WO2023049977A1

WO2023049977A1 - Method for obtaining an information referring to a container, method for calculating an information referring to a container, processing means for calculating an information referring to a container, and device for obtaining an information referring to a container

Info

Publication number: WO2023049977A1
Application number: PCT/BR2022/050378
Authority: WO
Inventors: Luis Fernando GOMEZ GONZALES; Erick MASCAGNI FERDINANDO; Alexandre Luiz JUNQUEIRA MARTINS
Original assignee: Gfd Administração Patrimonial E Participações Ltda.; Mvbr Tech Ltda.; Inmetrics S/A
Priority date: 2021-09-29
Filing date: 2022-09-26
Publication date: 2023-04-06
Also published as: AR127130A1; BR102021019569A2

Abstract

This invention relates to methods, means and devices for obtaining information referring to a container, particularly to methods, means and devices that allow measuring the level of solid or liquid material inside containers, based on the unfilled portion inside such container, or, in other words, filled with gaseous material (such as air), through acoustic response from this container to artificial or natural excitation.

Description

Specification of the Patent for “METHOD FOR OBTAINING AN INFORMATION REFERRING TO A CONTAINER, METHOD FOR CALCULATING AN INFORMATION REFERRING TO A CONTAINER, PROCESSING MEANS FOR CALCULATING AN INFORMATION REFERRING TO A CONTAINER, AND DEVICE FOR OBTAINING AN INFORMATION REFERRING TO A CONTAINER”

[001] This invention refers to methods, means and devices for obtaining an information referring to a container.

[002] Particularly, this invention refers to methods, means and devices that allow measuring the level of solid or liquid material inside containers, considering the portion inside said container that is unfilled, or filled with gaseous material (such as air).

Background

[003] In spite of the various methods currently known to measure the amount of liquid or solid material inside containers, all of them require the insertion of an equipment or device inside the relevant container, meaning that most methods commercially available are invasive.

[004] A few exceptions to the above comprise measures that are only effective in conductive containers containing liquid, the physical features of which must be well known prior to the measurement (and must be non-conductive), as happens with capacitive fuel level sensor. Methods that depend on specific characteristics of the container and of the liquid or solid cannot be applied in a flexible manner.

[005] The invasive methods currently available in the literature and in the market are always based on general characteristics, such as distance or weight, and can be applied without prior knowledge of the characteristics of the material to be measured. Among such methods, one should emphasize the measurements by light reflection and ultrasound reflection, that use said waves to measure the distance from a certain spot of the container, such as the top, to the upper portion of the material contained therein. So, the operation of these techniques requires the installation of a transmitter/receiver set inside the container, or of a signal transportation pipe inside it. Another technique widely used is the measurement of the container’s weight. Nevertheless, it depends on the knowledge of the effective density of the material inside it, and presents cost concerns when applied to high volumes, such as grain bins, mealy or animal food tanks, or large fuel containers.

[006] For instance, the document US3912954 refers to a measurement system using a narrow audio beam. However, the method disclosed by the document is based on the reflex of an acoustic wave on a surface, wherein the time lapsed between transmission and receipt is proportional to the distance measured. This provides a significant complexity to the method, that implies the use of more specific components and consequently high production costs.

[007] In another example, the document US5793705 refers to an ultrasonic measurement system. The technology disclosed by said document uses the spread time of the ultrasonic sound wave (time until the surface and back to detector) to measure the distance. This method presents the same characteristics and inconveniences shown by the prior document (US3912954).

[008] The document US4247784 refers to a measurement system that can be used to closed containers. However, due to the use of reflex from a light source, its disadvantages are similar to the ones disclosed by the prior documents.

[009] Other methods, such as the use of radiofrequency (US7515095), and combination between capacitive and ultrasonic sensors (US7610805) are also primarily based on the time required for a certain electromagnetic or mechanic wave to be reflected on the surface of the material or on the intensity reflected by this latter. This last document US7610805 only uses a capacitive sensor to deactivate the ultrasonic when the volume of the container is full. All these documents share the characteristics and deficiencies mentioned in relation to the document US3912954.

[0010] The documents US20160258803 and US5251482 disclose methods for determining the level or content of containers through detection and treatment of acoustic responses. However, the methods revealed therein can only be applied in small containers particularly designed for laboratory purposes and require coupling an element to the container nozzle to the insertion of the sensors, meaning that this is not a solution implemented outside the container. There is no lesson disclosed by these documents about the possibility or feasibility of applying the technology to large containers; instead, such application would be unfeasible, given the high costs for adapting the method to exponentially larger containers.

[0011] A characteristic shared by all the documents that describe technologies relating to the use of mechanic or electromagnetic waves to measure volume or distance is the use of sensors partially (in a small hole, for example) or completely inside the container to the measured, which necessarily implies an inconvenience for the installment and maintenance of said device, in addition to the other above-mentioned concerns.

Objectives of the Invention

[0012] A first objective of this invention is to provide methods, meanss and devices that allow the identification of an information referring to a recipient through a solution arranged outside said container, without need of intrusive implementation.

[0013] A second objective of this invention is to provide methods, meanss and devices to allow measuring the amount of liquid or solid material inside the container, considering the portion thereof that is unfilled. [0014] A third objective of this invention is to provide methods, meanss and devices that allow the identification of information referring to the container on a non-invasive manner, meaning that they do not require the installation of devices or equipment inside the container.

[0015] A fourth objective of this invention is to provide methods, meanss and devices to identify information referring to the container that can be used in a flexible manner and in a wide range of containers, regardless of the size thereof, of the material it is made of, or of the material inside it.

Brief Description of the Invention

[0016] This invention addresses a method for obtaining an information referring to a containing, that comprises the steps of measuring, through a measurement means, the acoustic response of a container to an acoustic excitation on it, and of calculating, through a processing means, at least one information referring to the container based on the acoustic response as measured.

[0017] In a possible embodiment, the acoustic excitation that acts on the container is a noise from the environment where the container is located.

[0018] In another possible embodiment, the acoustic response is the first full multiple of acoustic response frequency that can be captured by the measurement.

[0019] In another possible embodiment, the method comprises the steps of identifying if the acoustic excitation amplitude as measured is proportional to a harmonic; and, if it is, inferring which is the order of this harmonic considering the data previously measured.

[0020] In another possible embodiment, the method comprises the steps of identifying if there is any ambiguity in the acoustic excitation amplitudes as measured, and, if there is any such ambiguity, inferring the amplitude or information referring to the container, based on information previously obtained in relation to the container.

[0021] In another possible embodiment, the method comprises the step of generating, through an acoustic excitation generation means, an acoustic excitation on the container.

[0022] In another possible embodiment, the method comprises the steps of identifying, through a processing means, if the measurement captured an acoustic response from the container, and, if not, activating, through a processing means, the acoustic excitation generation means. [0023] In another possible embodiment, the calculation of at least one information referring to the container is performed in an analytic manner, or through “Machine Learning”.

[0024] Further, this invention contemplates a method of analytic calculation of an information referring to a container, that comprises the steps of obtaining a function of amplitude by frequency through the application of a Fourier Transform to the acoustic response; identifying a multiplicity of peaks in a derived graph of the function amplitude by frequency; identifying the frequency f corresponding to each peak identified; calculating a characteristic length to each peak identified, by using the following equation:

And further: excluding the results of characteristic length that coincide with a known measure of the container; separating the results of characteristic length into groups, according to a statistic weight given by the integrated amplitude in each group; identifying the group of characteristic length with highest statistic weight; calculating a mean of the values of characteristic length found in the group of highest statistic weight; and obtaining an information referring to the container based on the mean of values calculated for the length.

[0025] This invention still contemplates a method to calculate an information referring to a container, that comprises the steps of feeding, at the entry of a neural network, an acoustic response obtained through a measurement means and at least one of the following: artificial acoustic excitation generated by an acoustic excitation generation means, a natural acoustic excitation generated by environment noise and the values of dimensions of the container; and obtaining an information referring to the container, based on the information fed.

[0026] This invention still contemplates a processing means to calculate an information referring to a container, wherein the processing means is configured to perform the method of calculating information referring to an aforesaid container, in any of its possible embodiments.

[0027] This invention still contemplates a device for obtaining information referring to a container, wherein the device is configured to perform the method of obtaining information referring to an aforesaid container, in any of its possible embodiments.

[0028] In a possible embodiment, the device comprises a measurement means configured to measure an acoustic response of a container to an acoustic excitation acting on the container, as well as a processing means configured to calculate at least one information referring to the container, based on the acoustic response as measured. [0029] In another possible embodiment, the device comprises an acoustic excitation generation means, configured to generate an acoustic excitation on the container.

[0030] In another possible embodiment, the device is connected to an external device to display the information obtained in relation to the container.

Summarized Description of the Drawings [0031] This invention shall be described in further details below, according to an exemplary embodiment depicted in the drawings. The figures show:

[0032] Figure 1 - is a schematic representation of the method, means and device of this invention to obtain an information referring to a container, wherein they are applied to a container in a preferential embodiment;

[0033] Figure 2 - is a schematic representation of the device of this invention, in a preferential embodiment;

[0034] Figure 3 - is a flow chart of the method of this invention for obtaining an information of a container, in a preferential embodiment;

[0035] Figure 4 - is a flow chart of the method of this invention to calculate an information referring to the container, in a preferential embodiment.

Detailed Description of the Figures

[0036] Firstly, one should point out that the term “preferential” as used herein should not be understood as “mandatory” or “imperative”, as it merely characterizes a particularly efficient embodiment of the invention, among multiple possible other embodiments.

[0037] For a better understanding of this invention, the steps of the methods proposed shall be referenced in the format “letter + number”, such as “A1”, “A2”, etc.

[0038] The figure 1 depicts the application of the method, means and device for obtaining information referring to a container, in its preferential embodiments. For obtaining information referring to the container, the following steps are implemented:

[0039] - measure A1 , through a measurement means 10, an acoustic response of a container 20 to an acoustic excitation 30 acting on the container 20;

[0040] - calculate A2, through a processing means 40, at least one information referring to the container 20, based on the acoustic response as measured.

[0041] The measurement means 10 can be any element, device or equipment that allows capturing an acoustic signal, particularly an acoustic response from the container 20 to an acoustic excitement 30. Preferably, the measurement means 10 can be configured to convert the acoustic response into an electric signal for further processing by a calculation unit 40. Accordingly, the measurement means 10 can be a microphone, for instance. For the sake of clarity, the kind of microphone selected to the measurement depends on the desired frequency scale, as well as on the data acquisition system, and the most recommendable microphones are the electret model and the solid state-type for acquisition of frequencies within the audible interval. The microphone, or microphones are preferably positioned at the external door opposite to the acoustic excitement generation means 31 , as seen below, but it is possible to install them at any position in the container, depending on the peculiarities of the application.

[0042] The acoustic excitation 30 acting on the container 20 can be any acoustic stimulation able to cause resonance on the structure of the container 20, the intensity of which can be captured by the measurement means 10. In this respect, two exemplary forms of acoustic excitation 30 are proposed to act on the container 20, namely: (i) an acoustic excitation 30 resulting from the sound naturally generated in the environment 1002 where the container 20 is located, and (ii) an artificial acoustic excitation 30 generated by an acoustic generation means 31 .

[0043] In the first proposal (i) of acoustic excitation generation 30, the environment 1002 that hosts the container 20 has a level of noise or environmental sound that is enough to generate, in the container 20, an acoustic response with intensity enough to be captured by the measurement means 10. In such cases, an artificial acoustic excitation generation is not required.

[0044] In the second proposal (ii) of acoustic excitation generation 30, the environment 1002 is not able to generate a noise or sound that is sufficient to generate, in the container 20, an acoustic response with intensity enough to its suitable capture by the measurement means 10. In such cases, the use of an artificial acoustic excitation 30 is needed, preferably generated by an acoustic excitation generation means 31 . The acoustic excitation generation means 31 can be, for instance, a loudspeaker connected to a processing unit 40 through an amplifier 41 , as seen in the preferential embodiment of the figure 2. Preferably, the acoustic excitation generation means 31 is placed in the container 20, on a wall or structure opposite to the one where the measurement means 10 is placed. Preferably, the acoustic excitation generation means 31 generates a known acoustic wave and can be a sequence of single frequency or a liner chirp, with a frequency linearly increased through the time. Still preferably, the acoustic excitation generation means 31 is put in physical contact with the container 20, so as to transfer the mechanic wave to the container 20.

[0045] In a possible embodiment, the processing unit 40 can be connected to the measurement means 10 and configured to identify A11 , whenever the measurement means 10 captures any distance of acoustic response from the container 20. Such identification A1 1 or capture checking through the measurement means 10 can be performed, for instance, just upon activation of the processing unit 40 by an operator. The identification can be reiterated in multiple occasions, until the measurement means 10 captures an acoustic response, or until expiry of a certain, such as some seconds, or until the operator sends a command to the processing unit to force the artificial acoustic excitation generation. Whenever the measurement means 10 does not capture any acoustic response from the container 20 under the aforesaid conditions, the processing unit 40 can activate A12 the acoustic excitation generation means 31 to generate an artificial acoustic excitation 30 that is sufficient for the container to generate an acoustic response likely to be captured by the measurement means 10. The activation A12 of the acoustic excitation generation means 31 by the processing unit 40 can be performed in any suitable manner, such as the transmission of an analogic signal to the amplifier that subsequently sends such amplified signal to the loudspeaker 31. The figure 3 discloses a flowchart that summarizes the above-mentioned steps.

[0046] In this respect, the lowest frequency to be generated by the acoustic excitation generation means 31 to allow the measurement means 10 capturing an acoustic response from the container 20 can be obtained by the following equation:

[0047] The acoustic response issued by the container 20 is represented, in the figure 1 , by the references R1 and R2, wherein R1 is the first resonance harmonic of the response and R2 the first full multiple of this frequency. In this respect, the first harmonic presents higher amplitude, and could not be captured by some measurement means 10. For instance, if the measurement means 10 is a microphone, the kind of microphone used to capture the acoustic response can be unable to capture a considerably high amplitude. However, it is recommendable using the highest amplitude as possible, so as to differentiate resonance signal from environmental noise. Therefore, the full sequential multiple frequencies are assessed for the identification, among them, of a multiple likely to be captured by the measurement means 10. [0048] In view of the above, as the only measurement of frequency can be ambiguous to determine information about the container 20 (as measurements reflect not only the frequency of the major resonance, but also of its harmonics (full multiples)), in a possible embodiment, this method can use at least one of two steps to infer the correct information about the container 20: the amplitude of acoustic response as measure, and, if there is still any ambiguity, the background of prior information. In this respect, the amplitude observed in relation to resonance is lower for each harmonic of higher order (higher frequency) as measured, and thus allows inferring, by prior measurements, if a certain amplitude is proportional to the fundamental frequency or to a harmonic and, in this second case, inferring which is the order of such harmonic. If the environmental noise does not allow a clear separation of the amplitudes as measured, it is still possible to circumvent such ambiguity through the use of information on the container 20 that were previously calculated, thus inferring the correct information based on previously measured information. For instance, if this method obtains an information of 0.5m and 1 m height (ambiguous), and the measure obtained in an iteration immediately prior to implementation of the method was 0.55m, one can infer that the correct measure probably corresponds to 0.5m; if it is incorrect, the data shall be further likely to be rectified.

[0049] The container 20 itself can be formed by any materials, which is an advantage of this invention when compared to prior art techniques, as some measurement methods known from the state of art are only applicable to containers or to materials stored inside it having specific properties, or formed by specific materials. Moreover, the container 20 can be configured at any suitable formats, such as cylindric or parallelepiped forms.

[0050] The reference 1001 of figure 1 indicates the material inside the container, that can be either solid or liquid. The reference 1000 of figure 1 indicates the unfilled portion of the container. The term “unfilled portion” should be understood within the context of this invention as a portion that does not contain the material 1001 solid or liquid, but can be filed with a material that allows free transmission of acoustic stimuli and responses inside such portion 1000, such as, for instance, gaseous material and particularly air. The reference “Lv” of figure 1 indicates the height referring to the volume of the unfilled portion 1000 from the container 20. It is worth noting that the methods, means and devices of this invention allow measuring the information relating to the container 20 regardless of the kind of gaseous material inside the unfilled portion 1000, that can be, for instance, a flammable (such as gaseous steam) or corrosive material. Such benefit results from the fact that this invention does not require the placement of any of its elements inside the container 20, being not affected by the characteristics of the material inside the container 20, so that it is possible to operate with any kind of material.

[0051] So, the step of calculating A2 at least one information referring to the container 20 based on the acoustic response as measured is performed by a processing means 40, that can be, for instance, a processing unit of any kind. Said calculation can be performed in an analytic manner, or through “Machine Learning”. A possible embodiment of the method of analytic calculation that can be performed to determine an information referring to the container 20 shall be detailed below, as well as in the flowchart of figure 4, and comprises the steps of:

[0052] - obtaining A20 a function of amplitude by frequency through application of Fourrier Transform on the acoustic response;

[0053] - identifying a multiplicity of peaks (preferably from 5 to 8 peaks) in a derived graph of function of amplitude by frequency;

[0054] - identifying A22 the frequency f corresponding to each peak identified;

[0055] - calculating A23 a characteristic length Cc for each peak identified, by using the following equation:

[0056] - excluding A24 the results of characteristic length Cc that coincide with a known measure of the container;

[0057] - separating A25 the results of characteristic length into groups, based on a statistic weight given by the integrated amplitude in each group;

[0058] - identifying A26 the group of characteristic length with higher statistic weight;

[0059] - calculating A27 a mean of values of characteristic length belonging to the group of higher statistic weight; and

[0060] - obtaining an information referring to the container 20, based on the mean of characteristic length as calculated.

[0061 ] For the sake of clarity, the step A25 of separating the results of characteristic length into groups is better explained below. The identification of the amplitude of each harmonic requires an integration of the values around the peak of a graph within the space of frequencies, considering that, in view of the application of the solution to an long body and of the lack of infinite resolution in the microphone, the values of frequency are not thin lines, being instead distributed around an upper value. Upon integration around the peak, the acoustic amplitude measured for this harmonic is observed, and the harmonics can be classified according to their integrated amplitude. Such classification allows ordering them from the most to the less significant, and grouping them into “constant values” (due to the intrinsic dimensions of the container), “values of interest” (response resulting from the variation of height of the material inside the container) and “environmental noise” (values of lower amplitude, that can be excluded)..

[0062] The step A28 of obtaining an information referring to the container 20 can be performed to obtain a variety of information. The mean values of characteristic length obtained in the step A27 already represents the height “Lv” of the unfilled portion of the container 20, so that the step A28 can be simply limited to characterize this information as such through a processing unit 40, and optionally to send it to an external device 42, such as a display device (like a terminal or a mobile device owned by the operator) to display said information to the operator. Alternatively, upon prior knowledge of the dimensions of the container 20 (such as diameter or length of the walls), the step A28 can consist in calculating the volume of unfilled portion 1000 of the container, based on the height of this unfilled portion as calculated in the step A27. In another possible configuration, upon prior knowledge of the total height of the container 20, one can calculate the volume of unfilled portion 1000, and then calculate the volume of portion 1001 in the container 20 that is filled with material. Further, in another possible configuration, upon knowledge of the relevant characteristics of the material inside the container (such as density), and upon calculation of the volume of filled portion 1001 , one can calculate other variables, such as weight (mass) of the material inside the container 20. These possibilities for obtaining information in the step A28 are only non-exhaustive illustrations, and any person skilled in the art may clearly conceive the possibility of obtaining other kinds of information by using this same logic.

[0063] For the sake of clarity, there is still a possible implementation through “Machine Learning”. The assessment through Machine Learning requires a prior step referred to as training, wherein acoustic data from containers showing several formats and containing different known volumes are acquired and used to train the weights for the suitable model. As this is an analysis of time series, the model selected for it is preferably a convolutional neural network. So, the steps to the analysis by using Machine Learning upon treatment of the model can be:

[0064] (i) the acoustic response obtained through the measurement means 10 and the artificial acoustic excitation generated by the acoustic excitation generation means 31 , or the environmental noise are fed at the entry of the neural network. On an optional basis, it is also possible to add, at the entries, the values of dimensions of the container, if such information is available.

[0065] (ii) the result obtained from the neural network corresponds to the height of the unfilled portion 1001 of the container 20.

[0066] A person skilled in the art shall clearly understand that, once obtained the height of the unfilled portion 1001 in the container 20, a multiplicity of related information could be obtained, including, without limitation, the ones illustrated in relation to the step A28 of the aforesaid method of analytic calculation.

[0067] According to the information provided above, this invention still contemplates a processing means 40 configured to perform the method of analytic calculation of information referring to a container 20, such as the aforesaid one.

[0068] On an alternative basis, the above-mentioned calculations (both analytic and the ones performed through machine learning) can be performed by an equipment outside the processing unit 40, such as an external processing unit belonging to a server or computer connected to the processing unit 40 of this invention.

[0069] In accordance with the information provided above, this invention still contemplates a device for obtaining information referring to a container 20, that is configured to perform the method for obtaining information referring to the aforesaid container 20. In a preferential embodiment, such device can comprise a processing means 40 and a measurement means 10 as the above-mentioned ones, in any of their possible embodiments. Said device can still comprise an acoustic excitation generation means 31 , such as a loudspeaker, that also implies the use of an amplifier 41. Said device can be still connected to an external device 42, such as a terminal or a mobile device of the operator, to the display of information obtained in relation to the container 20.

[0070] In view of the above information, this invention clearly introduces a series of advantages to the state of art, including, but not limited to:

[0071] (i) flexibility for application at any kind of container containing any kind of material;

[0072] (ii) convenience in the installation and maintenance of the device, as there is no need of installing any elements inside the container;

[0073] (iii) longer useful life of the device, due to the external application thereof;

[0074] (iv) better adaption to existing containers and systems; and [0075] (v) lower implementation costs when compared to other methods and devices previously known, as this method does not make use of highly expensive specific components.

[0076] One should also refer to exemplary illustrations of possible applications of this invention: measurement of volume of grains or animal food in bins used poultry and pig farming; measurement of volume of bins storing agricultural and general food products; measurement of volume of fuel tanks, distributors or gas tanks; measurement of water volume in water boxes.

[0077] Once described an example of preferential embodiment, it should be understood that the scope of this invention encompasses other possible variations, being exclusively limited by the content of the attached claims, including its possible equivalents.

Claims

1. Method for obtaining information referring to a container, characterized by the fact that it comprises the steps of:

- measuring (A1), through measurement means (10), an acoustic response from a container (20) to an acoustic excitation (30) acting on the container (20),

- calculating (A2), through a measurement means (40), at least one information referring to the container (20), based on the acoustic response as measured.

2. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that the acoustic response is the first full multiple (R2) of acoustic response frequency that can be captured by the measurement means (10).

3. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that it comprises the steps of:

- identifying if the acoustic excitation amplitude observed by the measurement means is proportional to a harmonic, and if the acoustic excitation amplitude measured by the measurement means (10) is proportional to a harmonic, inferring which is the order of this harmonic, based on data previously measured.

4. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that it comprises the step of:

- identifying if there is any ambiguity in the acoustic excitation amplitudes measured by the measurement means (10), and

- if any such ambiguity is identified, inferring the amplitude or information referring to the container, based on information previously obtained in relation to the container.

5. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that the acoustic excitation (30) acting on the container (20) is a noise from the environment (1002) where the container (20) is located.

6. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that it comprises the step of:

- generating (A0), through an acoustic excitation generation means (31), an acoustic excitation on the container (20).

7. Method for obtaining information referring to a container according to the claim 6, characterized by the fact that it comprises the steps of:

- identifying (A11), through the processing means (40), if the measurement means (10) captured an acoustic response from the container (20); and

- if not, activating (A12), through the processing means (40), the acoustic excitation generation means (31).

8. Method for obtaining information referring to a container according to the claim 1 , characterized by the fact that the calculation (A2) of at least one information referring to the container (20) is performed in an analytic manner, or through “Machine Learning”.

9. Method to calculate (A2) information referring to a container (20), characterized by the fact that it comprises the steps of:

- obtaining (A20) a function of amplitude by frequency through application of Fourrier Transform on the acoustic response;

- identifying (A21) a multiplicity of peaks in a derived graph of function of amplitude by frequency;

- identifying (A22) the frequency f corresponding to each peak identified;

- calculating (A23) a characteristic length (Cc) to each peak identified, by using the following equation:

- excluding (A24) the results of characteristic length (Cc) that coincide with a container’s measure already known;

- separating (A25) the results of characteristic length into groups, based on a statistic weight given by the integrated amplitude in each group;

- identifying (A26) the group of characteristic length with highest statistic weight;

- calculating (A27) a mean of values of characteristic length belonging to the group of highest statistic weight, and

- obtaining (A26) information referring to a container (20), based on the mean values of length as calculated.

10. Method to calculate (A2) information referring to a container (20), characterized by the fact that it comprises the steps of:

- feeding, at the entry of a neural network, an acoustic response obtained by a measurement means (10), and at least one among the following:

- an artificial acoustic excitation generated by an acoustic excitation generation means (31),

- a natural acoustic excitation generated by environmental noise, and

- the values of dimension of the container (20), and

- obtaining information referring to the container (20) based on the information fed.

11. Processing means (40) to calculate information 21 referring to a container (20), characterized by the fact that it is configured to perform the method as defined by the claim 6.

12. Device for obtaining information referring to a container (20), wherein the device is characterized by the fact that it is configured to perform the method as defined by any of the claims 1 to 8.

13. Device for obtaining information referring to a container (20) according to the claim 12, characterized by the fact that it comprises:

- a measurement means (10) configured to measure an acoustic response from a container (20) to an acoustic excitation (30) acting on the container (20), and

- a measurement means (40) configured to calculate at least one information referring to the container (20), based on the acoustic response as measured.

14. Device for obtaining information referring to a container (20) according to the claim 12, characterized by the fact that it comprises an acoustic excitation generation means (31 ), configured to generate an acoustic excitation on the container (20).

15. Device for obtaining information referring to a container (20) according to the claim 12, characterized by the fact that it is connected to an external device (42) for display of the information obtained in relation to the container (20).