Adaptive Feeding Device and Method for Swimming Fish Based on Photo-acoustic Coupling Technology

Abstract

Disclosed is an adaptive feeding device for swimming fish based on photo-acoustic coupling technology. The device comprises a recirculating aquaculture pond, a recirculating water treatment system, a high-definition waterproof camera, a feeding machine having a feeding port, and a LED supplement light, a PLC, a digital signal processor, a display, and a hydrophone. The device mainly uses the combination of machine vision technology and acoustic technology to adaptively and accurately analyze and evaluate the fish's real-time feeding desire during the feeding process, so as to formulate feeding strategies. The device of the present invention has simple structure, precise and simple method. The self-adaptive feeding device and method of the present invention are suitable for recirculating aquaculture mode and can effectively solve the problem of feed feeding in the existing recirculating aquaculture system.

Claims

1. An adaptive feeding device for swimming fish based on photo-acoustic coupling technology, comprising: a recirculating aquaculture pond, a recirculating water treatment system, a high-definition waterproof camera, a feeding machine having a feeding port, and a LED supplement light, a PLC, a digital signal processor, a display, and a hydrophone; wherein the recirculating water treatment system is installed outside the recirculating aquaculture pond; the high-definition waterproof camera is installed directly above the recirculating aquaculture pond, and the high-definition waterproof camera is connected to an input end of the digital signal processor; the feeding machine is installed directly above the recirculating aquaculture pond, and there is the feeding port of the feeding machine at both sides of the high-definition waterproof camera; there are several LED supplementary lights under the feeding machine; the feeding machine is connected to an output end of the PLC; the hydrophone is secured inside the recirculating aquaculture pond and connected to the input end of the digital signal processor; an output end of the digital signal processor is connected to the input end of the PLC and the display at the same time.

2. A method using the device of claim 1 for adaptive feeding the swimming fish, comprising the following steps: 1) transmitting, by the high-definition waterproof camera, real-time video images captured by the high-definition waterproof camera to a digital signal processor; 2) receiving and pre-processing, by the digital signal processor, the video images; extracting an image information of each frame of the video image; and performing threshold segmentation on the video image; letting g(x)=w.sub.0.sup.αβ*(u.sub.0−u).sup.2+w.sub.1.sup.αβ*(u.sub.1−u).sup.2; when g(x) takes the maximum value, x is the segmentation threshold; the foreground spot and background spot are divided by x, wherein when the gray level is greater than x, it is the background spot; when the gray level is lower than x, it is the foreground spot; wherein w.sub.0 is the proportion of the image occupied by the foreground spot, u.sub.0 is the average gray level of the foreground spot; w.sub.1 is the proportion of the image occupied by the background spot; u.sub.1 is the average gray level of the background spot; u=w.sub.0*u.sub.0+w.sub.1*u.sub.1 is the illumination coefficient of the current frame, which is determined by the illumination intensity of the breeding environment; the value range of α is 0 to 1; the stronger the light is, the greater the value of α; β is the turbidity coefficient of the aquaculture water body, which is determined by the turbidity degree of the aquaculture water body; the value range of β is 0 to 1; the higher the turbidity degree of the aquaculture water body, the smaller the value of β; 3) based on the above threshold and segmentation result, calculating the number S1 of the pixel representing the fish body information, i.e. the foreground spot, in the video frame; if S1>0.5S, where S is the number of all pixels in the frame image, the digital signal processor inputs the processing results to the PLC, and the PLC controls the feeding machine to work and feed for 10 seconds; 4) after the feeding starts, the camera still normally transmits real-time video information to the digital signal processor; the digital signal processor extracts the picture information of each frame in the real-time video, and divides each frame into two parts: the feeding center area T1 and the feeding edge area T2; wherein the feeding center area T1 is centered on the center of the recirculating aquaculture pool, and the radius is: $r=0.8*\frac{{.Math.}_{i=1}^n{l}_i}{{\mathrm{nl}}_{\max }}{r}_0,$  wherein r.sub.0 is the radius of the circulation pool; n is the number of fish cultured in the recirculating aquaculture pond, l.sub.i is the body length of the ith fish in the recirculating aquaculture pond; and l.sub.max is the maximum body length of the fish in the recirculating aquaculture pond; the areas outside the aquaculture ponds are all marginal areas of feeding, except the feeding center area; 5) calculating the optical flow change values F1.sub.t and F2.sub.t between adjacent video frames in the two areas by using the dense optical flow algorithm; setting the movement vector with coordinate (i, j) in the area T1 to (x.sub.ij, y.sub.ij); and setting the movement vector with coordinate (i′, j′) in the area T2 to (x.sub.ij′, y.sub.ij′); wherein the optical flow change values of the two areas are: $F{1}_t=\frac{{.Math.}_{\mathrm{ij}}\sqrt{x_{\mathrm{ij}}^2+y_{\mathrm{ij}}^2}}{N_1}\mathrm{and}F{2}_t=\frac{{.Math.}_{i^{\prime }{j}^{\prime }}\sqrt{{\left(x_{\mathrm{ij}}^{\prime }\right)}^2+{\left(y_{\mathrm{ij}}^{\prime }\right)}^2}}{N_2}\text{;}$ wherein, N.sub.1 is the total number of pixels in the area T1; N.sub.2 is the total number of pixels in the area T2; the dynamic change of the optical flow change value over time will be calculated and displayed on the display; 6) comparing the mean values F1 and F2 of the optical flow changes in the two areas calculated within the time period t with the feeding center area threshold FT1 and feeding edge area threshold FT2: $F1=\frac{{.Math.}_{i=1}^{t}F{1}_t}{t-1},F2=\frac{{.Math.}_{i=1}^{t}F{2}_t}{t-1}\text{;}$  FT1=1.4μF1′, FT2=1.2μF2′; wherein, F1′ and F2′ are the mean values of optical flow changes in area T1 and T2 in the non-feeding state, respectively; μ is the comprehensive water quality correction factor, $\mu =1+.Math.\frac{\Delta T}{T}.Math.+.Math.\frac{\Delta P_h}{P_h}.Math.+.Math.\frac{\Delta D_o}{D_o}.Math.\text{;}$ wherein, T is the standard temperature of aquaculture water; ΔT is the difference between the temperature of the water body and the standard temperature T; P.sub.h is the standard pH of the aquaculture water; ΔP.sub.h is the difference between the pH of the water body and the standard pH of the water; D.sub.o is the standard dissolved oxygen content of the aquaculture water; ΔD.sub.o is the difference between the dissolved oxygen content of the water body and the standard dissolve oxygen content of the water body; if F1>FT1 and F2<FT2, the next feeding will be carried out; the feeding time is the same as the previous one, and the feeding amount is: $m=\left(0.65*\frac{F1-\mathrm{FT}1}{\mathrm{FT}1}+0.35*\frac{\mathrm{FT}2-F2}{\mathrm{FT}2}\right)m_0\text{;}$ wherein m.sub.0 is the minimum feeding amount to meet the normal growth and nutritional requirements of fish; 7) if $F_1<\left(1+\frac{{.Math.}_i^n{l}_i}{{\mathrm{nl}}_{\max }}\right){\mathrm{FT}}_1\mathrm{or}{F}_2>\left(1-\frac{{.Math.}_i^n{l}_i}{{\mathrm{nl}}_{\max }}\right){\mathrm{FT}}_2,$ then the digital signal processor will automatically switches the machine vision control feeding to the acoustic system for feeding control; the hydrophone collects 1500-3000 Hz audio information generated during fish feeding and transmits it to the digital signal processor in real time; when the collected audio sound pressure level effective value Z>ZT, the system starts feeding; wherein, ZT is the effective valve threshold of the audio sound pressure level to determine the feeding; ZT=(60*log.sub.10 T)dB re 1 uPa; wherein Tis the real-time water temperature; the feeding amount is: $m=\left(0.5+\frac{Z-\mathrm{ZT}}{\mathrm{ZT}}\right)m_0\text{;}$ 8) if Z<ZT, then sending, by the digital signal controller, a stop feeding instruction to the PLC, and controlling, by the PLC, the feeding machine to stop working; automatically switching, by the PLC, the feeding control system to the machine vision, and waiting for the start of the next feeding work.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a schematic diagram of a photo-acoustic coupling swimming fish adaptive feeding device applied to circulation water.

[0026] In the drawings:

[0027] 1—recirculating aquaculture pond; 2—recirculating water treatment system; 3—high—definition waterproof camera; 4—feeding port of feeding machine; 5—feeding machine; 6—LED supplement light; 7—PLC; 8—digital signal processor; 9—display; 10—hydrophone.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0028] The present disclosure will be described in detail below in conjunction with the drawings. The following specific embodiments are used to illustrate the present invention, but not to limit the scope of the present invention.

[0029] Referring to FIG. 1, it is a specific example of a swimming fish adaptive feeding device based on photo-acoustic coupling technology according to one embodiment of the present disclosure. The adaptive feeding device comprises a recirculating aquaculture pond 1, a recirculating water treatment system 2, a high-definition waterproof camera 3, and a feeding machine 5 having a feeding port 4, a LED fill light 6, a PLC 7, a digital signal processor 8, a display 9, and a hydrophone 10.

[0030] The recirculating water treatment system 2 is installed on the outer left side of the recirculating aquaculture pond 1. The recirculating water treatment system 2 sends the aquaculture wastewater to the recirculating aquaculture pond 1 after a series of operations such as filtration, sterilization, and aeration. This greatly increases the resource utilization.

[0031] The high-definition waterproof camera 3 is installed directly above the middle of the recirculating aquaculture pond 1 and fixed directly under the feeding machine 5. The high-definition waterproof camera 3 is connected to the input end of the digital signal processor 8. The installation position of the camera can ensure that the sight of the camera may cover the entire feeding area. The camera is directly fixed under the feeding machine, which is convenient for loading and unloading without the need for additional mounting frames.

[0032] The feeding machine 5 is installed directly above the recirculating aquaculture pond 1, and there is a feeding port 4 of the feeding machine on both sides of the high-definition waterproof camera 3. There are two feeding ports 4 arranged on the lower circumference of the feeding machine 5. Additionally, there are six LED supplementary lights 6 evenly distributed on the lower circumference of the feeding machine 5 along with the two feeding ports 4. Furthermore, the feeding machine 5 is connected to the output end of the PLC 7. Two feeding ports of the feeding machine can ensure that the feed can evenly cover the entire feeding area, and appropriately expand the feeding area. The installation position of the LED supplementary light will not affect the work of the camera and the feeding machine.

[0033] The uniformly distributed LED supplementary light 6 can change the brightness according to the change of the actual breeding environment light, which not only provides suitable lighting conditions for the adaptive feeding system, but also provides a suitable growth light environment for fish.

[0034] The hydrophone 10 is secured at the lower right inside the recirculating aquaculture pond 1 and connected to the input of the digital signal processor 8. The hydrophone can collect the sound information emitted by the fish during feeding and transmit it to the digital signal processor.

[0035] The output end of the digital signal processor 8 is connected to the input end of the PLC 7 and the display 9 at the same time. The digital signal processor receives the image information input by the camera and the sound information input by the hydrophone and performs corresponding processing. Firstly, analyzing the fish's real-time feeding desire through the image processing technology, and determining the feeding machine to perform feeding operations. If the digital signal processor determines that the feeding desire is strong, the machine vision technology controls the feeding process, which includes feeding time and feeding amount, otherwise it will be automatically switched to acoustic technology control. The digital signal processor transmits the processing results to the PLC to control the feeding machine, and on the other hand, it can display the processing results on the display, which is more intuitive.

[0036] A feeding method using the above device for adaptive feeding the swimming fish comprises the following steps:

[0037] 1) transmitting, by the high-definition waterproof camera 3, real-time video images captured by the high-definition waterproof camera to a digital signal processor 8;

[0038] 2) receiving and pre-processing, by the digital signal processor 8, the video images; extracting an image information of each frame of the video image; and performing threshold segmentation on the video image; letting g(x)=w.sub.0.sup.αβ*(u.sub.0−u).sup.2+w.sub.1.sup.αβ*(u.sub.1−u).sup.2; when g(x) takes the maximum value, x is the segmentation threshold. The foreground spot and background spot are divided by x, wherein when the gray level is greater than x, it is the background spot; when the gray level is lower than x, it is the foreground spot; wherein w.sub.0 is the proportion of the image occupied by the foreground spot, u.sub.0 is the average gray level of the foreground spot; w.sub.1 is the proportion of the image occupied by the background spot; u.sub.1 is the average gray level of the background spot; u=w.sub.0*u.sub.0+w.sub.1*u.sub.1 is the illumination coefficient of the current frame, which is determined by the illumination intensity of the breeding environment; the value range of α is 0 to 1; the stronger the light is, the greater the value of α; β is the turbidity coefficient of the aquaculture water body, which is determined by the turbidity degree of the aquaculture water body; the value range of β is 0 to 1; the higher the turbidity degree of the aquaculture water body, the smaller the value of β;

[0039] 3) based on the above threshold and segmentation result, calculating the number S1 of the pixel representing the fish body information, i.e. the foreground spot, in the video frame; if S1>0.5S, where S is the number of all pixels in the frame image, the digital signal processor inputs the processing results to the PLC, and the PLC controls the feeding machine to work and feed for 10 seconds;

[0040] 4) after the feeding starts, the camera still normally transmits real-time video information to the digital signal processor; the digital signal processor extracts the picture information of each frame in the real-time video, and divides each frame into two parts: the feeding center area T1 and the feeding edge area T2; wherein the feeding center area T1 is centered on the center of the recirculating aquaculture pool, and the radius is:

[00008]$r=0.8*\frac{{\Sigma }_{i=1}^n{l}_i}{n{l}_{\max }}{r}_0,$

wherein r.sub.0 is the radius of the circulation pool; n is the number of fish cultured in the recirculating aquaculture pond, l.sub.i is the body length of the ith fish in the recirculating aquaculture pond; and l.sub.max is the maximum body length of the fish in the circulating water aquaculture pond; the areas outside the aquaculture ponds are all marginal areas of feeding, except the feeding center area;

[0041] 5) calculating the optical flow change values F1.sub.t and F2.sub.t between adjacent video frames in the two areas by using the dense optical flow algorithm; setting the movement vector with coordinate (i, j) in the area T1 to (x.sub.ij, y.sub.ij); and setting the movement vector with coordinate (i′, j′) in the area T2 to (x.sub.ij′, y.sub.ij′); wherein the optical flow change values of the two areas are:

[00009]$F{1}_t=\frac{{.Math.}_{\mathrm{ij}}\sqrt{x_{\mathrm{ij}}^2+y_{\mathrm{ij}}^2}}{N_1}\mathrm{and}F{2}_t=\frac{{.Math.}_{i^{\prime }{j}^{\prime }}\sqrt{{\left(x_{\mathrm{ij}}^{\prime }\right)}^2+{\left(y_{\mathrm{ij}}^{\prime }\right)}^2}}{N_2}\text{;}$

wherein, N.sub.1 is the total number of pixels in the area T1; N.sub.2 is the total number of pixels in the area 12; the dynamic change of the optical flow change value over time will be calculated and displayed on the display;

[0042] 6) comparing the mean values F1 and F2 of the optical flow changes in the two areas calculated within the time period t with the feeding center area threshold FT1 and feeding edge area threshold FT2:

[00010]$F1=\frac{{.Math.}_{i=1}^{t}F{1}_t}{t-1},F2=\frac{{.Math.}_{i=1}^{t}F{2}_t}{t-1}\text{;}$

FT1=1.4μF1′, FT2=1.2μF2′;

[0043] wherein, F1′ and F2′ are the mean values of optical flow changes in area T1 and T2 in the non-feeding state, respectively; μ is the comprehensive water quality correction factor,

[00011]$\mu =1+.Math.\frac{\Delta T}{T}.Math.+.Math.\frac{\Delta P_h}{P_h}.Math.+.Math.\frac{\Delta D_o}{D_o}.Math.\text{;}$

wherein, T is the standard temperature of aquaculture water; ΔT is the difference between the temperature of the water body and the standard temperature T; P.sub.h is the standard pH of the aquaculture water; ΔP.sub.h is the difference between the pH of the water body and the standard pH of the water; D.sub.o is the standard dissolved oxygen content of the aquaculture water; ΔD.sub.o is the difference between the dissolved oxygen content of the water body and the standard dissolve oxygen content of the water body; if F1>FT1 and F2<FT2, the next feeding will be carried out; the feeding time is the same as the previous one, and the feeding amount is:

[00012]$m=\left(0.65*\frac{F1-\mathrm{FT}1}{\mathrm{FT}1}+0.35*\frac{\mathrm{FT}2-F2}{\mathrm{FT}2}\right)m_0\text{;}$

wherein m.sub.0 is the minimum feeding amount to meet the normal growth and nutritional requirements of fish;

[0044] 7) if

[00013]$F_1<\left(1+\frac{{.Math.}_i^n{l}_i}{{\mathrm{nl}}_{\max }}\right){\mathrm{FT}}_1\mathrm{or}{F}_2>\left(1-\frac{{.Math.}_i^n{l}_i}{{\mathrm{nl}}_{\max }}\right){\mathrm{FT}}_2,$

then the digital signal processor will automatically switches the machine vision control feeding to the acoustic system for feeding control; the hydrophone collects audio information (1500-3000 Hz) generated during fish feeding and transmits it to the digital signal processor in real time; when the collected audio sound pressure level effective value Z>ZT, the system starts feeding; wherein, ZT is the effective valve threshold of the audio sound pressure level to determine the feeding; ZT=(60*log.sub.10 T)dB re 1 uPa; wherein T is the real-time water temperature; the feeding amount is:

[00014]$m=\left(0.5+\frac{Z-\mathrm{ZT}}{\mathrm{ZT}}\right)m_0\text{;}$

[0045] 8) if Z<ZT, then sending, by the digital signal controller, a stop feeding instruction to the PLC, and controlling, by the PLC, the feeding machine to stop working; automatically switching, by the PLC, the feeding control system to the machine vision, and waiting for the start of the next feeding work.

[0046] The foregoing are only specific embodiments of the present disclosure, and various changes and modifications made without departing from the concept and scope of the present disclosure, and all equivalent technical solutions also belong to the scope of the present invention.