Estimation device, estimation system, estimation method, estimation program, sorting system, and sorting method for estimating size of target object

Abstract

To estimate the size of an object in a short time.SOLUTION: An estimation device 4 for estimating the size of an object F includes an amplitude acquisition unit 41 that acquires the amplitude of a resonance sound generated in a Helmholtz resonator 5 when the resonance sound is generated in the Helmholtz resonator 5 in a case where the object F is not present in the Helmholtz resonator 5, and an estimation unit 42 that estimates the size of the object F on the basis of the amplitude.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for estimating the size of an object, and more particularly to a technique for estimating the size of an object by utilizing Helmholtz resonance. [Background technology]

[0002] In fish farming, if there is a difference in the growth of fry in the tank, the smaller fry will not be able to eat enough food, which will slow their growth or cause them to starve. To prevent this, farmers sort the fry by size and work to make sure that all the fry in the tank are the same size. Currently, farmers do this sorting manually, which is inefficient, so there is a need to develop technology that can automatically sort fry by size.

[0003] In response to this, Patent Documents 1 and 2 disclose technologies that utilize Helmholtz resonance to measure the volume of fry in an aquarium and automatically sort the fry. Helmholtz resonance is a phenomenon in which, when a periodic pressure fluctuation is applied to a fluid in a container with a neck, the fluid in the neck vibrates resonantly at a specific frequency. This resonant frequency depends on the bulk modulus of the fluid, and the bulk modulus of the fluid can be calculated from the resonant frequency. When water and fish are placed in a Helmholtz resonator, the resonant frequency decreases compared to when there is only water, because the bulk modulus of the fish is smaller than that of water. The amount of this decrease is known to depend on the volume of the fish, and this can be used to estimate the volume of fry without contact. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6103713 [Patent Document 2] Patent No. 7390664 Summary of the Invention [Problem to be solved by the invention]

[0005] In the techniques disclosed in Patent Documents 1 and 2, a sine wave is swept over an appropriate frequency range through the fluid in a Helmholtz resonator to measure the resonant frequency. Therefore, it takes about 2 to 10 seconds to estimate the size of the fry, and since the fry must remain in the container during that time, there is a problem in that sorting takes time.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to estimate the size of an object in a short time. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention includes the following aspects. Section 1. An estimation device for estimating the size of an object, comprising: an amplitude acquisition unit that acquires the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; an estimation unit that estimates the size of the object based on the amplitude; An estimation device comprising: Section 2. Item 2. The estimation device according to item 1, wherein the sound is a resonant sound that occurs in the Helmholtz resonator when the object is not present in the Helmholtz resonator. Section 3. Item 3. The estimation device according to item 1 or 2, wherein the estimation unit estimates a volume of the object. Section 4. The estimation device according to any one of items 1 to 3, a Helmholtz resonator through which the object passes; An estimation system comprising: Section 5. The Helmholtz resonator is a container for storing a liquid; an opening provided in the container; a sound generating unit that generates the sound in the liquid; a sound collection unit that collects the sound; Equipped with Item 5. The estimation system according to item 4, wherein the amplitude acquisition unit acquires the amplitude of the sound collected by the sound collection unit. Section 6. a tube passing through the Helmholtz resonator through the opening; Item 6. The estimation system according to item 5, wherein the object passes through the tube. Section 7. Item 7. The estimation system according to item 6, wherein the tube is a soft PVC tube. Section 8. 8. The estimation system according to any one of items 4 to 7, wherein the object is a fish. Section 9. 1. A sorting system for sorting objects, comprising: The estimation system according to any one of items 4 to 8, a sorting mechanism that sorts the objects based on the estimation result by the estimation unit; A sorting system comprising: Section 10. 1. An estimation method for estimating a size of an object, comprising: an amplitude acquisition step of acquiring the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; an estimation step of estimating a size of the object based on the amplitude; An estimation method, including: Section 11. A sorting method for sorting objects, comprising: Each step of the estimation method described in item 10; a sorting step of sorting the objects based on the estimation result from the estimation step. Section 12. An estimation program for estimating the size of an object, an amplitude acquisition unit that acquires the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; and an estimation unit that estimates the size of the object based on the amplitude; An estimation program that makes a computer function as a [Effects of the Invention]

[0008] According to the present invention, the size of an object can be estimated in a short time. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration of a sorting system according to an embodiment of the present invention. [Figure 2] 10 is a graph showing an example of the relationship between the weight of a fish and the amplitude of a resonance sound. [Figure 3] 1 is a flowchart showing the processing steps of an estimation method and a sorting method according to an embodiment of the present invention. [Figure 4] FIG. 10 is a block diagram showing a modified example of the sorting system. [Figure 5] FIG. 1 is a schematic diagram of an experimental system in Example 1. [Figure 6] FIG. 1 is a schematic diagram of an experimental system in Example 1. [Figure 7] FIG. 1 is a schematic diagram of an experimental system in Example 1. [Figure 8] 1 is a graph showing the relationship between the amount of air and the resonant frequency in Example 1 when no tube is present and when the tubes of Samples 1 to 5 are inserted into the Helmholtz resonator. [Figure 9] 1 is a graph showing the relationship between the amount of air and the amplitude of resonance sound when the tubes of Samples 1 to 5 are inserted into a Helmholtz resonator in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0011] (System Configuration) FIG. 1 is a block diagram showing the configuration of a sorting system 1 according to one embodiment of the present invention. The sorting system 1 is a system that sorts multiple objects based on their size, and includes an estimation system 2 and a sorting mechanism 3 that sorts the objects. In this embodiment, the objects are multiple fish F of different sizes, and more specifically, the fish are farmed juvenile fish. The fish F before sorting are contained in a source aquarium T1.

[0012] The estimation system 2 includes an estimation device 4, a Helmholtz resonator 5 through which an object passes, and a tube (hose) 6 that passes through the Helmholtz resonator 5.

[0013] The estimation device 4 is a device for estimating the size of an object and can be configured with a general-purpose computer. The hardware configuration of the estimation device 4 includes a processor (not shown) such as a CPU or GPU, a main storage device (not shown) such as a DRAM or SRAM, and an auxiliary storage device 40 such as an HDD or SSD. The auxiliary storage device 40 stores an estimation program P, correlation data D, etc.

[0014] The estimation device 4 includes, as functional blocks, an amplitude acquisition unit 41 and an estimation unit 42. These functional blocks may be realized in hardware, such as a logic circuit formed on an integrated circuit, but in this embodiment, they are realized in software by a processor of the estimation device 4 reading an estimation program P into a main storage device and executing it. The estimation program P may be downloaded to the estimation device 4 via a communication network such as the Internet, or may be recorded in advance on a computer-readable non-transitory recording medium such as a CD-ROM or an SD card and transferred to the estimation device 4 via the recording medium.

[0015] The amplitude acquisition unit 41 acquires the amplitude of a sound of a predetermined frequency when the sound is emitted when a fish F is present in the Helmholtz resonator 5. In this embodiment, the sound of the predetermined frequency is a resonant sound that occurs in the Helmholtz resonator 5 when no fish F is present in the Helmholtz resonator 5, but the sound may have a frequency different from that of the resonant sound.

[0016] The estimation unit 42 estimates the size of the fish F based on the amplitude acquired by the amplitude acquisition unit 41. The principle of estimating the size of the fish F based on the amplitude will be described later.

[0017] The Helmholtz resonator 5 includes a container 51 for storing a liquid, an opening 52 provided in the container 51, a sound generating unit 53 for emitting sound into the liquid, and a sound collecting unit 54 for collecting the sound.

[0018] The container 51 is placed in the water stored in the measurement water tank T2. The size and shape of the container 51 are not particularly limited as long as they can generate Helmholtz resonance.

[0019] The openings 52 are provided at two opposing positions on the side surface of the container 51. The tube 6 passes through the Helmholtz resonator 5 through the openings 52.

[0020] The sound generator 53 is a speaker that emits sound, and in this embodiment, emits a resonant sound. The resonant sound is set by identifying the resonant frequency while sweeping the sound emitted from the sound generator 53 in a state where at least the fish F is not present in the Helmholtz resonator 5 but the tube 6 is present.

[0021] The sound collection unit 54 is provided at a position facing the sound generation unit 53 across the tube 6, and collects the resonance sound emitted by the sound generation unit 53. The sound collection unit 54 can be configured by a hydrophone.

[0022] The tube 6 runs from the source tank T1, which contains the fish F before sorting, through the Helmholtz resonator 5 to the sorting tank T3, which contains the fish F after sorting. The portion of the tube 6 that passes through the Helmholtz resonator 5 is preferably made of a flexible material, and is particularly preferably a soft PVC tube. The outer diameter of the portion of the tube 6 that passes through the Helmholtz resonator 5 can be selected appropriately depending on the size of the fish to be passed through. An example of the outer diameter is 30 to 58 mm. The thickness of the material of the tube 6 should be thin in terms of sound wave permeability, and is preferably 2 mm or less, and more preferably 1 mm or less.

[0023] The source tank T1 is installed at a higher position than the sorting tank T3, so that the water in the source tank T1 flows into the sorting tank T3 through a tube 6. The sorting tank T3 is provided with a first cage B1 for accommodating large fish F and a second cage B2 for accommodating small fish F. The water in the sorting tank T3 is pumped up by a pump 7 and returned to the source tank T1 through a circulation path 8.

[0024] The sorting mechanism 3 is a device that sorts fish F based on the estimation results of the estimation unit 42 of the estimation device 4. During the sorting operation, the fish F are passed through the tube 6 one by one while the sound generating unit 53 emits a resonant sound of a predetermined amplitude. If the sorting mechanism 3 estimates that the volume of the fish F passing through the Helmholtz resonator 5 is larger than a predetermined volume, it controls the tube 6 so that the terminal end thereof is directed toward the first cage B1. If the sorting mechanism 3 estimates that the volume of the fish F passing through the Helmholtz resonator 5 is smaller than a predetermined volume, it controls the tube 6 so that the terminal end thereof is directed toward the second cage B2. As a result, larger fish F are housed in the first cage B1, and smaller fish F are housed in the second cage B2.

[0025] In addition, to prevent multiple fish F from passing through the Helmholtz resonator 5 at the same time or within a short period of time, for example, an openable / closable valve may be provided at the entrance of the tube 6 or between the entrance and the Helmholtz resonator 5, and when one fish F passes through the valve of the tube 6, the valve may be closed until the fish F exits from the end of the tube 6.

[0026] (Estimation principle) Next, the principle of estimating the size of a fish will be explained.

[0027] When a sound of a specific resonant frequency (resonant sound) is emitted from the sound generator 53 inside the Helmholtz resonator 5, the amplitude of the resonant sound is larger than the amplitude of sounds of other frequencies. When a fish F is present inside the Helmholtz resonator 5, the resonant frequency decreases as the volume of the fish F (the swim bladder of the fish F) increases. In other words, the larger the volume of the fish F inside the Helmholtz resonator 5, the larger the difference between the resonant frequency when the fish F is not present and the resonant frequency when the fish F is present. Therefore, if a fish F is placed inside the Helmholtz resonator 5 while a resonant sound of a constant amplitude is emitted when the fish F is not present inside the Helmholtz resonator 5, the amplitude of the resonant sound decreases simply in accordance with the volume of the fish F.

[0028] 2 is a graph showing an example of the relationship between the weight of a fish and the amplitude of the resonance sound. This graph was obtained from an experiment in Example 2, which will be described later. Since the weight and volume of a fish are proportional, it can be seen that the amplitude of the resonance sound decreases as the volume of fish F increases.

[0029] In this embodiment, the volume of the fish and the amplitude of the resonance sound are measured in advance through experiments, and a regression curve (or regression line) showing the correlation between the fish volume and the amplitude of the resonance sound is determined, for example, by regression analysis or the like, and stored as correlation data D in the auxiliary storage device 40. In addition, a resonance sound that is generated in the Helmholtz resonator 5 when no fish F is present in the Helmholtz resonator 5 is set in advance. Then, a fish F of unknown volume is passed through the Helmholtz resonator 5 while the sound generator 53 generates the resonance sound, and the amplitude acquirer 41 acquires the amplitude of the resonance sound collected by the sound collector 54. The estimation unit 42 can estimate the volume of the fish F based on the amplitude of the resonance sound by referring to the correlation data D.

[0030] As described above, in this embodiment, since it is not necessary to change the frequency of the sound emitted from the sound generator 53 and it is only necessary to measure the amplitude, the size of the fish F can be estimated in a short time (for example, about 0.001 seconds). Since it takes about 0.2 seconds for the fish F to pass through the Helmholtz resonator 5, the size of the fish F can be estimated while the fish F is passing through the Helmholtz resonator 5. Therefore, it is not necessary to confine the fish F within the Helmholtz resonator 5, and the fish F can be easily sorted in a short time.

[0031] (Processing Procedure) 3 is a flowchart showing the processing steps of the estimation method and the sorting method according to this embodiment. The estimation method mainly includes steps S1 to S6, and the sorting method further includes step S7.

[0032] In step S1, a plurality of fish F to be sorted are placed in a source tank T1.

[0033] In step S2, the sound generator 53 generates a sound of a predetermined frequency. In this embodiment, when no fish F is present in the Helmholtz resonator 5, the sound generator 53 generates a sound that causes Helmholtz resonance in the resonator 5.

[0034] In step S3, one fish F is passed through the Helmholtz resonator 5 via the tube 6 while the sound generator 53 is emitting a sound.

[0035] In step S4, the sound collection unit 54 collects the sound from the sound generation unit 53. The waveform data of the collected sound is output to the estimation device 4.

[0036] In step S5 (amplitude acquisition step), the amplitude acquisition unit 41 acquires the amplitude of the sound collected by the sound collection unit .

[0037] In step S6 (estimation step), the estimation unit 42 estimates the size of the fish F based on the amplitude.

[0038] In steps S7 to S9 (sorting steps), the sorting mechanism 3 sorts the fish F based on the estimation result by the estimation unit 42. Specifically, if the size of the fish F is equal to or larger than a predetermined size (YES in step S7), the sorting mechanism 3 controls the end of the tube 6 to be directed toward the first basket B1, and the fish F is contained in the first basket B1 (step S8). On the other hand, if the size of the fish F is smaller than a predetermined size (NO in step S7), the sorting mechanism 3 controls the end of the tube 6 to be directed toward the second basket B2, and the fish F is contained in the second basket B2 (step S9).

[0039] Thereafter, steps S3 to S9 are repeated until all of the fish F have been sorted (YES in step S10). Note that the amplitude of the sound emitted by the sound generator 53 is constant in each cycle.

[0040] (Additional notes) Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0041] In the above embodiment, the estimation unit 42 estimates the volume of the fish F passing through the Helmholtz resonator 5, and the sorting mechanism 3 sorts the fish F based on the estimated volume, but estimating the volume is not essential. For example, the estimation unit 42 may compare the amplitude of the resonance sound acquired by the amplitude acquisition unit 41 with a predetermined value, and estimate that the fish F is small if the amplitude is greater than the predetermined value, and estimate that the fish F is large if the amplitude is less than the predetermined value. In this case, the sorting mechanism 3 directs the terminal end of the tube 6 toward the first cage B1 when the fish F is estimated to be large, and directs the terminal end of the tube 6 toward the second cage B2 when the fish F is estimated to be small.

[0042] Furthermore, in the above embodiment, the fish F are sorted into two categories, "large" and "small," but the number of categories is not particularly limited.

[0043] In the above embodiment, a soft PVC tube is used as the tube 6, but the material of the tube 6 is not particularly limited as long as it allows sound waves to pass through. Furthermore, as shown in Fig. 4, the portion 61 of the tube 6 that penetrates the Helmholtz resonator 5 may be made of a mesh tube (net tube) that allows liquid to pass through. In this case, the material of the mesh tube is not particularly limited. [Example]

[0044] In Example 1, an experiment was carried out to examine the material and diameter of the tube 6 for passing the fish F. Figure 5 is a schematic diagram of the experimental system used in this example.

[0045] The Helmholtz resonator 5 was placed in the water tank T4, and water was stored in the water tank T4. The water depth was 35 cm and the water temperature was 3°C.

[0046] Furthermore, five types of tubes 6 with different diameters were prepared, designated as samples 1 to 5. A soft PVC tube (manufactured by Hinode Kasei Co., Ltd.) was used as the tube 6. The inner diameter and outer diameter of each sample are shown in Table 1.

[0047] [Table 1]

[0048] One tube 6 was inserted into the opening 52 of the Helmholtz resonator 5 and fixed in place by the support 9. A sweep sound varying from 200 Hz to 400 Hz over two seconds was emitted from the sound generator 53. The sound generator 53 was a UW30 manufactured by Electro Voice. The amplifier 11 (AK170 manufactured by FLAMEER) was operated so that the sweep sound was loud enough to overcome the noise. The sound collector 54 that collected the sweep sound was an AQH020 manufactured by Aquasound. The resonant frequency (the frequency at which the amplitude is maximized) was determined by performing a fast Fourier transform on the recorded data using a computing device 12 (Endeavor NJ4300E manufactured by EPSON) to obtain a power spectrum.

[0049] First, the resonant frequency was measured when no air was introduced into tube 6. Next, as a sample in place of the fish swim bladder, air A was injected into tube 6 in amounts from 0.1 mL to 1.0 mL at 0.1 mL intervals using syringe 10, and the resonant frequency corresponding to each amount of air was measured. This series of measurements was performed for each of samples 1 to 5.

[0050] 6, the resonant frequency was measured without inserting the tube 6 into the Helmholtz resonator 5. Next, as shown in FIG. 7, air A was injected into the Helmholtz resonator 5 in amounts from 0.1 mL to 1.0 mL at 0.1 mL intervals, and the resonant frequency corresponding to each amount of air was measured.

[0051] Fig. 8 is a graph showing the relationship between the air volume and the resonant frequency when the tube 6 is not present and when the tubes 6 of samples 1 to 5 are inserted into the Helmholtz resonator 5. From this result, it was found that when the outer diameter of the tube 6 is 30 to 58 mm, the amplitude decreases with increasing air volume. It was also found that when the outer diameter of the tube 6 is 51 mm, the amount of change for air volumes of 0.0 mL to 1.0 mL is the largest.

[0052] Furthermore, a single tone of a fixed frequency (approximately 300 Hz) was emitted from sound generator 53, and the amplitude of the sound collected by sound collector 54 was measured when no air was introduced into tube 6 and when air A was introduced into tube 6 in amounts from 0.1 mL to 1.0 mL at 0.1 mL intervals. The measurement results are shown in Figure 9.

[0053] In all of Samples 1 to 5, the amplitude increased when 0.1 mL of air was introduced. In Sample 1, which had the smallest diameter (outer diameter 30 mm), the amplitude decreased as the air volume increased further. In Samples 2 to 5, the amplitude increased until the air volume reached 0.2 mL or 0.3 mL, and then began to decrease. Therefore, although the frequency of the sound emitted from sound generator 53 differs from the resonant frequency, it was found that it is possible to estimate the air volume from the amplitude as long as the air volume range yields an amplitude smaller than the amplitude at an air volume of 0.0 mL. In other words, it was found that even if the sound has a frequency different from the resonant frequency, it is possible to estimate the size of an object depending on the size range of the object.

[0054] The widest range of estimable air volume was obtained when sample 1 (outer diameter 30 mm) was used, and even when focusing on the amount of change in amplitude, the amount of change was greatest between 0.0 mL and 1.0 mL of air volume, indicating that tube 6, with an outer diameter of 30 mm, is particularly suitable for volume estimation.

[0055] From the above, it has been found that the outer diameter of at least the portion of the tube 6 that passes through the Helmholtz resonator 5 is preferably 30 to 58 mm, and particularly preferably 30 mm and 51 mm. [Example]

[0056] In Example 2, fish F were sorted using the sorting system 1 shown in FIG. 1. The Helmholtz resonator 5 used in this example was the same as that used in Example 1. The tube 6 used in this example was the same as sample 4 (inner diameter 45 mm, outer diameter 51 mm) used in Example 1. Two types of goldfish, "Koaka" (body length approximately 2 cm) and "Anekin" (body length approximately 4 cm), were used as fish F. The weight of each fish F was measured in advance. A Raspberry Pi was used as the estimation device 4. The sorting mechanism 3, which switches the direction of the end of the tube 6, was realized by tying a servo motor and the tube 6 together with a string.

[0057] First, to investigate the relationship between the size (weight) of fish F and the amplitude of the resonant sound, a total of eight fish F, four "small red" fish and four "elder goldfish," were placed in the source tank T1, and all of the fish F were passed through the tube 6 in a predetermined order while a single tone of 1014 Hz, which is the resonant sound when no fish F are present in the tube 6, was played from the sound generator 53. The amplitude acquisition unit 41 of the estimation device 4 obtained the amplitude of the single tone by calculating the envelope of the recording data from the sound collector 54. This cycle was repeated six times, and the average amplitude of all cycles was calculated for each fish F.

[0058] The measurement results are shown in Figure 2, and it was found that the amplitude of the resonance sound decreased as the volume of fish F increased. Based on this, the amplitude threshold for estimating whether fish F was a "small red" or "elder goldfish" was set to 6800.

[0059] Next, an experiment was conducted to sort a total of 16 fish F, including 11 "small red" fish and 5 "golden fish," using the sorting system 1. Specifically, the 16 fish F were placed in the source tank T1 and left so that each fish F was randomly sucked into the tube 6. A single tone of 1014 Hz was emitted from the sound generator 53, and the estimation unit 42 of the estimation device 4 estimated that the fish F was a "small red" fish if the amplitude of the sound collected by the sound collector 54 when the fish F passed through the Helmholtz resonator 5 was 6800 or greater. If the amplitude was less than 6800, the estimation unit 42 estimated that the fish F was a "golden fish." Based on this estimation result, the sorting mechanism 3 sorted the fish F estimated to be a "golden fish" into the first basket B1 and the fish F estimated to be a "small red" into the second basket B2.

[0060] As a result, five fish F were contained in the first cage B1, four of which were "Anekin." Eleven fish F were contained in the second cage B2, ten of which were "Koaka." In other words, 14 of the 16 fish were correctly sorted.

[0061] It was found that the reason the two fish were mistakenly sorted was because multiple fish F passed through the Helmholtz resonator 5 in a short period of time, and that the size of the fish F was accurately estimated. Therefore, it is preferable to provide a mechanism (such as the valve described above) that allows the fish F to be sucked into the tube 6 at regular time intervals. [Industrial Applicability]

[0062] The present invention is particularly suitable for sorting fish, but the objects to be sorted are not particularly limited as long as they are objects that pass through the Helmholtz resonator (for example, marine products including fish and shellfish). [Explanation of symbols]

[0063] 1. Sorting system 2. Estimation System 3. Sorting mechanism 4 Estimation device 40 Auxiliary storage 41 Amplitude acquisition section 42 Estimation part 5 Helmholtz resonator 51 Container 52 Opening 53 Pronunciation section 54 Sound collection section 6 tubes 61 parts 7. Pump 8 Circulation path 9 Support stand 10 syringes 11 Amplifier 12 Arithmetic unit A. Air D Correlated Data F Fish (object) P estimation program T1 Original tank T2 measuring tank T3 Sorting Tank T4 Aquarium

Claims

1. An estimation device for estimating the size of an object, comprising: an amplitude acquisition unit that acquires the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; an estimation unit that estimates the size of the object based on the amplitude; An estimation device comprising:

2. The estimation device according to claim 1 , wherein the sound is a resonance sound generated in the Helmholtz resonator when the object is not present in the Helmholtz resonator.

3. The estimation device according to claim 1 , wherein the estimation unit estimates a volume of the object.

4. The estimation device according to claim 1 ; a Helmholtz resonator through which the object passes; An estimation system comprising:

5. The Helmholtz resonator is a container for storing a liquid; an opening provided in the container; a sound generating unit that generates the sound in the liquid; a sound collection unit that collects the sound; Equipped with The estimation system according to claim 4 , wherein the amplitude acquisition unit acquires the amplitude of the sound collected by the sound collection unit.

6. a tube passing through the Helmholtz resonator through the opening; The estimation system according to claim 5 , wherein the object passes through the tube.

7. The estimation system of claim 6 , wherein the tube is a flexible PVC tube.

8. The estimation system according to claim 4 , wherein the object is a fish.

9. 1. A sorting system for sorting objects, comprising: The estimation system according to any one of claims 4 to 8; a sorting mechanism that sorts the objects based on the estimation result by the estimation unit; A sorting system comprising:

10. 1. An estimation method for estimating a size of an object, comprising: an amplitude acquisition step of acquiring the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; an estimation step of estimating a size of the object based on the amplitude; An estimation method, including:

11. A sorting method for sorting objects, comprising: Each step of the estimation method according to claim 10; a sorting step of sorting the objects based on the estimation result from the estimation step.

12. An estimation program for estimating the size of an object, an amplitude acquisition unit that acquires the amplitude of a sound when the object is present within the Helmholtz resonator and the sound has a predetermined frequency; and an estimation unit that estimates the size of the object based on the amplitude; An estimation program that makes a computer function as a

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