WO2025186147A1

WO2025186147A1 - Apparatus and method for processing measurement data of a spectrometer, mobile device, server and method for enabling plausibility determination for measurement data of a spectrometer at run-time

Info

Publication number: WO2025186147A1
Application number: PCT/EP2025/055629
Authority: WO
Inventors: Szu-Yu Huang; Felix Schmidt; Matthias STEEG; Henning ZIMMERMANN
Original assignee: TrinamiX GmbH
Current assignee: TrinamiX GmbH
Priority date: 2024-03-07
Filing date: 2025-03-03
Publication date: 2025-09-12
Anticipated expiration: 2026-09-07
Also published as: WO2025186147A8

Abstract

Provided is an apparatus for processing measurement data of a spectrometer. The apparatus includes processing circuitry configured to receive the measurement data and determine whether the measurement data are plausible. If it is determined that the measurement data are plausible, the processing circuitry is further configured to forward the measurement data to a process for evaluation of the measurement data.

Description

APPARATUS AND METHOD FOR PROCESSING MEASUREMENT DATA OF A SPECTROMETER, MOBILE DEVICE, SERVER AND METHOD FOR ENABLING PLAUSIBILITY DETERMINATION FOR MEASUREMENT DATA OF A SPECTROMETER AT RUN-TIME

Description

Field

The present disclosure relates to the processing of measurement data of a spectrometer. In particular, examples of the present disclosure relate to an apparatus and a method for processing measurement data of a spectrometer, a mobile device, a server and a method for enabling plausibility determination for measurement data of a spectrometer at run-time.

Background

Using a spectrometer to gather information about a sample requires the user to perform various measurements. The user is in many cases not an expert in spectroscopy or optics and is, hence, not aware of the importance of performing the measurement correctly. For example, in case of spectrometers integrated into consumer electronics such as mobile phones, the user is usually not an expert. However, mistakes of the user result in wrong or invalid measurements. For example, the user may perform one or more of the following mistakes when perform the measurements with the spectrometer. The user may, e.g., conduct a wrong open port measurement and place a reference sample or a target sample on a sample interface of the spectrometer. Similarly, the user may conduct a wrong reference sample measurement without the reference being placed on the sample interface or with the target sample being placed on the sample interface. When placing a sample on the sample interface, the user may make mistakes with respect to the positioning and/or orientation of the sample relative to the sample interface. Spectrometers and samples are in many cases sensitive to the position/orientation of the sample at the sample interface due to their optical scattering characteristics. Hence, mistakes in the positioning and/or orientation of the sample are very likely to result in wrong or invalid measurement results.

In case wrong or invalid measurement results are input to data analysis models such as chemometric models, the models will output erratic results or conclusions. For example, if wrong or invalid measurement results are input to a model for determining which type of plastic a measured object is made of, the model may output the wrong type of plastic - which may lead to user frustration.

Hence, there may be a demand for improved processing of measurement data of spectrometers. Summary

This demand is met by an apparatus and a method for processing measurement data of a spectrometer, a mobile device, a server, a method for enabling plausibility determination for measurement data of a spectrometer at runtime, a non-transitory machine-readable medium and a program in accordance with the independent claims. Advantageous embodiments are defined by the dependent claims.

According to a first aspect, the present disclosure provides an apparatus for processing measurement data of a spectrometer. The apparatus comprises processing circuitry configured to receive the measurement data and determine whether the measurement data are plausible. If it is determined that the measurement data are plausible, the processing circuitry is further configured to forward the measurement data to a process for evaluation of the measurement data.

According to a second aspect, the present disclosure provides a mobile device. The mobile device comprises an apparatus for processing measurement data of a spectrometer according to the first aspect. Furthermore, the mobile device either comprises the spectrometer or interface circuitry configured to receive the measurement data from the spectrometer. In the first case, the spectrometer is configured to generate the measurement data based on measured radiation. In the second case, the spectrometer is external to the mobile device.

According to a third aspect, the present disclosure provides a server. The server comprises an apparatus for processing measurement data of a spectrometer according to the first aspect. Additionally, the server comprises interface circuitry configured to receive the measurement data from the spectrometer.

According to a fourth aspect, the present disclosure provides a method for processing measurement data of a spectrometer. The method comprises receiving the measurement data and determining whether the measurement data are plausible. In addition, the method comprises forwarding the measurement data to a process for evaluation of the measurement data if it is determined that the measurement data are plausible.

According to a fifth aspect, the present disclosure provides a non-transitory machine-readable medium having stored thereon a program having a program code for performing the method according to the fourth aspect, when the program is executed on a processor or a programmable hardware.

According to a sixth aspect, the present disclosure provides a program having a program code for performing the method according to the fourth aspect, when the program is executed on a processor or a programmable hardware.

According to a seventh aspect, the present disclosure provides a method for enabling plausibility determination for measurement data of a spectrometer at run-time. The method comprises performing a factory calibration of the spectrometer under defined conditions. Further, the method comprises determining one or more reference values from measurement data generated by the spectrometer during the factory calibration. The method additionally comprises storing the one or more reference values in a data storage accessible by an apparatus used for determining whether measurement data generated by the spectrometer during user operation are plausible.

According to the proposed technology, only plausible measurement data are fed to the process for evaluation of the measurement data. Accordingly, input of wrong or invalid measurement data to data analysis models such as chemometric models may be avoided, which in turn allows to prevent bad user experience.

Brief description of the Figures

Some examples of apparatuses and/or methods will be described in the following by way of example only, and with reference to the accompanying figures, in which

Fig. 1 illustrates an example of an apparatus for processing measurement data of a spectrometer;

Fig. 2 illustrates an exemplary spectrometer;

Fig. 3 illustrates an exemplary comparison of a measurement value to a reference curve;

Fig. 4 illustrates an exemplary mobile device;

Fig. 5 illustrates an exemplary server;

Fig. 6 illustrates a flowchart of an example of a method for processing measurement data of a spectrometer; and

Fig. 7 illustrates a flowchart of an example of a method for enabling plausibility determination for measurement data of a spectrometer at run-time.

Detailed Description

Some examples are now described in more detail with reference to the enclosed figures. However, other possible examples are not limited to the features of these embodiments described in detail. Other examples may include modifications of the features as well as equivalents and alternatives to the features. Furthermore, the terminology used herein to describe certain examples should not be restrictive of further possible examples. Throughout the description of the figures same or similar reference numerals refer to same or similar elements and/or features, which may be identical or implemented in a modified form while providing the same or a similar function. The thickness of lines, layers and/or areas in the figures may also be exaggerated for clarification.

When two elements A and B are combined using an "or”, this is to be understood as disclosing all possible combinations, i.e. only A, only B as well as A and B, unless expressly defined otherwise in the individual case. As an alternative wording for the same combinations, "at least one of A and B" or "A and/or B" may be used. This applies equivalently to combinations of more than two elements.

If a singular form, such as "a”, "an” and "the” is used and the use of only a single element is not defined as mandatory either explicitly or implicitly, further examples may also use several elements to implement the same function. If a function is described below as implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity. It is further understood that the terms "include", "including", "comprise" and/or "comprising", when used, describe the presence of the specified features, integers, steps, operations, processes, elements, components and/or a group thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and/or a group thereof.

Fig. 1 illustrates an apparatus 100 for processing measurement data 101 of a spectrometer 120.

The spectrometer 120 is a device adapted (designed, configured) to measure the spectral composition of electromagnetic radiation at (specific, predefined) discrete wavelengths or within a specified (predefined) wavelength range. In particular, the spectrometer 120 may be adapted to measure the spectral composition of light at (specific, predefined) discrete wavelengths or within a specific (predefined) wavelength range. In other words, the spectrometer 120 may be an optical spectrometer. The spectrometer 120 may comprise various components such as a light source, a dispersive element (e.g., a diffraction grating or prism), a sample interface on which a sample to be measured may be placed, one or more optical filters and a detector to capture and quantify the intensity of light at one or more wavelengths or wavelength ranges. The detector may comprise one or more photo-sensitive pixels (sensors). Each photosensitive pixel may comprise semiconductor material such as one or more inorganic photoconductive materials like lead sulfide (PbS), lead selenide (PbSe), germanium (Ge), indium gallium arsenide (InGaAs), indium antimonide (InSb) or mercury cadmium telluride (HgCdTe or MCT). Incident light may penetrate the semiconductor material of the respective photo-sensitive pixel and cause generation of charge carriers (e.g. electrons or holes) and, hence, an electrical signal in the semiconductor material. For example, the one or more photo-sensitive pixels may be a Charge-Coupled Devices (CCDs) or Complementary Metal-Oxide-Semiconductor (CMOS) devices.

For example, a reference measurement of an external reference sample placed on the sample interface of the spectrometer 120 may be performed by a user with the spectrometer 120. The external reference sample may be a sample (object) with known spectral characteristics. The external reference sample may, e.g., exhibit a 99% reflectance and diffusive (Lambertian) reflective scattering properties. The reference measurement allows to calibrate or validate the spectrometer 120, ensuring its accuracy and reliability. Further, a sample measurement of a target sample placed on the sample interface of the spectrometer 120 may be performed by the user with the spectrometer 120. The target sample may be a sample (object) with unknown spectral characteristics. In other words, the target sample may be examined for its spectral characteristics. The target sample may be a liquid, a gas or a solid. For example, the target sample may be (e.g., human) skin, textile, a plastic or a food item. Still further, a background measurement (also known as open port measurement) with no sample being placed on the sample interface of the spectrometer 120 may be performed by the user with the spectrometer 120. The background measurement allows to determine the baseline or background that is present when no sample is present in the measurement path (e.g., an optical path) of the spectrometer 120. The background measurement allows to correct and account for ambient or instrumental signals that could affect the accuracy of the sample measurements.

The measurement data 101 of the spectrometer 120 may be data obtained through the operation of the spectrometer 120, capturing the intensity or amplitude of electromagnetic radiation (e.g., light) at one or more specific (predefined) wavelengths (e.g., within a designated spectral range). The measurement data 101 may be derived from the interaction between the emitted radiation and the sample (e.g., reference sample or target sample) or from the background measured by the spectrometer 120 in the respective measurement. The measurement data 101 may represent the spectral characteristics measured in the respective measurement with the spectrometer 120. For example, the measurement data 101 may represent the spectral characteristics of a measured sample or the background. The measurement data 101 may indicate (be encoded with) respective measurement values of one or more measurements with/by the spectrometer 120 (e.g., one or more background measurements, reference measurements and/or sample measurements). The measurement data 101 may, e.g., comprise or indicate numerical values corresponding to the intensity or amplitude of the detected (measured) radiation at one or more (specific, predefined) discrete wavelengths or wavelength regions for one or more measurements with/by the spectrometer 120. For example, the measurement data 101 may indicate respective measurement values of one or more photo-sensitive pixels of the spectrometer 120 for one or more of a reference measurement, a background measurement and a sample measurement with/by the spectrometer 120.

Additionally, the measurement data 101 may comprise metadata indicating further information about the data elements representing the measured spectral characteristics (i.e., the measurement values). For example, the metadata may indicate a time of a measurement with the spectrometer 120. In other words, the data elements of the measurement data 101 representing the measurement values may be provided with a time stamp indicating the measurement time(s) of the measured spectral characteristics. Alternatively or additionally, the metadata may indicate an environmental status while performing a measurement with the spectrometer 120. In other words, the data elements of the measurement data 101 representing the measurement values may be provided with further information about the status of the spectrometer 120's environment while performing the measurement. For example, the metadata may indicate a temperature while performing the measurement with the spectrometer 120. Further alternatively or additionally, the metadata may indicate the type of spectrometer used for generating the measurement values, i.e. , the type of spectrometer used for the measurement. However, it is to be noted that the present disclosure is not limited the foregoing examples. The metadata may indicate additional, less or different pieces of information.

The apparatus 100 comprises processing circuitry 110. The processing circuitry 110 is configured to receive and process the measurement data 101. For example, the processing circuitry 110 may be a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which or all of which may be shared, a digital signal processor (DSP) hardware, an application specific integrated circuit (ASIC), a neuromorphic processor, a sys- tem-on-a-chip (SoC) or a field programmable gate array (FPGA). The processing circuitry 110 may optionally be coupled to, e.g., memory such as read only memory (ROM) for storing software, random access memory (RAM) and/or non-volatile memory. For example, the apparatus 100 may comprise memory configured to store instructions, which when executed by the processing circuitry 110, cause the processing circuitry 110 to perform the steps and methods described herein.

The processing circuitry 110 is configured to determine whether the measurement data 101 are plausible. In other words, the processing circuitry 110 is configured to assess or evaluate the plausibility of the measurement data 101 . The term "plausible” in this context may mean whether the measurement data 101 is logically or reasonably acceptable based on certain criteria or standards. In other words, the processing circuitry 110 is configured to evaluate the credibility, validity or reasonableness of the measurement data. In still other words, the processing circuitry 110 is configured to check if the provided measurement data 101 make sense or are reasonable according to predefined criteria. For example, the processing circuitry 110 may determine whether the measurement data 101 show an expected (e.g., predefined or learned) behavior or structure. The criteria or standards for determining the plausibility of the measurement data 101 may be manifold. Specific examples will be described in the following. However, it is to be noted that the present disclosure is not limited thereto. Additional or different criteria or standards for determining the plausibility of the measurement data 101 may be used.

The processing circuitry 110 is configured to forward the measurement data 101 to a process 130 for evaluation of the measurement data 101, (only, exclusively) if it is determined that the measurement data 101 are plausible. The process 130 is illustrated as a separate element in Fig. 1. For example, the process 130 may be performed by circuitry different from the processing circuitry 110. The separate circuitry for performing the process 130 may be part of the apparatus 100 in some examples. In alternative examples, the separate circuitry for performing the process 130 is not part of the apparatus 100. It is to be noted that the process 130 may be performed by the processing circuitry 110 according to examples of the present disclosure. The process 130 may be a process that receives the measurement data 101 (and optionally further data) as input and outputs a conclusion or analysis result such as a composition of a measured object (e.g., which type of plastic a measured object is made), a maturity of an agricultural product, the moisture level of the measured object (e.g., the object being the human skin) or a health or fitness level of a person (if a part of the person's body is measured). In some examples, the process 130 may output a recommendation or suggestion such as to apply a certain fertilizer to measured soil (e.g., based on the minerals content of the soil being determined from the measurement data 101 by the process 130) or to administer a dose of insulin (e.g., based on the blood glucose level of a human being determined from the measurement data 101 by the process 130). The process 130 may further output a confidence value indicating the confidence of the determined information (e.g., a conclusion, analysis result or recommendation). It is to be noted that the present disclosure is not limited to the foregoing examples. Other information may be derived from the measurement data 101 depending on the use case and the measured object. The process 130 may, e.g., use a data analysis model such as a chemometric model to derive the conclusion, analysis result or recommendation based on the input measurement data 101. The data analysis model may, e.g., be a mechanistic (i.e., rule-based) model, a trained machine-learning model or a combination thereof.

The apparatus 100 forwards plausible measurement data to the process 130 for evaluation of the measurement data 101. On the other hand, if it is determined that measurement data 101 are not plausible, the processing circuitry 110 may be further configured to not forward the measurement data 101 to the process 130 for evaluation of the measurement data 101. Accordingly, feeding of wrong or invalid measurement results to the process 130 and, hence, output of erratic results or conclusions by the process 130 may be avoided. This may prevent bad user experience.

In case the measurement data 101 are implausible, the measurement data 101 cannot be used for the evaluation by the process 130. The measurement may be repeated to obtain plausible, i.e., valid, measurement data which may be input to the process 130. Therefore, if it is determined that measurement data 101 are not plausible, the processing circuitry 110 may in some examples further be configured to cause a Human-Machine-Interface (HMI) 140 to output a notification to repeat one or more measurements with the spectrometer 120. For example, the HM1 140 may be or be part of a mobile device (such as mobile phone, a wearable or tablet-computer) used/accessible by the user. For example, the mobile device may comprise or be communicatively coupled with the spectrometer 120. The notification may be manifold. For example, the notification may be a graphical notification on a Graphical User Interface (GUI) output at a display of the mobile device or an acoustic notification such as a spoken notification output by a loudspeaker of the mobile device. The processing circuitry 110 may, e.g., be configured to transmit control data to the HM1 140. The control data is encoded with one or more control commands for controlling (instructing) the HM1 140 to output the notification. The output of the notification allows to make the user aware that one or more measurements with the spectrometer 120 need to be repeated obtain plausible (valid) measurement data. It is to be noted that the HM1 140 is not restricted to mobile devices. The HM1 140 may be or be part of any terminal device used/accessible by the user.

Implausible measurement results such as false measurements are often caused by a user not performing the measurement correctly. For example, the user may conduct a wrong background measurement and place a reference sample or a target sample on a sample interface of the spectrometer 120. Similarly, the user may conduct a wrong reference sample measurement without the reference being placed on the sample interface or with the target sample being placed on the sample interface. When placing a sample on the sample interface, the user may make mistakes with respect to the positioning and/or orientation of the sample relative to the sample interface. The user is in many cases not an expert in spectroscopy or optics. Providing guidance to the user in cause of implausible measurement data may in many cases lead to plausible measurement results in a next measurement. Accordingly, the processing circuitry 110 may in some examples further be configured to determine at least one suggestion for improvement for the repetition of the one or more measurements with the spectrometer 120 and cause the HMI to output the at least one suggestion for improvement. By outputting the at least one suggestion for improvement, the user may be supported in performing the measurement(s) correctly. Hence, the user experience may be improved. For example, if it is determined that measurement data 101 are not plausible, the processing circuitry 110 may be configured to determine a suspected error (fault) in performing the measurement with spectrometer based on the measurement data 101. The at least one suggestion for improvement may, e.g., be selected from a Look-Up Table (LUT) based on the suspected error. The LUT may store a plurality of suggestions for improvement for different suspected errors. For example, if analysis of the measurement data 101 for a background measurement indicates that an object was placed on the sample interface of the spectrometer during the background measurement, the suggestion for improvement may be to remove the object from the sample interface and/or to clean the sample interface for the repetition of the background measurement. If analysis of the measurement data 101 for a sample measurement indicates that the positioning and/or orientation of the target sample on the sample interface was not correct, the suggestion for improvement may be to change (adjust) the positioning and/or orientation of the target sample on the sample interface. It is to be noted that the present disclosure is not limited the foregoing examples. Other suggestions may be used as well.

As indicated above, various criteria or standards may be used for determining the plausibility of the measurement data 101. In the following, a plurality of examples will be described in greater detail. It is to be noted that the criteria or standards described in the following may be used separately or in combination to determine the plausibility of the measurement data 101.

For determining whether the measurement data 101 are plausible, the processing circuitry 110 may, e.g., analyze metadata included in the measurement data 101. For example, the processing circuitry 110 may be configured to extract metadata for a plurality of measurements forming a measurement set from the measurement data 101 . The measurement set may be a series or plurality of measurements such as a series of one or more background measurements, one or more reference measurement and one or more sample measurement. If the metadata satisfy a predefined criterion, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible for the measurements forming the measurement set. On the other hand, if the metadata do not satisfy the predefined criterion, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible for the measurements forming the measurement set. The metadata may indicate various pieces of information as described above. For example, the metadata may indicate a time of measurement for the respective measurement of the measurement set and/or a temperature while performing the respective measurement of the measurement set. The spectrometer 120 may, e.g., comprise an internal clock for determining the time of measurement for the respective measurement of the measurement set and/or a temperature sensor for measuring the temperature at the times of performing the measurements forming the measurement set.

The measurements of the measurement set should be performed under reasonably similar conditions. Even though compensation methods (approaches) are known to those skilled in the art for compensating slightly different environmental conditions while performing measurements with a spectrometer, the deviation should not be too much. For example, if the measurement set comprises a reference measurement and sample measurement and if the temperature difference between a temperature at a time of performing the reference measurement with the spectrometer 120 and a temperature a time of performing the sample measurement with the spectrometer 120 is too high, conventional approaches for compensating the temperature difference may lead to unacceptable measurement accuracy. Accordingly, if the metadata indicate the temperature while performing the respective measurement of the measurement set, the temperature differences between the temperatures indicated by the metadata may be determined by the processing circuitry 110 and, e.g., compared to a threshold value (being an example for a predefined criterion). If the determined temperature differences between the temperatures indicated by the metadata are smaller than the threshold value, the processing circuitry 110 may determine that the measurement data 101 are plausible for the measurements forming the measurement set. On the other hand, if at least part (e.g., one or more) of the determined temperature differences between the temperatures indicated by the metadata is above the threshold value, the processing circuitry 110 may determine that the measurement data 101 are not plausible for the measurements forming the measurement set. The threshold value may, e.g., be based on (given by) a compensation algorithm used by the process 130 for compensating different temperatures at the times of performing the measurements forming the measurement set.

The environmental conditions in the surrounding of the spectrometer 120 vary over time in many cases. Therefore, also the time of measurement for the respective measurement of the measurement set may be an indicator for the plausibility of the measurements forming the measurement set. For example, if the time difference between individual measurements of the measurements forming the measurement set is too large, it is likely that the environmental conditions in the surrounding of the spectrometer 120 have changed significantly (too much). Accordingly, if the metadata indicate the time of measurement for the respective measurement of the measurement set, the time differences between the times of measurement indicated by the metadata may be determined by the processing circuitry 110 and, e.g., compared to a threshold value (being an example for a predefined criterion). If the determined time differences between the times of measurement indicated by the metadata are smaller than the threshold value, the processing circuitry 110 may determine that the measurement data 101 are plausible for the measurements forming the measurement set. On the other hand, if at least part (e.g., one or more) of the determined time differences between the times of measurement indicated by the metadata is above the threshold value (i.e., if time stamps of the measurements forming the measurement set show a too large difference), the processing circuitry 110 may determine that the measurement data 101 are not plausible for the measurements forming the measurement set. If the measurement data 101 are not plausible for the measurements forming the measurement set, the processing circuitry 110 may be configured to not forward the measurement data 101 to the process 130. In other words, the processing circuitry 110 may reject the measurement data 101. In this case, the processing circuitry 110 may, e.g., be further be configured to cause the HM1 140 to output a notification to repeat one or more measurements of the measurement set with the spectrometer 120 to obtain a valid measurement set.

Analyzing the metadata included in the measurement data may allow to reject measurements or measurement sets with a too large (expected or actual) variation of the measurement values for the different measurements.

In some examples, photo-sensitive pixels of the spectrometer 120 sensitive to light in the same wavelength range may be used for the plausibility determination. Using the measurement results from multiple photo-sensitive pixels for the same wavelength range, the sample measurement may be verified. For example, the measurement data 101 may indicate respective measurement values of two or more photo-sensitive pixels of the spectrometer 120 for a reference measurement, a background measurement and a sample measurement. The two or more photo-sensitive pixels of the spectrometer 120 may be sensitive to light in the same wavelength range. In other words, the two or more photo-sensitive pixels of the spectrometer 120 may measure the same portion of the electromagnetic spectrum. For example, the two or more photo-sensitive pixels of the spectrometer 120 may comprise PbS as photoconductive material and be sensitive to light in the wavelength range between 1 m and 3 pm.

For determining whether the measurement data 101 are plausible, the processing circuitry 110 may be configured to determine, for each of the two or more photo-sensitive pixels of the spectrometer 120, a respective absorbance value of the target sample based on the respective measurement values for the reference measurement, the background measurement and the sample measurement. The absorbance of the target sample may be calculated as follows: with a_t being the respective absorbance value of the target sample for each of the two or more photo-sensitive pixels of the spectrometer 120, S_t being the respective measurement value of the respective photo-sensitive pixel for the sample measurement, R_t being the respective measurement value of the respective photo-sensitive pixel for the reference measurement and O_t being the respective measurement value of the respective photo-sensitive pixel for the background measurement. The index i = 1, 2, ... denotes the respective photo-sensitive pixel of the spectrometer 120.

All photo-sensitive pixels operating at the same wavelength should yield the same absorbance. Accordingly, the processing circuitry 110 may be further configured to determine that the measurement data 101 are plausible if the determined absorbance values a_t differ by less than a threshold (value) from each other. On the other hand, the processing circuitry 110 may be further configured to determine that the measurement data 101 are not plausible if the determined absorbance values a_t differ by more than the threshold (value) from each other. If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130. In other words, if the calculated absorbance values differ by more than a given acceptance margin for the photo-sensitive pixels sensitive to the same wavelength, the processing circuitry 130 may be configured to reject the measurement. The threshold value may, e.g., be 1 % or less, 5 % or less, 10 % or less or 20 % or less.

If the process 130 (e.g., as a part of a specific application or use case) is designed (adapted) for a certain group of target samples such as target samples belonging to a certain group of material, information about the expected spectra or absorbances of the group of target samples may be known. This information may be used for the plausibility determination for the measurement data 101. For example, the measurement data 101 may indicate respective measurement values of one or more photo-sensitive pixels of the spectrometer 120 for a reference measurement, a background measurement and a sample measurement. For determining whether the measurement data 101 are plausible, the processing circuitry 110 may be configured to determine, for the one or more photo-sensitive pixels, a respective absorbance value of the target sample based on the respective measurement values for the reference measurement, the background measurement and the sample measurement. The respective absorbance value may, e.g., be calculated according to above mathematical expression (1).

If, for each of the one or more photo-sensitive pixels, the respective determined absorbance value is within a reference value range for the respective photo-sensitive pixel, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible. On the other hand, the processing circuitry 110 may be further configured to determine that the measurement data 101 are not plausible if, for at least part (e.g., one or more) of the one or more photo-sensitive pixels, the respective determined absorbance value is not within the reference value range for the respective photo-sensitive pixel. If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130. In other words, processing circuitry 130 may be configured to reject a sample measurement, if the calculated absorbance is not within the known or expected range of values. For example, if a measurement of a target sample being made of a certain type of material is expected by the process 130 (e.g., measurement of a plastic material), expected spectra or absorbance ranges for the type of material may be known. The reference value range for the respective pixel may be derived from the expected spectra or absorbance ranges for the type of material. For example, if the one or more photo-sensitive pixels are sensitive to different wavelengths or wavelength ranges, the respective reference value range may be derived for the respective wavelength or wavelength range in which the respective photo-sensitive pixel is sensitive. The reference value ranges for the one or more photo-sensitive pixel may, e.g., be determined or provided as part of a factory calibration. If the measured target sample is made up of the expected type of material, the respective determined absorbance value should be within the respective reference value range. If the measured target sample is made up of a different material than the expected type of material (e.g., metal instead of plastic), the respective determined absorbance value is likely not within the respective reference value range. Even though the spectrum measurement itself may have been performed correctly by the user in this case, the sample measurement as part of the measurement data 101 may be rejected as further processing (e.g., classification) performed by the process 130 may be incorrect since the target sample is not conforming to the designated group of samples expected by the process 130.

In some examples, the measurement data 101 may indicate measurement values of a photo-sensitive pixel of the spectrometer 120 for a reference measurement and a background measurement. In other words, a background measurement and a reference measurement were performed by the spectrometer 120. If both background and reference measurements are performed, it may be checked whether they are behaving as expected compared to each other. For determining whether the measurement data 101 are plausible, the processing circuitry 110 may be configured to determine a deviation of a ratio of the measurement value for the reference measurement to the measurement value for the background measurement from a reference ratio (e.g., a calibration factor). If the deviation is smaller than a threshold value, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible. On the other hand, the processing circuitry 110 may be further configured to determine that the measurement data 101 are not plausible if the deviation is above the threshold value. If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130. In other words, if the quotient of the obtained reference and backgrounds measurements is not within a certain margin to the calibration factor, the measurement set may be declared false or invalid.

The comparison to the threshold value may be expressed as follows:

\R/O - C\ < W (2) with R denoting the measurement value of the photo-sensitive pixel of the spectrometer 120 for the reference measurement, O denoting the measurement value of the photo-sensitive pixel for the background measurement, C denoting the reference ratio and W denoting the threshold value. The reference ratio C may, e.g., be determined or provided as part of a factory calibration. For example, the reference ratio C may be temperature-dependent and the value for the reference ratio C(T) may be selected by the processing circuitry 110 based on metadata of the measurement data 101 for the reference measurement and the background measurement. The metadata may, e.g., indicate the temperature while performing the respective one of the reference measurement and the background measurement and allow the processing circuitry 110 to select a proper value of the temperature-dependent reference ratio C(T). The threshold value may, e.g., be 1 % of the reference ratio or less, 5 % of the reference ratio or less, 10 % of the reference ratio or less or 20 % of the reference ratio or less.

In some examples, the spectrometer 120 may comprise an internal reflection target, i.e., a predefined reflection target within the spectrometer 120. Measurement values obtained for measurements of the predefined reflection target may be used for the plausibility determination according to examples of the present disclosure. Fig. 2 illustrates an exemplary spectrometer 200 comprising an internal reflection target. The spectrometer 200 may be used for the spectrometer 120 illustrated in Fig. 1.

Analogously to what is described above for the spectrometer 120, the spectrometer 200 comprises a detector 210, light source 220 (e.g., a laser diode and/or a Light-Emitting Diode, LED) and a sample interface 240. As illustrated in Fig. 2, a sample 299 such as a reference sample or a target sample may be placed on the sample interface 240. Light 221 emitted by the light source 220 traverses the sample interface 240 and is reflected by the sample 299. The reflected light 22T traverses the sample interface 240 and reaches the detector 210. The detector 210 comprises one or more photo-sensitive pixels configured to measure the reflected light 22T incident on the respective pixel. Based on the electrical signal(s) generated by the one or more photo-sensitive pixels, the measurement data for the respective measurement is generated.

The spectrometer 200 additionally comprises an internal reflection target (internal reference sample) 250, i.e. , a predefined reflection target (predefined reference sample)within the spectrometer 200. Like the external reference sample described above, the predefined reflection target 250 is a sample with known spectral characteristics. For example, the predefined reflection target 250 may exhibit a 99% reflectance and diffusive (Lambertian) reflective scattering properties.

The spectrometer 200 further comprises a second light source 230 (e.g., a laser diode and/or a LED). The second light source 230 emits light 231 towards the predefined reflection target 250. The light 231 is reflected by the predefined reflection target 250. The reflected light 23T reaches the detector 210. The one or more photo-sensitive pixels of the detector 210 measure the reflected light 23T incident on the respective pixel. Based on the electrical signal(s) generated by the one or more photo-sensitive pixels, the measurement data for the respective measurement with the predefined reflection target 250 is generated.

The first light source 220 and the second light source 230 may be configured to emit their light simultaneously or subsequently. In other words, the first light source 220 and the second light source 230 may operate at the same time or one after the other (i.e., in a Time-Division Duplexing, TDD, manner). In case the first light source 220 and the second light source 230 emit their light simultaneously, Frequency Division Duplexing (FDD) may be used. That is, the first light source 220 and the second light source 230 may modulate their emitted light with different modulation frequencies. For example, the first light source 220 and the second light source 230 may be configured to emit squarewave modulated light with different modulation frequencies. Accordingly, the received reflections 22T and 23T may be distinguished by the detector 210 and be assigned (allocated) to the respective one of the first light source 220 and the second light source 230.

In the example of Fig. 2, two separate light sources 220 and 230 are used for illuminating the predefined reflection target 250 and the sample 299. However, the present disclosure is not limited thereto. In other examples a single light source may be used instead. For example, the spectrometer 200 may comprise a beam splitter configured to split the light beam emitted by the single light source into two light beams. The first split light beam may be guided via a first optical path to the sample interface 240 analogously to the light 221 illustrated in Fig. 2, whereas the second split light beam is guided via a different second optical path to the predefined reflection target 250 analogously to the light 231 illustrated in Fig. 2.

Further elements of the spectrometer 200 such as one or more optical filters, the aforementioned beam splitter, dispersive elements like a diffraction grating or prism, or signal processing circuitry such as amplifiers or Analog-to-Digi- tal Converters (ADCs) are omitted in Fig. 2 for reasons of simplicity.

As mentioned above, measurement values obtained for measurements at the predefined reflection target 250 may be used for determining the plausibility of measurement values obtained for other measurements such as reference measurements or background measurements. In the following, a few examples will be described in greater detail with reference to Fig. 1 and Fig. 2.

For example, the measurement data 101 may indicate a respective first measurement value of one or more photosensitive pixels of the spectrometer 120, 200 for a reference measurement and a respective second measurement value of the one or more photo-sensitive pixels for an auxiliary reference measurement. For the reference measurement, the external reference sample is expected to (should) be placed on the sample interface of the spectrometer 120, 200 and the reflections of emitted light at the external reference sample are measured by the spectrometer 120, 200 - analogously to what is shown for the sample 299 in Fig. 2. For the auxiliary reference measurement, the reflections of emitted light at the predefined reflection target within the spectrometer are measured by the spectrometer 120, 200 - analogously to what is shown for the predefined reflection target 250 in Fig. 2. The reference measurement and the auxiliary reference measurement may be performed simultaneously or one after the other - analogously to what is explained above.

As illustrated in Fig. 2, the optical path of the first light source 220 interacts with the sample interface 240 such that the measurement values output by the detector 210 for the reflected light 22T change based on the sample 299 placed on the sample interface 240. The second light source 230 uses another optical path to the predefined reflection target 250 within the spectrometer. Hence, the measurement values output by the detector 210 for the reflected light 23T are not depending on what is placed on the sample interface 240. In other words, the measurement values output by the detector 210 for the reflected light 23T are substantially independent from what is placed on the sample interface 240.

As the reference sample may have known spectral characteristics, a reference measurement with the reference sample may be performed during factory calibration of the spectrometer 120, 200 and additionally an auxiliary reference measurement for the predefined reflection target 250 within the spectrometer 120, 200 may be performed during the factory calibration in order to determine a reference ratio of the detector output for the reference measurement and the detector output for the auxiliary reference measurement.

Whether a reference measurement was correctly performed at run-time of the spectrometer 120, 200 may then be determined by comparing the relation of the detector output for the reference measurement at run-time and the detector output for the auxiliary reference measurement at run-time to the reference ratio obtained during factory calibration.

In other words, for determining whether the measurement data 101 are plausible, the processing circuitry 110 may be configured to determine a respective deviation of a respective ratio of the respective first measurement value to the respective second measurement value from a respective reference ratio for the one or more photo-sensitive pixels. Further, the processing circuitry 110 may be configured to determine whether the measurement data 101 for the reference measurement are plausible based on the respective deviation. In this approach, the impact of different conditions such as different temperatures at factory calibration and at run-time of the spectrometer 120, 200 cancels out via the quotient as the same detector, light source(s), etc. are used.

Various criteria may be used for determining whether the measurement data 101 for the reference measurement are plausible based on the respective deviation. For example, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible if the respective deviation is smaller than a first threshold. This may be expressed as follows:

\R₁/R₂ - H\ < K₁ (3) denoting the respective first measurement value of the one or more photo-sensitive pixels of the spectrometer 120, 200 for the reference measurement, R₂ denoting the respective second measurement value of the one or more photo-sensitive pixels for the auxiliary reference measurement, H denoting the reference ratio and K_± denoting the first threshold value. The first threshold value may, e.g., be 1 % of the reference ratio or less, 5 % of the reference ratio or less, 10 % of the reference ratio or less or 20 % of the reference ratio or less. On the other hand, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible if at least one of the one or more deviations is larger than the first threshold. If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130. For example, if the target sample is placed on the sample interface of the spectrometer 120, 200 instead of the reference sample for the reference measurement, the ratio /?i //?₂ may significantly differ from the reference ratio H. As consequence, the measurement data 101 for the reference measurement may be determined to be implausible and not be forwarded to the process 130. Accordingly, erratic output of the process 130 may be avoided. In alternative examples in which the spectrometer 120, 200 comprises a plurality of photo-sensitive pixels, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible if relative differences between the deviations for the plurality of photo-sensitive pixels are smaller than a second threshold. On the other hand, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible if not all relative differences between the deviations for the plurality of photo-sensitive pixels are smaller than the second threshold. The second threshold value may, e.g., be 1 % or less, 5 % or less, 10 % or less or 20 % or less. In other words, the reference measurement may be determined to be valid if the relative difference to the reference ratio (which may be a calibration factor) is similar for all measurement values of the detector.

The foregoing approach may be used analogously for determining the plausibility of background measurements. For example, the measurement data 101 may indicate a respective first measurement value of the one or more photosensitive pixels of the spectrometer 120, 200 for a background measurement and a respective second measurement value of the one or more photo-sensitive pixels for an auxiliary background measurement. For the background measurement, no sample is expected to (should) be placed on the sample interface of the spectrometer 120, 200 and light received from the environment of the spectrometer 120, 200 via the sample interface 240 is expected to (should) be measured by the spectrometer 120, 200.

For the auxiliary background measurement, the reflections of emitted light at the predefined reflection target within the spectrometer are measured by the spectrometer 120, 200 - analogously to what is shown for the predefined reflection target 250 in Fig. 2. The auxiliary background measurement and the auxiliary reference measurement may be performed in the same way. The background measurement and the auxiliary background measurement may be performed simultaneously or one after the other - analogously to what is explained above.

A reference background measurement under defined conditions may be performed during factory calibration of the spectrometer 120, 200 and additionally an auxiliary background measurement for the predefined reflection target 250 within the spectrometer 120, 200 may be performed during the factory calibration in order to determine a reference ratio of the detector output for the background measurement and the detector output for the auxiliary background measurement.

Whether a background measurement was correctly performed at run-time of the spectrometer 120, 200 may then be determined by comparing the relation of the detector output for the background measurement at run-time and the detector output for the auxiliary background measurement at run-time to the reference ratio obtained during factory calibration.

In other words, for determining whether the measurement data 101 are plausible, the processing circuitry 110 may configured to determine a respective deviation of a respective ratio of the respective first measurement value to the respective second measurement value from a respective reference ratio for the one or more photo-sensitive pixels. Further, the processing circuitry 110 may be configured to determine whether the measurement data 101 for the reference measurement are plausible based on the respective deviation. In this approach, the impact of different conditions such as different temperatures at factory calibration and at run-time of the spectrometer 120, 200 cancels out via the quotient as the same detector, light source(s), etc. are used.

Various criteria may be used for determining whether the measurement data 101 for the background measurement are plausible based on the respective deviation. For example, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible if the respective deviation is smaller than a first threshold. This may be expressed as follows:

\ O₁/O₂ - G \ < L₁ (4) with denoting the respective first measurement value of the one or more photo-sensitive pixels of the spectrometer 120, 200 for the background measurement, O₂ denoting the respective second measurement value of the one or more photo-sensitive pixels for the auxiliary background measurement, G denoting the reference ratio and denoting the first threshold value. The first threshold value may, e.g., be 1 % of the reference ratio or less, 5 % of the reference ratio or less, 10 % of the reference ratio or less or 20 % of the reference ratio or less. On the other hand, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible if at least one of the one or more deviations is larger than the first threshold. If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130. For example, if a sample is placed on the sample interface of the spectrometer 120, 200 or dirt is present on the sample interface of the spectrometer 120, 200 during the background measurement, the ratio O₁/O₂ may significantly differ from the reference ratio G. As consequence, the measurement data 101 for the background measurement may be determined to be implausible and not be forwarded to the process 130. Accordingly, erratic output of the process 130 may be avoided.

In alternative examples in which the spectrometer 120, 200 comprises a plurality of photo-sensitive pixels, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible if relative differences between the deviations for the plurality of photo-sensitive pixels are smaller than a second threshold. On the other hand, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible if not all relative differences between the deviations for the plurality of photo-sensitive pixels are smaller than the second threshold. The second threshold value may, e.g., be 1 % or less, 5 % or less, 10 % or less or 20 % or less. In other words, the background measurement may be determined to be valid if the relative difference to the reference ratio (which may be a calibration factor) is similar for all measurement values of the detector. The first and second threshold values used for determining the plausibility of the measurement data 101 for the reference measurement and the measurement data 101 for the background measurement may be identical to or be different from each other.

The measurement value(s) of the spectrometer 120, 200 for a background measurement are affected by the physical change of the spectrometer 120, 200's optical path, e.g., by placing an object on the sample interface of the spectrometer 120, 200. A background measurement needs to be performed with no sample or object being placed on the sample interface. A user may place on object on the sample interface by mistake or dirt may be present on the sample interface.

Reference measurement values for background measurements may be obtained for different temperatures of the spectrometer 120, 200's environment during factory calibration under control conditions. These reference measurement values allow to verify whether the optical path is as demanded during a background measurement at run-time.

For example, the measurement data 101 may indicate a measurement value of a photo-sensitive pixel of the spectrometer 120, 200 for a background measurement. The measurement data 101 may further indicate a temperature while performing the background measurement. Metadata of the measurement data 101 may, e.g., indicate the temperature.

For determining whether the measurement data 101 are plausible, the processing circuitry 110 may be configured to determine a deviation of the measurement value from a temperature-dependent reference curve for the background measurement. The temperature-dependent reference curve indicates reference values for the background measurement for different temperatures. For example, the temperature-dependent reference curve may be determined by the processing circuitry 110 based on stored reference measurement values for background measurements obtained during factory calibration and/or at run-time of the spectrometer 120. In other examples, the temperature-dependent reference curve may be determined during factory calibration and be stored in a storage accessible by the processing circuitry 110.

If the deviation is smaller than a threshold value, the processing circuitry 110 may be configured to determine that the measurement data 101 are plausible. This may be expressed as follows:

\0 - E(T)\ < U (5) with O denoting the measurement value of the photo-sensitive pixel of the spectrometer 120, 200 for the background measurement, E(T) denoting the temperature-dependent reference curve and U denoting the threshold value. The threshold value may, e.g., be 1 % or less, 5 % or less, 10 % or less or 20 % or less. On the other hand, the processing circuitry 110 may be configured to determine that the measurement data 101 are not plausible if the deviation is larger than the threshold value. By comparing the measurement value of the photo-sensitive pixel of the spectrometer 120 to the temperature-dependent reference curve, it is possible to detect whether the user performed the background measurement correctly (e.g., no object was placed on the sample interface during the background measurement). If the measurement data 101 are not plausible, the processing circuitry 130 may be configured to not forward the measurement data 101 to the process 130.

The comparison of an exemplary measurement value 310 to an exemplary temperature-dependent reference curve 320 is illustrated in Fig. 3. Fig. 3 illustrates a diagram 300. The abscissa denotes the temperature T and the ordinate denotes the values V of the background measurement and the dependent reference curve. The measurement value 310 is measured for a background measurement performed at a temperature T . If the measurement value 310 deviates by less than the threshold value from the temperature-dependent reference curve 320, i.e., if the distance between the measurement value 310 and temperature-dependent reference curve 320 along the ordinate is less than [/, the measurement data may be determined to be plausible.

As described above, the temperature-dependent reference curve may be determined by the processing circuitry 110 based on stored reference measurement values for background measurements obtained during factory calibration and/or at run-time of the spectrometer 120 (e.g., the measurement values of the N last background measurements determined plausible). For example, the processing circuitry 110 may be configured to generate the temperaturedependent reference curve based on N stored measurement values of the photo-sensitive pixel for background measurements. The N stored measurement values of the photo-sensitive pixel for background measurements may be obtained during factory calibration and/or at run-time of the spectrometer 120 (e.g., measurement values of previous background measurements determined plausible). N may be any integer number greater than one. The temperature-dependent reference curve may be updated at run-time of the spectrometer 120. This is further illustrated in Fig. 3. In the example of Fig. 3, the temperature-dependent reference curve 320 is based on the stored measurement values 301, 302, 303 and 304, i.e., TV = 4 in the example of Fig. 3. For example, the temperature-dependent reference curve may be generated by a curve fit to the N stored measurement values.

If it is determined that the measurement data 101 for the background measurement are plausible based on the comparison of measurement value to the temperature-dependent reference curve, the processing circuitry 110 may be configured to replace one of the N stored measurement values with the measurement value of the photo-sensitive pixel indicated in the measurement data 101 for the background measurement. For example, the oldest of the N stored measurement values may be replaced with the measurement value of the photo-sensitive pixel indicated in the measurement data 101 for the background measurement. This allows to keep the N stored measurement values updated. In the example of Fig. 3, the stored measurement value 301 is the oldest value among the stored measurement values 301, 302, 303 and 304. Accordingly, the stored measurement value 301 may be replaced by the measurement value 310 if the measurement value 310 deviates by less than the threshold value from the temperaturedependent reference curve 320. Alternatively or additionally, if one of the N stored measurement values is measured for the same temperature as the measurement value of the photo-sensitive pixel indicated in the measurement data 101 for the background measurement or for a temperature that deviates by less than a temperature threshold (e.g., 0.1 °C or less, 0.5 °C or less, 1 °C or less or 2 °C or less) from the temperature for which the measurement value of the photo-sensitive pixel indicated in the measurement data 101 for the background measurement is measured, the one stored measurement value may be replaced with the measurement value of the photo-sensitive pixel indicated in the measurement data 101 for the background measurement. In the example of Fig. 3, the stored measurement value 304 is measured for a temperature which is most similar to the temperature for which the measurement value 310 is measured. Accordingly, the stored measurement value 304 may be replaced by the measurement value 310 if the temperature for which the stored measurement value 304 is measured deviates by less than the temperature threshold from the temperature T_± for which the measurement value 310 is measured.

For illustrative purposes only, Fig. 3 further illustrates an exemplary updated temperature-dependent reference curve 330 generated by the processing circuitry 110 after the replacement of one of the stored measurement values 301, 302, 303 and 304 by the measurement value 310.

Updating the N stored measurement values used for the generation of the temperature-dependent reference curve allows to replace outdated measurement values. For example, one or more of the N stored measurement values may be outdated due to external factors such as a physical damage of the spectrometer's sample interface.

As described above, the foregoing exemplary approaches for determining the plausibility of measurement data of a spectrometer may be used separately or in combination by the processing circuitry 110 to determine the plausibility of the measurement data 101.

The apparatus 100 described above may be used in various devices. Two exemplary devices using the apparatus 100 will be described in the following with reference to Fig. 4 and Fig. 5. However, it is to be noted that the present disclosure is not limited thereto. The apparatus 100 may be used in other devices as well.

Fig. 4 schematically illustrates an example of a mobile device 400 (e.g. a mobile phone, smartphone, tablet-computer or laptop) comprising the above described apparatus 100 for processing measurement data 101 of a spectrometer.

The mobile device 400 may further comprise a spectrometer 410 configured to generate the measurement data 101 based on measured radiation. For example, the spectrometer 410 may be implemented like the spectrometers 120 and 200 described above. In other words, the mobile device 400 may comprise an integrated spectrometer. The apparatus 100 is communicatively coupled to the spectrometer 410.

In alternative examples, mobile device 400 may omit the spectrometer 410 and instead comprise interface circuitry 420 configured to receive the measurement data 101 from a spectrometer 430 external to the mobile device 400. In other words, the mobile device 400 may alternatively receive the measurement data 101 from a spectrometer which is separate from the mobile device. Also the spectrometer 430 may be implemented like the spectrometers 120 and 200 described above. The apparatus 100 is communicatively coupled to the interface circuitry 420. The interface circuitry 420 may be configured for wireless and/or wired communication with the external spectrometer 430.

The mobile device 400 may comprise further elements such as, e.g., an application processor, a baseband processor, memory, wireless communication circuitry (e.g., for wireless communication according to a mobile communication standard defined by the 3rd Generation Partnership Project, 3GPP, or a wireless communication standard such as 802.11 defined by the Institute of Electrical and Electronics Engineers, IEEE), an audio driver, a camera driver, a touch screen, a display driver, sensors, memory, removable memory, a power management integrated circuit or a battery.

The above described process 130 for evaluation of measurement data considered plausible may be performed by circuitry of the mobile device 400 such as an application processor. In other examples, the above described process 130 may be performed at a server or a computing cloud communicatively coupled to the mobile device 400. In these examples, the mobile device 400 may be configured to transmit measurement data considered plausible to the server or computing cloud running the above described process 130. The mobile device 400 may further be configured to receive the conclusion, analysis result or recommendation output by the process 130 from the server or computing cloud running the above described process 130. The mobile device 130 may, e.g., be configured to output a GUI comprising graphical elements such as text and/or figures which represent the conclusion, analysis result or recommendation output by the process 130.

Fig. 5 schematically illustrates an example of server 500 comprising the above described apparatus 100 for processing measurement data 101 of a spectrometer. The server 500 may, e.g., be part of a data center or a computing cloud.

The server 500 comprise interface circuitry 510 configured to receive the measurement data 101 from a spectrometer 520 external to the server 500. In other words, the server 500 receives the measurement data 101 from a spectrometer which is separate from the server 500. The spectrometer 520 may be implemented like the spectrometers 120 and 200 described above. The apparatus 100 is communicatively coupled to the interface circuitry 510. The interface circuitry 510 may be configured for wireless and/or wired communication with the external spectrometer 520 or an intermediate device (e.g., a mobile phone or a tablet-computer) relaying the measurement data 101 from the spectrometer 520 to the server.

The above described process 130 for evaluation of measurement data considered plausible may be performed by circuitry of the server 500 such as the processing circuitry of the apparatus 100 or further processing circuitry of the server. The server 500 may further be configured to transmit the conclusion, analysis result or recommendation output by the process 130 from the server to a terminal device (e.g., a mobile phone, a tablet-computer, a desktop computer or a laptop computer) of a user for output of the conclusion, analysis result or recommendation to the user.

For further highlighting the measurement data processing described above, Fig. 6 illustrates a flowchart of an exemplary method 600 for processing measurement data of a spectrometer. The method 600 comprises receiving 602 the measurement data and determining 604 whether the measurement data are plausible. If it is determined that the measurement data are plausible, the method 600 comprises forwarding 606 the measurement data to a process for evaluation of the measurement data. On the other hand, if it is determined that measurement data are not plausible, the method 600 may comprise not forwarding 608 the measurement data to the process for evaluation of the measurement data.

Analogously to what is described above, the method 600 feds only plausible measurement data the process for evaluation of the measurement data. Accordingly, input of wrong or invalid measurement data to data analysis models such as chemometric models may be avoided, which in turn allows to prevent bad user experience.

More details and aspects of the method 600 are explained in connection with the proposed technique or one or more examples described above (e.g., Fig. 1 to Fig. 5). The method 600 may comprise one or more additional optional features corresponding to one or more aspects of the proposed technique or one or more examples described above.

In some of the above examples, one or more reference values such as reference ratios or reference thresholds are used for the plausibility determination at run-time. The one or more reference values may be pre-prepared according to examples of the present disclosure. Fig. 7 illustrates a flowchart of an exemplary method 700 for enabling plausibility determination for measurement data of a spectrometer at run-time.

The method 700 comprises performing 702 a factory calibration of the spectrometer under defined conditions. The factory calibration is the process of calibrating the spectrometer at the manufacturing facility according to a defined standard specifying the defined conditions before it is shipped to a user or reseller. During the factory calibration, the spectrometer is adjusted to ensure that it meets specified accuracy standards and performs within the expected tolerances. Further, the method 700 comprises determining 704 one or more reference values from measurement data generated by the spectrometer during the factory calibration. The one or more reference values may, e.g., be one of the values used for the plausibility determination at run-time in one or more of the examples described above. The method 700 additionally comprises storing 706 the one or more reference values in a data storage accessible by an apparatus used for determining whether measurement data generated by the spectrometer during user operation are plausible. As described above, the apparatus 100 used for determining whether measurement data generated by the spectrometer during user operation are plausible may be part of a mobile device or a server. Accordingly, the data storage may be part of the mobile device or the server. In other examples, the data storage may be a cloud storage accessible by the apparatus 100. The method 700 allows to provide one or more reference values so that they can be used for plausibility determination at run-time according to one or more of the above examples.

The aspects and features described in relation to a particular one of the previous examples may also be combined with one or more of the further examples to replace an identical or similar feature of that further example or to additionally introduce the features into the further example.

Examples may further be or relate to a (computer) program including a program code to execute one or more of the above methods when the program is executed on a computer, processor or other programmable hardware component. Thus, steps, operations or processes of different ones of the methods described above may also be executed by programmed computers, processors or other programmable hardware components. Examples may also cover program storage devices, such as digital data storage media, which are machine-, processor- or computer-readable and encode and/or contain machine-executable, processor-executable or computer-executable programs and instructions. Program storage devices may include or be digital storage devices, magnetic storage media such as magnetic disks and magnetic tapes, hard disk drives, or optically readable digital data storage media, for example. Other examples may also include computers, processors, control units, (field) programmable logic arrays ((F)PLAs), (field) programmable gate arrays ((F)PGAs), graphics processor units (GPU), ASICs, integrated circuits (ICs) or SoCs programmed to execute the steps of the methods described above.

It is further understood that the disclosure of several steps, processes, operations or functions disclosed in the description or claims shall not be construed to imply that these operations are necessarily dependent on the order described, unless explicitly stated in the individual case or necessary for technical reasons. Therefore, the previous description does not limit the execution of several steps or functions to a certain order. Furthermore, in further examples, a single step, function, process or operation may include and/or be broken up into several sub-steps, -functions, -processes or -operations.

If some aspects have been described in relation to a device or system, these aspects should also be understood as a description of the corresponding method. For example, a block, device or functional aspect of the device or system may correspond to a feature, such as a method step, of the corresponding method. Accordingly, aspects described in relation to a method shall also be understood as a description of a corresponding block, a corresponding element, a property or a functional feature of a corresponding device or a corresponding system.

The following claims are hereby incorporated in the detailed description, wherein each claim may stand on its own as a separate example. It should also be noted that although in the claims a dependent claim refers to a particular combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed, unless it is stated in the individual case that a particular combination is not intended. Furthermore, features of a claim should also be included for any other independent claim, even if that claim is not directly defined as dependent on that other independent claim.

Claims

Claims What is claimed is:

1. An apparatus (100) for processing measurement data (101) of a spectrometer (120, 200), the apparatus (100) comprising processing circuitry (110) configured to: receive the measurement data (101); determine whether the measurement data (101) are plausible; and forward the measurement data (101) to a process (130) for evaluation of the measurement data (101) if it is determined that the measurement data (101) are plausible.

2. The apparatus (100) of claim 1, wherein the measurement data (101) indicate a respective first measurement value of one or more photo-sensitive pixels of the spectrometer (120, 200) for a reference measurement of an external reference sample placed on a sample interface of the spectrometer (120, 200) and a respective second measurement value of the one or more photo-sensitive pixels for an auxiliary reference measurement of a predefined reflection target within the spectrometer (120, 200), and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine a respective deviation of a respective ratio of the respective first measurement value to the respective second measurement value from a respective reference ratio for the one or more photo-sensitive pixels; and determine whether the measurement data (101) for the reference measurement are plausible based on the respective deviation.

3. The apparatus (100) of claim 1 or claim 2, wherein the measurement data (101) indicate a respective first measurement value of one or more photo-sensitive pixels of the spectrometer (120, 200) for a background measurement with no sample being placed on a sample interface of the spectrometer (120, 200) and a respective second measurement value of the one or more photo-sensitive pixels for an auxiliary background measurement of a predefined reflection target within the spectrometer (120, 200), and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine a respective deviation of a respective ratio of the respective first measurement value to the respective second measurement value from a respective reference ratio for the one or more photo-sensitive pixels; and determine whether the measurement data (101) for the background measurement are plausible based on the respective deviation.

4. The apparatus (100) of claim 2 or claim 3, wherein the processing circuitry (110) is configured to determine that the measurement data (101) are plausible if: the respective deviation is smaller than a first threshold; and/or relative differences between the deviations for the plurality of photo-sensitive pixels are smaller than a second threshold.

5. The apparatus (100) of claim 1 or claim 2, wherein the measurement data (101) indicate a measurement value of a photo-sensitive pixel of the spectrometer (120, 200) for a background measurement with no sample being placed on a sample interface of the spectrometer (120, 200) and further indicate a temperature while performing the background measurement, and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine a deviation of the measurement value from a temperature-dependent reference curve for the background measurement, the temperature-dependent reference curve indicating reference values for the background measurement for different temperatures; and determine that the measurement data (101) for the background measurement are plausible if the deviation is smaller than a threshold.

6. The apparatus (100) of claim 5, wherein the processing circuitry (110) is further configured to: generate the temperature-dependent reference curve based on N stored measurement values of the photosensitive pixel for background measurements; and replace one of the N stored measurement values with the measurement value of the photo-sensitive pixel indicated in the measurement data (101) for the background measurement if it is determined that the measurement data (101) for the background measurement are plausible.

7. The apparatus (100) of claim 1 , wherein the measurement data (101) indicate respective measurement values of two or more photo-sensitive pixels of the spectrometer (120, 200) for a reference measurement of an external reference sample placed on a sample interface of the spectrometer (120, 200), a background measurement with no sample being placed on the sample interface and a sample measurement of a target sample placed on the sample interface, wherein the two or more photo-sensitive pixels are sensitive to light in the same wavelength range, and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine, for each of the two or more photo-sensitive pixels, a respective absorbance value of the target sample based on the respective measurement values for the reference measurement, the background measurement and the sample measurement; determine that the measurement data (101) are plausible if the determined absorbance values differ by less than a threshold from each other.

8. The apparatus (100) of claim 1 , wherein the measurement data (101) indicate respective measurement values of one or more photo-sensitive pixels of the spectrometer (120, 200) for a reference measurement of an external reference sample placed on a sample interface of the spectrometer (120, 200), a background measurement with no sample being placed on the sample interface and a sample measurement of a target sample placed on the sample interface, and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine, for the one or more photo-sensitive pixels, a respective absorbance value of the target sample based on the respective measurement values for the reference measurement, the background measurement and the sample measurement; determine that the measurement data (101) are plausible if, for each of the one or more photo-sensitive pixels, the respective determined absorbance value is within a reference value range for the respective photosensitive pixel.

9. The apparatus (100) of claim 1, wherein the measurement data (101) indicate measurement values of a photo-sensitive pixel of the spectrometer (120, 200) for a reference measurement of an external reference sample placed on a sample interface of the spectrometer (120, 200) and a background measurement with no sample being placed on the sample interface, and wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: determine a deviation of a ratio of the measurement value for the reference measurement to the measurement value for the background measurement from a reference ratio; and determine that the measurement data (101) for the reference measurement and the background measurement are plausible if the deviation is smaller than a threshold.

10. The apparatus (100) of any one of claims 1 to 9, wherein, for determining whether the measurement data (101) are plausible, the processing circuitry (110) is configured to: extract metadata for a plurality of measurements forming a measurement set from the measurement data (101), wherein the metadata indicate at least one of a time of measurement for the respective measurement of the measurement set and a temperature while performing the respective measurement of the measurement set; and determine that the measurement data (101) are plausible for the measurements forming the measurement set if the metadata satisfy a predefined criterion.

11. The apparatus (100) of any one of claims 1 to 10, wherein, if it is determined that measurement data (101) are not plausible, the processing circuitry (110) is further configured to cause a human-machine-interface to output a notification to repeat a measurement with the spectrometer (120, 200).

12. The apparatus (100) of claim 11, wherein the processing circuitry (110) is further configured to: determine at least one suggestion for improvement for the repetition of the measurement with the spectrometer (120, 200); and cause the human-machine-interface to output the at least one suggestion for improvement.

13. A mobile device (400), comprising: an apparatus (100) for processing measurement data (101) of a spectrometer according to any one of claims

1 to 14; and one of the following: the spectrometer (410), wherein the spectrometer (410) is configured to generate the measurement data (101) based on measured radiation; or interface circuitry (420) configured to receive the measurement data (101) from the spectrometer (430), wherein the spectrometer (430) is external to the mobile device (400).

14. A method (600) for processing measurement data of a spectrometer, comprising: receiving (602) the measurement data; determining (604) whether the measurement data are plausible; and forwarding (606) the measurement data to a process for evaluation of the measurement data if it is determined that the measurement data are plausible.

15. A non-transitory machine-readable medium having stored thereon a program having a program code for performing the method according to claim 14, when the program is executed on a processor or a programmable hardware.