maximum detection distance of the scanning sonar.For example, if the range is 1000 m as mentioned above, about 14
The spiral scanning line of the book will pass, and in this case, the range data setting circuit 8 specifies the number of pieces of information, for example 14.

Similarly, each time the range is converted, the corresponding number is specified. The selector circuit 7 selects the designated number of spiral detection signals from the newest or oldest according to the number designation from the range data setting circuit 8.

The information value, that is, the signal strength, of each of the selected spiral detection signals is compared by the comparator circuit 9, and the spiral detection signal with the highest peak value among the spiral detection signals is selected. The value signal is output to the image storage circuit 3. At this time, similarly to the conventional example, the spiral detection signal is converted from the polar coordinate system to a pixel signal of the XY coordinate system, and this converted signal is stored in the image storage circuit 3.

On the other hand, as in the conventional example, a readout scanning signal is outputted from the raster scanning signal generator 10 to the image storage circuit 3, and a writing scanning signal is outputted to the color cathode ray tube display 5. The readout scanning signal and the writing scanning signal are synchronized, and the information stored in the image storage circuit 3 is read out by the reading scanning signal. It will be displayed in the corresponding position.

In this way, according to this embodiment, the peak value with the highest signal strength among the spiral detection signals passing through each pixel is stored in the image storage circuit 3,
Color display on a color cathode ray tube is performed based on this peak value. As a result, the information density of pixels can be increased, and even small schools of fish can be reliably captured. In addition, as mentioned above, the fish school image is not distributed in a simulated manner, that is, as described above, red, which has a high fish school density, is mixed with blue, where the fish school density is almost zero, or other colors are not distributed. The colors appear to change naturally from red, orange, yellow, etc. as you move from the location to the location where the density of the fish school is low, so it is possible to accurately grasp the distribution of the fish school, and the color image is extremely easy to see. This is something that can be obtained.

(Effects of the invention) Since the present invention is configured as described above, the information density of each pixel is increased, and even a school of small fish can be reliably captured and displayed as an image.

In addition, the fish school image projected on the color cathode ray tube does not look like a fake display with a mixture of colors as seen in conventional devices, and the colors are natural, moving from the high density of the fish school to the low position. Since the display changes, it is possible to accurately grasp the distribution of fish schools, and it is also possible to obtain an extremely easy-to-read color display.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.
Fig. 2 is a detailed block diagram of the peak hold circuit shown in Fig. 1, Fig. 3 is a block diagram showing a conventional scanning sonar display device, and Fig. 4 has a pixel array of m horizontal by n vertical pixels. An explanatory diagram showing an image display area in a region of maximum detection distance of a certain radius on a color cathode ray tube. Fig. 5 is an explanation of the operation showing the signal conversion state between a spiral detection signal in a polar coordinate system and a pixel signal in an X-Y coordinate system. It is a diagram. 1...detection device, 2...A/D converter, 3...
Image storage circuit, 4...XY coordinate conversion circuit, 5...
Color cathode ray tube display, 6... Peak hold circuit, 7... Selector circuit, 8... Range data setting circuit, 9... Comparison circuit, 10... Raster scanning signal generator, 11... Spiral scanning signal generator, 12...pixel, _M1 ...memory circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A detection device that detects a received signal of a scanning sonar in a polar coordinate system by spiral scanning, and a spiral detection signal in the polar coordinate system detected by the detection device to a pixel in an X-Y coordinate system. A scanning sonar pixel display device including a conversion means for converting into a signal, and a pixel storage circuit for storing the pixel signal converted by the conversion means and outputting the pixel signal to a color cathode ray tube display as appropriate,
A peak hold is provided between the detection device and the image storage circuit for selectively holding a peak value signal among a plurality of spiral detection signals in a polar coordinate system included in each pixel in an X-Y coordinate system as a pixel signal for that pixel. A scanning sonar image display device characterized by being provided with a circuit. (2) The peak hold circuit includes a signal storage circuit that stores multiple spiral detection signals included in a corresponding pixel, a selector circuit that specifies the number of spiral detection signals stored in the signal storage circuit to be extracted, and a selector circuit. and a comparison circuit that selects a signal with a peak value from among each number of spiral detection signals specified by and outputs it to an image storage circuit. scanning sonar image display device.