JPH05673B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to an image display device for scanning sonar, and in particular, by displaying images obtained by sequentially changing the elevation and elevation angles in a time-sharing manner, The present invention relates to an image display device that allows the distribution of fish schools in the depth direction to be grasped.

<Conventional technology> Normally, schools of fish are often distributed over a certain depth, so when searching for schools of fish using scanning sonar, as shown in Figure 3,
The ultrasonic beam is transmitted while changing the elevation angle by a constant angle θ over time. Then, the received signal obtained by receiving the reflected waves from a school of fish under a certain elevation angle is temporarily stored in the image memory as image data, and then the image data is read out from the image memory in synchronization with TV scanning. The system outputs the data to a CRT monitor to display images of schools of fish.

<Problems to be solved by the invention> As described above, in the conventional image display device,
The image data obtained based on the transmission and reception of ultrasound beams is transferred directly to the CRT via a single image memory.
Since it is output to a monitor, when the angle of elevation changes, the image of the school of fish changes accordingly.

Therefore, when a school of fish is located close to the scanning sonar, the transmission and reception period of the ultrasonic beam is short, so the angle of elevation can be changed rapidly, and accordingly, the image of the school of fish is It is relatively easy to understand the fish school distribution because the switching period becomes short, but if the fish school is located far away, the transmission and reception period of the ultrasonic beam becomes longer, so the elevation angle also changes accordingly. As a result, the frequency at which images of schools of fish are switched becomes longer, for example, at intervals of 10 to 15 seconds. As described above, when the cycle of video switching becomes longer, the relationship between the displayed images before and after switching becomes unclear, making it difficult to understand the fish school distribution three-dimensionally.

The present invention has been made in view of the above circumstances, and allows images of schools of fish to be switched and displayed at regular time intervals, as if watching a video, and is not affected by the length of the transmission/reception period of the ultrasonic beam. The purpose is to make it easy to understand the distribution of fish schools in three dimensions without having to worry about the situation.

<Means for Solving the Problems> In order to achieve the above object, the present invention adopts the following configuration.

That is, the image display device of the present invention includes a plurality of image memories that store received signals of ultrasonic beams obtained by the transducer as image data, and also displays the image data in synchronization with switching of the elevation angle by the elevation angle control circuit. image memory selection means for sequentially selecting an image memory into which image data is to be written from among a plurality of image memories; image data reading means for reading out image data corresponding to the elevation angle from each of the image memories in parallel; data output selection means for sequentially selecting and outputting each image data read out in parallel by the data reading means to a display section in response to a constant cycle switching clock applied asynchronously to the writing/reading operation of the image memory; It is composed of:

<Operation> Every time the elevation angle of the ultrasonic beam is changed by the elevation angle control circuit, the image memory selection means sequentially selects an image memory into which image data is to be written from among the plurality of image memories in synchronization with the change in the elevation angle. select.
As a result, image data obtained each time the elevation angle is changed is individually stored in each image memory.

On the other hand, each image data corresponding to the elevation angle read out in parallel from each image memory by the image data reading means is asynchronously read out from the image memory by the data output selection means. They are sequentially selected and output to the display section in response to a given constant cycle switching clock.

As a result, the images of the school of fish are sequentially switched and displayed at regular intervals as the angle of elevation changes, just like watching a video. Therefore, the distribution of fish schools at each depth can be grasped three-dimensionally.

<Embodiment> FIG. 1 is a block diagram including an image display device of a scanning sonar. In the figure, reference numeral 1 denotes a transducer, which includes a transducer 2 that transmits and receives an ultrasonic beam, a transmitter 4 that outputs excitation pulses for the transducer 2,
It is composed of a receiving section 6 that amplifies and detects the received signal of the ultrasonic beam obtained by the transducer 2. Also, 8
is an elevation angle control circuit that sequentially changes the elevation angle of the ultrasonic beam output from the transducer 2 of the transducer 1 over time. 10 is an A/D converter that digitizes the received signal from the receiving section 6. 12a-1
2n is a plurality of image memories that store A/D-converted received signals of ultrasound beams as image data.

14 is a write permission signal generation circuit that generates a write permission signal in response to a transmission trigger pulse outputted from the elevation angle control circuit 8 every time the elevation angle is changed; Image memory selection means inputs a transmission trigger pulse and sequentially selects an image memory into which image data is to be written from among the plurality of image memories 12a to 12n in synchronization with the input, and is composed of, for example, a ring counter. The write permission signal outputted from the write permission signal generation circuit 14 is transmitted to the image memory selection means 16 and the OR gate 17.
It is applied to read/write mode setting terminals R/W of image memories 12a to 12n via terminals a to 17n.

Reference numeral 18 denotes a write address generation circuit that generates a write address for image data for each of the image memories 12a to 12n, and converts polar coordinates (r, θ) corresponding to the spiral scanning of the received signal to rectangular coordinates (r, θ) corresponding to the raster scanning of the CRT. includes a coordinate conversion circuit that converts the coordinates into x, y). 20 is each image memory 1
By generating image data read addresses for 2a to 12n, each image memory 12a
This is a read address generation circuit as an image data read means for reading out image data corresponding to the elevation angle from ~12n in parallel.

22 sequentially selects each image data corresponding to the elevation angle read out in parallel from each of the image memories 12a to 12n in response to a constant cycle switching clock provided asynchronously with the writing/reading operations of the image memories 12a to 12n. A data output selection circuit 24 outputs the data to a display section 24 to be described later, and 24 is a display section that displays an image of the fish school distribution based on the image data selected by the data output selection circuit 22.

Next, the operation of the above configuration will be explained.

In order to understand the distribution of fish schools, it is necessary to transmit and receive ultrasonic beams while changing the elevation angle by a constant angle θ over time. A transmission trigger pulse is output for generating an ultrasonic beam by switching the elevation angle θ at a predetermined period in consideration of the beam transmission and reception period. This transmission trigger pulse is transmitted to the transmitting section 4, the receiving section 6, and the write permission signal generating circuit 14.
and image memory selection means 16, respectively. The transmitting unit 4 outputs an excitation pulse to the transducer 2 in response to this transmission trigger pulse, and the transducer 2 transmits an ultrasonic beam. The echo of the ultrasonic beam reflected by the school of fish is received by the transducer 2 again, and the received signal from the transducer 2 is amplified by the receiver 6.
After being detected, it is digitized by the A/D converter 10, and the data is commonly input to each of the image memories 12a to 12n as image data.

The write permission signal generation circuit 14 writes data in a predetermined period from when a transmission trigger pulse is input to when the next transmission trigger pulse is input, based on the transmission trigger pulse and the horizontal/vertical synchronization signal of the TV. Outputs write permission signal. That is, writing of image data to the image memories 12a to 12n/
Since reading is much faster in the latter than in the former, in this example, image data is written in cycle steals during data reading periods from each of the image memories 12a to 12n. Therefore, the write permission signal generation circuit 14 outputs a high level write permission signal during the blanking period of the horizontal/vertical synchronization signal. This write permission signal is given to the write address generation circuit 18 and the image memory selection means 16. The write address generation circuit 18 is
A write address is generated in response to the write permission signal. On the other hand, image memory selection means 16
sequentially switches the signal output terminals 16a to 16n each time a transmission trigger pulse is input. Therefore, each time a transmission trigger pulse is output, one image memory is selected, and image data is written into the selected image memory only during the period in which the write permission signal is applied.
As a result, image data obtained each time the elevation angle is changed is individually stored in each of the image memories 12a to 12b. For example, if the image memory is for 7 screens, and the central elevation angle is 30°, and the elevation angle is changed by 2° within a range of ±6° (i.e., from 24° to 34°), , when the image data obtained at an elevation angle of 30° is stored in the fourth image memory, the next image data is stored at an elevation angle of 32°, the sixth at an elevation angle of 34°, and the seventh at an elevation angle of 36°.゜, 24゜ for the first, 2
The second image is 26 degrees, the third is 28 degrees, the fourth is 30 degrees, etc. Each time the angle of elevation changes, image memories are sequentially selected and image data is stored.

Next, the image data stored separately in each of the image memories 12a to 12n according to the elevation angle is read out in parallel by the read address generation circuit 20. At this time, since the image memory to which the image data is written is also in the read mode during the period when the write permission signal is not output, the image data is read out in the same way as other image memories. And each image data is
The signal is applied to the data output selection circuit 22. The data output selection circuit 22 includes image memories 12a to 12n.
It is asynchronous with the write/read timing of
A switching pulse with a constant cycle (for example, 0.3 seconds) that is neither too fast nor too slow for the human eye is given, and images read out in parallel from the image memories 12a to 12n in response to this switching pulse. Select and output data sequentially. As a result, the screen of the display unit 24 shows the angle of elevation as shown in FIG.
Images of a school of fish obtained by changing the angle sequentially from 24° to 26° are displayed, switching sequentially every 0.3 seconds. Therefore, the distribution of fish schools at each depth can be grasped three-dimensionally.

In this embodiment, the image memories 12a to 12b are selected in synchronization with the vibration transmission trigger pulse output from the elevation angle control circuit 8.
It is also possible to perform a display similar to the above by switching the elevation angle within one period of the vibration trigger pulse and storing image data obtained for each elevation angle in the image memory.

<Effects of the Invention> According to the present invention, images of a school of fish are switched and displayed at regular time intervals as if viewing a moving image. Therefore, excellent effects such as being able to easily grasp the distribution of fish schools in three dimensions without being affected by the length of the transmission/reception period of the ultrasonic beam are exhibited.

[Brief explanation of drawings]

1 and 2 show embodiments of the invention,
Fig. 1 is a block diagram including a scanning sonar image display device, Fig. 2 is an explanatory diagram showing an example of image display obtained by changing the elevation angle over time, and Fig. 3 is an explanatory diagram showing an example of displaying an image obtained by changing the elevation angle over time. FIG. 3 is an explanatory diagram for exploring the distribution of fish schools. 1... Transducer/receiver, 8... Elevation angle control circuit, 12a~
12n... Image memory, 16... Image memory selection means, 22... Data output selection circuit.

Claims (1)

[Scope of Claims] 1. An image display device provided in a scanning sonar equipped with an elevation angle control circuit that sequentially changes the elevation angle of an ultrasonic beam output from a transducer, comprising: The image memory is provided with a plurality of image memories that store received signals of the obtained ultrasound beams as image data, and into which image data is written from among the plurality of image memories in synchronization with switching of the elevation angle by the elevation angle control circuit. an image memory selection means for sequentially selecting image data; an image data reading means for reading out image data corresponding to the elevation angle from each of the image memories in parallel; and each image data read out in parallel by the image data reading means; Image memory writing/
1. A scanning sonar image display device comprising: data output selection means for sequentially selecting and outputting data to a display unit in response to a constant cycle switching clock applied asynchronously with a readout operation.