Method and computer program for calibrating an electronic device for characterizing a fluid, and corresponding electronic device

Abstract

A method of calibrating an electronic device for characterizing a fluid includes storing a plurality of reference calibration signatures (YREF r,i ) and a parametric drift model (MOD(α,t)) (100, 102). For each of the plurality of calibration fluids, a calibration signature (YDEV r,i ) is obtained (104) through interaction with the device. At least one parameter value (α r , t r ) is determined (106) by comparing the obtained calibration signature (YDEV r,i ) with a reference calibration signature (YREF r,i ). The calibration fluids are more accurately assigned to a plurality of calibration groups, and the parameter values are determined specifically for each calibration group (106).

Description

Technical Field

[0001] The present invention relates to a method for calibrating an electronic device for characterizing a fluid using at least one sensor designed to interact with the fluid by comparing it with a reference electronic property evaluation device. The present invention relates to a corresponding computer program and a calibrated electronic device for characterizing a fluid by providing a signature obtained from an electrical measurement signal.

[0002] The present invention is particularly applicable to a calibration method including the following steps: storing in a memory a plurality of reference calibration signatures each associated with the interaction of a plurality of predetermined calibration fluids with at least one sensor of a reference electronic device; storing in a memory a parametric model having at least one adjustable parameter for drift of an electronic device to be calibrated with respect to the reference electronic device; for each of the plurality of predetermined calibration fluids, obtaining a calibration signature by the interaction of the at least one sensor of the electronic device to be calibrated; determining at least one value of the at least one adjustable parameter by comparing the obtained calibration signature with the reference calibration signature.

[0003] Thus, by applying at least one determined value of the adjustable parameter to the parametric drift model, it is possible to correct any signature obtained by the interaction of any fluid with the at least one sensor of the thus calibrated electronic device.

[0004] Such a calibration procedure is taught, for example, in the paper "On-line sensor calibration transfer among electronic nose instruments for monitoring volatile organic chemicals in indoor air quality" by Zhang et al. (Sensors and Actuators B: Chemicals, Vol. 160, No. 1, pp. 899 - 909, published on December 15, 2011). In this paper, a global affine transformation drift model is used based on the assumption of linear homogeneity between electronic devices for the evaluation of the olfactory characteristics of fluids. Although the hypothesis is proven to be valid, the reality of drift unfortunately does not fully follow the model.

[0005] To refine the parametric drift model, it can be made more complex. However, it also makes the calibration more complex.

[0006] Therefore, there may be a desire to provide a calibration method that avoids at least some of the above-described problems and constraints.

[0007] Therefore, a method for calibrating an electronic device for characterizing a fluid using at least one sensor designed to interact with the fluid by comparing it with a reference electronic characteristic evaluation device is proposed, the method including the following steps: storing in a memory a plurality of reference calibration signatures respectively associated with the interaction of a plurality of predetermined calibration fluids with at least one sensor of a reference electronic device; storing in a memory a parametric model having at least one adjustable parameter for drift of the electronic device to be calibrated with respect to the reference electronic device; for each of the plurality of predetermined calibration fluids, obtaining a calibration signature by the interaction of the at least one sensor of the electronic device to be calibrated; determining at least one value of the at least one adjustable parameter by comparing the obtained calibration signature with a reference calibration signature, The predetermined calibration fluid is divided into several different calibration groups, and the determination of the at least one value of the at least one adjustable parameter is specifically performed for each calibration group.

[0008] Thus, by cleverly providing several different calibration groups where each parameter value of the parametric drift model is unique and thus empirically different for each calibration group, the calibration method can be more granular and closer to the reality of possible drifts without the need to complicate the parametric drift model used. Substantial improvements have been experimentally measured. Furthermore, it should be noted that this calibration method is applicable to both the drift over time of a single electronic fluid property evaluation device, i.e., the repeatability drift of this device, and the manufacturing drift of several electronic fluid property evaluation devices, i.e., the reproducibility drift of these devices.

[0009] Optionally, the calibration method according to the invention may further comprise applying the at least one adjustable parameter value within the parametric drift model to correct any signature obtained by the interaction of any fluid with the at least one sensor of the electronic device to be calibrated, this step comprising the selection of a calibration group associated with any fluid based on that signature, and then the correction of that signature using the at least one adjustable parameter value of the selected group. It is certainly wise to associate the step of preselecting a calibration group for any fluid characterized based on that signature with the above-described principle of calibration by the identified group, even before correcting that signature by calibration taking into account the drift model specific to the selected group.

[0010] Optionally, the selection of a calibration group associated with any fluid includes automatically classifying that signature into one of the calibration groups by comparing this signature with the calibration signature(s) obtained from the calibration fluid(s) within each calibration group.

[0011] Optionally, the correction of any fluid signature includes inverting a parametric drift model to which the at least one adjustable parameter value of the selected calibration group is applied.

[0012] Optionally, obtaining a calibration signature for each of a plurality of predetermined calibration fluids includes obtaining a first calibration signature having N≧1 component(s), and then transforming this first calibration signature by normalization and / or component reduction.

[0013] Optionally, the parametric drift model is a two-parameter adjustable affine model YDEV r,i =α r ·YREF r,i +t r where YDEV r,i is the obtained calibration signature of a predetermined calibration fluid of index i of a calibration group of index r , YREF r,i is the reference calibration signature of a predetermined calibration fluid of index i of a calibration group of index r , α r is the value of the first adjustable multiplicative parameter of the affine model of a calibration group of index r , and t r is the value of the second adjustable additive parameter of the affine model of a calibration group of index r .

[0014] Optionally, the correction of the signature of any fluid is calculated

Number

[0015] Optionally, one of the first adjustable multiplicative parameter and the second adjustable additive parameter is independent of the calibration group.

[0016] Also proposed is a computer program downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor capable of exchanging data with a memory. The memory includes a plurality of reference calibration signatures respectively related to the interaction of a plurality of predetermined calibration fluids with at least one sensor of a reference electronic property evaluation device, and a parametric model having at least one adjustable parameter for the drift of an electronic property evaluation device calibrated with respect to a reference electronic device, are stored, The processor for each of the plurality of predetermined calibration fluids, obtaining a calibration signature by the interaction of at least one sensor of the electronic device to be calibrated; and determining at least one value of the at least one adjustable parameter by comparing the obtained calibration signature with the reference calibration signature, and includes instructions for performing the steps. The predetermined calibration fluids are divided into several different calibration groups, and the instructions are designed such that the determination of the at least one value of the at least one adjustable parameter is specifically performed for each calibration group.

[0017] Also, a calibrated electronic device for characterizing a fluid by providing a signature obtained from an electrical measurement signal is proposed, the calibrated electronic device comprising: at least one sensor designed to interact with the fluid; a transducer designed to interact with the at least one sensor to provide an electrical measurement signal; a memory storing: a parametric model having at least one adjustable parameter for drift of the calibrated electronic device relative to a reference electronic characterization device; at least one value of the at least one adjustable parameter calculated by pre-calibrating the calibrated electronic device by comparison with a reference electronic device based on a plurality of predetermined calibration fluids; a processor for correcting the signature by applying the at least one adjustable parameter value. The predetermined calibration fluids are divided into several different calibration groups, the memory storing at least one specific value of the at least one adjustable parameter for each of the calibration groups, and the processor is programmed to more specifically select a calibration group associated with the fluid to be characterized based on its signature and then correct its signature using the at least one specific adjustable parameter value of the selected group.

Brief Description of the Drawings

[0018] The present invention is given by way of example only and will be better understood with the help of the following description made with reference to the accompanying drawings.

Figure 1

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Figure 8

[0019] An electronic device 10 for evaluating olfactory properties of a fluid by providing a SIG signature obtained from an electrical measurement signal S, as schematically shown in FIG. 1, is a non-limiting example of an electronic fluid property evaluation device according to a first embodiment of the present invention for non-limiting applications of odor discrimination by multi-valued olfactory measurements. It includes a measurement chamber 12 designed to receive a fluid, such as a gas like ambient air. For this purpose, it includes a suction device 14 designed to draw air from inside the measurement chamber 12 and discharge it outside. It further includes an air inlet 16 that can be selectively closed to maintain ambient air inside the measurement chamber 12 or can be opened to allow ambient air to be discharged from the measurement chamber 12 and updated by operating the suction device 14. Thus, it is provided with means for controlling the incoming and outgoing flows.

[0020] In the measurement chamber 12, the electronic olfactory property evaluation device 10 includes several sensors, particularly olfactory sensors 18, which are arranged close to the fluid to be analyzed by the device 10 and are designed to interact with compounds that are likely to be present in the measurement chamber 12 when these compounds are released, particularly when the air inlet 16 is close to the fluid in question. They are respectively distributed over, for example, about 60 reaction sites. The released compounds are generally volatile organic compounds, but the present invention is not limited to such compounds.

[0021] Each olfactory sensor 18 itself is, for example, a biosensor designed to interact with compounds from a specific family of volatile organic compounds. In practice, each olfactory sensor 18 can include molecules such as peptides immobilized on a substrate or polymers covering the surface that are complementary to the compounds of the family associated with this olfactory sensor 18.

[0022] Alternatively, the electronic olfactory property evaluation device 10 can be adapted to contact any fluid (liquid or gas) other than ambient air. Particularly in a simple version, it may not include the suction device 14, the air inlet 16, and further the measurement chamber 12. In this simple version, the olfactory sensors 18 can be brought into direct contact with the fluid to be analyzed without flow control.

[0023] The olfactory sensor 18 is associated with and interacts with at least one transducer 20. This transducer 20 is arranged and configured to measure any change in physical properties caused by the interaction between the olfactory sensor 18 and the fluid to be analyzed. This provides, for example, an electrical measurement signal S in the form of a sequence of electrical measurement signals, which characterizes this fluid, since this sequence represents volatile organic compounds with which the olfactory sensor 18 can interact within the measurement chamber 12.

[0024] More specifically, the transducer 20 can be a surface plasmon resonance (SPR) imaging system configured to measure any change in refractive index resulting from the interaction of the fluid under investigation with at least one of the olfactory sensors due to the plasmon effect. Such a transducer includes a metal layer whose first surface with reaction sites functions as a support for the olfactory sensor 18, an optical prism arranged with respect to the second surface opposite to the first surface of the metal layer, a device for illuminating this second surface of the metal layer with collimated and polarized light through the light input surface of the optical prism, and a camera arranged at the light output of the optical prism to provide a sequence of measurement signals S in the form of a sequence of grayscale images of the reaction sites where the olfactory sensor 18 is arranged. For example, the reaction sites on the first side of the metal layer are organized in a positioning matrix grid.

[0025] Alternatively, the transducer 20 may be a Mach-Zehnder interferometer optical refractive index fluctuation amplification system, such as Mach-Zehnder interferometer (MZI) matrix technology, or more specifically MZI multimode interference (MZI / MMI) technology. Such a system is configured to measure any change in refractive index due to the interaction of the fluid under investigation with at least one of the olfactory sensors resulting from a detectable phase shift between the reference arm of the interferometer and the sensing arm where any such reaction sites are arranged. The resulting transducer provides a sequence of measurement signals S in the form of a sequence of images of the phase shift represented in radians of the olfactory sensor 18.

[0026] In another variant, the transducer 20 may be a NEMS (nanoelectromechanical system) or MEMS (microelectromechanical system) amplification system. Such a system is configured to measure any change in the resonant frequency of the diaphragm where any one of the olfactory sensors is arranged. The reaction sites where the olfactory sensor 18 is arranged are arranged in a matrix of NEMS or MEMS diaphragms, for example, to provide a sequence of measurement signals S in the form of a sequence of resonant frequency shift signals of the olfactory sensor 18.

[0027] Using a simple adaptation of the electronic olfactory property evaluation device 10 that is not disclosed because it is within the reach of those skilled in the art, other alternative forms can be considered by implementing any other equivalent physical conversion device (i.e., optical, mechanical, etc.). Regardless of the choice of transducer 20, the general idea remains of using an olfactory sensor 18 (i.e., biosensor, polymer, carbon nanotube, etc.) to functionalize the reaction site to distinguish, adsorb, and desorb volatile organic compounds, generate a molecular interaction response distinguished from the olfactory sensor, and amplify the response in the form of a sequence S of electrical measurement signals using a physical conversion device.

[0028] The electronic olfactory property evaluation device 10 further includes several functional modules disclosed below. In the disclosed examples, these modules are software modules. Thus, the device 10 includes an element 22 such as a computer that includes a processing unit 24 and an associated memory area 26 in which several computer programs or several functions of the same computer program are stored. These computer programs include instructions designed to be executed by the processing unit 24 to perform the functions of the software modules. Although they are shown as separate, this distinction is purely functional. They can be easily grouped in any combination into one or more software packages. Their functions may be at least partially microprogrammed or micro-wired into an application-specific integrated circuit such as a digital circuit. Alternatively, the computer 22 may be replaced by an electronic device composed only of digital circuits (without a computer program) to perform the same functions.

[0029] Thus, the electronic olfactory property evaluation device 10 first includes a software module 28 executed by the processing unit 24 to control the suction device 14 (if provided in the device 10), the air inlet 16 (if provided in the device 10), and the transducer 20.

[0030] Optionally but preferably, the electronic olfactory property evaluation device 10 further includes a software module 30 that is executed by the processing unit 24 and selects a subset of sensors sensitive to the volatile component characteristics of a desired olfactory fingerprint from among the olfactory sensors 18 of the electronic olfactory property evaluation device 10. These characteristic volatile components also vary the selection of olfactory sensors performed by the software module 30 and can vary for each application or fluid being investigated so as to be parameterized. The selected subset includes, for example, M≧1 olfactory sensors (possibly plural), preferably several olfactory sensors (M≧2).

[0031] The electronic olfactory property evaluation device 10 further includes a software module 32 for extracting M sensorgrams

Number

Number

[0032] Thus, FIG. 2 shows several 60 sensorgrams acquired over a period of about 190 seconds using an MZI or MZI / MMI amplification system according to a well-controlled measurement protocol that includes control of the suction device 14 and the air inlet 16. [Number] showing the superimposed time plots of The olfactory sensor 18 is first exposed to a carrier fluid reference fluid environment in which the target compound of the fluid being analyzed is absent, during a first reference state identifiable by the first part PH1 of the sensorgram. Then, it is exposed to the fluid being analyzed during a second analysis state of adsorption caused by the controlled injection of this fluid into the measurement chamber 12, this second state being identifiable by the second part PH2 of the sensorgram. During a third final desorption state, it is finally re-exposed to the reference fluid environment by the controlled discharge of the fluid being analyzed from the measurement chamber 12, this third state being identifiable by the third part PH3 of the sensorgram.

[0033] Returning to FIG. 1, the electronic olfactory property evaluation device 10 further includes an optional software module 34 executed by the processing unit 24 to perform any preprocessing on the M sensorgrams [Number] provided by the software module 32.

[0034] This preprocessing includes, for example, low-pass filtering in the form of a digital filter with a finite or infinite impulse response. This includes filtering the high-frequency measurement noise in the raw signal provided by the software module 32. A first-order Butterworth filter with a finite impulse response and a normalized cut-off frequency of 0.45 (i.e., the ratio between the cut-off frequency equal to 0.45 and the sampling frequency) is appropriate.

[0035] This preprocessing is, for example, M filtered and / or normalized sensorgrams [Number] to obtain, M filtered sensorgrams or unfiltered sensorgrams [Number] and further includes norm calculation within the scope of the meaning of International Publication No. WO 2020 / 141281 for the patent document with respect to the patent document.

[0036] The electronic olfactory property evaluation device 10 is M sensorgrams [Number] or [Number] and further includes a software module 36 executed by the processing unit 24 to obtain the characteristic evaluation or GIS signature of the composition of the fluid analyzed from, in a manner not known in detail. This characteristic evaluation or GIS signature can take the form of a standardized olfactory signature as shown in FIG. 3 in the form of a pie chart. Note that this module can proceed in two stages. First, obtain a first intermediate signature, and then convert this first intermediate signature by normalization.

[0037] The electronic olfactory property evaluation device 10 further includes an optional software module 38 executed by the processing unit 24 to convert the GIS signature into another YDEV signature simplified by component reduction, regardless of whether it is standardized. Linear discriminant analysis (LDA), principal component analysis (PCA), independent component analysis (ICA), autoencoders, etc. are all suitable. In the case of a 64-component GIS signature as shown in FIG. 3, a simplified 2-component or 3-component YDEV signature can be obtained.

[0038] The electronic olfactory property evaluation device 10 further includes a portion 40 of a memory area 26 for storing a parameter model MOD having at least one adjustable parameter of drift with respect to a reference electronic property evaluation device. This parametric drift model is, for example, an affine model MOD(α, t) having two adjustable parameters α and t, where α is the first adjustable multiplicative parameter of the affine model and t is the second adjustable additive parameter of the affine model. Note that the reference electronic property evaluation device may be a specifically identified electronic device as a standard, a set of specifically identified electronic devices as a standard, or a virtual electronic device resulting from such a set by, for example, an average, a median, or any other relevant aggregation calculation.

[0039] The portion 40 of the memory area 26 further stores a plurality of reference calibration signatures each associated with the interaction of a plurality of predetermined calibration fluids with at least one sensor of the reference electronic device. For consistency, the reference device includes the same olfactory sensors as the electronic olfactory property evaluation device 10. According to the general principle of the present invention, the predetermined calibration fluids are divided into several different calibration groups. This means that if there are any number G≧2 of different calibration groups, there are more than G calibration fluids distributed among these G calibration groups at a ratio of at least one calibration fluid for each group. The distribution can be random, depending on signature similarity according to a similarity criterion, or any other distribution rule within the reach of those skilled in the art. For example, YREF r,i is the simplified reference calibration signature of a predetermined calibration fluid of index i of a calibration group of index r. Each signature YREF r,i may be, for example, the result of an aggregation calculation of measured values taken with several electronic fluid property evaluation devices, such as an average value, a median value, a maximum value, a minimum value, etc. Next, the reference electronic device represents a theoretical, i.e., virtual, aggregate of these electronic fluid property evaluation devices.

[0040] The electronic olfactory property evaluation device 10 further includes a software module 42 executed by the processing unit 24 to perform calibration by comparison with a reference electronic property evaluation device. This calibration software module 42 receives, as input, calibration signatures obtained by the interaction of a predetermined calibration fluid with the olfactory sensor 18 of the electronic olfactory property evaluation device 10, and stores them in a portion 44 of the memory area 26. These calibration signatures specific to the electronic olfactory property evaluation device 10 are more specifically obtained by executing software modules 28 to 38 for each of the predetermined calibration fluids. For example, YDEV r,i is the acquired simplified calibration signature of the predetermined calibration fluid of index i of calibration group of index r .

[0041] According to the general principle of the present invention, calibration consists in determining, for each of the adjustable parameters, here α and t for the aforementioned affine model, in particular the values for each calibration group. More specifically, the aim here is to determine, for each calibration group of index r, for each predetermined calibration fluid of index i of index r, a pair of specific values (α r,i =α r ·YREF r,i +t r ) such that it can be considered that YDEV r,i . This determination is performed by the software module 42 using a known optimization software method such as least squares error minimization or maximum likelihood estimation. Then, as a result, that is, a pair of specific values (α r ,t r ) of different calibration groups is stored in a portion 44 of the memory area 26. Then, the electronic olfactory property evaluation device 10 can be considered calibrated. r r

[0042] The parameters α r and t r can take scalar values, but the signatures YDEV r,i and YREF r,iNote that a vector value having the same number of components can also be obtained.

[0043] Also, according to the general principle of the present invention, note that one of the first adjustable multiplication parameter α and the second addition parameter t is independent of the calibration group. In this way, the adjustable multiplication parameter α can take different values α from one calibration group to the next calibration group r and, on the other hand, the adjustable addition parameter t remains constant at t0, where t0 can even be 0. Similarly, the adjustable addition parameter t can take different values t from one calibration group to the next calibration group r and, on the other hand, the adjustable multiplication parameter α remains constant at α0, α0, and in some cases is neutral at 1.

[0044] The electronic olfactory property evaluation device 10 further includes two software modules 46 and 48 executed by the processing unit 24 to perform correction on the measured signature of any fluid to be property evaluated. More specifically, the software module 46 selects a calibration group associated with the fluid to be property evaluated based on its signature, and the software module 48 corrects this signature using the specific values of the adjustable parameters of the selected group.

[0045] Specifically, the selection software module 46 receives an input signature, for example, a simplified signature YDEV, obtained by the interaction between the fluid to be analyzed and the olfactory sensor 18 of the electronic olfactory property evaluation device 10. More specifically, this signature is obtained by executing the software modules 28 to 38 for the fluid to be property evaluated. Next, the selection software module 46 compares this simplified signature YDEV with the calibration signature YDEV r,iSelect a calibration group with an exponent r that, compared to [the reference], is deemed to most represent this signature according to a given criterion. This can be achieved by several known somewhat simplistic methods. Advantageously, the selection is made by comparing this signature with the calibration signature(s) obtained from the calibration fluid(s) within each calibration group, and automatically classifying the simplified signature YDEV into one of the calibration groups. In particular, the k-nearest neighbor method (k ≥ 1) is ideally suited to this situation.

[0046] The correction software module 48 receives, as input, the exponent of the selected group [Number] and applies the corresponding parameter value [Number] and [Number] to the inversion of the parametric drift model. Specifically, in the example of the affine model described above, this means applying the following correction to the signature YDEV. [Number]

[0047] Thus, YCOR is the simplified signature of the fluid whose characteristics are evaluated after correction.

[0048] According to a second embodiment of the present invention, an electronic device 10' for evaluating the olfactory characteristics of a fluid, schematically shown in FIG. 4, differs from the electronic device of FIG. 1 in that an air inlet 16 is connected to a thermal desorption concentrator 50 to receive the fluid to be analyzed. Since all other components of the electronic device 10' remain the same as those of the electronic device 10, they retain the same reference numbers. The thermal desorption concentrator 50 is a known device not detailed here. It functions by accumulating compounds in the fluid by adsorption onto a resin. The resin is then heated to a set temperature, for example 200 °C, to induce desorption of these compounds from the resin. When the set temperature is reached, the compounds are injected into the electronic device 10'.

[0049] This results in a rapid injection of a concentration peak rather than a continuous injection of the compound in the context of the measurements as disclosed in the previous embodiment. This concentration peak then generates a distinct time signal in the form of a peak rather than the time-expanded sensorgram of FIG. 2. However, by a legitimate misuse of language, these distinct time signals can also be called sensorgrams since, even though this introduction is done in a different way, they are the response of the transducer 20 to the introduction of the fluid to be analyzed into the measurement chamber 12.

[0050] Thus, FIG. 5 shows several 60 sensorgrams obtained using an MZI or MZI / MMI amplification system over a period of about 80 seconds according to a well-controlled measurement protocol using a thermal desorption concentrator 50

Number

[0051] Next, the successive steps of a calibration method for the electronic olfactory characteristic evaluation device 10 or 10' are detailed with reference to FIG. 6.

[0052] In step 100, a reference signature YREF of a predetermined calibration product r,iIt is stored in the memory 40 of the electronic olfactory characteristic evaluation device 10 or 10'. These are obtained by executing software modules equivalent to the software modules 28 to 38 of a virtual or other electronic reference device similar to the electronic olfactory characteristic evaluation device 10 or 10'.

[0053] In step 102, which is executed before, during, or after step 100, the parametric drift model MOD(α,t) of the electronic olfactory characteristic evaluation device 10 or 10' that is calibrated against the reference electronic device is also stored in the memory 40.

[0054] In step 104, which is executed by executing software modules 28 to 38, the calibration signature YDEV of a predetermined calibration product r,i is obtained by the interaction with the sensor 18 of the electronic olfactory characteristic evaluation device 10 or 10'.

[0055] In step 106, which is executed by executing software module 42, the calibration signature YDEV r,i is stored in the memory 44. In the same step, the specific values (α r , t r ) of the adjustable parameters of the parametric model MOD(α,t) are determined and stored in the memory 44 for each of the different calibration groups.

[0056] At the end of this step, the electronic olfactory characteristic evaluation device 10 or 10' can be considered calibrated.

[0057] In a subsequent step 108, which is executed by executing software modules 28 to 38, the fluid to be characterized is carried near the electronic olfactory characteristic evaluation device 10 or 10' for its interaction with the olfactory sensor 18. The result is a simplified signature YDEV.

[0058] In a subsequent step 110 executed by executing the software module 46, a calibration group of an exponent r that is considered to best represent the simplified signature YDEV is selected.

[0059] Finally, in a last step 112 executed by executing the software module 48, this signature YDEV is

Number

[0060] Note that the calibration method described above provides possible simplification of the signature by dimensionality reduction before application of the calibration parameters, so that if the calibration parameters are vector-based, the calibration parameters are adapted to the reduced dimensionality after simplification. Alternatively, if the calibration parameters are vector-based, the calibration can be performed before dimensionality reduction so that the calibration parameters are adapted to the initial dimensionality before simplification.

[0061] The figures in FIGS. 7 and 8 show experimental results obtained on a given fluid sample on which signatures are measured on a number of different electronic property evaluation devices. The signature is simplified by principal component analysis, and two first principal components PC1, PC2 are retained for characterizing the sample. For the measurement, seven sample types of a nonane sample, a β-pinene sample, an aglunitrile sample, an R-carboxylic sample, a PEA (phenylethyl alcohol) sample, an octanol sample, and a cis-3-hexenol sample are available.

[0062] Figure 7 shows the distribution of various simplified signatures obtained in the principal component planes PC1 and PC2 without prior calibration. A clustering quality score (CQS), such as taught in, for example, International Patent Publication No. 2022 / 053690, can be calculated for each of the sample types proposed for measurement and averaged across all samples. Clearly, it is difficult to characterize the different types of samples in Figure 7. Experimentally, the nonane sample had a CQS score of 13.2%, the β-pinene sample had a CQS score of 1.6%, the aglunitrile sample had a CQS score of 9.1%, the R-carboxylic sample had a CQS score of 10.3%, the PEA sample had a CQS score of 47%, the octanol sample had a CQS score of 3.0%, the cis-3-hexenol sample had a CQS score of 5.8%, and the overall average CQS score was 12.9%. This is not very satisfactory.

[0063] When performing the calibration according to the present invention, results as shown in the figure of Figure 8 can be obtained. Three calibration groups are defined, for example, a first group composed of nonane and β-pinene samples, a second group of octanol and cis-3-hexenol, and a third group of aglunitrile and R-carboxylic. For example, the PEA sample is not used for calibration. The selected parametric drift model is an affine model, and the value α of the multiplicative parameter α r is a scalar, and the value t of the additive parameter t r is vector-based. Figure 8 shows the distribution of various simplified and corrected signatures obtained after the aforementioned calibration in the plane of the principal components PC1 and PC2. More specifically, Figure 8 shows the vector value t of the additional parameter t rThe case of the simplification of the calibrated signature is shown such that it is of the dimension of the signature before dimensionality reduction. Four groups of signatures are more distinct than in FIG. 7. The first group GR1 includes most of the nonane and β-pinene samples. The second group GR2 includes most of the octanol and cis-3-hexenol samples. The third group GR3 includes most of the aglunitrile and R-carboxylic samples. The fourth group GR4 is shown by a dotted line as it includes compounds that were not part of the calibration group and includes most of the PEA samples. Theoretically, the nonane sample showed an experimentally improved CQS score of 54.7%, the β-pinene sample showed an improved CQS score of 51.2%, the aglunitrile sample showed an improved CQS score of 63.9%, the R-carboxylic sample showed an improved CQS score of 64.5%, PEA showed an improved CQS score of 52.4%, octanol showed an improved CQS score of 65.7%, cis-3-hexenol showed an improved CQS score of 65.6%, and showed a significantly improved average CQS score of 59.7% overall.

[0064] It is clear that the calibration method as described above can effectively compensate for the drift in the performance of the electronic fluid property evaluation device over time and also from one device to the next. This improves the identification of the fluid being characterized.

[0065] It should also be noted that the present invention is not limited to the previously disclosed embodiments.

[0066] In particular, although a single parametric drift model has been presented, other models may be considered depending on the reality of the possible drift. Just note that the more parameters that are set, the more calibration groups or the more calibration fluids per group there will be.

[0067] More generally, it will be apparent to those skilled in the art that various modifications can be made to the embodiments previously disclosed herein in view of the just-disclosed teachings. In the foregoing detailed description of the present invention, the terms used should not be construed as limiting the present invention to the embodiments described in the disclosure, but should be construed as including all equivalents within the reach of those skilled in the art by applying the general knowledge of those skilled in the art to the practice of the just-disclosed teachings.

Claims

1. A method for calibrating an electronic device (10) for characterizing a fluid using at least one sensor (18) designed to interact with the fluid, by comparison with a reference electronic characterization device, Multiple reference calibration signatures (YREF) associated with the interaction between multiple predetermined calibration fluids and at least one sensor of the reference electronic characterization device. ｒ，ｉ The process (100) involves storing the data in memory (40), A step (102) of storing in memory (40) a parametric model (MOD(α,t)) having at least one adjustable parameter (α,t) of the drift of the electronic device (10) to be calibrated against the reference electronic characterization device, For each of the plurality of predetermined calibration fluids, the calibration signature (YDEV) is obtained by the interaction of the electronic device (10) being calibrated with the at least one sensor (18). ｒ，ｉ The process of obtaining (104) The acquired calibration signature (YDEV ｒ，ｉ ) is the reference calibration signature (YREF ｒ，ｉ By comparing with the above, at least one value (α, t) of the at least one adjustable parameter (α, t) ｒ ,t ｒ The process includes (106) determining the following: The predetermined calibration fluid is divided into several different calibration groups, and the at least one value (α, t) of the at least one adjustable parameter (α, t) ｒ ,t ｒ A calibration method characterized in that the determination (106) of the above is specifically performed for each calibration group.

2. To correct any signature (YDEV) obtained by the interaction of the at least one sensor (18) of the electronic device (10) calibrated with any fluid, the at least one adjustable parameter value (α ｒ , t ｒ ) is further included in the step (110, 112) of applying, and this step is a calibration group associated with any fluid based on its signature (YDEV) [Math 1] A calibration method according to claim 1, comprising: selecting (110) a group; and then correcting its signature using the at least one adjustable parameter value of the selected group (112).

3. The calibration method according to claim 2, wherein the selection (110) of calibration groups associated with any fluid includes automatically classifying the signature (YDEV) into one of the calibration groups by comparing the signature (YDEV) with the calibration signature(s) obtained from the calibration fluid(s)(s) within each calibration group.

4. The calibration method according to claim 2, wherein the correction (112) of an arbitrary fluid signature (YDEV) includes inversion of the parametric model (MOD(α, t)) to which the at least one adjustable parameter value of the selected calibration group is applied.

5. Calibration signature (YDEV) for each of the plurality of predetermined calibration fluids ｒ，ｉ The calibration method according to claim 1, wherein obtaining (104) is to obtain a first calibration signature having N components (which may be more than one) such that N≧1, and then transforming the first calibration signature by normalization and / or component reduction.

6. The aforementioned parametric model (MOD(α,t)) is a tunable two-parameter affine model and YDEV ｒ，ｉ = α ｒ ・YREF ｒ，ｉ +t ｒ YDEV ｒ，ｉ However, the index ｒ The acquired calibration signature of the predetermined calibration fluid for the index i of the calibration group, YREF ｒ，ｉ However, the index ｒ The index i of the calibration group is the reference calibration signature of the predetermined calibration fluid, α ｒ However, the index ｒ The value of the first adjustable multiplicative parameter of the affine model of the calibration group, t ｒ However, the index ｒ The calibration method according to claim 1, wherein the value is the second adjustable additive parameter of the affine model of the calibration group.

7. The step (110, 112) of applying the at least one adjustable parameter value (αr, tr) in the parametric model (MOD(α, t)) to correct an arbitrary signature (YDEV) obtained by the interaction of the electronic device (10) to be calibrated with an arbitrary fluid with the at least one sensor (18), wherein the step of applying the at least one adjustable parameter value (αr, tr) in the parametric model (MOD(α, t)) is associated with the arbitrary fluid based on the signature (YDEV) [Math 2] The process includes selecting (110) and then correcting the signature of the selected group using the at least one adjustable parameter value of the selected group (112), The correction (112) of the arbitrary signature (YDEV) of the arbitrary fluid is calculated [Math 3] This includes, where YDEV is the arbitrary signature obtained by the interaction of the arbitrary fluid with the at least one sensor (18) of the electronic device (10) being calibrated, and YCOR is the arbitrary signature of the corrected arbitrary fluid. [Math 4] The calibration method according to claim 6, wherein is the index of the selected calibration group.

8. The calibration method according to claim 6, wherein one of the first adjustable multiplicative parameter and the second adjustable additive parameter is independent of the calibration group.

9. A computer program that is downloadable from a communication network and / or recorded on a computer-readable medium (22) and / or executable by a processor (24) that can exchange data with memory (40), wherein the memory contains: Multiple reference calibration signatures (YREF) associated with the interaction between multiple predetermined calibration fluids and at least one sensor of a reference electronic characterization device. ｒ，ｉ )and, A parametric model (MOD(α,t)) having at least one adjustable parameter of the drift of the electronic characterization device (10) calibrated against the aforementioned reference electronic characterization device is stored. When the aforementioned computer program is executed on the computer, For each of the plurality of predetermined calibration fluids, a calibration signature (YDEV) is generated by interaction with at least one sensor (18) of the electronic device (10) being calibrated. ｒ，ｉ The process of obtaining (104) The acquired calibration signature (YDEV ｒ，ｉ ) is the reference calibration signature (YREF ｒ，ｉ By comparing with the above, at least one value (α, t) of the at least one adjustable parameter (α, t) ｒ ,t ｒ The process includes (106) determining the result, and an instruction to execute the command. The predetermined calibration fluid is divided into a plurality of different calibration groups, and the instruction more specifically controls the at least one value (α, t) of the at least one adjustable parameter (α, t). ｒ ,t ｒ A computer program characterized in that the determination (106) of the above is designed to be performed specifically for each calibration group.

10. A calibrated electronic device (10) for characterizing a fluid by providing a signature (YDEV) obtained from an electrical measurement signal (S), At least one sensor (18) designed to interact with the fluid, A transducer (20) designed to interact with at least one sensor (18) to provide the electrical measurement signal (S), Memory (40, 44), A parametric model (MOD(α,t)) having at least one adjustable parameter (α,t) for the drift of the calibrated electronic device (10) relative to a reference electronic characterization device, At least one value of the at least one adjustable parameter (α, t) calculated by pre-calibration of the calibrated electronic device by comparison with the reference electronic characterization device based on a plurality of predetermined calibration fluids (α, t) ｒ ,t ｒ ) and memory to store, A processor (24) for correcting the signature (YDEV) by applying at least one adjustable parameter value, The predetermined calibration fluid is divided into several different calibration groups, and the memory stores at least one specific value (α, t) of the at least one adjustable parameter (α, t) for each of the calibration groups. ｒ ,t ｒ ) Remember this, More specifically, the processor (24) selects a calibration group associated with the fluid to be characterized based on its signature (YDEV), and then sets the at least one specific adjustable parameter value (α) of the selected group. ｒ ,t ｒ A calibrated electronic device characterized by being programmed to correct its signature using (46, 48).

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