A method for improving the target resolution of fishing sonar images

Abstract

The present invention relates to a method for improving the target resolution of a fishing sonar image, belonging to the technical field of fishing sonar. The method for improving the target resolution of a fishing sonar image includes the following steps: obtaining the echo data uploaded by the sonar signal processing host, and preprocessing the data to obtain preprocessed echo data data; performing interpolation visualization imaging on the preprocessed echo data data to obtain an initial fishing sonar image; introducing a gain Gain to adjust the echo intensity value of the initial fishing sonar image to obtain an adjusted echo intensity value Image data of the initial fishing sonar image; performing interpolation visualization imaging on the adjusted echo intensity value Image data to obtain an adjusted fishing sonar image. The method for improving the target resolution of a fishing sonar image provided by the present invention adjusts the display of the fishing sonar image target by introducing a gain Gain to adjust the echo intensity value of the initial fishing sonar image so as to make up for the loss of the echo intensity of the long-distance caused by the hardware of the signal receiver.

Description

Technical Field

[0001] The present invention belongs to the technical field of fishing sonars, and particularly relates to a method for improving the target resolution of fishing sonar images. Background Art

[0002] As one of the important fishing aids for precise detection and fishing in marine fisheries, fishing sonars are widely used in marine fishery production. The working principle of a fishing sonar is the same as that of an active sonar. Both emit acoustic wave signals underwater through a signal processing host. When the signals encounter fish schools, they are reflected and received by the receiver to achieve rapid tracking and positioning of the fish schools. Users mainly estimate information such as the orientation and density of fish schools by viewing sonar images in real time, so as to achieve precise fishing. Due to reasons such as the acoustic absorption of the seawater medium itself, the expansion of the wavefront during the acoustic wave propagation process, and various inhomogeneous scatterings in the seawater, the propagation speed of acoustic waves is different in different sea areas, and the energy propagation of acoustic waves in water decreases as the distance increases. Therefore, most of the sonar images obtained by fishing sonars are distorted, and the image quality is poor, which is not conducive to the development of marine fisheries. Currently, people use TVG gain in the receiver to make up for the energy loss caused by long-distance propagation to improve the image resolution. The TVG gain compensation curve of the commonly used AD8338 chip in the prior art is as Figure 1 shown. As can be seen from Figure 1 , the maximum value of the variable gain amplifier in the circuit is 80 dB. When the detection distance is less than 3000 m, the TVG gain has reached the maximum value. When the detection distance is greater than 3000 m, the TVG gain compensation will maintain a certain fixed value. It can be seen from this that the adjustment range of the TVG gain is limited, and the cost of a device with a larger adjustable range is also higher. Therefore, this method has many limiting conditions in actual use and is difficult to popularize and apply. Summary of the Invention

[0003] In view of the deficiencies in the related art, the present invention provides a method for improving the target resolution of fishing sonar images to make up for the loss of the echo intensity at long distances caused by the hardware of the signal receiver, improve the target resolution of sonar images, and can change the gain in real time and display the current fish school image information, greatly improving the detection efficiency of fishing sonars and reducing the research and development cost thereof.

[0004] The present invention provides a method for improving the target resolution of fishing sonar images, including the following steps:

[0005] Step 1: Obtain the echo data uploaded by the sonar signal processing host, and preprocess the data to obtain preprocessed echo data data;

[0006] Step 2: Perform interpolation visualization imaging on the preprocessed echo data data obtained in Step 1 to obtain an initial fishing sonar image;

[0007] Step 3: Introduce the gain Gain to adjust the echo intensity value of the initial fishing sonar image in Step 2 to obtain the adjusted echo intensity value Image data of the initial fishing sonar image;

[0008] Step 4: Perform interpolation visualization imaging on the adjusted echo intensity value Image data in Step 3 to obtain the adjusted fishing sonar image.

[0009] This technical solution compensates for the loss of the echo intensity of long-distance signals caused by the hardware of the signal receiver by introducing the gain Gain to adjust the echo intensity value of the initial fishing sonar image, improves the resolution of the image, and thus realizes the accurate detection and efficient gathering of fish school targets.

[0010] In some embodiments, the calculation formula for the adjusted echo intensity value Image data in Step 3 is:

[0011] Image data = 20 * lg(data) + Gain.

[0012] In some embodiments, the calculation formula for the gain Gain is:

[0013]

[0014] In the formula, C - digital gain, used to adjust the overall echo intensity information of the sonar image, and the value range of the digital gain C is -50 to 50 dB;

[0015] R - detection range, km;

[0016] P - screen resolution;

[0017] L - detection distance, the numerical range is 0 to P, excluding the blind area;

[0018] D - gain compensation coefficient, and the value of the gain compensation coefficient D is an integer between 1 and 10.

[0019] In some embodiments, the digital gain C is valued according to the echo intensity value of the initial fishing sonar image.

[0020] In some of these embodiments, in step 1, based on the echo data uploaded by the sonar signal processing host, the maximum value of the real-time echo intensity max_data is obtained, and the echo intensity value of the initial fishing sonar image is judged by comparing the maximum value of the real-time echo intensity max_data with the preset echo intensity mid_data; the digital gain C is preset with an initial value C0. When the maximum value of the real-time echo intensity max_data is greater than the preset echo intensity mid_data, the initial value C0 is reduced by 3 dB as the digital gain C. When the maximum value of the real-time echo intensity max_data is less than the preset echo intensity mid_data, the initial value C0 is increased by 3 dB as the digital gain C.

[0021] In some of these embodiments, the gain compensation coefficient D is valued according to the numerical value of the detection range R.

[0022] In some of these embodiments, when the numerical value of the detection range R is below 1000 m, the numerical value of the gain compensation coefficient D is ≥8; when the numerical value of the detection range R is between 1000 m and 2000 m, the numerical value of the gain compensation coefficient D is 6 - 8; when the numerical value of the detection range R is between 2000 m and 4000 m, the numerical value of the gain compensation coefficient D is 4 - 6; when the numerical value of the detection range R is above 4000 m, the numerical value of the gain compensation coefficient D is ≤4.

[0023] Based on the above technical solutions, in the embodiments of the present invention, a method for improving the target resolution of a fishing sonar image compensates for the loss of the echo intensity caused by the signal receiver hardware for long distances, improves the resolution of the image, not only improves the detection efficiency of the fishing sonar, but also reduces the cost of its development; moreover, it does not require changing the signal processing host (i.e., the lower computer), and is simple and easy to operate. Description of the Drawings

[0024] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 is the TVG gain compensation curve of the AD8338 chip in the prior art;

[0026] Figure 2 is the gain compensation coefficient D curve when the detection range R is 2000 m in an embodiment of the method for improving the target resolution of a fishing sonar image of the present invention;

[0027] Figure 3 is the gain compensation coefficient D curve when the detection range R is 4000 m in an embodiment of the method for improving the target resolution of a fishing sonar image of the present invention;

[0028] Figure 4 This is a flowchart of an embodiment of the method for improving the target resolution of a fishing sonar image according to the present invention;

[0029] Figure 5 This is a schematic diagram of the working principle of an embodiment of the method for improving the target resolution of a fishing sonar image according to the present invention. Specific embodiments

[0030] Next, the technical solutions in the embodiments will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In a schematic embodiment of the method for improving the target resolution of a fishing sonar image according to the present invention, the method for improving the target resolution of a fishing sonar image includes the following steps:

[0032] Step 1: Obtain the echo data uploaded by the sonar signal processing host, and preprocess the data to obtain preprocessed echo data data;

[0033] Step 2: Perform interpolation visualization imaging on the preprocessed echo data data obtained in Step 1 to obtain an initial fishing sonar image;

[0034] Step 3: Introduce a gain Gain to adjust the echo intensity value of the initial fishing sonar image in Step 2 to obtain an adjusted echo intensity value Image data of the initial fishing sonar image;

[0035] Step 4: Perform interpolation visualization imaging on the adjusted echo intensity value Image data in Step 3 to obtain an adjusted fishing sonar image.

[0036] It should be noted that in the above-mentioned schematic embodiment, the preprocessed echo data data in Step 1 includes the echo intensity value of the initial fishing sonar image in Step 2. It should also be noted that in Step 4, the adjusted fishing sonar image is the final fishing sonar image, and the resolution of the adjusted fishing sonar image is much higher than that of the initial fishing sonar image.

[0037] In the above-mentioned schematic embodiment, the calculation formula for the adjusted echo intensity value Image data in Step 3 is:

[0038] Image data = 20 * lg(data) + Gain.

[0039] In the above-mentioned schematic embodiment, the calculation formula for the gain Gain is:

[0040]

[0041] In the formula, C is the digital gain, which is used to adjust the overall echo intensity information of the sonar image. The value range of the digital gain C is -50 to 50 dB;

[0042] R is the detection range, in km;

[0043] P is the screen resolution;

[0044] L is the detected distance, and the numerical range is 0 to P, excluding the blind area;

[0045] D is the gain compensation coefficient, and the value of the gain compensation coefficient D is an integer between 1 and 10.

[0046] Among them, the digital gain C is valued according to the echo intensity value of the initial fishing sonar image.

[0047] The gain compensation coefficient D is valued according to the value of the detection range R. When the value of the detection range R is below 1000 m, the value of the gain compensation coefficient D is ≥8; when the value of the detection range R is between 1000 m and 2000 m, the value of the gain compensation coefficient D is 6 to 8; when the value of the detection range R is between 2000 m and 4000 m, the value of the gain compensation coefficient D is 4 to 6; when the value of the detection range R is above 4000 m, the value of the gain compensation coefficient D is ≤4.

[0048] It should be noted that the above-mentioned schematic embodiments are adjusted based on the display and control system of the fishing sonar. As Figure 4 and Figure 5 shown, the working principle of the fishing sonar is as follows: The multi-beam fishing sonar receives the echo data from the lower computer and transmits the original data to the display and control system through UDP communication; the display and control system first performs data preprocessing, and then visualizes the image using the algorithms and programs of the existing technology; the user judges whether to perform gain adjustment according to the image effect displayed on the screen. If no gain adjustment is required, the image displayed on the display and control system screen is the final fishing sonar image; if gain adjustment is required, the display and control system sets a manual adjustment mode and an automatic adjustment mode, and the user can arbitrarily select one of the modes for adjustment. The adjustment processes of the manual adjustment mode and the automatic adjustment mode will be specifically described by way of embodiments below.

[0049] Embodiment 1

[0050] In the manual mode, the sonar echo intensity value can be judged by observing the image information displayed on the display and control system screen. The specific adjustment process is as follows:

[0051] If the sonar echo intensity is small, resulting in unclear display of sonar image targets and filtering out some fish school targets, at this time, it is necessary to increase the value of the digital gain C so that the fish school targets can be clearly visible. The adjustment process needs to be carried out multiple times, and the adjustment amplitude each time is +3dB until the fish school targets are clearly visible. If the echo intensity is too large, resulting in overly prominent sonar image targets or too much noise to distinguish the targets, at this time, it is necessary to decrease the value of the digital gain C to reduce the intensity of the noise and reverberation and highlight the target intensity. The adjustment process needs to be carried out multiple times, and the adjustment amplitude each time is -3dB until the fish school target information can be accurately identified.

[0052] In addition, it is also necessary to adjust the value of the gain compensation coefficient D according to the detection range R. When detecting underwater targets at a relatively long distance (i.e., the detection range R is large), due to the loss of acoustic wave energy and the influence of noise and reverberation, it is difficult to distinguish the distal targets. When detecting targets near the ship (i.e., the detection range R is small), the loss of acoustic wave energy is small, and the image resolution of sonar detection is high. When the value of the detection range R is below 1000m, the value of the gain compensation coefficient D is ≥8; when the value of the detection range R is between 1000m and 2000m, the value of the gain compensation coefficient D is 6 - 8; when the value of the detection range R is between 2000m and 4000m, the value of the gain compensation coefficient D is 4 - 6; when the value of the detection range R is above 4000m, the value of the gain compensation coefficient D is ≤4. Attached Figure 2 and attached Figure 3 are the gain compensation curves when the detection range R is 2000m and 4000m respectively, and select the appropriate gain compensation coefficient D.

[0053] It should be noted that in order to control a single variable and obtain an image with a relatively high resolution quickly, the adjustment processes of the digital gain C and the gain compensation coefficient D are usually independent of each other.

[0054] Embodiment 2

[0055] In the automatic selection mode, the echo intensity value of the initial fishing sonar image is judged by comparing the maximum real-time echo intensity max_data with the preset echo intensity mid_data. The specific adjustment process is as follows:

[0056] In step 1, according to the echo data uploaded by the sonar signal processing host, the maximum real-time echo intensity max_data is obtained. The digital gain C is preset with an initial value C0. When the maximum real-time echo intensity max_data is greater than the preset echo intensity mid_data, the initial value C0 is decreased by 6dB as the digital gain C. When the maximum real-time echo intensity max_data is less than the preset echo intensity mid_data, the initial value C0 is increased by 6dB as the digital gain C.

[0057] When the value of the detection range R is below 1000 m, the value of the gain compensation coefficient D is 8; when the value of the detection range R is between 1000 m and 2000 m, the value of the gain compensation coefficient D is 6; when the value of the detection range R is between 2000 m and 4000 m, the value of the gain compensation coefficient D is 4.

[0058] It should be noted that when the automatic selection mode is selected, parameter modification and adjustment can also be performed manually to achieve the optimal display of the fishing sonar image.

[0059] In the above-mentioned illustrative embodiment, the method for improving the target resolution of the fishing sonar image can, without changing the signal processing host (i.e., the lower computer), introduce a gain Gain to adjust the echo intensity value of the initial fishing sonar image to make up for the loss of the echo intensity caused by the signal receiver hardware for long-distance echoes, improve the image resolution, and thus achieve the precise detection and efficient aggregation and capture of fish school targets, not only improving the detection efficiency of the fishing sonar but also reducing the cost of its development.

[0060] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. For the same or similar parts between the various embodiments, reference can be made to each other.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered by the scope of the technical solutions claimed in the present invention.

Claims

1. A method for improving the target resolution of fishing sonar images, characterized in that, It includes the following steps: Step 1: Obtain the echo data uploaded by the sonar signal processing host, and preprocess the data to obtain the preprocessed echo data data; Step 2: Perform interpolation visualization imaging on the preprocessed echo data data obtained in Step 1 to obtain an initial fishing sonar image; Step 3: Introduce a gain Gain to adjust the echo intensity value of the initial fishing sonar image in Step 2 to obtain the adjusted echo intensity value Image data of the initial fishing sonar image; the calculation formula for the adjusted echo intensity value Image data is: Image data = 20 * lg(data) + Gain The calculation formula for the gain Gain is: In the formula, C - digital gain, used to adjust the overall echo intensity information of the sonar image, and the value range of the digital gain C is -50 to 50 dB; R - detection range, km; P - screen resolution; L - detected distance, with a numerical range of 0 to P, excluding the blind area; D - gain compensation coefficient, and the value of the gain compensation coefficient D is an integer between 1 and 10; Step 4: Perform interpolation visualization imaging on the adjusted echo intensity value Image data in Step 3 to obtain an adjusted fishing sonar image.

2. The method for improving the target resolution of fishing sonar images according to claim 1, characterized in that, The digital gain C is valued according to the echo intensity value of the initial fishing sonar image.

3. The method for improving the target resolution of fishing sonar images according to claim 2, characterized in that, In Step 1, according to the echo data uploaded by the sonar signal processing host, obtain the maximum real-time echo intensity max_data, and judge the echo intensity value of the initial fishing sonar image by comparing the maximum real-time echo intensity max_data with the preset echo intensity mid_data; the digital gain C is preset with an initial value C0. When the maximum real-time echo intensity max_data is greater than the preset echo intensity mid_data, reduce the initial value C0 by 3 dB as the digital gain C. When the maximum real-time echo intensity max_data is less than the preset echo intensity mid_data, increase the initial value C0 by 3 dB as the digital gain C.

4. The method for improving the target resolution of fishing sonar images according to claim 1, characterized in that, The gain compensation coefficient D is valued according to the numerical value of the detection range R.

5. The method for improving the target resolution of fishing sonar images according to claim 4, characterized in that, When the numerical value of the detection range R is below 1000 m, the value of the gain compensation coefficient D is ≥8; when the numerical value of the detection range R is between 1000 m and 2000 m, the value of the gain compensation coefficient D is 6 - 8; when the numerical value of the detection range R is between 2000 m and 4000 m, the value of the gain compensation coefficient D is 4 - 6; when the numerical value of the detection range R is above 4000 m, the value of the gain compensation coefficient D is ≤4.

Images