Portable Spectrometer Instruments

Abstract

A portable spectrometer device (110) is proposed for obtaining at least one item of spectral information. The portable spectrometer device (110) comprises at least one spectrometer unit (130). The spectrometer unit (130) comprises at least one wavelength selection element (134) configured to separate incident light into constituent wavelengths of a spectrum and at least one detector device (136) configured to detect at least a portion of the constituent wavelengths. The portable spectrometer device (110) further comprises at least one control unit (146) and at least one status inquiry device (148) configured to retrieve at least one item of status information related to a current environmental status of the portable spectrometer device (110). The control unit (146) is configured to automatically trigger at least one reference measurement by means of the detector device (136) in response to the realization of at least one predetermined environmental status condition.

Description

[Technical field]

[0001] The present invention relates to a portable spectrometer device for obtaining at least one item of spectral information, for example on an object or on a number of objects. Furthermore, the present invention relates to a method for performing a reference measurement with the portable spectrometer device, and to a computer program and a computer-readable storage medium comprising instructions for carrying out the method. The method and device can be used in particular for calibrating spectrometer devices used for infrared spectroscopy, in particular in the near-infrared and mid-infrared spectral regions, with mobile devices such as smartphones. However, other uses are also possible. [Background technology]

[0002] Spectroscopic methods are widely used in research, industrial and customer applications, enabling multiple applications such as optical analysis and / or quality control. Use cases can be found, for example, in the fields of food production and quality control, agriculture, pharmaceuticals, medical applications, and life sciences, among many more. Various methods are available, such as photometry, absorption, fluorescence and Raman spectroscopy, allowing qualitative and / or quantitative sample analysis. These methods typically involve obtaining at least one item of spectral information by using at least one spectrometer device having at least one wavelength selection element and at least one detector device. Various types of spectrometer devices of spectrometer units that can further be used in the context of the present invention and are specifically described in more detail further below are disclosed, for example, in WO2019 / 115594A2. However, it should be noted that other types of spectrometers are also applicable in the context of the present invention.

[0003] To achieve reliable results and long-term stability of spectroscopic measurements, spectrometer devices typically require reference measurements on a regular basis. Thus, for example, reference measurements may be performed at regular time intervals to counteract the effects of drift or other long-term changes.

[0004] Under well-defined laboratory conditions, the reference measurement may be performed by using at least one reference target with known characteristics, which may typically be placed in front of the aperture or spectrometer port of the spectrometer device. Additionally or alternatively, one or more reference light sources or reference light paths may be used, by which reference light with known characteristics is provided to the detector device. Thus, by way of example, a reference light path may be provided that provides reference light during every measurement and / or during a reference measurement cycle.

[0005] According to the disclosure of WO2018 / 203831A1, calibrating the spectrometer module includes performing measurements using the spectrometer module to generate wavelength vs. operating parameter calibration data for the spectrometer module, performing measurements using the spectrometer module to generate optical crosstalk and dark noise calibration data for the spectrometer module, and performing measurements using the spectrometer module to generate total system response calibration data to a known reflectivity standard for the spectrometer module. The method further includes storing a calibration record incorporating the wavelength vs. operating parameter calibration data, the optical crosstalk and dark noise calibration data, and the total system response calibration data in a memory coupled to the spectrometer module, and applying the calibration record to the measurement by the spectrometer module.

[0006] EP3460509A1 discloses a method for calibrating a time-of-flight system having a time-of-flight sensor arranged behind a cover plate (CP). The method includes emitting a number of sending pulses (EP) of light in response to respective trigger pulses of a control signal (CS1) and detecting received pulses (RP, RP') of light. Respective difference values ​​representative of a time period between one of the sending pulses (EP) and one of the received pulses (RP, RP') are determined. The difference values ​​are accumulated in a number of bins (1,...,N) of at least one histogram. The method further includes recording at least one crosstalk response (CTP) in the histogram within a predefined range of bins (1,...,M) and calibrating the histogram using the recorded crosstalk response (CTP). Finally, an output signal (OS) indicative of the time-of-flight is generated based on an evaluation of the calibrated histogram.

[0007] US Patent Application No. 2018 / 184972A1 discloses a system for analyzing the physical obesity level of a human body, the system including a spectrometer, e.g., a handheld spectrometer, configured to generate spectral data from one or more locations on the body of a subject being tested, and a processor configured to receive the spectral data using a model and output the physical obesity level of the tested subject.

[0008] DE102019219945A1 provides a method for operating a spectrometer device, the method comprising connecting an energy storage device to a charging device, determining a first temperature in the spectrometer device, determining a first reference spectrum on a reference material at the first temperature, determining a second temperature in the spectrometer means during or after loading, determining a second reference spectrum with the spectrometer means on the reference material at the second temperature, comparing the reference spectra and performing compensation for the determined difference in the determined spectra.

[0009] US Patent Application Publication No. 2020 / 271572A1 describes an embodiment of a method for automatically generating background measurements in a spectrometer. The method includes collecting a plurality of candidate scans in the spectrometer, determining for each of the plurality of candidate scans whether the candidate scan correlates with an orthonormal basis set associated with a recent background description, storing each candidate scan correlated with the orthonormal basis set as a background scan in a scan cache, and generating a new background measurement from the plurality of background scans stored in the scan cache if a current background measurement is older than a preselected time interval.

[0010] US Patent No. 5,040,889A discloses a fiber optic probe mounted within a light instrument to irradiate a sample with visible, near infrared and ultraviolet light. A glass fiber carries visible and near infrared light from a visible and near infrared source to the probe, and a quartz fiber carries ultraviolet light from an ultraviolet source to the probe. The glass fiber carries the visible and near infrared light emanating from the sample to a spectrometer having a fixed grating and an array of photodetectors to receive the spectrum dispersed by the grating within the spectrometer housing. Amplifiers individually connected to the photodetectors are also included within the spectrometer housing to amplify the output signals of the photodetectors. The probe is provided with a standard white sample pivoted in a suitable position to receive light from the visible light source. The computer is programmed to automatically calibrate whenever the temperature within the housing changes by more than a small predetermined amount. The automatic calibration is accomplished by pivoting the white standard to a suitable position and calculating a calibration value from the resulting photodetector output. Auto-calibration is further performed when the ratio of output signals from selected ones of the photodetectors changes by more than a predetermined small percentage.

[0011] The result of the reference measurement may be used as a standard or for normalization purposes. Thus, by way of example, the reference measurement may provide a reference measurement signal or reference measurement data that may be used to correct offsets and / or as a standard for comparison or normalization purposes when performing measurements with real samples. Among them, typically at least two main reference measurement methods are commonly used: the so-called "open-port" reference measurement and the so-called "dark" reference measurement. In the open-port reference measurement, the light source, e.g. the light source of a spectrometer device, is switched on and spectral information is acquired when no object is placed in front of the sensor. In the case of the dark reference measurement, the light source may be switched off and spectral information is acquired. In both cases, a reference measurement signal may be acquired that may be used in subsequent measurements, such as a dark reference measurement to remove offsets and an open-port reference measurement to normalize the measurement results. Subtracting dark reference measurements from actual measurements is commonly known to those skilled in the art, as described, for example, in Ibsen Photonics, "Technical Note-Subtracting dark spectra," available online at: https: / / ibsen.com / wp-content / uploads / Tech-Note-Short-note-on-subtracting-dark-spectra-v1.0-1.pdf.

[0012] However, these methods of performing a reference measurement typically require either active user interaction or at least a priori information that the spectrometer device is in a well-defined state during the reference measurement. Thus, under laboratory conditions, the aperture spectrometer port of the spectrometer device is typically placed far away from any potentially reflective surfaces. Furthermore, under laboratory conditions, the user typically ensures that no light sources in the relevant wavelength range are within the field of view of the spectrometer device.

[0013] While these reference measurement conditions are largely achievable under laboratory conditions, an increasing number of spectral measurements must be performed in the field by using portable spectrometer devices. Establishing reference conditions in the field may require user support and user interaction with the portable spectrometer device that is often undesirable for practical purposes and reasons of convenience.

[0014] One option for convenient reference measurements with portable spectrometer devices is continuous reference measurements. As an example, the mobile phone-mounted spectrometer device "Seek Thermal Compact" (www.thermal.com / compact-series.html) is configured to perform continuous reference measurements at regular time intervals by using an integrated shutter as an integrated reference target. A similar principle is also described in A. Tempelhahn et al., "Shutter-less calibration of uncooled infrared cameras", J. Sens. Sens. Syst., 5, 9-16, 2016, available online under https: / / jsss.copernicus.org / articles / 5 / 9 / 2016 / . However, the use of a shutter requires additional moving mechanical elements in the spectrometer device, which is often undesirable, especially for highly compact portable spectrometer devices.

[0015] Thus, despite the progress that has been made in the field of mobile spectroscopy in recent years, several challenges remain: in particular, means and methods for increasing the reliability, precision and long-term stability of measurements remain desirable. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] WO2019 / 115594A2 [Patent Document 2] WO2018 / 203831A1 [Patent Document 3] EP3460509A1 [Patent Document 4] U.S. Patent Application No. 2018 / 184972A1 [Patent Document 5] DE102019219945A1 [Patent Document 6] U.S. Patent Application No. 2020 / 271572A1 [Patent Document 7] U.S. Patent No. 5,040,889A [Non-patent literature]

[0017] [Non-Patent Document 1] Ibsen Photonics, "Technical Note-Subtracting dark spectra," available online at http: / / ibsen.com / wp-content / uploads / Tech-Note-Short-note-on-subtracting-dark-spectra-v1.0-1.pdf [Non-Patent Document 2] A. Tempelhahn et al., "Shutter-less calibration of uncooled infrared cameras," J. Sens. Sens. Syst., 5, 9-16, 2016, available online under http: / / jsss.copernicus.org / articles / 5 / 9 / 2016 / Summary of the Invention [Problem to be solved by the invention]

[0018] It would therefore be desirable to provide means and methods that address the above-mentioned technical challenges in the field of mobile spectroscopy, in particular, that enable highly reliable and long-term stable mobile spectroscopic measurements that require minimal user interaction and minimal effort. [Means for solving the problem]

[0019] This problem is addressed by a portable spectrometer device, a method for performing a reference measurement with a portable spectrometer device, a computer program and a computer readable storage medium with the features of the independent claims. Advantageous embodiments, which may be realized in isolation or in any arbitrary combination, are recited in the dependent claims as well as throughout the specification.

[0020] As used herein, the terms "have", "comprise" or "include", or any grammatical variants thereof, are used in a non-exclusive manner. Thus, these terms can refer to both situations where, in addition to the features introduced by these terms, further features are not present in the entity described in this context, and situations where one or more further features are present. As an example, the expressions "A and B", "A comprises B", and "A includes B" can both refer to situations where, other than B, there are no other elements in A (i.e., A consists solely and exclusively of B), and situations where, other than B, there are one or more further elements in entity A, such as element C, elements C and D, or further elements.

[0021] Furthermore, it should be noted that the terms "at least one," "one or more," or similar language indicating that a feature or element may be present one or more times, are typically used only once when introducing each feature or element. In most cases, when referring to each feature or element, the language "at least one" or "one or more" will not be repeated, despite the fact that each feature or element may be present one or more times.

[0022] Furthermore, as used herein, the terms "preferably", "more preferably", "in particular", "more particularly", "particularly", "more particularly", or similar terms are used in conjunction with optional features without limiting alternative feasibility. Thus, features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. The invention may be implemented by using alternative features, as will be recognized by those skilled in the art. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any limitations on alternative embodiments of the invention, without any limitations on the scope of the invention, and without any limitations on the feasibility of combining the feature so introduced with other optional or non-optional features of the invention.

[0023] In a first aspect of the present invention, a portable spectrometer device for obtaining at least one item of spectral information is disclosed. The spectrometer device includes at least one spectrometer unit. The spectrometer unit includes at least one wavelength selection element configured to separate incident light into constituent wavelengths of a spectrum, and at least one detector device configured to detect at least a portion of the constituent wavelengths. The portable spectrometer device further includes at least one control unit and at least one status inquiry device configured to retrieve at least one item of status information related to a current environmental status of the portable spectrometer device. The control unit is configured to automatically trigger at least one reference measurement with the detector device in response to the realization of at least one predetermined environmental status condition.

[0024] As used herein, the term "spectrometer device" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically, but not exclusively, refer to obtaining at least one item of spectral information regarding at least one object. Specifically, the at least one item of spectral information may refer to at least one optical property or optically measurable property determined as a function of wavelength for one or more different wavelengths. More specifically, the at least one item of spectral information may relate to at least one property characterizing at least one of transmission, absorption, reflection, and emission of the at least one object. At least one optical property for one or more wavelengths may be determined. The spectrometer device may specifically form an instrument capable of recording signal intensities, such as wavelength intervals, for corresponding wavelengths of or a section of the spectrum, and the signal intensities may preferably be provided as an electrical signal that can be used for further evaluation.

[0025] By way of example, the at least one spectrometer device may include at least one light source, which may be, by way of example, at least one of a tunable light source, a light source having at least one constant emission wavelength, and a broadband light source. Thus, in general, the portable spectrometer device may include at least one light source, specifically, at least one light source for illuminating at least one object to be analyzed by spectroscopy with light, more specifically, with infrared light, more specifically, with near infrared light. As used herein, the term "light source" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term may specifically, but is not limited to, refer to any element, device, or combination of devices capable of emitting light. By way of example, as further outlined in detail below, the light source may include at least one thermal light source, such as at least one incandescent lamp, and / or at least one semiconductor light source, such as at least one light emitting diode (LED). More specifically, the light source may include at least one infrared light emitting diode and / or at least one infrared incandescent lamp. Other examples are possible. At least one light source may be integrated into the spectrometer unit. However, additionally or alternatively, one or more other light sources integrated into the portable spectrometer device may be used. Thus, by way of example, at least one light source integrated into a mobile communication device, such as a smartphone, may be used for spectroscopic measurement purposes as well.

[0026] As further outlined in detail below, the spectrometer unit further includes at least one detector device configured to detect light, such as light that is at least one of transmitted, reflected, or emitted from the at least one object. By way of example, light emitted by the at least one optional light source of the portable spectrometer device may be at least one of scattered and reflected by the object to be analyzed and from which spectral information is to be gathered, and may be detected by the detector device of the spectrometer unit.

[0027] The spectrometer unit further includes at least one wavelength selective element, such as a grating, a prism, and a filter, e.g., a variable length filter having transmission characteristics that vary across its lateral extent. The wavelength selective element may be used to separate the incident light into a spectrum of constituent wavelength signals, the intensity of each of which is determined by utilizing a detector device, such as a detector device having an array, described in more detail below.

[0028] As used herein, the term "portable" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any specialized or customized meaning. The term may specifically, but not exclusively, refer to the property of at least one object that is moved by human power, such as by a single user. Specifically, an object characterized by the term "portable" may have a mass not exceeding 10 kg, specifically not exceeding 5 kg, more specifically not exceeding 1 kg, or even not exceeding 500 g. Additionally or alternatively, the dimensions of an object characterized by the term "portable" are such that the object extends no more than 0.3 m in any dimension, specifically no more than 0.2 m in any dimension. The object may specifically, but not exclusively, have a mass not exceeding 0.03 m. 3 Specifically, 0.01m 3 Less than or equal to 0.001m 3 It may have the following volumes:

[0029] As used herein, the term "item of spectral information" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically refer, without limitation, to an item of information regarding at least one object and / or radiation emitted by at least one object that characterizes at least one optical property of the object, more specifically, at least one item of information that characterizes, e.g., qualifies and / or quantifies, at least one of transmission, absorption, reflection, and emission of at least one object. By way of example, the at least one item of spectral information may include at least one intensity information, e.g., information regarding the intensity of light as a function of wavelength over one or more wavelengths, e.g., over a range of wavelengths, that has been at least one of transmission, absorption, reflection, or emission by the object.

[0030] As used herein, the term "spectrometer unit" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically, but not exclusively, refer to a device, unit, or component of another device capable of acquiring at least one item of spectral information as defined above. In particular, the portable spectrometer device may be configured to serve one or more different purposes than acquiring at least one item of spectral information, as outlined above, and the spectrometer unit specifically refers to a part of the spectrometer device configured to determine at least one item of spectral information. The spectrometer unit may include a single piece unit, or may include multiple interacting units.

[0031] As outlined above, the spectrometer unit includes at least two components, namely at least one wavelength-selective element configured to separate the incident light into constituent wavelengths of a spectrum, and at least one detector device configured to detect at least a portion of the constituent wavelengths, which may include, for example, separation by a grating, a prism, or a filter, as outlined above.

[0032] As used herein, the term "wavelength-selective element" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically, but not exclusively, refer to a device or combination of devices that can perform a spectral separation of components of incident light, whereby constituent wavelengths of the spectrum are generated, i.e., the spectral components in the light are spatially resolved or, for example, resolved by angle. By way of example, the at least one wavelength-selective element may be or include at least one of a length-variable filter, a filter such as a single wavelength bandpass, an array of bandpass filters, a prism, and a grating. In particular, the at least one wavelength-selective element may include one or more filters, such as individual filters, configured to provide well-defined spectral portions of the incident light to a dedicated light-sensitive element.

[0033] As used herein, the term "detector device" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term can specifically refer to, but is not limited to, a device configured to measure at least one measurable characteristic of at least one object. The detector can specifically be or include at least one photodetector configured to measure at least one optical characteristic of at least one object. The detector device can specifically include at least one photosensitive element. More specifically, the detector device can include at least one detector array. By way of example, the wavelength-selective element may include one or more filters, such as a single-wavelength band-pass filter and / or an array of band-pass filters and / or a variable-length filter, such that each photosensitive element of the detector device is assigned to a respective filter having a different transmission spectrum, and the filters are disposed on top of the array of the detector device. As a result, each photosensitive element of the detector device detects a different spectral portion of the incident light. However, other embodiments are also possible.

[0034] The portable spectrometer device, more specifically the spectrometer unit, may further include one or more further components. Specifically, the portable spectrometer device and / or the spectrometer unit may include at least one light source. Thus, specifically, the portable spectrometer device may include at least one infrared light source, more specifically at least one light source emitting in the near infrared spectral range. The light source may be or include at least one broadband light source, or may be or include at least one light source emitting at one or more isolated wavelengths. The light source may be or include a thermal light source, such as a broadband emitter such as an incandescent lamp, for example. Additionally or alternatively, the light source may be or include one or more semiconductor light sources, such as one or more light emitting diodes. Furthermore, additionally or alternatively, the light source may be or include one or more lasers. Other options are also possible. The light source may be configured to illuminate at least one object in the field of view of the portable spectrometer device with light, specifically with infrared light.

[0035] As further outlined above, the portable spectrometer device further includes at least one control unit. As used herein, the term "control unit" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a specialized or customized meaning. The term may specifically refer to, but is not limited to, a device or combination of devices capable of and / or configured to perform at least one computing operation and / or control at least one function of at least one other device, such as at least one other component of the portable spectrometer device. Specifically, the at least one control unit may be embodied as and / or include at least one processor, and the processor may be configured to perform one or more operations, specifically by software programming. As used herein, the term "processor" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a specialized or customized meaning. The term may specifically, but not exclusively, refer to any logic circuitry configured to perform basic operations of a computer or system, and / or generally to a device configured to perform calculations or logical operations. In particular, a processor may be configured to process basic instructions that run a computer or system. By way of example, a processor may include at least one arithmetic logic unit (ALU), at least one floating point unit (FPU), such as a math coprocessor or a math coprocessor, a number of registers, specifically registers configured to provide operands to the ALU and store results of operations, and memory, such as L1 and L2 cache memories. In particular, a processor may be a multi-core processor. In particular, a processor may be or include a central processing unit (CPU).Additionally or alternatively, the processor may be or include a microprocessor, and thus, in particular, the elements of the processor may be included in one single integrated circuit (IC) chip. Additionally or alternatively, the processor may be or include one or more application specific integrated circuits (ASICs) and / or one or more field programmable gate arrays (FPGAs) and / or one or more tensor processing units (TPUs) and / or one or more chips, such as dedicated machine learning optimization chips, or the like. The processor may be specifically configured, such as by software programming, to perform one or more evaluation operations.

[0036] As further outlined above, the portable spectrometer device further includes at least one status inquiry device configured to retrieve at least one item of status information related to the current environmental status of the portable spectrometer device. As used herein, the term "status inquiry device" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art and is not limited to a special or customized meaning. The term may specifically, but not exclusively, refer to a device or combination of devices capable of retrieving or configured to retrieve at least one item of status information as outlined above. As will be further outlined in more detail below, specifically, the status inquiry device may include at least one of an interface, such as a wireless or wirebound interface, for retrieving an item of status information in an electronic format, such as a data format, and / or at least one device, such as at least one sensor device, configured to generate an item of status information. The status inquiry device may further be fully or partially integrated with the control unit. Additionally or alternatively, the status inquiry device may include one or more devices integrated into the portable spectrometer device, such as one or more integrated sensors.

[0037] As used herein, the term "current environmental state of the portable spectrometer device" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically, but not exclusively, refer to a state in which the portable spectrometer device is momentarily in a state of inquiry, i.e., at the moment of inquiry and / or in a predefined time frame around the moment of inquiry. In that regard, the term "environmental state" may relate to at least one state of the environment, specifically the surroundings, in which the portable spectrometer device is in at least one relationship and / or facing, such as a location and / or orientation between the portable device and the surroundings. By way of example, the environmental state may refer to at least one of the lighting conditions of the environment, the weather conditions of the environment, the temperature of the environment, the orientation of the portable spectrometer device in the environment, the location of the portable spectrometer device in the environment, and the relative orientation and / or location between the portable spectrometer device and at least one item in the environment. Further exemplary embodiments are given below.

[0038] As used herein, the term "retrieve" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a specialized or customized meaning. The term may specifically refer to, but is not limited to, a process of providing at least one object or item to at least one entity. The process may include generating at least one item or object, or obtaining at least one item or object from another source, and providing at least one item or object to at least one entity. Thus, with respect to retrieving at least one item of status information regarding the current environmental state of the portable spectrometer device, retrieving may, for example, include obtaining the item of status information from at least one source, such as, for example, from at least one external source via at least one interface, such as a wireless and / or wirebond interface, which may, for example, be the Internet. Additionally or alternatively, for deriving the at least one item of state information, the portable spectrometer device may further include one or more sensors or sensing devices for measuring at least one measurable value from which the at least one item of state information relating to the current environmental state of the portable spectrometer device may be derived directly or indirectly. Exemplary embodiments of sensor devices are given below.

[0039] As outlined above, the control unit is configured to automatically trigger at least one reference measurement with the detector device in response to the realization of at least one predetermined environmental state condition. As used herein, the term "automatically triggering" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art and is not limited to a special or customized meaning. The term can specifically, but not exclusively, refer to a process that initiates an operation without the need for human interaction, specifically without any human interaction or only with optional human interaction.

[0040] Furthermore, as used herein, the term "reference measurement" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term can specifically refer to, but is not limited to, the process of measuring at least one reference value or obtaining at least one item of reference information by measurement. The reference value or item of reference information may then be used for improving the accuracy of the actual measurement, for example, by comparing at least one measurement value obtained in the actual measurement with at least one reference value or item of reference information and / or by using at least one reference value or item of reference information to correct for adjusting the measurement value obtained in the actual measurement. Reference measurements are widely used in optical measurements, such as spectrometry, for example, to correct for background light, noise, detector sensitivity, and the like.

[0041] As outlined above, the at least one reference measurement is automatically triggered upon the realization of at least one predefined environmental condition. As used herein, the term "environmental condition" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to any special or customized meaning. The term may specifically, but not exclusively, refer to a condition of the environment in which the portable spectrometer device is located and / or a condition of the relationship between the portable spectrometer device and the environment that is predefined as sufficient to perform the reference measurement. By way of example, the at least one environmental condition may be at least one condition that must be realized by at least one item of state information regarding the current environmental condition of the portable spectrometer device. By way of example, the item of state information may be compared with at least one maximum or minimum threshold value, the condition may be realized, and the reference measurement may be automatically triggered when the item of state information exceeds or falls below the minimum or maximum threshold value, respectively, by way of example. Additionally or alternatively, the environmental state condition may be realized when at least one item of status information relating to the current environmental state of the portable spectrometer device and / or at least one secondary value derived from the at least one item of status information by using a predetermined relation or function is within at least one predetermined range. Thus, by way of example, the control unit can obtain from the status inquiry device at least one item of status information relating to the current environmental state of the portable spectrometer device, optionally convert the at least one item of status information into at least one secondary value, and then check whether the at least one item of status information and / or the at least one secondary value realizes an environmental state condition, such as having a predetermined target value or being within a predetermined range. When this environmental state condition is realized, the control unit can automatically trigger, with or without delay, at least one reference measurement, such as by triggering the detector device to obtain a spectral measurement value.

[0042] Thus, when the predetermined environmental condition conditions indicate that the environmental conditions are suitable for at least one reference measurement, the use of at least one item of status information relating to the current environmental conditions of the portable spectrometer device may enable the portable spectrometer device to repeatedly perform the reference measurement, the at least one item of status information being particularly capable of being retrieved by using integrated means of the portable spectrometer device.

[0043] In particular, the portable spectrometer device may be or include a mobile communication device. As used herein, the term "mobile communication device" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art and is not limited to a special or customized meaning. The term may specifically refer to, but is not limited to, a mobile device configured for voice communication and / or electronic communication. In particular, the mobile communication device may include at least one of a mobile phone, in particular a smartphone, a smart watch, a tablet computer, and a notebook computer. In particular, the mobile communication device may include at least one user interface, such as a display or touch screen, and preferably at least one camera.

[0044] The mobile communication device may have at least one of the spectrometer units integrated therein and attached thereto. Thus, by way of example, the spectrometer unit may be integrated on the back side of the mobile communication device, with at least one spectrometer port allowing light to enter the spectrometer unit, be spectrally separated by a wavelength selection element, and reach the detector device. As used herein, the term "spectrometer port" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term may specifically refer, but is not limited to, to an opening or window that may be completely open or covered by a transparent shield, specifically the shield is completely or partially transparent in the infrared spectral range, thereby allowing light to enter the spectrometer unit.

[0045] The integration of the spectrometer unit into a mobile communication device such as a smartphone brings many advantages. Thus, in particular, a typical mobile communication device such as a smartphone includes a number of integrated sensor devices to sense a number of values ​​such as position, tilt, acceleration, temperature, and magnetic field. In addition, a typical mobile communication device such as a smartphone further includes a sensor device in the form of at least one camera that can be used to retrieve and confirm environmental conditions. Thus, in general, a portable spectrometer device including at least one mobile communication device may be configured to use at least one integrated sensor device of the mobile communication device as at least one part of at least one status inquiry device. An exemplary embodiment of the integrated sensor device is given below.

[0046] The portable spectrometer device may include a housing, such as a housing of a mobile communication device. The housing may provide an encapsulation surrounding the components of the portable spectrometer device, or a shell that completely or partially surrounds them. The housing may be configured to provide protection against mechanical and / or environmental influences to these components. The housing may be made of a hard material, such as, by way of example, a metallic material and / or a hard plastic material. In particular, the portable spectrometer device may be a single device with only one component, including the spectrometer unit surrounded by the housing and integrated therein. In particular, the at least one control unit and the status inquiry device, and preferably also the spectrometer unit, may be integrally included in the housing.

[0047] The portable spectrometer device may specifically be or be configured to function as an infrared spectrometer. Thus, specifically, the portable spectrometer device may be configured to obtain at least one item of spectral information at least in the infrared spectral range, specifically in the near infrared spectral range. Thus, by way of example, a spectrum of at least a portion of the infrared spectral range may be obtained. The term "infrared spectral range" (IR) may generally refer to electromagnetic radiation from 760 nm to 1000 μm, the range from 760 nm to 1.5 μm being commonly referred to as the "near infrared spectral range" (NIR), while the range from 1.5 μm to 15 μm is denoted as the "mid infrared spectral range" (MidIR), and the range from 15 μm to 1000 μm is denoted as the "far infrared spectral range" (FIR). In particular, the light used for typical purposes of the present invention is light in the infrared (IR) spectral range, more preferably in the near infrared (NIR) and mid-infrared spectral range (MidIR), in particular light having a wavelength of 1 μm to 5 μm, preferably 1 μm to 3 μm. Thus, in particular, the spectrometer unit may be an infrared spectrometer unit, in particular a near infrared spectrometer unit.

[0048] As outlined above, the spectrometer unit may be integrated into a portable spectrometer device, in particular into a mobile communication device such as a smartphone. Since in a mobile communication device, construction space is always an issue and moving mechanical parts are often detrimental to the stability of the device, the infrared spectrometer unit may in particular be a shutterless infrared spectrometer unit. Since the portable spectrometer device may be configured to perform the reference measurement only under suitable environmental conditions, the use of a shutter is generally not necessary, since the control unit may be configured to determine whether predefined environmental conditions are provided that allow an open-shutter measurement, also referred to as an open-port reference measurement, or whether predefined environmental conditions are provided that allow a closed-shutter measurement, also referred to as a dark reference measurement, and may trigger the corresponding dark reference measurement. The environmental conditions that allow the respective reference measurement may, for example, be determined empirically, for example by varying the environmental conditions in a controlled manner, for example in a laboratory, and determining whether the reference measurement is still possible within a predefined tolerance range. Additionally or alternatively, theoretical or semi-empirical considerations may further be used to determine the environmental conditions for the reference measurement.

[0049] Thus, in general, the reference measurement may include at least one reference measurement selected from the group consisting of an open-port reference measurement and a dark reference measurement. As used herein, the term "open-port reference measurement" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term may specifically, but not exclusively, refer to the above-defined reference measurement in which the spectrometer port of the portable spectrometer device is open and spectral information about the background of the portable spectrometer device is collected within its field of view without aiming the portable spectrometer device or its spectrometer port at a specific object. Specifically, during the open-port reference measurement, the spectrometer port may be far away from any potential reflective surfaces and / or light sources in the relevant wavelength range, specifically in the infrared, more specifically in the near-infrared spectral range, within the field of view of the portable spectrometer device. Thus, specifically, during the open-port reference measurement, there may be no object in front of the spectrometer port and within a distance of at least 1 cm, more specifically at least 5 cm, even at least 10 cm, within the field of view of the spectrometer unit. The open-port reference measurement may include switching on at least one light source of the portable spectrometer device while no object is present within a field of view in front of the spectrometer port, such as within at least the distances mentioned above. During the open-port measurement, the light source may remain switched on and spectral information may be collected under this condition.

[0050] As further used herein, the term "dark reference measurement" is a broad term and should be given its ordinary and conventional meaning to those skilled in the art, and is not limited to a special or customized meaning. The term may specifically, but not exclusively, refer to the reference measurement defined above in which the light source of the portable spectrometer device is switched off. Furthermore, the dark reference measurement may be performed without further use of an external light source, at least within a relevant spectral range, specifically within the infrared spectral range, more specifically within the near infrared spectral range, within the field of view of the portable spectrometer device, such as within a distance of at least 1 cm, more specifically within a distance of at least 5 cm, or even at least 10 cm.

[0051] As outlined above, the at least one status inquiry device may in particular be or include a status inquiry device configured to retrieve at least one item of information on the current environmental status of the portable spectrometer device by measurement. Thus, the portable spectrometer device, and in particular the at least one status inquiry device, may include at least one sensor device configured to obtain at least a part of the at least one item of environmental status information. As outlined above, the at least one sensor device may in particular be or include at least one sensor device integrated into the portable spectrometer device, such as integrated into a mobile communication device, such as a smartphone. Thus, one or more integrated sensor devices present in the mobile communication device anyway, such as for one or more other purposes, may be used.

[0052] In general, and more particularly in the case of the use of a mobile communication device, the status inquiry device may include at least one device selected from the group consisting of a rear camera located on the same side as the spectrometer port of the spectrometer unit in the portable spectrometer device, a front camera located on the opposite side of the spectrometer port of the spectrometer unit in the portable spectrometer device, a location sensor, particularly a GPS sensor, an illumination sensor configured to determine at least one state of illumination in the environment of the portable spectrometer device, particularly in the field of view of the spectrometer unit, a temperature sensor, a motion sensor, particularly an acceleration sensor, a gyroscope sensor, a magnetic sensor, a 3D sensor configured to determine at least one geometric shape of at least one object in the vicinity of the portable spectrometer device, and a material sensor configured to determine at least one material property of at least one object in the vicinity of the portable spectrometer device. These devices may further include sensors that are fully or partially composed of one or more virtual sensors, such as at least one virtual sensor that determines the status of the device by indirect means or by learned patterns. This may further include the user's behavior, the time of day, or other interrelated pieces of information. Many or even all of these devices, in particular the sensor devices, are typically integrated into a mobile communication device such as a smartphone. Each of said devices is generally configured to provide at least one item of status information regarding the current environmental conditions of the portable spectrometer device. In particular, said device or one or more of said devices or even all of said devices may provide information that can be used to determine whether the environmental conditions are such that at least one reference measurement can be triggered. Signals from one or more of the devices may be used in isolation or in combination to determine whether the conditions for a reference measurement are given.

[0053] As outlined above, the at least one reference measurement may include a single reference measurement, or may be a single reference measurement, or may include multiple reference measurements. Each reference measurement may include a single reference measurement step, or multiple reference measurement steps, such as different types of reference measurements. Furthermore, as also outlined above, the at least one reference measurement may include repeated reference measurements. Thus, in particular, the control unit may be configured to repeatedly and automatically trigger the reference measurements with the detector device. By way of example, the control unit may be configured to perform status checks at predefined time points. Each status check may include receiving at least one item of status information regarding the current environmental state and checking whether at least one predefined environmental condition has been realized. The control unit may further be configured to trigger at least one reference measurement depending on whether at least one environmental condition has been realized. The status checks may be performed at regular time intervals. However, additionally or alternatively, other predetermined points in time may be provided, such as after switching on the portable spectrometer device and / or whenever the portable spectrometer function is activated on the portable spectrometer device, such as a mobile communication device, e.g. a smartphone.

[0054] As outlined above, various environmental conditions may affect the suitability of a situation for performing at least one reference measurement. In the case where the at least one reference measurement includes different types of reference measurements, such as at least one open-port reference measurement and at least one dark reference measurement, different types of predefined environmental condition conditions may be provided for the different types of reference measurements, such as at least one first predefined environmental condition condition for the open-port reference measurement and at least one second predefined environmental condition condition for the dark reference measurement. Specifically, the at least one environmental condition condition may be: - the level of ambient light, in particular in the infrared spectral range, more particularly in the near infrared spectral range, is within a predetermined range of suitable levels for performing a reference measurement, in particular a reference measurement below a predetermined threshold level; - the portable spectrometer device is in a suitable location to perform a reference measurement, in particular in an indoor environment having a low level of ambient light, more particularly a low level of ambient infrared light; - the portable spectrometer device is in a suitable orientation for performing a reference measurement, in particular in an orientation facing away from the light source; - the portable spectrometer device is not pointed towards external light sources in the portable spectrometer device light source environment; and - the portable spectrometer device is not in close proximity to or directed at the object; and - a portable spectrometer device is disposed within the pocket; and - the portable spectrometer device is at a temperature within a predetermined temperature range suitable for reference measurements; - Transient temperature changes are within predetermined limits appropriate for reference measurements; - weather conditions are within predetermined ranges suitable for reference measurements; - the portable spectrometer device is not currently being used for another function, in particular a mobile communications function.

[0055] As outlined above, various types of items of information about the current environmental state of the portable spectrometer device can be used to determine whether suitable conditions are provided for at least one reference measurement. In particular, the at least one item of status information may include at least one item of information selected from the group consisting of: environmental lighting conditions; an item of position information of the portable spectrometer device, in particular an absolute position of the portable spectrometer device in at least one dimension and a relative position of the portable spectrometer device in at least one dimension with respect to at least one object; an item of orientation information of the portable spectrometer device, in particular an absolute orientation in at least one rotational dimension and a relative orientation in at least one rotational dimension with respect to at least one object; an item of temperature information representing the current temperature; an item of handling information representing a current mode of handling of the portable spectrometer device by a user, in particular an item of information representing at least one of a method of using a display device of the portable spectrometer device, manual steering of the portable spectrometer device by a user, and a method of using at least one other function of the portable spectrometer device apart from the spectrometer function of the portable spectrometer device; and at least one item of information available via at least one network, in particular a wireless network, in particular the Internet, more particularly at least one item of information regarding current weather conditions.

[0056] In a further aspect of the invention, a method for performing a reference measurement using a portable spectrometer device is disclosed. The method suggests using a portable spectrometer device including at least one spectrometer unit, the spectrometer unit including at least one wavelength selection element configured to separate the incident light into constituent wavelengths of a spectrum, and at least one detector device configured to detect at least a portion of the constituent wavelengths. The method may suggest using a portable spectrometer device according to the invention, in particular according to any of the embodiments described above and / or according to any of the embodiments described in more detail further below. Therefore, for possible details and options of the portable spectrometer device used in the method, reference may be made to the above or below description of the portable spectrometer device.

[0057] The method specifically includes the following method steps, which may be performed in a given order. However, different orders are also feasible. The method may further include additional method steps not listed. Moreover, one or more or even all of the method steps may be performed only once or repeatedly.

[0058] The method is as follows: i. specifically, retrieving at least one item of status information relating to a current environmental state of the portable spectrometer device by using at least one status inquiry device of the portable spectrometer device; ii. specifically, verifying whether at least one environmental condition for performing at least one reference measurement is realized by using at least one control unit of the portable spectrometer device; iii. automatically triggering at least one reference measurement with the detector device when the environmental status condition in step ii. is realized, in particular by using the control unit.

[0059] As outlined above, the method may use a portable spectrometer device according to the invention, in particular according to any of the embodiments described above and / or according to any of the embodiments described in more detail further below.

[0060] As further outlined above, one or more of the method steps may be performed iteratively. Thus, in particular, method steps i.-iii. may be performed iteratively, such as in a given order. Moreover, by way of example, as further outlined above, the repetition may be performed at regular time intervals and / or at determinable or predefined times. The predefined times may include, by way of example, when the portable spectrometer device is started, or when a spectrometer application software on a portable spectrometer device, such as a mobile communication device, e.g. a smartphone, is started.

[0061] The at least one reference measurement may specifically include at least one reference measurement selected from the group consisting of an open port reference measurement and a dark reference measurement. For further definitions and options, reference may be made to the description of the portable spectrometer device given above.

[0062] The method of any of the aspects described herein may specifically be at least partially computer-implemented and / or computer-driven, such as by a control unit or by a processor of the control unit of the portable spectrometer device. Specifically, the control unit may thus be configured by a suitable software configuration to trigger retrieval of at least one item of state information and to perform a check whether at least one environmental state condition has been achieved, as well as to automatically trigger a reference measurement.

[0063] Thus, in a further aspect, a computer program is disclosed, the computer program comprising instructions which, when executed by a control unit of a portable spectrometer device disclosed herein, such as according to any of the embodiments described above and / or according to any of the embodiments described in further detail below, cause the control unit of the portable spectrometer device to perform a method disclosed herein, such as according to any of the embodiments described above and / or according to any of the embodiments described in further detail below.

[0064] In a further aspect, a computer readable storage medium, in particular a non-transitory computer readable storage medium, is disclosed, which when executed by a control unit of a portable spectrometer device disclosed herein, such as according to any of the embodiments described above and / or according to any of the embodiments described further in more detail below, causes the control unit to perform a method disclosed herein, such as according to any of the embodiments described above and / or according to any of the embodiments described further in more detail below. As used herein, the term "computer readable storage medium" may in particular refer to a non-transitory data storage means, such as a hardware storage medium, having computer executable instructions stored thereon. The computer readable data carrier or storage medium may in particular be or include a storage medium, such as a random access memory (RAM) and / or a read only memory (ROM).

[0065] In general, in a further aspect, a non-transitory computer-readable medium is disclosed that includes instructions that, when executed by one or more processors, cause the one or more processors to perform a method disclosed herein, such as according to any of the embodiments described above and / or according to any of the embodiments described in more detail further below.

[0066] The portable spectrometer device and method disclosed herein offers numerous advantages over known devices and methods of the same kind. In particular, the above-mentioned technical challenges are addressed. Reference measurements may be performed in a reliable manner, such as at regular time intervals and / or at predefined or determinable time points, e.g., to counter the effects of offset and / or drift or other long-term changes. Both open-port and dark reference measurements can be performed.

[0067] The portable spectrometer device and method generally do not require active user interaction or a priori information to the user that the spectrometer module is in a well-defined state suitable for a reference measurement. In particular, as outlined above, this state may be a state with an open inlet port or spectrometer port far away from any potential reflective surfaces. Additionally or alternatively, the state may be a state in which no light source of the relevant wavelength range is located within the field of view of the portable spectrometer device. The existence of said state may be automatically confirmed by checking if at least one predefined environmental condition is realized, and user action or triggering may be avoided. Furthermore, as further outlined above, by way of example, the presence of an external reference target may be recognized, so that the reference measurement may be performed without a predefined and integrated reference target, such as a shutter. Thereby, moving mechanical parts may be avoided in the portable spectrometer device and / or the spectrometer unit. Thus, the spectrometer unit may be designed without any moving parts, such as a shutter.

[0068] The present invention may be applied in particular to a mobile communication device that includes a spectrometer unit and in which the spectrometer unit is integrated. In particular, as outlined above, many sensors are already available in mobile communication devices such as smartphones, and many sensors may be used as and / or as part of at least one status inquiry device. Thus, by way of example, applying already available sensors to a smartphone, situation sensing can be reached, whereby the portable spectrometer device can perform a reference measurement in a situation in which the conditions for a successful reference measurement are met.

[0069] By way of example, at least one sensor selected from the following group may be selected as and / or as part of at least one status inquiry device for retrieving at least one of the respective items of status information enumerated for the respective sensor and / or for verifying the realization of at least one of the respective predefined environmental status conditions enumerated for the respective sensor: - Portable spectrometer devices, specifically smartphone rear cameras: ○ Identifying whether a portable spectrometer device, specifically a smartphone, is pointed towards a light source; o Identifying whether the portable spectrometer device, in particular the smartphone, is in a highly illuminated area (which may indicate the presence of sunlight and therefore the presence of an undesirable amount of near infrared (NIR) light), for example in an area having an illuminance higher than a predefined threshold; ○ Identify indoor scenes that suggest NIR-less lighting conditions and preferred reference measurement conditions; and / or - Portable spectrometer device, specifically the front camera off the smartphone: ○ Identifying whether a portable spectrometer device, specifically a smartphone, is pointed towards a light source; o Identifying whether the portable spectrometer device, in particular the smartphone, is in a highly illuminated area (which may indicate the presence of sunlight and therefore the presence of an undesirable amount of near infrared (NIR) light), for example in an area having an illuminance higher than a predefined threshold; o Identifying indoor scenes that may suggest NIR-less lighting conditions and preferred reference measurement conditions, specifically for performing open-port and / or dark reference measurements; and / or - Proximal detector: o Identifying whether a portable spectrometer device, specifically a smartphone, is in close proximity to a material, face, or surface (which may indicate that a dark reference measurement may be feasible, even though an open-port reference measurement is not); and / or - 3D Imaging System: ○ Identifying whether a portable spectrometer device, specifically a smartphone, is in close proximity to a material or a face; and / or - Inertial Measurement System: ○ Identifying if a portable spectrometer device, specifically a smartphone, is in a pocket; and / or - GPS sensor: o Identifying whether the portable spectrometer device, specifically a smartphone, is located in an indoor location and / or in a shaded area by noting the signal strength of the GPS signal; and / or - Temperature sensor: ○ Identifying whether a portable spectrometer device, specifically a smartphone, is in contact with a body, such as a human body; o Identifying whether there is a strong temporary temperature shift and / or thermal growth in at least a part of the portable spectrometer device (which may result in temperature changes during the open-port or dark reference measurements and thus be detrimental to at least one of these reference measurements); and / or - Display on / display off state: o Identifying whether a portable spectrometer device, specifically a smartphone, is being held in the hand by a user; and / or - The call state of the portable spectrometer device, specifically a smartphone, such as at least one of the following: use of a loudspeaker, use of a headset, and the portable spectrometer device being held towards the face: ○ Identifying whether a portable spectrometer device, specifically a smartphone, is likely to be in close proximity to a material or a face; and / or - online information such as weather reports, e.g. online information retrieved via at least one wireless or wirebound interface: o Identify whether illumination by sunlight can be expected since most artificial lighting scenarios have little near-infrared and / or short-wave infrared content, e.g. scenes illuminated by LED lighting;

[0070] As outlined above, various combinations from said list of possible sensors, as well as possible information of status information and / or environmental state conditions are possible. Furthermore, the realization of various types of environmental state conditions can be derived from the sensor signals (as outlined above), from which the suitability of the current situation is given against at least one reference measurement, such as against at least one open-port reference measurement and / or at least one dark reference measurement.

[0071] By way of example, the environmental state conditions listed in Table 1 may be predefined to verify suitability of a situation for an open port reference measurement and / or a dark reference measurement. Additionally, any combination and / or subgrouping of these items of state information with the respective environmental state conditions is also possible.

[0072] [Table 1]

[0073] Other reference measurements or system state measurements are sometimes necessary, and some of the reference measurements can be separated and performed at different times if conditions are met. Thus, in general, the present invention can provide a simple manner of performing reference measurements with a portable spectrometer device under well-defined conditions and without the need for user interaction. Furthermore, the use of a mobile communication device such as a smartphone can result in a large number of sensor devices that can be used alone or in combination as at least one state inquiry device to reliably check whether conditions for the reference measurement are realized without the need to actively perform these conditions, such as by providing a shutter or other well-defined experimental equipment for the reference measurement.

[0074] In summary, without excluding further possible embodiments, the following embodiments can be envisaged:

[0075] Embodiment 1: A portable spectrometer device for obtaining at least one item of spectral information, the portable spectrometer device comprising at least one spectrometer unit, the spectrometer unit comprising at least one wavelength selection element configured to separate incident light into constituent wavelengths of a spectrum, and at least one detector device configured to detect at least a portion of the constituent wavelengths, the portable spectrometer device further comprising at least one control unit and at least one status inquiry device configured to retrieve at least one item of status information relating to a current environmental status of the portable spectrometer device, the control unit being configured to automatically trigger at least one reference measurement using the detector device in response to the realization of at least one predetermined environmental status condition.

[0076] Embodiment 2: A portable spectrometer apparatus according to the preceding embodiment, wherein the portable spectrometer apparatus includes a mobile communication device in which the spectrometer unit is at least one of integrated therein and attached thereto, and in particular the mobile communication device is selected from the group consisting of a mobile phone, in particular a smartphone, a tablet computer, and a notebook.

[0077] Embodiment 3: A portable spectrometer device according to the preceding embodiment, wherein the portable spectrometer device is configured to use at least one integrated sensor device of the mobile communication device as at least a part of the at least one status inquiry device.

[0078] Embodiment 4: The portable spectrometer device according to any one of the preceding embodiments, further comprising at least one light source, in particular at least one light source for illuminating at least one object to be analyzed by spectroscopy with light, more in particular with infrared light, more in particular with near infrared light.

[0079] Embodiment 5: A portable spectrometer device according to any one of the preceding embodiments, wherein the portable spectrometer device comprises a housing, and at least one control unit and a status inquiry device, and preferably further a spectrometer unit, are integrally included within the housing.

[0080] Embodiment 6: A portable spectrometer device according to any one of the preceding embodiments, wherein the portable spectrometer device is configured to obtain at least one item of spectral information at least in the infrared spectral range, in particular in the near infrared spectral range, using a spectrometer unit that is in particular an infrared spectrometer unit.

[0081] Embodiment 7: A portable spectrometer device according to any one of the preceding embodiments, wherein the infrared spectrometer unit is a shutterless infrared spectrometer unit.

[0082] Embodiment 8: The portable spectrometer device according to any one of the preceding embodiments, wherein the reference measurement includes at least one reference measurement selected from the group consisting of an open-port reference measurement and a dark reference measurement.

[0083] Embodiment 9: A portable spectrometer device according to any one of the preceding embodiments, wherein the status inquiry includes at least one sensor device configured to obtain at least a portion of at least one item of environmental status information.

[0084] Embodiment 10: A portable spectrometer device according to any one of the preceding embodiments, wherein the status inquiry device includes at least one device selected from the group consisting of a rear camera positioned on the same side as the spectrometer port of the spectrometer unit in the portable spectrometer device, a front camera positioned on the opposite side of the spectrometer port of the spectrometer unit in the portable spectrometer device, a location sensor, in particular a GPS sensor, an illumination sensor configured to determine at least one state of illumination in an environment of the portable spectrometer device, in particular within the field of view of the spectrometer unit, a temperature sensor, a motion sensor, in particular an acceleration sensor, a gyroscope sensor, a magnetic sensor, a 3D sensor configured to determine at least one geometric shape of at least one object proximate to the portable spectrometer device, a material sensor configured to determine at least one material property of at least one object proximate to the portable spectrometer device, and at least one virtual sensor.

[0085] Embodiment 11: A portable spectrometer device according to any one of the preceding embodiments, wherein the control unit is configured to repeatedly and automatically trigger the reference measurement using the detector device.

[0086] Embodiment 12: A portable spectrometer device according to the preceding embodiment, wherein the control unit is configured to perform status checks at predetermined times, each status check including receiving at least one item of status information relating to a current environmental state and checking whether at least one predetermined environmental state condition has been achieved, and wherein the control unit is further configured to trigger at least one reference measurement depending on whether the at least one environmental state condition has been achieved.

[0087] Embodiment 13: A portable spectrometer device according to the preceding embodiments, wherein the status check is performed at regular time intervals.

[0088] Embodiment 14: At least one environmental condition is: - the level of ambient light, in particular in the infrared spectral range, more particularly in the near infrared spectral range, is within a predetermined range of suitable levels for carrying out a reference measurement, in particular below a predetermined threshold level; - the portable spectrometer device is in a suitable location to perform a reference measurement, in particular in an indoor environment having a low level of ambient light, more particularly a low level of ambient infrared light; - the portable spectrometer device is in a suitable orientation for performing a reference measurement, in particular in an orientation facing away from the light source; - the portable spectrometer device is not aimed towards external light sources, i.e. light sources within the environment of the portable spectrometer device; - the portable spectrometer device is not in close proximity to or directed at the object; and - a portable spectrometer device is disposed within the pocket; and - the portable spectrometer device is at a temperature within a predetermined temperature range suitable for reference measurements; - Transient temperature changes are within predetermined limits appropriate for reference measurements; - weather conditions are within predetermined ranges suitable for reference measurements; - the portable spectrometer device is not currently being used for another function, in particular a mobile communication function.

[0089] Embodiment 15: The portable spectrometer device according to any one of the preceding embodiments, wherein the at least one item of status information includes at least one item of information selected from the group consisting of: environmental lighting conditions; an item of position information of the portable spectrometer device, in particular an absolute position of the portable spectrometer device in at least one dimension and a relative position of the portable spectrometer device in at least one dimension with respect to at least one object; an item of orientation information of the portable spectrometer device, in particular an absolute orientation in at least one rotational dimension and a relative orientation in at least one rotational dimension with respect to at least one object; an item of temperature information representing a current temperature; an item of handling information representing a current mode of handling of the portable spectrometer device by a user, in particular an item of information representing at least one of a method of using a display device of the portable spectrometer device, manual steering of the portable spectrometer device by a user, and a method of using at least one other function of the portable spectrometer device apart from the spectrometer function of the portable spectrometer device; and at least one item of information available via at least one network, in particular a wireless network, in particular the Internet, more particularly at least one item of information regarding current weather conditions.

[0090] Embodiment 16: A method of performing a reference measurement using a portable spectrometer device, the portable spectrometer device including at least one spectrometer unit, the spectrometer unit including at least one wavelength selection element configured to separate incident light into constituent wavelengths of a spectrum, and at least one detector device configured to detect at least a portion of the constituent wavelengths, the method comprising: i. specifically, retrieving at least one item of status information relating to a current environmental state of the portable spectrometer device by using at least one status inquiry device of the portable spectrometer device; ii. specifically, by using at least one control unit of the portable spectrometer device, verifying whether at least one environmental condition for performing at least one reference measurement is realized; iii. automatically triggering at least one reference measurement with the detector device when the environmental state condition in step ii. is realized, in particular by using the control unit.

[0091] Embodiment 17: A method according to the preceding claims, wherein the method uses a portable spectrometer device according to any one of the preceding embodiments relating to a portable spectrometer device.

[0092] Embodiment 18: A method according to any one of the preceding embodiments relating to a method, wherein method steps i. to iii. are performed repeatedly, in particular at regular time intervals and / or at determinable or predetermined time points.

[0093] Embodiment 19: A method according to any one of the preceding embodiments relating to the method, wherein the at least one reference measurement includes at least one reference measurement selected from the group consisting of an open-port reference measurement and a dark reference measurement.

[0094] Embodiment 20: A method according to any one of the preceding embodiments relating to a method, wherein the method is at least partially computer-implemented.

[0095] Embodiment 21: A computer program comprising instructions, which when executed by a control unit of a portable spectrometer device according to any one of the preceding embodiments relating to a portable spectrometer device, causes the control unit to perform a method according to any one of the preceding embodiments relating to a method.

[0096] Embodiment 22: A computer-readable storage medium comprising instructions which, when executed by a control unit of a portable spectrometer device according to any one of the preceding embodiments relating to a portable spectrometer device, cause the control unit to perform a method according to any one of the preceding embodiments relating to a method.

[0097] Embodiment 23: A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform a method according to any one of the preceding embodiments relating to methods.

[0098] Further optional features and embodiments will be disclosed in detail in the following description of the embodiments, preferably in conjunction with the dependent claims, where each optional feature may be implemented in an isolated manner as well as in any possible combination, as realized by a person skilled in the art. The scope of the present invention is not limited by the preferred embodiments. The embodiments are depicted diagrammatically in the drawings, where identical reference numbers in these drawings refer to identical or functionally comparable elements. [Brief description of the drawings]

[0099] [Figure 1] FIG. 1 illustrates a cross-section of an embodiment of a portable spectrometer device configured to obtain at least one item of spectral information about an object. [Diagram 2]2 illustrates a flowchart of an embodiment of a method for performing a reference measurement using a portable spectrometer device, such as the portable spectrometer device depicted in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0100] In Fig. 1, a schematic cross-sectional view of a portable spectrometer device 110 for obtaining at least one item of spectral information on an object 112 is shown. In this embodiment, the portable spectrometer device 110 may be specifically embodied as a mobile communication device 114, more specifically as a smartphone 116. The smartphone 116 may have integrated therein a number of sensor devices 118, such as a front camera 120, a rear camera 122, and one or more sensors, such as a tilt sensor, a GPS sensor, an acceleration sensor, a gyroscope sensor, and a temperature sensor, as is usually the case for a typical smartphone 116. For possible sensor devices 118, reference may be made to the description given above.

[0101] A portable spectrometer device 110, such as a smartphone 116, may further include one or more user interfaces 126, such as one or more displays or touch screens. Additionally, the portable spectrometer device 110 may include one or more electronic interfaces 128, such as one or more wireless and / or wirebound interfaces for data exchange with other devices and / or with one or more networks.

[0102] The portable spectrometer device 110 further includes at least one spectrometer unit 130, which may be specifically integrated into the housing 132 of the portable spectrometer device 110. The spectrometer unit 130 includes at least one wavelength-selecting element 134 configured to separate the incident light into constituent wavelengths of a spectrum. Thus, light emitted, reflected, or scattered from the object 112 and to be analyzed by the portable spectrometer device 110 to obtain at least one item of spectral information may be spectrally separated by the wavelength-selecting element 134 before being detected by the at least one detector device 136. Specifically, the at least one wavelength-selecting element 134 may include at least one variable-length filter having spectral transmission characteristics that vary over its lateral extension. The detector device 136 may include, by way of example, an array of light-sensitive elements that may be positioned beneath the variable-length filter such that each of the light-sensitive elements detects a different portion of the spectrum of the incident light. The spectrometer unit 130 may optionally include additional elements, such as a light collector, or a lens. Light from the object 112 may enter the spectrometer unit 130 through at least one spectrometer port 138, such as at least one opening in the housing 132, which may be completely or partially covered by a transparent material that is at least partially transparent to the light to be detected, such as infrared light, and more specifically, light in the near-infrared spectral range.

[0103] The portable spectrometer device 110 may further include at least one light source 140, which may be configured to illuminate the object 112 with light 142, as depicted in FIG. 1. By way of example, the light source 140 may be or include an infrared light source, such as a light source emitting in the near-infrared spectral range. In addition to the at least one light source 140, the portable spectrometer device 110 may further include a light source 144, e.g., one or more light sources 144 used in conjunction with the cameras 120, 122. The light sources 120, 122 may emit in a different spectral range than the light source 140 used for spectroscopic measurement purposes, such as in the visible spectral range.

[0104] The portable spectrometer device 110 further includes at least one control unit 146. The control unit 146 may include, for example, a processor. The control unit 146 may be, for example, a centralized or distributed control unit configured to control one or more or even all of the functions of the portable spectrometer device 110, in particular the mobile communication device 114, more particularly the smartphone 116. The portable spectrometer device, and in particular the control unit 146, may further include one or more data storage devices. The control unit 146 may, for example, be connected to all of the above-listed elements and may be able to communicate unidirectionally and / or bidirectionally with these elements, for example to retrieve data and / or to provide control commands.

[0105] The portable spectrometer device includes at least one status inquiry device 148. The status inquiry device 148 is configured to retrieve at least one item of status information related to a current environmental state of the portable spectrometer device 110, such as a state describing a state of the environment, the portable spectrometer device 110 being in a state such as a temperature change or a temporary change related to a temporary gradient of the temperature of the environment and the illumination of the environment, and / or related to a relationship between the portable spectrometer device 110 and at least a part of the environment, such as the location of the portable spectrometer device 110, the orientation of the portable spectrometer device 110, or the relative position or orientation of the portable spectrometer device 110 and at least one object in the environment. The status inquiry device 148 may specifically include at least one of the sensor devices 118, whereby an item of status information can be retrieved directly or indirectly by measurement, such as illumination and / or temperature. The status inquiry device 148 may thus utilize at least one of the integrated sensors 124 and the cameras 120, 122. Additionally or alternatively, the status inquiry device may be further configured to retrieve at least one item of status information via at least one network, such as the Internet. For this purpose, the status inquiry device 148 may further utilize at least one electronic interface 128, which may also be part of the status inquiry device 148.

[0106] As also outlined above, the control unit 146 is configured to automatically trigger at least one reference measurement in response to the realization of at least one predetermined environmental state condition. The reference measurement is performed by using the detector arrangement 136.

[0107] Thus, by way of example, the control unit 146 can firstly obtain from the at least one status inquiry device 148 at least one item of status information relating to the current environmental state of the portable spectrometer device 110. Thus, by way of example, by using a brightness sensor of the portable spectrometer device 110 at least one item of information relating to the environmental brightness can be retrieved and evaluated by the control unit 146. By way of example, the environmental brightness can be compared with one or more thresholds to determine whether the portable spectrometer device is located in a highly illuminated area, such as having a threshold of 10 kLux. If the environmental brightness is higher than the threshold, by way of example, the control unit 146 can determine that the environmental condition conditions for performing an open-port reference measurement with the light source 140 switched on are not realized, and also the environmental condition conditions for performing a dark reference measurement with the light source 140 switched off are not realized. A combination of environmental condition conditions is also possible, and by way of example, for a suitable condition of a reference measurement, multiple environmental condition conditions may have to be realized simultaneously. For further examples of environmental condition conditions, reference may be made to the description given above.

[0108] In Fig. 2, an exemplary embodiment of a method for performing a reference measurement using a portable spectrometer device 110, such as the portable spectrometer device 110 described above in relation to Fig. 1, is shown as a schematic flow chart. The method specifically includes the following method steps, which may be performed in a given order. However, different orders are also possible. As will be outlined in more detail further below, one or more of the method steps, or even all of the method steps, may be performed iteratively. Furthermore, the method may include additional method steps not listed here.

[0109] By way of example, the method may be run continuously whenever the portable spectrometer device 110 and / or a software application driving the portable spectrometer device 110 is running, for example, on the mobile communications device 114. However, other options are also possible.

[0110] In a first method step, step i., indicated by reference numeral 210, at least one item of status information relating to a current environmental condition of the portable spectrometer device 110 is retrieved, for example, by using at least one status inquiry device 148. Step 210 may involve retrieving a single item of status information or multiple items of status information.

[0111] In a further method step, step ii., indicated by reference number 212, the realization of at least one environmental condition for performing a reference measurement is performed. Different types of environmental condition conditions may be provided if different types of reference measurements have to be performed, such as an open-port reference measurement and a dark reference measurement. Furthermore, as further outlined above, the at least one environmental condition may further include multiple environmental condition conditions that have to be realized simultaneously. Thus, by way of example, the environmental condition conditions may exclude the presence of one or more light sources, in particular light sources emitting in the infrared spectral range, within the field of view 150 of one or both of the cameras 120, 122 in order to enable an open-port reference measurement and / or a dark reference measurement.

[0112] If at least one environmental state condition for performing at least one reference measurement is not realized, the method, which may be fully or partially computer-controlled, can automatically determine that the environmental conditions are not suitable for performing at least one reference measurement. In this branch, indicated by "N" in Figure 2, the method can optionally return to step 210 after a wait period 214.

[0113] On the other hand, if at least one environmental condition or a combination of environmental condition conditions is realized, indicated by branch "Y" in Figure 2, the method may determine that the environmental condition conditions are suitable for performing at least one reference measurement. In this case, the method may proceed to automatically triggering the at least one reference measurement to be performed using the detector arrangement 136. This method step, step iii. in Figure 2, is indicated by reference numeral 216.

[0114] After performing at least one reference measurement in step 216, the method may optionally return to step 210 after a waiting period 214. Thereby, repeated reference measurements may be performed at predefined time points, such as at regular time intervals. Other predefined time points are also possible.

[0115] The method depicted in FIG. 2 gives a rather simple embodiment of the method proposed herein. It is noted that other embodiments are possible. Thus, by way of example, it can be seen that, in particular, in the case where reference measurements of different types are to be performed repeatedly, in step 212, at least one environmental condition for a first type of reference measurement may be realized, but at least one further environmental condition for a second type of reference measurement may not be realized. In this case, the method can proceed by automatically triggering a reference measurement of the first type in step 216, but in this case, a reference measurement of the second type is not performed. It may further be possible to run separate methods for the different types of reference measurements.

[0116] List of reference numbers 110 Portable Spectrometer Equipment 112 Object 114 Mobile communication devices 116 Smartphones 118 Sensor Device 120 Front Camera 122 Rear Camera 124 Sensors 126 User Interface 128 Electronic Interface 130 Spectrometer Unit 132 Housing 134 Wavelength Selection Element 136 Detector Equipment 138 Spectrometer Port 140 light source 142 light 144 More Light Sources 146 Control Unit 148 Status Inquiry Device 150 field of view 210 Retrieving an Item of State Information 212 Confirmation of the realization of environmental conditions 214 Waiting Time 216 Automatic triggering of reference measurements

Claims

1. 1. A portable spectrometer device (110) for obtaining at least one item of spectral information, the portable spectrometer device (110) comprising at least one spectrometer unit (130) comprising at least one wavelength selection element (134) configured to separate incident light into constituent wavelengths of a spectrum and at least one detector device (136) configured to detect at least a portion of the constituent wavelengths, the portable spectrometer device (110) further comprising at least one control unit (146) and at least one status inquiry device (148) configured to retrieve at least one item of status information relating to a current environmental status of the portable spectrometer device (110), the control unit (146) being configured to automatically trigger at least one reference measurement using the detector device (136) in response to the realization of at least one predetermined environmental status condition.

2. The portable spectrometer device (110) of claim 1, wherein the portable spectrometer device (110) includes a mobile communication device (114) in which the spectrometer unit (130) is at least one of integrated therein and attached thereto, and the portable spectrometer device (110) is configured to use at least one integrated sensor device (118) of the mobile communication device (114) as at least a part of the at least one status inquiry device (148).

3. The portable spectrometer device (110) of claim 1 or 2, further comprising at least one light source (140).

4. The portable spectrometer device (110) of any one of claims 1 to 3, wherein the portable spectrometer device (110) is configured to obtain at least one item of spectral information at least in the infrared spectral range.

5. The portable spectrometer device (110) of any one of claims 1 to 4, wherein the infrared spectrometer unit (130) is a shutterless infrared spectrometer unit (130).

6. The portable spectrometer device (110) of any one of claims 1 to 5, wherein the reference measurement comprises at least one reference measurement selected from the group consisting of an open port reference measurement and a dark reference measurement.

7. The status inquiry device (148) includes a rear camera (122) positioned on the same side of the portable spectrometer device (110) as the spectrometer port (138) of the spectrometer unit (130), a front camera (120) positioned on the opposite side of the portable spectrometer device (110) to the spectrometer port (138) of the spectrometer unit (130), a location sensor, a lighting sensor configured to determine at least one status of lighting in the environment of the portable spectrometer device (110), a temperature sensor, a motion sensor, and a gyroscope. A portable spectrometer device (110) as described in any one of claims 1 to 6, comprising at least one device selected from the group consisting of a sensor, a magnetic sensor, a 3D sensor configured to determine at least one geometric shape of at least one object proximate the portable spectrometer device (110), a material sensor configured to determine at least one material property of at least one object proximate the portable spectrometer device (110), and at least one virtual sensor that determines the state of the device by indirect means or by learning patterns.

8. 8. The portable spectrometer device (110) of claim 1, wherein the control unit (146) is configured to repeatedly and automatically trigger reference measurements using the detector device (136), the control unit (146) is configured to perform status checks at predetermined times, each of the status checks including receiving the at least one item of status information relating to the current environmental state and checking whether the at least one predetermined environmental state condition has been achieved, and the control unit (146) is further configured to trigger the at least one reference measurement depending on whether the at least one environmental state condition has been achieved.

9. The at least one environmental condition is: the ambient light level is within a predetermined range of preferred levels for performing the reference measurement; - said portable spectrometer device (110) is in a suitable location to perform a reference measurement; - said portable spectrometer device (110) is in a suitable orientation for performing a reference measurement; - the portable spectrometer device (110) is not aimed towards an external light source; - the portable spectrometer device (110) is not in the vicinity of or directed towards an object (112); - said portable spectrometer device (110) is placed in a pocket; - the portable spectrometer device (110) is at a temperature within a predetermined temperature range suitable for a reference measurement; - the transient temperature changes are within predetermined limits appropriate for reference measurements; - weather conditions are within predetermined limits suitable for reference measurements; The portable spectrometer device (110) of any one of claims 1 to 8, further comprising at least one condition selected from the group consisting of: - the portable spectrometer device (110) is not currently being used for another function.

10. A portable spectrometer device (110) as described in any one of claims 1 to 9, wherein the at least one item of status information includes at least one item of information selected from the group consisting of environmental lighting conditions, an item of position information of the portable spectrometer device (110), an item of orientation information of the portable spectrometer device (110), an item of temperature information representing a current temperature, an item of handling information representing a current mode of handling of the portable spectrometer device (110) by a user, and at least one item of information available via at least one network.

11. 1. A method of performing a reference measurement using a portable spectrometer device (110), the portable spectrometer device (110) comprising at least one spectrometer unit (130), the spectrometer unit (130) comprising at least one wavelength selection element (134) configured to separate incident light into constituent wavelengths of a spectrum, and at least one detector device (136) configured to detect at least a portion of the constituent wavelengths, the method comprising: i. retrieving at least one item of state information relating to a current environmental condition of said portable spectrometer device (110); ii. determining whether at least one environmental state condition is realized to perform at least one reference measurement; and iii. automatically triggering at least one reference measurement with said detector device (136) if said environmental state condition in step ii. is realized.

12. The method of claim 11, wherein the method steps i.-iii. are performed iteratively.

13. The method of claim 11 or 12, wherein the at least one reference measurement comprises at least one reference measurement selected from the group consisting of an open port reference measurement and a dark reference measurement.

14. A computer program comprising instructions, which when executed by a control unit (146) of a portable spectrometer device (110) as described in any one of claims 1 to 10 relating to a portable spectrometer device (110), causes the control unit (146) to perform a method as described in any one of claims 11 to 13 relating to a method.

15. A computer readable storage medium comprising instructions which, when executed by a control unit (146) of a portable spectrometer device (110) as described in any one of claims 1 to 10 relating to a portable spectrometer device (110), cause the control unit (146) to perform a method as described in any one of claims 11 to 13 relating to a method.

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