Method of preparing a spectrum-determined of at least one measured object in a target application

Abstract

The invention relates to a method for preparing a spectrometric determination of at least one measured object in a target application, wherein: on the basis of reference data recorded in an application in the target application and / or in an application of the same type as the target application, a normalized measured object master spectrum having a spectral profile as a characteristic of the measured object is determined; on the basis of the measured object master spectrum, a synthetic spectrum is generated, which covers a value range which is greater than or equal to or actually greater than the value range covered by the reference values; and on the basis of the synthetic spectrum, one or more pieces of information required for the spectrometric determination are determined and available, which information in particular includes properties of the optical path length of a spectrometer suitable for performing the spectrometric determination, a wavelength range and / or a path length range, and / or includes calculation rules with which, on the basis of a measurement spectrum which can be captured in the target application, a measurement value of the measured object can be determined.

Description

Technical Field

[0001] The present invention relates to a method for preparing at least one quantifiable object of a medium for spectral determination in a target application of a predetermined type of application by means of a spectrometer, and the use of the method. Background Technology

[0002] Spectral determination of the measured object in a medium is now being used in a wide variety of applications—for example, in water treatment plants, laundry facilities, and factories that deliver drinking water.

[0003] For this purpose, a spectrometer is typically used, comprising a spectral unit equipped with a radiation source and a detector. Radiation is radiated into a medium via this spectral unit, and the detector receives the measurement radiation resulting from the interaction of this radiation with the medium. Depending on the design of the spectral unit, different forms of interaction between the radiation and the medium can occur, such as transmission, reflection, or scattering. In this case, the spectrometer can be used as a stand-alone device, for example, at the point of use, or it can be integrated into a measurement device or system, for example, into a sensor and / or into a probe that can be immersed in a medium. The measurement spectrum corresponding to the spectral intensity of the measurement radiation within the wavelength range covered by the detector is derived from the measurement radiation received by the detector. Depending on the wavelength range of the measurement radiation, UV, vis, NIR, and MIR spectra, as well as combinations thereof, can be distinguished. For example, Endress+Hauser Group provides and sells spectrometers that operate in different wavelength ranges.

[0004] Using a spectrometer, it is possible to determine how the analyte affects the measured spectrum in a quantitatively detectable manner and in a way that depends on the measured value of the analyte. Examples of this include the concentration of the analyte contained in the medium, such as the nitrite and / or nitrate content of the medium. Other examples include the chemical or biological oxygen requirement of the medium and the coloration or turbidity of the medium.

[0005] In order to determine the measured value of a specific measurand based on a measured spectrum, it is necessary to first determine the dependence of the spectral distribution of the measured spectrum on the measured value of the measurand, which is a characteristic of the measurand. In this case, those wavelengths at which the intensity of the measured radiation varies according to the measured value of the measurand are identified, and the dependence of the spectral distribution of the measured spectrum appearing at these wavelengths is determined from the measured value. A calculation rule is then derived from this, by means of which the measured value of the measurand can be calculated based on the measured spectrum derived in subsequent measurement operations. This calculation rule is determined, for example, in the form of a mathematical and / or statistical model, such as a model referred to in the art as a chemometrics model.

[0006] When determining the calculation rules, a spectrometer is typically installed in the target application, and the measurement spectrum is continuously recorded using the spectrometer. In parallel, a reference measurement of the measurand is performed, through which a measurement reference value of the measurand determined by the reference measurement is assigned to each of the measurement spectra. The calculation rules are then determined based on the measurement data, including the measurement spectra and the associated measurement reference values.

[0007] However, the applicability of calculation rules determined in this way is often limited to the range of values ​​of the measurand covered by the measurement data. One reason for this is that the calculation rules and / or the models on which they are based, extrapolated to ranges of measurements not covered by the measurement data, are often affected by large measurement uncertainties. However, particularly high and very low measurements of the corresponding measurands rarely occur in most applications. This necessitates either limiting the measurement range to measurements that frequently occur in the target application or requiring a significant investment of time and effort in recording the measurement data.

[0008] Alternatively, samples collected and / or artificially generated in the target application can be measured in the laboratory, for example, by means of spikes or dilution. However, it has been shown that the measurement spectra obtained in this way, especially in the case of complex biological matrices, such as those found in water treatment plants, do not perfectly correspond to the measurement spectra recorded in the field in actual applications. Furthermore, when measurements are performed in the laboratory, especially with samples of low stability, there is the problem that sample properties can change—for example, through biodegradation or transformation. Additionally, samples can potentially represent biological and / or chemical hazards. This can be the case, for example, with potentially infectious samples collected from water treatment plants, in the case of toxic samples, and in the case of potentially explosive samples collected from processes. Depending on the target application, sample stability and / or the hazards associated with sampling and / or its measurement can make measurements to be performed in the laboratory more difficult or even impossible. Measurements based on artificial laboratory standards also often do not correspond to the spectral matrix present in the field at the target application. Therefore, despite the aforementioned drawbacks, measurement spectra recorded in the field at the relevant application generally represent a better alternative, given the established rules of calculation.

[0009] Another challenge is interference variables, such as components that may be present in the medium—often called interferometric analytes—which affect the measurement spectrum within the same wavelength range as the analyte. Interferometric variables, such as interferometric analytes, and their concentrations, often vary depending on the application and can, in some cases, significantly impair the spectral determination of the analyte, or even render it impossible in extreme cases.

[0010] It is possible to consider the influence of interferometric analytes contained in the medium in a specific application, for example, by recording measurement data containing the measured spectrum, relevant measurement reference values ​​of the measured object, and relevant measurement reference values ​​of interferometric variables, such as the measured concentration of the interferometric analyte. However, this makes recording measurement data more complex. Even more challenging is that in most target applications, the composition of the medium, especially the concentration of the interferometric analyte, cannot be varied in a controllable manner.

[0011] In conjunction with interferometric analytes, US 2006 / 0197015 A1 describes a method for measuring the concentration of a target analyte contained in a medium sample (such as glucose concentration in a blood sample), wherein the measurement spectrum of the sample is recorded, and, based on interferometric spectra collected in a database, the interferometric analytes present in the sample are identified, such as drugs. In the next step, synthetic spectra with different interferometric analyte concentrations are calculated from the measurement spectra and the corresponding concentrations of the measurement data and interferometric spectra containing the target analyte. Using these synthetic spectra, calibration constants for measuring the target analyte concentration are determined, thereby minimizing the measurement error in the measurement of the target analyte concentration caused by the interferometric analytes contained in the respective sample. However, this method is very complex because new calibration constants must be determined for each individual sample. Furthermore, the measurement range capable of determining the concentration of the target analyte in a given sample with high measurement accuracy is also limited here to a range of measurement spectra and associated concentration values ​​contained in the measurement data.

[0012] Another potential problem in determining the calculation rules based on measurement data recorded in the target application is that the spectrometer used to record the measurement data in the target application must be suitable for the spectral determination of the measurand in the target application. In this case, whether a particular measurand can be measured using a spectrometer depends particularly on the composition of the medium and the optical path length of the spectrometer used. If the measurement spectrum recorded based on the spectrometer already installed in the target application reveals that the spectrometer used is unsuitable, then the spectrometer must be replaced with a more suitable one, and the measurement data must be re-recorded. This situation can occur, for example, when optical saturation occurs due to interferometric analytes contained in the medium in the case of the initially used spectrometer. In this case, the medium absorbs so much light that determining the measurand based on the measurement spectrum is no longer possible or at least not accurate enough. If a replacement spectrometer is required, this involves additional effort and is usually associated with additional costs. Summary of the Invention

[0013] The object of this invention is to specify a more efficient preparation method for preparing a spectral determination of at least one quanta to be performed in a target application, the method being able to measure (one or more) quanta in the target application as accurately as possible over a wider measurement range.

[0014] For this purpose, the present invention includes a method for preparing at least one quantifiable object of a medium for spectral determination in a target application of a predetermined type of application by means of a spectrometer, wherein:

[0015] A normalized master spectrum of the measurand is determined based on reference data, which includes a reference spectrum of the measurand and associated reference values, recorded in the target application and / or applications of the same type as the target application.

[0016] Based on the master spectrum of the measured object, synthetic spectra are generated, each synthetic spectrum comprising a separate spectrum generated based on a specific individual value of the master spectrum of the measured object, wherein the individual value of the separate spectrum generally covers a range of values ​​greater than, equal to, or substantially greater than the range of values ​​covered by the reference value, and

[0017] Based on the synthesized spectrum, one or more pieces of information required to perform the spectral determination of the measured object in the target application are determined and available.

[0018] The one or more pieces of information particularly include attributes such as the optical path length, wavelength range, and / or path length range of a spectrometer suitable for performing the spectral determination of the measured object in the target application, and / or include calculation rules that can be used with the spectrometer in the target application, using which the measurement value of the measured object can be determined based on the measurement spectrum that can be captured by the spectrometer in the target application.

[0019] The advantage of this preparation method is that it enables the highly efficient determination of the spectral characteristics of the measurand in the target application based on the synthetic spectrum. In this case, the large range of values ​​covered by the synthetic spectrum provides the advantage that the recording of reference data can be limited to the values ​​of the measurand that frequently occur in the application type of the target application without associated limitations and / or quality loss. In this respect, this information particularly makes it possible to select the most suitable measurement task in the target application and accordingly utilize a spectrometer with high measurement accuracy over a large measurement range. Furthermore, the calculation rules based on the synthetic spectrum, due to the large range of values ​​covered by the synthetic spectrum (especially within the measurement range), make it possible to achieve measurement results with high accuracy that rarely occur in practice and / or for which little or no reference data is available. This provides the advantage that measurement results with higher measurement accuracy can be achieved using calculation rules based on synthetic spectra over a larger measurement range compared to calculation rules based on reference data. Using this preparation method, it is therefore possible to reduce the complexity associated with recording reference data and increase the measurement range and improve measurement accuracy.

[0020] One embodiment includes a preparation method, wherein:

[0021] In each case, the reference data for each reference spectrum includes the optical path length of the spectrometer that records the corresponding reference spectrum;

[0022] The reference spectrum is normalized to a reference value for the corresponding measured object and a reference value for the optical path length, and

[0023] The main spectrum of the measured object is determined based on a normalized reference spectrum, which is the main spectrum of the measured object normalized to the reference value of the measured object and the reference value of the optical path length.

[0024] One development of this embodiment includes a preparation method in which the main spectrum of the measured object is determined by means of mean or median formation performed based on a normalized reference spectrum, and / or by using at least one spectral decomposition algorithm and / or at least one smoothing filter for smoothing the reference spectrum and / or the normalized reference spectrum.

[0025] Another embodiment of the preparation method specifies

[0026] The main spectrum of the measured object and the composite spectrum are absorption spectra, and

[0027] The individual spectra are calculated by means of a linear relationship between the spectral absorption and the value of the measured object, or each is determined based on a nonlinear calculation rule that reflects the correlation between the spectral absorption and the value of the measured object.

[0028] According to the first development, at least one interfering variable appearing in the target application is considered in the following aspects.

[0029] For each interference variable to be considered, a normalized master interferometric spectrum is determined, specifically a master interferometric spectrum normalized to the reference values ​​of the corresponding interference variable and the optical path length. This master interferometric spectrum possesses the spectral distribution characteristics of the corresponding interference variable, and...

[0030] The synthesized spectrum includes individual spectra, which are determined based on the main spectrum of the measured object and the interference spectrum for each interference variable to be considered, and the individual spectra take into account the effects of one or more of the interference variables.

[0031] According to the second development, optical saturation is considered in the following respect: the synthesized spectra are generated such that they include individual spectra that take into account the optical saturation and / or individual spectra that take into account the optical saturation and the effects of each interference variable to be considered.

[0032] According to the third development, the synthesized spectra are generated such that for one or more limiting values, they each include a separate spectrum that takes into account the optical saturation and / or a separate spectrum that takes into account the optical saturation and the effects of each interference variable to be considered, wherein:

[0033] In each case, each limiting value corresponds to a constant or wavelength-dependent upper limit of the absorption value, which can be metrologically detected above which optical saturation occurs.

[0034] In the determination of the individual spectrum taking into account the optical saturation, it is determined based on the main spectrum (M) of the measured object and exceeds the corresponding limit value (a). max All of the spectral absorption values ​​of ) are reduced to the limiting value (a) max ),as well as,

[0035] In the determination of individual spectra that take into account the optical saturation and the effects of each interference variable to be considered, all spectral absorption values ​​that are determined based on the main spectrum of the measured object and the main interference spectrum of each interference variable to be considered and that exceed the corresponding limit value are reduced to the limit value.

[0036] According to one embodiment of the first, second, and / or third development, the information or at least one or each of the multiple pieces of information is determined based on the individual spectra that take into account the effects of the optical saturation and / or (one or more) of the interference variables.

[0037] The development of the first, second, and / or third developments includes a preparation method, wherein,

[0038] Based on the individual spectra that take into account the effects of one or more of the interfering variables and / or the individual spectra that take into account the effects of one or more of the interfering variables and the optical saturation, examine whether the measurand in the target application can be determined by spectroscopic methods with a predetermined measurement accuracy, provided that each interfering variable falls within a predetermined value range for the corresponding interfering variable.

[0039] The corresponding test results are available.

[0040] The second and / or third developments include a preparation method, wherein,

[0041] Based on the individual spectrum taking into account the optical saturation and / or based on the individual spectrum taking into account the effects of the optical saturation and (one or more) of the interference variables, determine the wavelength range, the path length range of the optical path length, and / or at least one additional property of the spectrometer suitable for performing the spectral determination of the quantum object in the target application, and

[0042] Each of these information entries is available, and / or the information is used to select the spectrometer that can be used in the target application.

[0043] Further developments of the second and / or third developments include a preparation method wherein, based on the individual spectrum taking into account the optical saturation and / or the individual spectrum taking into account the effects of the optical saturation and (one or more) of the interference variables:

[0044] A first target value for the optical path length of the spectrometer, which can be used in the target application, is determined and available, wherein the measurement range of the measured object is at its maximum value with a predetermined measurement accuracy.

[0045] A second target value for the optical path length of the spectrometer, which can be used in the target application, is determined and available, wherein the measurement accuracy of the measured object is at its maximum value within a predetermined measurement range, and / or

[0046] The maximum value of the optical path length of the spectrometer available in the target application is determined and available, which corresponds to the maximum possible optical path length at which the measurement of the object being measured can still be performed with a predetermined measurement accuracy.

[0047] The last development mentioned includes a preparation method, in which...

[0048] The spectrometer is selected for use in the target application based on the first target value, the second target value, and / or the maximum value, such that it has an optical path length corresponding to one of the target values ​​and / or less than the maximum value.

[0049] The calculation rules are determined based on the individual spectra generated for the optical path length of the spectrometer.

[0050] A further development includes a preparation method, wherein, based on the synthetic spectrum:

[0051] At least one endpoint of the measurement range is determined and available, wherein the measurement of the measured object can be performed with a predetermined measurement accuracy by means of the calculation rule, and / or

[0052] The achievable measurement accuracy is determined and available, and with the aid of the achievable measurement accuracy, the measurement of the measured object can be performed within a predetermined measurement range by means of the calculation rules.

[0053] Furthermore, the present invention includes a computer program for determining the spectrum of at least one quantified object of a medium to be prepared by means of a spectrometer in a target application of a predetermined type of application, having computer-readable program code elements that, when executed on a computer, cause the computer to perform the preparation method.

[0054] Furthermore, the present invention includes a computer program product having such a computer program and at least one computer-readable medium, wherein at least the computer program is stored on the at least one computer-readable medium.

[0055] Furthermore, the present invention includes the use of the preparation method in at least one method for determining the spectrum of at least one quantified object in a target application for preparing and performing an application of a predetermined type, wherein,

[0056] The preparation method is performed on the measured object or for each measured object.

[0057] Each calculation rule determined by the preparation method is stored in the memory of the spectrometer that can be used in the target application, and

[0058] In the target application, a spectrometer is used to perform at least one determination of the measured value of the measured object or at least one of the measured objects by means of the calculation rules determined for the corresponding measured object.

[0059] Furthermore, the present invention includes the use of at least one calculation rule determined by means of the preparation method in a spectrometer, wherein the spectrometer includes a measuring device designed to calculate the measurement value of the associated measurand based on a measurement spectrum derived from the spectrometer by means of the calculation rule, and output it as a measurement value and / or make it available via the spectrometer interface in the form of a measurement signal corresponding to the measurement value and / or in a form that can be read. Attached Figure Description

[0060] The invention and its advantages will now be explained in detail with the aid of the accompanying drawings, which illustrate an exemplary embodiment. The same elements are indicated by the same reference numerals in the drawings.

[0061] Figure 1 Shown: Spectrometer;

[0062] Figure 2 The method steps of the preparation method are shown.

[0063] Figure 3 shows reference spectra recorded at different values ​​of the measured object using a spectrometer with the same first optical path length;

[0064] Figure 4 shows reference spectra recorded at different values ​​of the measured object using a spectrometer with the same second optical path length;

[0065] Figure 5 shows reference spectra recorded at different values ​​of the measured object using a spectrometer with the same third optical path length;

[0066] Figure 6 shows the main spectrum of the measured object;

[0067] Figure 7 shows: the synthesized spectrum; and

[0068] Figure 8 shows the synthesized spectrum considering optical saturation. Detailed Implementation

[0069] The following describes a preparation method, particularly a computer-implemented method, for preparing a spectral determination of at least one quantifiable object of a medium to be performed in a target application of a predetermined type of application using a spectrometer.

[0070] This preparation method can be used in conjunction with a variety of different types of applications. In this regard, applications known from practice can be categorized into predetermined types, such as breweries, water monitoring facilities, water treatment plants (e.g., municipal water treatment plants or industrial water treatment plants used in certain industrial sectors), laundry facilities, or plants carrying drinking water, wherein the media have comparable properties, at least in terms of their main components, particularly their matrix. In each target application, depending on the type of application, different quantifiable parameters can be determined, such as the concentration of analytes contained in the measured medium, chemical oxygen demand (COD), biological oxygen demand (BOD), coloration, and / or turbidity of the medium. For example, a spectrometer is used in a water treatment plant to determine and / or monitor the nitrite and / or nitrate content of industrial water supplied to the plant and / or water treated in the plant.

[0071] For this purpose, depending on the type of the object being measured and / or the target application, spectrometers with different designs can be used, especially those with different optical path lengths. Figure 1 An example of a spectrometer is shown, operating in transmission, comprising: a radiation source 1 that radiates through a medium 3 during measurement operations; and a detector 5 that receives the measurement radiation emitted from the medium 3. In this case, the interaction of the radiation with the medium 3, such as absorption dependent on the length L of the optical path 7 and wavelength-dependent absorption properties of the medium 3, arises along the optical path 7 passing through the medium 3. The spectrometer includes a measurement electronics unit 9 connected to the detector 5, which measures the radiant intensity I of the measurement radiation detected by the detector 5 in a metrological manner at different wavelengths. gem (λ) Derive the measured spectrum A gem (λ). The measured spectrum can be determined, for example, by the measurement electronics unit 9, as raw digital spectral data or including intensity I. gem The values ​​of (λ) and the associated wavelength λ are represented by the simulated spectrum of the original signal in the form of an intensity spectrum. Alternatively, the measurement electronics 9 is designed to measure the spectrum A. gem (λ) is determined as the absorption spectrum. In this case, for example, according to: a(λ) i ):=-Log[I gem (λ i ) / I0(λ i ], appears at a specific wavelength λ i Measurement spectrum A at point gem The absorption values ​​a(λ) of (λ) i ) was determined to be at this wavelength λ i The radiation intensity I0(λ) entering medium 3 i ) and the detector 5 at this wavelength λ i The intensity I of the measured radiation from the impact on detector 5 is measured below. gem (λi The logarithm of the ratio of ).

[0072] The present invention is not limited to spectrometers that operate in a transmission manner, but can also be used in a completely similar manner with spectrometers that utilize another form of interaction between radiation and a medium, such as reflection or scattering.

[0073] exist Figure 2 The individual steps of the preparation method are illustrated in the flowchart below and described using an example of a single measurand. The preparation method can be performed in a completely similar manner for at least one other measurand determined by spectrometry using a spectrometer that can be used in the target application.

[0074] like Figure 1 As shown, the preparation method includes a first method step 100, wherein the main spectrum M of the measured object having the spectral distribution characteristics of the measured object is determined based on reference data D recorded in the target application and / or in an application of the same type as the target application.

[0075] For this purpose, reference data D includes reference spectra recorded using a spectrometer and reference values ​​assigned to individual reference spectra—for example, reference values ​​of the measurand determined by reference measurements. Absorption spectra are particularly suitable as reference spectra. The reference spectra included in reference data D can be, for example, reference spectra recorded using a spectrometer of the same design or with a spectrometer having the same optical path length L. Preferably, reference data D includes reference spectra recorded using spectrometers with different known optical path lengths L. In this case, reference data D for each reference spectrum additionally includes the optical path length L of the spectrometer used to record the corresponding reference spectrum.

[0076] In this regard, Figure 3 shows examples of reference spectra recorded using a spectrometer with the same first optical path length L1 at different values ​​of the measured object, Figure 4 shows reference spectra recorded using a spectrometer with the same second optical path length L2 at different values ​​of the measured object, and Figure 5 shows reference spectra recorded using a spectrometer with the same third optical path length L3 at different values ​​of the measured object. Figure 6 shows an example of the main spectrum M of the measured object derived from the reference spectra shown in Figures 3 to 5.

[0077] The creation of the main spectrum M of the measured object continues, for example, by normalizing the individual reference spectrum to the reference value m of the measured object. r If the entire reference spectrum is recorded using spectrometers with the same optical path length L, and a reference value L is also given for the optical path length L from the reference spectrum to the optical path length L given by the optical path length L of these spectrometers. rnormalization. If the reference spectra are recorded by means of spectrometers having different optical path lengths L, the reference spectra are additionally normalized to a reference value L of the optical path length L based on the respective optical path length L contained in the reference data D r . Subsequently, a measured object main spectrum M which reflects the characteristic properties of these normalized reference spectra is derived from the reference spectra normalized in this way. In this case, the measured object main spectrum M can be determined, for example, by means of average or median formation performed on the basis of the normalized reference spectra. Alternatively or additionally, for example, spectral decomposition algorithms and / or smoothing filters for smoothing the reference spectra and / or the normalized reference spectra can be used to determine the measured object main spectrum M.

[0078] With respect to the measured object given by the concentration of an analyte contained in medium 3, the measured object main spectrum M corresponds to an ideal spectrum of the pure substance at a concentration value corresponding to a reference value m r of the measured object, and an optical path length L corresponding to the reference value of the optical path length L r .

[0079] After the measured object main spectrum M is created, in method step 200 a synthetic spectrum E is generated based on the measured object main spectrum M. The synthetic spectrum E respectively comprises individual spectra E generated on the basis of the measured object main spectrum M for a specific individual value m i of the measured object jn . An example in this regard is shown in Figure 7. In connection with reference spectra designed as absorption spectra, the measured object main spectrum M and the synthetic spectrum E derived therefrom are also absorption spectra.

[0080] The advantage provided by the measured object main spectrum M is that it can be used for individually selectable individual values m i of the measured object within a very wide range, from which synthetic individual spectra E jn can be determined in any high number. Therefore, in particular, it is also possible for individual values m i of the measured object that do not appear at all or only appear in very small numbers in the reference data to determine individual spectra E jn . The synthetic spectrum E is generated such that the individual values m jn of the individual spectra E i generally cover a value range of the measured object that is greater than or equal to the value range of the measured object covered by the reference data D, wherein the value range is actually preferably larger than the value range covered by the reference data.

[0081] When determining the synthetic spectrum E, for most measured objects, such as the concentration of an analyte contained in medium 3, a linear relationship between spectral absorption and the value of the measured object can be assumed. In this case, the individual spectra Ejn Each is calculated from the main spectrum M of the measured object using a linear relationship. In cases where this assumption is unreasonable, at least a nonlinear calculation rule that approximates the relationship between spectral absorption and the measured object's value is used, for example, for the individual spectrum E. jn The value is determined.

[0082] Compared to reference spectra, synthetic spectra (E) offer the advantage of reflecting the expected spectral distribution of the measured object's value more comprehensively and accurately according to the reference data, especially in the marginal regions of the value range covered by the reference values, where typically only a limited amount of reference data is available. Furthermore, they reflect the expected spectral distribution more accurately, particularly for measured object values ​​located outside the value range covered by the reference values ​​or for measured object values ​​for which no reference data is available.

[0083] After generating the synthetic spectrum E, in method step 300, one or more pieces of information IF required for the spectral determination of the measured object in the target application are determined and available based on the synthetic spectrum E.

[0084] This information IF includes, for example, multiple pieces of information based on which the most suitable spectrometer for performing spectral determination of the measured object in the target application can be selected. Examples of such information IFs include attributes such as the optical path length L, wavelength range Δλ, and / or path length range ΔL of the spectrometer suitable for performing spectral determination of the measured object in the target application.

[0085] Alternatively or otherwise, the information IF preferably includes a calculation rule CM determined based on the synthesized spectrum E, for use with the spectrometer 11 in the target application, such as... Figure 1 The spectrometer shown can utilize this rule based on the measurement spectrum A that can be captured using spectrometer 11 in the target application. gem (λ) determines the measured value C of the measured object. gem The calculation rule CM is determined, for example, in the form of a mathematical and / or statistical model, such as a model referred to in the art as a chemometric model, and / or is available, for example, in the form of an algorithm.

[0086] If the optical path length L of all spectrometers used to record reference data D is equal to the optical path length Lz of spectrometer 11 available for the target application, then the optical path length L can be ignored during the derivation of the main spectrum M of the measured object, during the generation of the composite spectrum E, and during the determination of the calculation rule CM. If this is not the case, then the main spectrum M of the measured object is determined as a reference value L normalized to the optical path length L in the manner described above. rThe main spectrum M of the measured object is obtained, and the optical path length L is considered in the generation of the composite spectrum E and the calculation rule CM. Therefore, a separate spectrum E is generated from the main spectrum M of the measured object. jn This makes each individual spectrum E jn :=E jn (m i ,L k The individual value m reflected in the measured object i and optical path length L k Specific value combinations [m i ,L k The spectral profile at [ ]. In this case, the calculation rule CM is based on a separate spectrum E generated for the optical path length Lz of the spectrometer 11 available in the target application. jn It's confirmed.

[0087] This preparation method is used, for example, in a method for preparing and performing at least one spectral determination of at least one measurand in a target application. In the context of this method, the preparation method is performed for the measurand or for each measurand. Then, each calculation rule CM determined by the preparation method is stored in the memory 13 of the spectrometer 11, which can be used in the target application. Subsequently, the spectrometer 11 is used in the target application to determine, in each case, at least one measurement value C of the measurand or at least one of the measurands by means of the calculation rule CM determined for the corresponding measurand. gem .

[0088] like Figure 1 As shown, for this purpose, the measurement electronics 9 of the spectrometer 11 has, for example, a measurement device 15, such as a microprocessor, which is designed to be used to measure the spectrum A derived from the spectrometer 11 by means of a calculation rule CM. gem (λ) Calculate the measurement value C of the associated measured object. gem And outputs the measured value C via the interface 17 of the spectrometer 11. gem And / or corresponding to the measured value C gem The measurement signal is output in the form of a readable signal and / or made available in a readable form.

[0089] The advantage provided by using each calculation rule CM determined by means of the preparation method in spectrometer 11 is that, compared with conventional spectrometers that use calculation rules, whose application range is fully limited to the range covered by reference data, the spectrometer has a larger measurement range and / or higher measurement accuracy in each case relative to the corresponding measurand.

[0090] The present invention has the advantages described above. Optionally, the individual method steps and / or components of the spectrometer 11 that can be used in the target application can each have different embodiments, which can be used individually and / or in combination with each other. Some particularly preferred embodiments are described below.

[0091] Therefore, for example, at least one interference variable that occurs in the target application can be considered in the preparation method. An interference variable is an influencing factor that affects the intensity and / or spectral distribution of the intensity spectrum that can be quantitatively detected using detector 5 within the same wavelength range as the analyte, and thus may impair the spectral determination of the analyte. An example of this is, for instance, the concentration of interferometric analytes that may be present in the medium. Considering the determination of the nitrate content in water, nitrites, sulfates, and chlorides can, for example, be considered as interferometric analytes.

[0092] Considering one or more interferometric variables is performed by determining a normalized master interferometric spectrum Sn for each interferometric variable to be considered, which has a spectral distribution that is a characteristic of the corresponding interferometric variable. Similar to the determination of the master spectrum M of the measured object, the master interferometric spectrum Sn can also be determined in each case based on interferometric data, which includes the interferometric spectrum recorded using a spectrometer and the interferometric values ​​of the interferometric variables assigned to the individual interferometric spectra. Like the reference data D, the interferometric data is also recorded, for example, in the target application and / or in an application of the same type as the target application. Alternatively or additionally, it is also possible to use interferometric data recorded in other ways, such as data recorded in a laboratory, depending on the interferometric variables. Just as with the master spectrum M of the measured object, the master interferometric spectra Sn are also each determined, for example, such that they correspond to the ideal spectrum of a pure substance at a reference value of the corresponding interferometric variable—for example, a defined concentration. In this case, the master interferometric spectra Sn are also, for example, each normalized to the reference value of the corresponding interferometric variable, or alternatively, normalized to the reference value of the corresponding interferometric variable and the reference value L of the optical path length L. r .

[0093] The advantage offered by the master spectrum of the interferometric variables Sn is that they can be used to simulate the effects of individual interferometric variables based on their values, as well as the effects of individual interferometric variables based on their optical path length L.

[0094] To account for the interfering variables to be considered, or each interfering variable to be considered, synthetic spectra E are generated such that they include individual spectra E that account for the effects of one or more interfering variables. j1 (M;Sn) and determined by means of the main spectrum of the measured object and the interference spectrum Sn of each interference variable to be considered.

[0095] Alternatively, or in addition to considering one or more interference variables, optical saturation that may occur during measurement operations may be considered, for example, in the fabrication process. When the absorption occurring along optical path 7 exceeds the upper limit a illustrated in Figure 7 for the absorbance value that can be metrologically detected. max At this point, optical saturation occurs; exceeding this upper limit, further absorption no longer results in a quantitatively resolvable increase in the measured absorbance value. Limit value a max These are constant or even wavelength-dependent spectrometer properties that can be experimentally measured or numerically determined under every condition for various types of spectrometers. Limit value a max It can define, calculate and / or specify the optical path length L.

[0096] To account for optical saturation, synthetic spectra E are generated such that they include individual spectra E that account for optical saturation. j2 :=E j2 (M;a max ) and / or individual spectra E that take into account optical saturation and the effects of each interference variable to be considered. j3 :=E j3 (M;Sn;a max ).

[0097] In method step 200, for at least one or even several different limit values ​​a max Generate these individual spectra E j2 E j3 In this case, for example, the process is to determine each individual spectrum E... j2 E j3 At that time, all spectral absorption values ​​determined by Sn are determined based on the main spectrum M of the measured object or separately based on the main spectrum M of the measured object and the main interference spectrum of each interference variable to be considered. If they exceed the limit value a max Then it is reduced to the limit value a. max This results in the synthesized spectrum E shown in Figure 8, which takes into account optical saturation.

[0098] The ability to use optically saturated and / or individual spectra E that take into account one or more interference variables in different ways j1 E j2 E j3 The impact.

[0099] One embodiment specifies that, based on a single spectral E considering the effects of optical saturation and / or (one or more) interference variables. j1 E j2 E j3In each case, at least one and preferably each of the information IFs or multiple information IFs is determined, especially the wavelength range Δλ, the path length range ΔL, and / or the calculation rule CM.

[0100] As a result, especially in the presence of one or more interfering variables, it is possible to achieve improved selection of the most suitable spectrometer and higher measurement accuracy. However, this requires the ability to perform spectral determination of the quanta in the target application and the use of a spectrometer 11 suitable for performing these spectral determinations in the target application.

[0101] In this regard, the preparation method includes, for example, method step 210, wherein, based on a single spectrum E that takes into account the effects of one or more interference variables, j1 And / or based on individual spectral E considering the effects of one or more interference variables and optical saturation. j3 This involves checking whether, when each interfering variable falls within a predetermined range of values ​​for its corresponding interfering variable, the measurand in the target application can be determined using spectroscopy with a predetermined measurement accuracy. For this purpose, a separate spectral E is used to perform the check. j1 E j3 This includes individual spectra E generated by combining the values ​​of the measured object and specific values ​​of each interferometric variable. j2 E j3 Furthermore, this combination of values ​​covers a multidimensional region spanned by a pre-determined range of values ​​for the measured object and each interferometric variable. After the check, the corresponding check result U is made available, indicating whether the measurement can be performed.

[0102] Alternatively or additionally, the preparation method includes, for example, method step 220, wherein the synthesis is based in advance on the synthetic spectrum E, and preferably on a separate spectrum E taking into account optical saturation. j2 And / or individual spectra E considering the effects of optical saturation and (one or more) interference variables. j3 At least one of multiple information IFs that can be used to perform spectral determination of the measured object in the target application is identified. These information IFs include, in particular, the wavelength range Δλ, the optical path length range ΔL of the optical path length L, and / or at least one other attribute of the spectrometer suitable for performing spectral determination of the measured object in the target application. In this case, each of these information IFs is made available, and / or a spectrometer 11 that can be used in the target application is selected based on the information IF.

[0103] Optionally, in method step 220, for example, based on a single spectrum E that takes into account optical saturation. j2 And / or based on a separate spectrum E that takes into account the effects of optical saturation and (one or more) interference variables. j3At least one target value Ls1, Ls2 and / or the maximum value L of the optical path length L of the spectrometer 11 in the target application. max It is determined and available. In this case, for example, a first target value Ls1 for the optical path length L is determined, wherein the measurement area of ​​the measured object can be determined to be at its maximum value using a predetermined measurement accuracy. Alternatively or additionally, for example, a second target value Ls2 for the optical path length L is determined, wherein the measurement accuracy of the measured object can be determined to be at its maximum within a predetermined measurement range. Maximum value L max Corresponding to the maximum possible optical path length L, the measurement of the object being measured can still be performed with a predetermined measurement accuracy at this length. In this embodiment, the first target value Ls1, the second target value Ls2, and / or the maximum value L are used to determine the maximum target value Ls1, Ls2, and / or the maximum value Ls1. max Individual spectrum E j2 E j3 This includes, for example, several different limiting values ​​a corresponding to a specific optical path length L in each case. max The generated individual spectrum E j2 E j3 .

[0104] Below, for example, based on the first target value Ls1, the second target value Ls2, and / or the maximum value L max To select a spectrometer 11 that can be used in the target application, and the spectrometer 11 has a corresponding optical path length Lz, which corresponds to one of the target values ​​Ls1 and Ls2 and / or is less than the maximum value L. max Therefore, the individual spectrum E is also generated based on the optical path length Lz for this spectrometer 11. j2 E j3 To determine the calculation rules CM that can be used or applied in the spectrometer 11.

[0105] Alternatively or additionally, the preparation method may include, for example, method step 230, wherein, based on the synthetic spectrum E, the measurement range Δm:=[m min m max At least one measurement range endpoint m max In this process, a measurement of the measurand with a predetermined measurement accuracy can be performed using a calculation rule CM determined based on the synthetic spectrum E. Alternatively or additionally, based on the synthetic spectrum E, an achievable measurement accuracy ε(Δm) is determined and available, and with this measurement accuracy, a measurement of the measurand within a predetermined measurement range Δm can be performed using the calculation rule CM determined based on the synthetic spectrum E.

[0106] The preparation method is preferably designed as a computer-implemented method. In this respect, the invention also includes a computer program for preparing the spectra of at least one quantifiable object of medium 3 to be determined by means of a spectrometer in a target application of a predetermined type of application. This computer program includes computer-readable program code elements that, when executed on a computer, cause the computer to perform the previously described preparation method. Furthermore, the invention includes a computer program product having at least one computer-readable medium, on which at least one computer-readable medium is stored.

[0107] List of reference numerals

[0108] 1. Radiation source

[0109] 3. Medium

[0110] 5 detectors

[0111] 7 Optical Path

[0112] 9 Measurement Electronic Unit

[0113] 11. Spectrometer

[0114] 13 Memory

[0115] 15 Measuring equipment

[0116] 17 Interface

Claims

1. A method for determining the spectrum of at least one measured object of a medium (3) in a target application, wherein, The target application is an application within a predetermined type of application, wherein: For each measured object, a preparation method including the following steps is performed: Based on reference data (D), a normalized master spectrum (M) of the measurand with the spectral distribution characteristics of the measurand is determined, wherein the reference data (D) includes a reference spectrum of the measurand and associated reference values ​​recorded in at least one application of the predetermined type of application. Based on the main spectrum (M) of the measured object, a composite spectrum (E) is generated, each composite spectrum (E) including a specific individual value (m) for the measured object based on the main spectrum (M). i The generated individual spectra (E) j1 E j2 E j3 ), wherein the individual spectrum (E) j1 E j2 E j3 The individual value (m) i Overall, it covers a range of values ​​greater than or equal to the range covered by the reference value, and Based on the synthesized spectrum (E), one or more pieces of information (IF) required to perform the spectral determination of the measured object in the target application are determined and available. The one or more pieces of information (IF) include attributes such as the optical path length (L) of the spectrometer suitable for performing the spectral determination of the measured object in the target application, the wavelength range (Δλ), and / or the path length range (ΔL), and / or include calculation rules (CM) that can be used with the spectrometer (11) in the target application, which can be used based on the measurement spectrum (A) that can be captured by the spectrometer (11) in the target application. gem (λ) determines the measured value (C) of the measured object. gem ), Based on the one or more pieces of information (IF) provided by the preparation method, perform at least one of the following operations: Select a spectrometer suitable for the target application and / or implement the calculation rules in a spectrometer suitable for the target application. Using a spectrometer suitable for the target application, at least one spectral determination is performed on the metric medium in the target application.

2. The method according to claim 1, wherein: In each case, the reference data (D) for each reference spectrum includes the optical path length (L) of the spectrometer that records the corresponding reference spectrum; The reference spectrum is normalized to the reference value (m) of the corresponding measured object. r ) and the reference value of the optical path length (L) r ),and The main spectrum (M) of the measured object is determined as a reference value (m) normalized to the measured object based on a normalized reference spectrum. r ) and the reference value of the optical path length (L) r The main spectrum (M) of the measured object.

3. The method according to claim 2, wherein, The main spectrum (M) of the measured object is determined by means of average or median formation performed based on a normalized reference spectrum, and / or by using at least one spectral decomposition algorithm and / or at least one smoothing filter for smoothing the reference spectrum and / or the normalized reference spectrum.

4. The method according to any one of claims 1 to 3, wherein, The main spectrum (M) of the measured object and the composite spectrum (E) are absorption spectra, and The individual spectrum (E) j1 E j2 E j3 The values ​​are calculated using a linear relationship between the spectral absorption and the value of the measured object, or determined based on nonlinear calculation rules that reflect the correlation between the spectral absorption and the value of the measured object.

5. The method according to any one of claims 1 to 3, wherein, At least one interfering variable that occurs in the target application is considered in the following aspects. For each interference variable to be considered, a normalized master interference spectrum (Sn) is determined, which has the spectral distribution characteristics of the corresponding interference variable, and The synthesized spectrum (E) includes individual spectra (E... j1 E j3 The individual spectrum (E) j1 E j3 The value is determined based on the main spectrum (M) of the measured object and the main interferometric spectrum (Sn) for each interferometric variable to be considered, and the individual spectrum (E) j1 E j3 The influence of the interference variables was taken into account.

6. The method according to claim 5, The normalized main interferometric spectrum (Sn) is a reference value normalized to the corresponding interference variable and a reference value (L) for the optical path length (L). r The main interference spectrum (Sn) of ).

7. The method according to claim 5, wherein, Optical saturation is considered in the following respect: the synthesized spectra (E) are generated such that they include individual spectra (E) that take into account the optical saturation. j2 ) and / or individual spectra (E) that take into account the optical saturation and the effects of each interference variable to be considered. j3 ).

8. The method according to claim 7, wherein, The synthetic spectrum (E) is generated such that for one or more limiting values ​​(a max Each of these includes a separate spectrum (E) that takes into account the optical saturation. j2 ) and / or individual spectra (E) that take into account the optical saturation and the effects of each interference variable to be considered. j3 ),in: Each limit value (a) max This corresponds to a constant or wavelength-dependent upper limit for the measured value, which can be metrologically detected; above this upper limit, optical saturation occurs. Taking into account the optical saturation of the individual spectrum (E) j2 In the determination of ), the main spectrum (M) of the measured object is determined and exceeds the corresponding limit value (a). max All spectral absorbance values ​​of ) were reduced to the stated limiting value (a max ),and In the individual spectra (E) that take into account the optical saturation and the effects of each interference variable to be considered. j3 In determining the value of ), the main spectrum (M) of the measured object and the main interferometric spectrum (Sn) of each interferometric variable to be considered are used to determine and exceed the corresponding limit value (a). max All of the spectral absorption values ​​are reduced to the limiting value (a) max ).

9. The method according to claim 7, wherein, In each case, based on the individual spectrum (E) that takes into account the effects of the optical saturation and / or the interference variables. j1 E j2 E j3 Determine at least one of the information (IF) or the plurality of information (IF).

10. The method according to claim 7, wherein, Based on the individual spectrum (E) that takes into account the influence of the interference variables. j1 ) and / or the individual spectrum (E) that takes into account the effects of the interference variables and the optical saturation. j3 This involves checking whether the measurand in the target application can be determined by spectroscopy with a predetermined measurement accuracy, provided that each interfering variable falls within a predetermined value range for that corresponding interfering variable. The corresponding inspection result (U) is available.

11. The method according to any one of claims 7 to 10, wherein: Based on the individual spectrum (E) that takes into account the optical saturation j2 ) and / or based on the individual spectrum (E) that takes into account the effects of the optical saturation and the interference variables. j3 ), and determine the wavelength range (Δλ) and path length range (ΔL) of the spectrometer suitable for performing the spectral determination of the measured object in the target application, and Each of these information (IF) is available, and / or the information (IF) is used to select the spectrometer (11) that can be used in the target application.

12. The method according to any one of claims 7 to 10, wherein, Based on the individual spectrum (E) that takes into account the optical saturation j2 ) and / or the individual spectrum (E) that takes into account the effects of the optical saturation and the interference variables. j3 ): A first target value (Ls1) of the optical path length (L) of the spectrometer (11) that can be used in the target application is determined and available, wherein the measurement area (Δm) of the measured object can be determined to be at its maximum value with a predetermined measurement accuracy. A second target value (Ls2) of the optical path length (L) of the spectrometer (11) that can be used in the target application is determined and available, wherein the measurement accuracy (ε(Δm)) of the measured object can be determined to be at its maximum value within a predetermined measurement range (Δm), and / or The maximum value (L) of the optical path length (L) of the spectrometer (11) that can be used in the target application max The maximum value is determined and available, which corresponds to the maximum possible optical path length (L), at which the measurement of the object being measured can still be performed with a predetermined measurement accuracy.

13. The method according to claim 12, wherein, Based on the first target value (Ls1), the second target value (Ls2), and / or the maximum value (L... max Select the spectrometer (11) that can be used in the target application, such that it has one of the target values ​​(Ls1, Ls2) and / or is less than the maximum value (L). max The optical path length (Lz) and The calculation rule (CM) is based on the individual spectrum (E) generated for the optical path length (Lz) of the spectrometer (11). j2 E j3 It is certain.

14. The method according to any one of claims 1 to 3, wherein, Based on the synthesized spectrum (E): Measurement range (Δm:= [ m min ; m max At least one measurement range endpoint (m) of ]) max The calculation rule (CM) is determined and available, wherein the measurement of the object being measured can be performed with a predetermined measurement accuracy by means of the calculation rule (CM), and / or An achievable measurement accuracy (ε(Δm)) is determined and available, and with the aid of the achievable measurement accuracy, the measurement of the measured object can be performed within a predetermined measurement range (Δm) by means of the calculation rule (CM).

15. The method according to any one of claims 1 to 3, wherein, The reference data (D) recorded in at least one application of the predetermined type of application includes the reference data (D) recorded in the target application.

16. A computer program product for preparing a medium (3) for spectroscopic determination of at least one quantified object to be performed by means of a spectrometer in a target application of a predetermined type of application, the computer program product having a computer program and at least one computer-readable medium on which at least the computer program is stored, the computer program having computer-readable program code elements that, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 15.

17. Use of the method according to any one of claims 1 to 15 in a method for at least one spectral determination of at least one measured object in a target application for preparing and performing an application of a predetermined type, wherein, The preparation method is performed on the measured object or for each measured object. Each calculation rule (CM) determined by the preparation method is stored in the memory (13) of the spectrometer (11) that can be used in the target application, and In the target application, the spectrometer (11) is used to perform, in each case, the calculation rule (CM) determined for the corresponding measurand to measure the value (C) of the measurand or at least one of the measurands. gem At least one of the following is determined:

18. The use of at least one calculation rule (CM) determined by means of the method according to any one of claims 1 to 15 in a spectrometer (11), wherein, The spectrometer (11) includes a measuring device (15) designed to measure a spectrum (A) derived from the spectrometer (11). gem (λ)), using the calculation rule (CM) to calculate the associated measurement value (C) of the measured object. gem ), and output it as a measurement (C) gem ) and / or via the interface (17) of the spectrometer (11) to correspond to the measured value (C) gem ( ) the form of the measurement signal and / or make it available in a readable form.

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