Temperature drift correction

Abstract

At least one measurement signal S of at least one detector (124) meas from which at least one alternating current (AC) signal S AC is extracted is proposed. The measurement signal S meas is composed of the AC signal S AC and at least one direct current (DC) signal S DC . The AC signal S AC has at least one predetermined frequency f0. A method including the following steps: a) Monitoring the measurement signal S meas over time using the detector (124); b) Determining the DC signal S DC using at least one evaluation unit (128), the determination including evaluating the measurement signal S meas using at least one of the frequency f0 and at least one harmonic of the frequency f0; c) Determining the AC signal S meas by subtracting the DC signal S DC from the measurement signal S AC using the evaluation unit (128). Furthermore, a method for determining at least one information item regarding at least one measurement object (114), a photodetector (122), and a spectrometer (110) is proposed.

Description

[Technical field]

[0001] The present invention relates to a method for detecting at least one measurement signal S meas At least one alternating current (AC) signal S AC The present invention relates to a method for extracting information from a measurement object, a method for determining at least one item of measurement information on a measurement object, a photodetector and a spectrometer. Such methods and devices can be used in general for survey or monitoring purposes, in particular in the infrared (IR) spectral range, in particular in the near infrared (NIR) spectral range, as well as for the detection of heat, flame, fire or smoke. However, further applications are also possible. [Background technology]

[0002] Optical spectroscopy, especially in the near-infrared and mid-infrared spectral regions, allows insight into the molecular structure of objects by observing the vibrations of molecular bonds. Such methods can be used, for example, in spectroscopy, gas sensing, temperature measurement, etc. Mid-infrared light can be used to excite fundamental vibrational modes with high precision and absorption strength, while the near-infrared spectral region allows observation of overtones and combination bands with lower absorption strength. These advantages allow near-infrared spectroscopy to probe bulk objects and obtain information about their molecular composition. As a result, near-infrared spectroscopy has a wide range of applications in life sciences, natural sciences, medicine, material science, agriculture, food, and pharmaceutical industries, such as blood glucose measurement, pulse oximetry, fat content, material classification, and product fraud identification.

[0003] However, providing an analyzer for the near-infrared wavelength region is generally much more difficult compared to spectrometers operating in visible light: silicon-based photodetectors are not usually applicable to light with wavelengths exceeding 1.1 μm due to the relationship of the band structure. However, salts of indium, germanium, lead, and thermopiles are applicable. These materials can exhibit strong temperature dependence. In addition to temperature, effects due to the environment such as background light, stress, or humidity are also conceivable. As a result, the background signal may strongly drift on the time scale of environmental drifts such as direct current (DC) drift. The optical response such as an alternating current (AC) signal may be extracted using signal modulation, Fourier transform, or lock-in amplification methods. However, the extraction of the AC signal by Fourier analysis is generally strongly affected by the DC drift due to the broadband Fourier spectrum of the DC contribution.

[0004] Generally, NIR detectors of laboratory spectrometers and benchtop spectrometers are often thermoelectrically cooled using multiple stages in order to achieve low temperature, high detectivity, and stabilization against temperature drift. However, thermoelectric cooling generally brings about technical complexity, size, and power consumption, for example, hindering the widespread application of near-infrared spectroscopy to point-of-care analysis and consumer devices. Therefore, the operation of an IR spectrometer that does not require cooling is desired, where the detector material preferably functions under a wide range of operating conditions and ambient temperatures. As a result, it is necessary to correct for the drift caused by the temperature of the detector material when comparing the measured value with a reference signal or when repeating the measurement to reduce measurement noise.

[0005] In the prior art, devices and methods for applying temperature correction based on a temperature sensor or based on a second optical detector identical to the primary detector are known.

[0006] Patent Document 1 (Japanese Patent Laid-Open No. 7-1110225) discloses realizing a stable infrared radiometer without using mechanical parts such as a chopper by monitoring the temperature of an optical system and correcting the temperature drift at the zero point. A detector including a photodiode such as InSb or HgCdTe is placed in a vacuum vessel and cooled with liquid nitrogen. Infrared rays from the measurement point form an image on the light detection surface of the detector. The field of view of the detector is limited by a cold shield. The temperature of the optical system is monitored by a temperature sensor that uses its output to correct the temperature drift at the zero point of the infrared radiometer.

[0007] Patent Document 2 (CN 2359677 Y) discloses an infrared optical fiber temperature measuring device used in smelting (melting) and casting. The infrared optical fiber temperature measuring device includes a positioning cylinder, a hemispherical mirror, a condenser objective lens, an optical fiber bundle, a filter, a detector, and a temperature compensation circuit. The positioning cylinder is close to the surface of the molten steel. The hemispherical mirror buckles one end of the positioning cylinder onto the surface of the molten steel to be measured. The condenser objective lens is installed above the hemispherical mirror. One end face of the optical fiber bundle is installed at the focal distance position of the condenser objective lens, and the other end face is coupled to the detector through a filter. The output end of the detector is connected to the temperature compensation circuit.

[0008] Patent Document 3 (US 6852966 B1) discloses a method and apparatus for compensating a photodetector that enables both adjustment and monitoring of the photodetector to be performed by a common digital controller. The controller receives inputs of monitored operating parameters including received signal strength and temperature. The controller provides as an output a bias control signal that adjusts the bias voltage power supply on the positive or negative side of the photodetector. The controller maintains the bias voltage to the photodetector at a level. The controller includes corresponding digital signal strength and temperature compensators, and the outputs of these are summed with an analog summer to provide the bias control signal. The digital signal strength compensator also provides as an output a monitor signal at a level corresponding to the actual signal strength received by the photodetector after compensating for the variable gain of the photodetector due to the bias voltage level. Also disclosed are methods and means for monitoring the photodetector, as well as a transceiver.

[0009] Patent Document 4 (US 20110255075 A1) discloses a spectrometer assembly and method for determining the temperature value of a detector of a spectrometer. In a photoelectron detector, it is common to record the temperature of the detector using a thermal temperature sensor to correct for temperature fluctuations. However, due to the finite distance between the detector and the temperature sensor, there are limitations in the accuracy of temperature detection. In addition to means for spectrally splitting the incident light and a photodetector for spectrally resolving and detecting the spectral range of the split light, a second photodetector is provided for detecting a partial range of this spectral range as a reference detector.

[0010] Patent Document 5 (CN 109307550 A) discloses a temperature compensation method for temperature compensation of an optical power meter. This temperature compensation method includes the following steps: Install the optical power meter in a high-low temperature chamber, sequentially adjust the temperature from -10°C to 40°C, record the zero-point values of different gears at each temperature point by the CPU module, and calculate the zero drift of the current gear caused by the temperature difference according to the reference temperature; Obtain the optical power value detected by the photodetector by the CPU module, set the current optical power detection gear, obtain the real-time temperature detected by the temperature sensor, and for hardware circuit compensation, according to the temperature drift generated by the reference temperature of the current gear, send the zero drift correction coefficient to the secondary amplification circuit through the temperature compensation circuit by the CPU module.

[0011] Patent Document 6 (JP S61213650 Gazette) discloses an optical measuring device. The radiant energy light from the object to be measured is converged by a lens, narrowed by a slit, and then made into parallel light rays by a lens. Then, it is spectroscopically analyzed by a spectroscope and incident on each element of the detector as light with different wavelengths. The gradient or function of the change rate of the spectral sensitivity of the measurement wavelength of each element of the detector is stored in the memory in advance. The temperature T of the detector during measurement is detected by a temperature sensor, and the output of each element of the detector is calculated and corrected by an arithmetic unit based on the gradient or function of each element of the memory and the temperature T of the sensor.

[0012] Patent Document 7 (CN 103076087 A) discloses a mid-infrared photodetector drive circuit, a detector assembly, and a detector assembly array.

[0013] Patent Document 8 (DE 102009026951 A1) discloses a spectroscopic gas sensor including an infrared source, an absorption chamber, an optical filter, and a detector, which includes a detection element that forms a measurement beam from the infrared source through the absorption chamber and the optical filter to the detector. The detection element is arranged in the measurement beam and generates a measurement signal. The detector is a pyroelectric detector with a built-in temperature compensation device that generates a temperature compensation result signal from the measurement signal.

[0014] Patent Document 9 (US 2019 / 317016 A1) describes an analyzer for identifying, verifying, or otherwise characterizing a liquid-based drug sample, which includes: an electromagnetic radiation source for emitting electromagnetic radiation with at least one beam towards the sample, the electromagnetic radiation including at least two different wavelengths; a sample detector for detecting the affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample; and a processor for identifying or verifying the sample from the detected affected electromagnetic radiation, wherein each wavelength or at least two wavelengths are substantially between 1300 nm and 2000 nm, and each wavelength or at least two wavelengths are in the vicinity (or in a region spanning that region) of the wavelength(s) of the spectral characteristics in the liquid spectrum substantially between 1300 nm and 2000 nm.

[0015] Patent Document 10 (WO2014 / 054022A1) describes an integrated laser for emitting electromagnetic radiation with at least one beam towards a sample along a single mode (SM) and polarization maintaining (PM) channel, the electromagnetic radiation including at least two different wavelengths, a sample detector for detecting the affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample and providing an output representing the detected affected radiation, and a processor for characterizing the sample from the detector output representing the detected affected electromagnetic radiation.

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0017] Despite the advantages implied by the above-described apparatus and method, there is still a need for improvement. Specifically, an additional sensor or detector is required to correct for drift in the detector signal (such as drift due to temperature), which increases cost, complexity, and thus the susceptibility to errors in the apparatus and method. As an example, an additional detector may malfunction or the detector itself may drift. [Summary of the Invention] [Problems to be Solved by the Invention]

[0018] Therefore, it is desirable to provide a method and apparatus for compensating a measurement signal that at least substantially avoids the disadvantages of this type of known method and apparatus. In particular, it is desirable to provide a method and apparatus that can accurately and reliably compensate for detector drift, particularly temperature drift of an optical detector, in a simple and safe manner, particularly without the need to install additional components. [Means for Solving the Problems]

[0019] This problem is solved by the present invention having the features of the independent claims. Advantageous embodiments that can be implemented in an independent manner or in any combination are described in the dependent claims and throughout the specification.

[0020] In a first aspect of the present invention, at least one measurement signal S of at least one detector meas from which at least one alternating current (AC) signal S AC is extracted is disclosed. The measurement signal S meas is composed of an alternating current signal S AC and at least one direct current (DC) signal S DC . The alternating current (AC) signal S ACは has at least one predefined frequency f0. The method includes the following steps: a) Monitoring the measurement signal S meas over time using a detector; b) Determining the DC signal S DC using at least one evaluation unit, the determining including evaluating the measurement signal S meas using at least one of the frequency f0 and at least one harmonic of the frequency f0; c) Using the evaluation unit to determine the alternating current signal S meas by subtracting the direct current signal S DC from the measurement signal S AC .

[0021] The method steps can be executed in the order shown. However, it should be noted that different orders are also possible. The method may include additional method steps not listed. Further, one or more method steps may be performed once or repeatedly. Additionally, two or more method steps may be performed simultaneously or at appropriate times with repetition.

[0022] The method is applicable to the measurement signal S measIt may include correcting at least one environmental change that affects. Environmental changes specifically include at least one of temperature change, background light change, mechanical stress, and humidity change, and deterioration of at least a part of the detector. The term "correct" as used herein is a broad term including its grammatical variations and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. This term, without being particularly limited, may represent correcting (compensating) or readjusting an entity. The correction is the measurement signal S meas It may also include removing or eliminating perturbations that affect, specifically external perturbations. Specifically, the correction may include removing the contribution to the measurement signal S meas caused by environmental changes such as temperature change. Such a contribution may be represented by the DC signal S DC As an example, the detector may be a photodetector of a spectrometer configured to measure optical radiation. Other external influences other than the measured optical radiation may be of no interest in the measurement and may only interfere with the measurement signal S meas The spectrometer may further include a modulated radiation source. Therefore, the signal of interest may be the AC signal S AC External influences, such as temperature, may typically change on a larger time scale compared to the AC signal S AC and may be unidirectional at least during the monitored period. External influences usually contribute to the measurement signal S meas in the form of the DC signal S DC By identifying the DC signal S meas in the measurement signal S DC and removing the DC signal S meas from the measurement signal S DC , the AC signal S AC that is particularly of interest in the measurement may be obtained. Further options are also possible.

[0023] Known methods such as those described in US 2019 / 317016 A1 and WO 2014 / 054022 A1 propose removing the dark current component using a reference and sample detector, Fourier transform, and Fourier analysis. In contrast, the present invention proposes using only the measurement signal and determining the DC component using the frequency and / or at least one harmonic of the frequency, as described in steps b) and c). Possible options for determining the DC component are described in more detail below.

[0024] As used herein, the term "retrieving", including its grammatical variations, is a broad term and should be given its ordinary and customary meaning to one of ordinary skill in the art and should not be limited to a special or customized meaning. This term may, without specifically being limited thereto, represent at least one of determination, derivation, and filtering of a signal or at least a part of a signal. As described above, the measurement signal S meas is composed of an AC signal S AC and a DC signal S DC Retrieving may include identifying and / or separating the AC signal S meas in the measurement signal S AC Retrieving may include removing and / or eliminating the DC signal S meas from the measurement signal S DC Retrieving may include providing the AC signal S AC to a further entity for further processing and / or evaluation, such as for determining an item of information regarding at least one measurement object.

[0025] As used herein, the term "signal" is a broad term and is given the ordinary and customary meaning to those skilled in the art and is not limited to a special meaning or a customized meaning. Although not particularly limited, this term may represent an observable change in at least one physical quantity. A signal may be, or may include, a marker or a function that conveys information regarding at least one physical quantity. Specifically, a signal may be, or may include, at least one of an electronic signal, an optical signal, or an optoelectronic signal. A signal may particularly be a variable signal over time. A signal may be an analog signal. A signal may be at least one of a variable voltage, a variable current, a variable charge, a variable resistance, or generally a variable electromagnetic wave, or may include these. The variable electromagnetic wave may include at least one of a variable amplitude, a variable frequency, or a variable phase. A signal may be a digital signal. A signal may include at least one count. Further options are possible. Specifically, a signal may be related to at least one measurement. Specifically, a signal may be generated by at least one detector.

[0026] As used herein, the term "measurement signal" is a broad term and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special meaning or a customized meaning. Although not particularly limited, this term may represent a signal related to at least one measurement, more specifically, at least one measurement object. A measurement signal may be a signal generated by a detector when detecting at least one physical quantity such as a physical quantity of a measurement object. A measurement signal may include at least one electronic signal such as a current, a voltage, or a resistance. A measurement signal may include an analog signal. A measurement signal may include a digital signal such as a count. A measurement signal may be a superposition of two or more signals or sub-signals. The measurement may be affected by multiple factors such as illumination, temperature, humidity, or mechanical stress. Each factor may contribute to the measurement signal. A measurement signal may be divided into two or more sub-signals, and the sub-signals may be related to at least partially different effects.

[0027] Measured signal S meas is an alternating current (AC) signal S AC and at least one direct current (DC) signal S DC and includes. The term "direct current signal" (abbreviated as DC signal) used in this specification is a broad term and should be given the ordinary and customary meaning for those skilled in the art, and is not limited to a special meaning or a customized meaning. This term, although not particularly limited, may represent a signal that is unidirectional or at least essentially unidirectional over time, such as a signal that continuously increases over time or a signal that continuously decreases over time. As an example, the DC signal S DC may be a digital signal, and the count may continuously increase with time. The DC signal SDC は , may include at least one plateau over time. Deviations from a strictly unidirectional progression may occur, for example, due to signal noise or external perturbations.

[0028] The term "alternating current signal" (abbreviated as AC signal) used in this specification is a broad term and should be given the ordinary and customary meaning for those skilled in the art, and is not limited to a special meaning or a customized meaning. This term, although not particularly limited, may represent a signal that, over time, for example, periodically reverses direction and / or changes in magnitude. As an example, the AC signal S AC may be a digital signal in which the count alternately increases and decreases with time. The alternating current signal S AC may be a sine wave, a rectangular wave, a pulse width modulation signal, or a combination of the foregoing. The alternating current signal S AC may be a periodic signal or at least an essentially periodic signal. Deviations from a strictly periodic progression may occur, for example, due to signal noise or external perturbations. As described above, the alternating current signal S AC has at least one predetermined frequency f0.

[0029] As used herein, the term "frequency" is a broad term, given its ordinary and customary meaning to those skilled in the art, and is not limited to a special or customized meaning. Without particular limitation, this term may represent the number of occurrences of an event that repeats over time. Frequency can be defined as the reciprocal of a periodic period, such as the periodic period of a periodic signal. Frequency may be predefined by at least one predefined value, such as at least one predefined value in a measurement setup. A user can set a predefined value or select from a plurality of different predefined values. As an example, although described in more detail below, the detector may be a photodetector of a spectrometer, and the spectrometer may further include a modulated radiation source. Thus, for an alternating current signal S AC the frequency may be predefined by setting a specific modulation frequency in the modulated radiation source. Other options are possible.

[0030] Frequencies, such as frequency f0, generally have a plurality of harmonics. As used herein, the term "harmonic" is a broad term, given its ordinary and customary meaning to those skilled in the art, and is not limited to a special or customized meaning. Without particular limitation, this term may refer to a frequency that is a harmonic of a fundamental frequency, such as frequency f0. The harmonics of frequency f0 may be positive integer multiples of frequency f0, such as 2f0, 3f0, 4f0, etc.

[0031] As used herein, the term "detector" is a broad term, given its ordinary and customary meaning to those skilled in the art, and is not limited to a special or customized meaning. Without particular limitation, this term may represent a measuring device such as a sensor configured to generate at least one measurement signal. The detector may be configured to sense, detect, or monitor at least one physical quantity. The detector may be an electronic device or an optoelectronic device. The detector may be configured to generate at least one electronic signal such as current, voltage, or resistance. Specifically, as will be described in more detail below, the detector may be a photodetector or may include a photodetector. However, other types of detectors are also feasible.

[0032] The detector may include at least one photodetector. The photodetector may include at least one light-receiving region. Step a) may include measuring the measurement signal S meas using the light-receiving region of the photodetector. The measurement signal S meas may depend on the illumination of the photosensitive region. As used herein, the term "photodetector" is a broad term, given its ordinary and customary meaning to those skilled in the art, and is not limited to a special or customized meaning. Specifically, without limitation, this term may represent a photodetector or photosensor configured to detect light radiation, such as for detecting illumination and / or light spots generated by at least one light beam. The photodetector may include at least one substrate. A single photodetector may be a substrate having at least one single photosensitive region that generates a physical response to illumination within a given wavelength range.

[0033] The photodetector may include at least one photosensitive region. The photodetector may include a plurality of photosensitive regions, and these photosensitive regions may be arranged in at least one of an array or a matrix. As used herein, the term "photosensitive region" is a broad term and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special meaning or a customized meaning. This term, without particular limitation, may represent a unit of a photodetector configured to be illuminated, in other words, to receive light radiation, and to generate at least one signal such as an electronic signal in response to the illumination. The photosensitive region may be arranged on the surface of the photodetector. The photosensitive region may specifically be a single, closed, and uniform photosensitive region. However, other options may also be feasible. The photosensitive region may also be referred to as a pixel.

[0034] As used herein, the term "illumination" is a broad term and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special meaning or a customized meaning. This term, without particular limitation, may specifically represent light radiation within at least one of the visible, ultraviolet, or infrared spectral ranges. The term "ultraviolet" generally represents electromagnetic radiation having a wavelength of 1 nm to 380 nm, preferably 100 nm to 380 nm. Further, the term "visible" generally represents a wavelength of 380 nm to 760 nm. Further, the terms "infrared", abbreviated as "IR", generally represent a wavelength of 760 nm to 1000 μm, and a wavelength of 760 nm to 3 μm is usually referred to as "near infrared", abbreviated as "NIR". Preferably, the illumination used for typical purposes of the present invention is IR radiation, more preferably NIR radiation, particularly radiation having a wavelength of 760 nm to 3 μm, preferably 1 μm to 3 μm. Illumination may specifically be light radiation incident on the photodetector, more specifically on the photosensitive region. In this specification, the term "illumination" may also be referred to as "light radiation" or "light".

[0035] Illumination may be provided by at least one object to be measured, and the provision may include at least one of reflection, transmission, and radiation. Specifically, before interacting with the object to be measured, the illumination may be emitted, for example, by at least one radiation source. As used herein, the term "radiation source" is a broad term that is given its ordinary and customary meaning to those skilled in the art and is not limited to a special or customized meaning. Without particular limitation, this term may represent a device configured to emit optical radiation. The radiation source may be configured to emit optical radiation towards the object to be measured, such as in the form of an optical beam. The radiation source may be configured to emit optical radiation isotopically, for example, uniformly in all spatial directions, and only a part of the emitted optical radiation may impinge on the object to be measured. The radiation source may include at least one of a semiconductor-based radiation source or a thermal radiator. The at least one semiconductor-based radiation source may be selected from at least one of a light-emitting diode (LED) or a laser, particularly a laser diode. The LED may include at least one fluorescent material and / or phosphorescent material. The thermal radiator may be composed of at least one of an incandescent lamp, a blackbody emitter, and a microelectromechanical system (MEMS) emitter. Further types of radiation sources are also feasible.

[0036] Illumination may be modulated, for example, by using a modulated radiation source. The radiation source may be a modulated radiation source. The radiation source may be modulated at a frequency f0. Accordingly, the frequency f0 and the harmonics of the frequency f0 may be present in the optical radiation incident on the photodetector, and subsequently, may also be present in the measurement signal S meas generated by the photodetector. Specifically, the AC signal S AChas a frequency f0. The term "modulation" as used herein is a broad term including its grammatical variations and should be given its ordinary and customary meaning to those skilled in the art and is not limited to a special or customized meaning. In particular, this term may represent, without limitation, a process of changing at least one characteristic of an optical emission, in particular, one or both of the intensity or phase of the optical emission, specifically, changing periodically. As will be appreciated by those skilled in the art, the intensity is again related to the amplitude of the optical emission. The modulation may be a complete modulation from a maximum value to zero or a partial modulation from a maximum value to an intermediate value greater than zero. The modulation may include the use of a modulation element. The modulation element may be configured to mechanically modulate the optical emission, for example, by using a rotating chopper wheel, and / or to electronically modulate the optical emission, for example, by using an electro-optic effect and / or an acousto-optic effect by using, for example, a Pockels cell and / or a Kerr cell. Further options are possible.

[0037] The photodetector may be configured to detect optical emissions having wavelengths in the range of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, more specifically 1400 nm to 2000 nm. The photosensitive region may include at least one photoconductive material. The photoconductive material may be selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, and HgCdTe. Also, other options such as photodiodes and thermopiles are realizable. The photodetector can be configured to generate a measurement signal in response to illumination of the photosensitive region with at least one measurement signal, specifically a photocurrent. However, in addition to illumination, as is already known to those skilled in the art, the measurement signal can be affected by other influences. Specifically, environmental changes such as temperature changes may also affect the measurement signal and, more specifically, may lead to drift of the measurement signal.

[0038] Step a) is to use the detector to measure the measurement signal S measincluding monitoring over time. As used herein, the term "monitoring over time (monitoring)", including its grammatical variations, is a broad term and should be given its ordinary and customary meaning to one of ordinary skill in the art and should not be limited to a special or customized meaning. This term, without limitation, may represent at least one of measuring, observing, or recording an entity such as measurement signal S meas or the like, particularly over time. Monitoring may include recording the progress and / or development of measurement signal S meas over time.

[0039] Step b) includes determining DC signal S (DC)を using at least one evaluation unit, and the determining includes evaluating measurement signal S meas using at least one of frequency f0 and at least one harmonic of frequency f0. As used herein, the term "evaluate" is a broad term including its grammatical variations and should be given its ordinary and customary meaning to one of ordinary skill in the art and should not be limited to a special or customized meaning. This term may, in particular, represent without limitation processing or analyzing or interpreting an entity such as measurement signal S meas or the like. Evaluating may include performing at least one mathematical calculation including measurement signal S meas Evaluating may include converting and / or transforming measurement signal S meas Evaluating may include using at least one relationship, such as a predefined and / or predetermined relationship from a look-up table, or a variable relationship such as a function. Evaluating may include filtering and / or smoothing measurement signal S meas Evaluation may be from measurement signal S meas DC signal S DC and / or AC signal S AC of measurement signal S measmay include deriving at least one qualitative or quantitative information item, such as a contribution to. As will be outlined in more detail below, different approaches may be possible for such purposes.

[0040] The term "evaluation unit" as used herein is a broad term and should be given its ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. Specifically, but not limited to, this term may represent a device configured to analyze or interpret data, specifically, a device for determining at least one item of qualitative or quantitative information. The information may specifically be obtained by evaluating at least one signal, specifically a measurement signal S, such as a signal generated by a detector. meas The evaluation unit may be or include at least one of an integrated circuit, in particular an application-specific integrated circuit (ASIC), or a data processing device, in particular a digital signal processor (DSP), a field programmable gate array (FPGA), a microcontroller, a microcomputer, a computer, or an electronic communication unit, in particular a smartphone or a tablet. Further components, in particular at least one preprocessing device or data collection device, are also realizable. The evaluation unit may include at least one interface, in particular at least one of a wireless interface or a wired interface. The evaluation unit can be designed to control or drive further devices, such as a detector, either completely or partially. The evaluation unit may be designed to execute at least one measurement cycle in which a plurality of measurement signals can be picked up. The evaluation unit may be designed to control a detector in order to perform at least one measurement and / or to generate at least one measurement signal.

[0041] The information determined by the evaluation unit may be provided, in particular, to a further device or to the user, preferably in at least one of an electronic, visual, acoustic or tactile manner. The information may be stored in at least one data storage device, in particular in an internal data storage device included in a light detector, especially in an internal data storage device included in at least one evaluation unit, or in a separate storage device to which the information can be transmitted via at least one interface. The separate storage device may be included in at least one electronic communication unit. The storage device may in particular be configured to store at least one electronic table, such as at least one look-up table.

[0042] The evaluation unit may be configured to execute at least one computer program, in particular at least one computer program that performs or supports the step of generating information. As an example, one or more algorithms that perform a conversion to a part of the information may be implemented by using at least one measurement signal as at least one input variable. For this purpose, the evaluation unit may include at least one of at least one data processing device, in particular an electronic data processing device or an optical data processing device that may be designed to generate information by evaluating at least one measurement signal. The evaluation unit may be designed to use at least one measurement signal as at least one input variable and to generate information by processing at least one input variable. The processing can be performed continuously, in parallel or in combination. The evaluation unit may use any process to generate the information, in particular by calculation and / or by using at least one stored and / or known relationship.

[0043] The detector may include an evaluation unit and / or at least one interface for transmitting data from and / or to and / or into the evaluation unit. The term "interface" as used herein is a broad term and is given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. This term may specifically, but not limited to, represent an item or element that forms a boundary configured to transfer information. The interface may specifically be a communication interface. In particular, the interface may be configured to transfer information, such as transmitting or outputting information from a computing device, e.g., a computer, onto another device, for example. Further, or alternatively, the interface may be configured to transfer information to a computing device, e.g., a computer, such as receiving information. The interface may in particular also provide a means for transferring or exchanging information. In particular, the interface may provide a data transfer connection such as, for example, Bluetooth (R), NFC, inductive coupling, etc. As an example, the interface is or may include at least one port including one or more of a network or Internet port, a USB port, and a disk drive. The interface may include at least one web interface.

[0044] The evaluation unit may be at least partially cloud-based. The term "cloud-based" as used herein is a broad term and should be given its ordinary and customary meaning to those of ordinary skill in the art and should not be limited to a special or customized meaning. Specifically, this term may represent, without limitation, the outsourcing of the evaluation unit or a part of the evaluation unit to at least partially interconnected external devices, specifically, a computer or a computer network having greater computing power and / or data storage capacity. The external devices may be arbitrarily spatially distributed. The external devices may change over time, particularly in response to requests. The external devices may be interconnected by using the Internet and / or at least one intranet. Each of the external devices may include at least one interface, such as a communication interface for transferring data.

[0045] As shown, in step b), at least one of the frequency f0 and at least one harmonic of the frequency f0 may be used to determine the DC signal S DC There may be a plurality of specific approaches for determining. As an example, which will be outlined in more detail below, the measurement signal S meas may be converted to the frequency domain for filtering for the frequency f0 and / or at least one harmonic of the frequency f0. The filtered and converted measurement signal S meas is then used, for example, by fitting the DC signal S DC to the filtered and converted measurement signal S meas to determine the DC signal S DC . Below, specific approaches for determining the DC signal S DC are shown. These approaches may alternatively or additionally be performed, for example, continuously. There may be further approaches, which may be used to determine the DC signal S DC .

[0046] DC signal S DCIn addition to the frequency f0, the phase φ of the measurement signal S, specifically the phase φ of the AC signal S meas may be further used for determination. The evaluation of the measurement signal S AC may include determining local minima of the measurement signal S by using the frequency f0 and the phase φ, and at least one of at least one harmonic of the frequency f0. The DC signal S meas may be determined using local minima. As used herein, the term "phase" is a broad term and is given its ordinary customary meaning to those skilled in the art and is not limited to a special or customized meaning. This term, without particular limitation, may represent a position indicator within a periodic signal. Typically, the phase may be represented as an angle, as will be understood by those skilled in the art. The phase may depend on time, the frequency of the signal, and / or a phase offset. Specifically, the phase may indicate when a periodic portion of the entire signal, such as a periodic signal or a periodic sub-signal, reaches an extreme value such as a minimum or maximum value. As an example, the measurement signal S meas may exhibit at least an essentially periodic sub-signal due to using, for example, a modulated radiation source as already outlined. This sub-signal DC may correspond to the ultimately observed AC signal S meas but at this stage may drift, for example, due to environmental changes. The frequency f0 and the phase φ of this sub-signal may be used to identify the minima of the sub-signal, which may simultaneously be at least local minima (local minimum) of the entire measurement signal S AC . meas

[0047] As used herein, the term "local minimum (local minimum)" is a broad term and is given its ordinary customary meaning to those skilled in the art and is not limited to a special or customized meaning. This term, without particular limitation, may represent the lowest signal value within a signal interval, specifically within the period of a periodic signal. The measurement signal S meas ​Specifically, it may be recorded by the count number over time. As described above, the measurement signal is the AC signal S AC and the DC signal S DC and includes. The local minimum value may be the minimum signal value such as the lowest count in the time interval related to the period of the AC signal S AC . On the contrary, as will be understood by those skilled in the art, the global minimum value may be the minimum signal value over the entire signal. The signal may include a plurality of local minimum values. The local minimum values may have at least partially the same level. The local minimum values may specifically have at least partially different levels due to external perturbations such as environmental changes that affect the detector and / or the measurement signal. The evaluation of the measurement signal S meas may include adapting the DC signal S DC to the local minimum value of the measurement signal S meas . The DC signal S DC is a time-dependent function S DC (t) including at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter. The term "fitting" including its grammatical variations used herein is a broad term and should be given the ordinary and customary meaning for those skilled in the art and should not be limited to a special meaning or a customized meaning. This term may represent, without particular limitation, a regression analysis for estimating the relationship between at least two variables. The fitting may include at least one of linear regression, partial least squares regression, non-linear regression, interpolation, and extrapolation. The fitting may include at least one regression model (for example, a trained model). The fitting may include using at least one fitting function such as at least one of the above functions. The function S DC (t) is the measurement signal S measIt may also be a fitting function that fits the local minimum value. The fitting function may include at least one fitting parameter. The term "fitting parameter" as used herein is a broad term and should be given the ordinary and customary meaning to those skilled in the art and is not limited to a special meaning or a customized meaning. Specifically, although not particularly limited, this term may represent the parameter or coefficient of the fitting function. As an example, the fitting function may be a linear function, and the fitting parameters may be the slope and offset of the linear function. Generally, various further options are feasible and are known to those skilled in the art.

[0048] Measured signal S meas In addition to or alternatively to the above-described approach using the local minimum value of, in step b), the DC signal S DC may be determined by converting the measured signal S meas into the frequency domain. The term "frequency domain" as used herein is a broad term and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special meaning or a customized meaning. Specifically, although not particularly limited, this term may represent the analysis of the signal with respect to at least one frequency of the signal. The signal may usually be recorded over time in the time domain, which means that the signal value is related to a specific point in time. However, as will be understood by those skilled in the art, in various applications, it may be useful to analyze the signal with respect to the frequencies that make up the signal in the frequency domain. As an example, one overall signal may include a plurality of sub-signals, each of which includes a specific frequency. The sub-signals may be distinguished, for example, for further separated processing by analyzing the frequencies of the overall signal. In the frequency domain, the signal value may be associated with a specific frequency. The signal values such as the signal values of the overall signal may be plotted over the frequency interval in the frequency domain.

[0049] Measured signal S measmay be transformed into the frequency domain using a Fourier transform. The frequency domain may also be referred to as the Fourier space. The term "Fourier transform" as used herein is a broad term and is given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. This term, without particular limitation, may represent an integral transform for decomposing a space- or time-dependent integrable function into a function dependent on spatial frequency or temporal frequency. Usually, in this specification, the temporal frequency is simply represented as frequency. Specifically, the Fourier transform may be configured to decompose a time-dependent signal into a frequency-dependent signal. The Fourier transform may include at least one of Fourier analysis, continuous Fourier transform, discrete Fourier transform, and Fourier-related transforms such as, for example, Laplace transform. Further options are possible. Generally, there are several common and well-known conventions for defining or performing the Fourier transform of a function such as the fast Fourier transform and for defining the corresponding inverse Fourier transform. Transforms other than the Fourier transform are also applicable to the present invention. In step b), the DC signal S DC may be determined by setting to zero in the frequency domain at least one of the frequency f0 and at least one harmonic of the frequency f0, specifically, before re-transforming into the time domain using, for example, the inverse Fourier transform. Accordingly, step c) may be specifically performed again in the time domain.

[0050] The evaluation of the measurement signal S as performed in step b) meas is for at least one of the frequency f0 and at least one harmonic of the frequency f0, for the transformed measurement signal S measmay include filtering. As used herein, the term "filtering", including its grammatical variations, is a broad term and should be given its ordinary and customary meaning to those of ordinary skill in the art and should not be limited to a special or customized meaning. Specifically, this term may, without limitation, represent, for example, selectively extracting at least a portion of a signal, such as a specific signal interval, in the frequency domain. Filtering may include extracting a specific frequency or a sub-signal having a specific frequency from all signals in the frequency domain. Specifically, filtering may include extracting at least one of the fundamental frequency f0 and at least one harmonic of the fundamental frequency f0 from the measurement signal S meas The remainder of the original measurement signal S meas may remain as residue. The fundamental frequency f0 and the harmonics of the fundamental frequency f0 may represent an alternating current signal S AC The residue may represent a DC signal S DC Filtering may include using at least one electronic filter element, specifically, at least one frequency electronic filter element such as an electronic band-pass filter element. The electronic filter element may be an analog electronic filter element or a digital electronic filter element. Other options are also feasible and are generally known to those of ordinary skill in the art.

[0051] The evaluation of the measurement signal S meas may include using the filtered transformed measurement signal S DC to determine the DC signal S meas Specifically, the evaluation of the measurement signal S meas may include using the residue of the filtering of the transformed measurement signal S DC to determine the DC signal S meas The evaluation of the measurement signal S (meas)の may include using the DC signal S DC from the filtered transformed measurement signal S meas Specifically, the transformed measurement signal S measmay also include fitting to the remainder of the filtering. DC signal S DC is a time-dependent function S including at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter (DC) (t). The DC signal S (DC)は may carry non-zero power at the frequency f0 and at least one harmonic of the frequency f0. For details of the fitting, the definitions of the above terms are referred to.

[0052] Step c) includes determining the AC signal S meas by subtracting the DC signal S DC from the measurement signal S AC . The term "subtract" as used herein is a broad term including its grammatical variations and should be given the ordinary and customary meaning to those skilled in the art and should not be limited to a special or customized meaning. Specifically, this term may represent, without limitation, one or more of removing, eliminating, and deducing the DC signal S meas from the measurement signal S DC , especially over the entire period. Subtraction may include extracting the AC signal S meas from the measurement signal S AC . Subtraction may include at least one mathematical calculation. Subtraction may specifically subtract, for each time point over the entire period, the count of the DC signal S DC , for example the DC signal S DC , from the count of the measurement signal S meas , for example the measurement signal S meas . In this way, the alternating current signal S AC can be determined, for example, for each time point and thus for each selected time unit, for example each millisecond or each frame number of the photodetector. Other options are possible.

[0053] At least one measurement signal S meas to at least one alternating current signal S AC The method of searching may be at least partially computer-implemented. As used herein, the term "computer-implemented" is a broad term and should be given its ordinary and customary meaning to those of ordinary skill in the art and should not be limited to a special or customized meaning. Specifically, but not limited to, this term may represent a method including at least one computer and / or at least one computer network. The computer and / or computer network may include at least one processor configured to execute at least one of the method steps of the method according to the present invention. Specifically, each of the method steps may be executed by a computer and / or a computer network. The method may be executed completely automatically, specifically without user interaction.

[0054] Referring to the computer-implemented aspects of the present invention, one or more, or even all, of the method steps of the method according to one or more of the embodiments disclosed herein may be executed using a computer or a computer network. Thus, in general, any of the method steps including the provision and / or manipulation of data may be executed using a computer or a computer network. In general, these method steps may include any of the method steps, typically excluding method steps that require manual work, such as specific aspects of sample provision and / or actual measurement execution.

[0055] In a further aspect of the present invention, a method for determining at least one information item regarding at least one measurement object using at least one detector is disclosed.

[0056] This method comprises the following steps: i) Using a detector, at least one measurement signal S measThe step of determining; ii) Using a method according to any one of the embodiments disclosed in more detail above or below with reference to a method for searching for at least one AC signal S meas from at least one measurement signal S AC and determining the AC signal S AC ; and iii) The step of determining an item of information regarding the measurement object by evaluating the AC signal S AC using an evaluation unit.

[0057] The method steps may be executed in the order shown. However, it should be noted that different orders are also possible. The method may include further method steps not listed. Further, one or more method steps may be performed once or repeatedly. Further, two or more method steps may be performed simultaneously or timely and repeatedly. For further definitions and embodiments regarding the method for determining at least one item of information, refer to the above description.

[0058] As used herein, the term "item of information" is a broad term and is given its ordinary and customary meaning to those skilled in the art and is not limited to a special or customized meaning. Without particular limitation, this term may represent knowledge or evidence that provides at least one measurement, specifically a qualitative and / or quantitative description regarding at least one measurement object. An item of information may include at least one of the physical characteristics of the measurement object or the chemical composition of at least one measurement object. Physical characteristics may specifically include optical characteristics such as at least one absorbance of the measurement object and / or at least one emissivity of the measurement object. Chemical composition may specifically represent qualitative and / or quantitative information regarding at least one material that the measurement object is composed of.

[0059] As used herein, the term "object to be measured" is a broad term, which is given the ordinary and customary meaning to those skilled in the art and is not limited to a special meaning or a customized meaning. Specifically, this term may represent any object selected from living and non-living bodies without limitation. The object to be measured may specifically include at least one material to be investigated. The object to be measured may generally represent an object to be measured, for example, an object whose spectrum is recorded. In principle, the object to be measured may have any property, for example, any optical property or any shape. The object to be measured may include at least one solid sample. However, other objects to be measured such as fluids may also be feasible.

[0060] The detector may include at least one photodetector. The photodetector may include at least one light-receiving region. Step i) may include measuring the measurement signal S meas using the light-receiving region of the photodetector. The measurement signal S meas may depend on the illumination of the photosensitive region. For further definitions and embodiments regarding the photodetector, refer to the above description.

[0061] A method for determining at least one information item regarding at least one object to be measured may be at least partially computer-implemented. Referring to the computer-implemented aspect of the present invention, one or more of the method steps of the method according to one or more of the embodiments disclosed herein, or even all of the method steps, can be executed using a computer or a computer network. Therefore, generally, any of the method steps including the provision and / or manipulation of data can be executed using a computer or a computer network. Generally, these method steps may include any of the method steps, typically excluding the method steps that require manual work such as specific aspects of sample provision and / or actual measurement execution.

[0062] In a further aspect of the present invention, a non-transitory computer-readable medium is disclosed. The non-transitory computer-readable medium, when executed by one or more processors, includes instructions that cause the one or more processors to execute at least one of the method embodiments disclosed above or below in more detail.

[0063] Specifically, the non-transitory computer-readable medium, when executed by one or more processors, causes the one or more processors to, in accordance with the present invention, at least one measurement signal S of at least one detector meas to search for at least one alternating current (AC) signal S AC from. The measurement signal S meas includes the AC signal S AC and at least one direct current (DC) signal S DC , and the AC signal S AC has at least one predefined frequency f0. In particular, the non-transitory computer-readable medium includes instructions that cause the detector to monitor the measurement signal S meas over time. In particular, the non-transitory computer-readable medium includes instructions that cause the evaluation unit to determine the DC signal S DC , and determining includes evaluating the measurement signal S meas using at least one of the frequency f0 and at least one harmonic of the frequency f0. In particular, the non-transitory computer-readable medium includes instructions that cause the evaluation unit to subtract the DC signal S meas from the measurement signal S DC to determine the AC signal S AC .

[0064] The non-transitory computer-readable medium, when executed by one or more processors, may include instructions that cause the one or more processors to execute a method for determining at least one information item regarding at least one measurement object according to the present invention. In particular, the non-transitory computer-readable medium causes the detector to have at least one measurement signal S measincludes instructions for causing determination. In particular, the non-transitory computer-readable medium causes, using the method according to the present invention, an alternating current signal S AC includes instructions for causing determination. In particular, the non-transitory computer-readable medium causes an evaluation unit to determine an item of information regarding a measurement object by evaluating an alternating current signal S AC includes instructions for causing determination. In particular, the non-transitory computer-readable medium causes an evaluation unit to determine an item of information regarding a measurement object by evaluating an alternating current signal S

[0065] In a further aspect of the present invention, a photodetector for measuring optical radiation is disclosed. The photodetector is configured to execute a method for extracting at least one alternating current (AC) signal S meas from at least one measurement signal S AC according to any one of the embodiments disclosed above or below, and / or to execute a method for determining at least one item of information regarding the measurement object with reference to the method for determining at least one item of information regarding the measurement object, as further described in detail below, which is configured to execute a method for determining at least one item of information regarding the measurement object. The photodetector includes at least one light-receiving region.

[0066] Specifically, the photodetector is configured to execute a method for extracting at least one alternating current (AC) signal S meas from at least one measurement signal S AC according to the present invention. In particular, the photodetector is configured to monitor the measurement signal S meas over time. In particular, the photodetector includes an evaluation unit configured to determine a DC signal S DC or connectable to at least one evaluation unit, and the determination includes evaluating the measurement signal S meas using at least one of a frequency f0 and at least one harmonic of the frequency f0. The evaluation unit may be configured to determine an AC signal S meas from the measurement signal S DC by subtracting the DC signal S AC

[0067] ​Specifically, the photodetector is configured to execute a method for determining at least one information item regarding at least one measurement object according to the present invention. In particular, the photodetector is configured to determine at least one measurement signal S meas and is configured to determine the alternating current signal S AC using the method according to the present invention. In particular, the photodetector may be provided with an evaluation unit configured to determine an information item regarding the measurement object by evaluating the alternating current signal S AC or may be connectable to at least one evaluation unit.

[0068] The photodetector may be configured to detect light radiation having a wavelength in the range of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, and more specifically 1400 nm to 2000 nm. The photosensitive region may include at least one photoconductive material. The photoconductive material may be selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, and HgCdTe. Also, other options such as photodiodes and thermopiles may be realizable. The photodetector may include at least one evaluation unit and / or at least one interface for transmitting data from and / or to and / or within the evaluation unit. The evaluation unit may be at least partially cloud-based. For further definitions and embodiments regarding the photodetector, please refer to the above description.

[0069] In a further aspect of the present invention, a spectrometer for spectroscopically analyzing light radiation provided by at least one measurement object is disclosed. The spectrometer comprises the following configuration: - at least one radiation source configured to at least partially emit light radiation towards the measurement object; and - at least one photodetector according to any one of the embodiments described above with reference to the photodetector or disclosed in more detail below.

[0070] The term "spectrum", including its grammatical variations as used herein, is a broad term and should be given its ordinary and customary meaning to those of ordinary skill in the art, and should not be limited to a special or customized meaning. Specifically, although not limited thereto, this term may represent a partition of optical radiation, and a spectrum is composed of an optical signal defined by a signal wavelength and a corresponding signal intensity. In particular, a spectrum may include spectral information related to at least one object to be measured, for example, the type and composition of at least one material forming at least one object to be measured, which can be determined by recording at least one spectrum related to at least one object to be measured. The term "spectrometer" as used herein is a broad term and is given its ordinary and customary meaning to those of ordinary skill in the art, and is not limited to a special or customized meaning. Specifically, this term may represent, without limitation, an apparatus configured to determine spectral information by recording at least one measured value of at least one signal intensity related to at least one corresponding signal wavelength of optical radiation and evaluating at least one measurement signal related to the signal intensity.

[0071] The spectrometer may further include at least one evaluation unit. The evaluation unit may be further configured to generate at least one item of spectral information regarding the object to be measured. The evaluation unit may further be configured to control a radiation source such as the modulation frequency of the radiation source. The spectrometer may further include at least one optical filter element. The optical filter element may be configured to filter light radiation, or more specifically, a selected wavelength of the light radiation. At least one filter element may specifically be arranged in the beam path in front of at least one light-receiving region of the photodetector. The spectrometer may include a plurality of light-receiving regions and a plurality of optical filter elements, where at least one optical filter element may be arranged in the beam path in front of at least one light-receiving region, and the plurality of optical filter elements may be configured to at least partially filter different wavelengths.

[0072] For further definitions and embodiments regarding the spectrometer, refer to the descriptions of the above methods and apparatuses. In a further aspect of the present invention, the use of a spectrometer according to any one of the embodiments disclosed above or below in more detail with reference to the spectrometer is disclosed for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; thermal exploration applications; flame detection applications; fire detection applications; smoke detection applications; temperature detection applications; spectroscopy applications; exhaust gas monitoring applications; combustion process monitoring applications; pollution monitoring applications; industrial process monitoring applications; chemical process monitoring applications; food processing process monitoring applications; water quality monitoring applications; air quality monitoring applications; quality control applications; temperature control applications; motion control applications; exhaust control applications; gas detection applications; gas analysis applications; motion detection applications; chemical detection applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications such as animal feed applications; cosmetic applications such as cosmetic applications related to hair.

[0073] Further disclosed and proposed herein is a computer program comprising computer-executable instructions for performing the method according to the present invention in one or more of the embodiments included herein when the program is executed on a computer or a computer network. Specifically, the computer program may be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0074] As used herein, the terms "computer-readable data carrier" and "computer-readable storage medium" may specifically represent non-transitory data storage means such as a hardware storage medium on which computer-executable instructions are stored. A computer-readable data carrier or storage medium may specifically be, or may include, a storage medium such as random access memory (RAM) and / or read-only memory (ROM).

[0075] Accordingly, specifically, one, more than one, or all of the method steps as shown above may be executed using a computer or a computer network, preferably using a computer program.

[0076] Further disclosed and proposed herein is a computer program product having program code means for performing the method according to the invention in one or more method embodiments included herein when the program is executed on a computer or a computer network. Specifically, the program code means may be stored on a computer-readable data carrier and / or on a computer-readable storage medium.

[0077] Further disclosed and proposed herein is a data carrier having a data structure stored thereon, which data carrier may execute a method according to one or more method embodiments disclosed herein after being loaded into a computer or a computer network, such as the working memory or main memory of a computer or a computer network.

[0078] Further disclosed and proposed herein is a computer program product having program code means stored on a machine-readable carrier for executing, when the program is run on a computer or computer network, a method according to one or more of the method embodiments disclosed herein. As used herein, a computer program product represents a program as a tradable product. The product may generally exist in any form, such as in paper form or on a computer-readable data carrier and / or on a computer-readable storage medium. Specifically, the computer program product may be distributed via a data network.

[0079] Finally, disclosed and proposed herein is a modulated data signal comprising instructions readable by a computer system or computer network for executing a method according to one or more of the method embodiments disclosed herein.

[0080] Referring to the computer implementation of the present invention, one or more, or even all, of the method steps of a method according to one or more of the method embodiments disclosed herein may be performed using a computer or computer network. Thus, generally, any of the method steps, including those involving the provision and / or manipulation of data, may be performed using a computer or computer network. Generally, these method steps may include any of the method steps, typically excluding those method steps that require manual work, such as the provision of samples and / or the performance of actual measurements in a particular manner.

[0081] Specifically, further disclosed herein are the following: - A computer or computer network comprising at least one processor, the processor being adapted to perform a method according to one of the method embodiments described herein. - A computer-loadable data structure adapted to execute a method according to one of the embodiments described herein while the data structure is being executed on a computer, - A computer program adapted to execute a method according to one of the embodiments described herein while the program is being executed on a computer, - A computer program including program means for executing a method according to one of the method embodiments described herein while the computer program is being executed on a computer or on a computer network, - A computer program comprising program means according to the above-described embodiment, the program means being stored on a computer-readable storage medium, - A storage medium having a data structure stored thereon, the data structure being adapted to execute a method according to one of the method embodiments described herein after being loaded into the main and / or working storage device of a computer or a computer network, and - A computer program product having program code means, the program code means being capable of being stored on or being stored on a storage medium for executing a method according to one of the method embodiments described herein when executed on a computer or on a computer network.

[0082] The methods and apparatuses disclosed herein have significant advantages over the prior art. Specifically, the methods and apparatuses disclosed herein can accurately and reliably compensate for detector drift, particularly temperature drift of a photodetector, in a simple and safe manner. They can rely purely on data analysis and thus avoid using additional components such as temperature sensors or other additional detectors (typically reflected in cost, complexity, and sensitivity to errors) to compensate for drift.

[0083] As used herein, the terms "have", "comprise", "include", or any grammatical variations thereof are used in a non-exclusive sense. Thus, these terms may represent both a situation where there are no additional features in the entity described in this context other than the features introduced by these terms, and a situation where there are one or more additional features. As an example, the expressions "A has B", "A comprises B", and "A includes B" may refer to both a situation where there are no other elements in A besides B (i.e., a situation where A consists only of B), and a situation where there are one or more additional elements such as element C, elements C and D, or still other elements in entity A besides B.

[0084] Furthermore, it should be noted that the terms "at least one", "one or more", or similar expressions indicating that a feature or element may be present one or more times are typically used only once when introducing each respective feature or element. In most cases, when referring to each respective feature or element, the expressions "at least one" or "one or more" are not repeated, regardless of the fact that each respective feature or element may be present one or more times.

[0085] Furthermore, as used herein, the terms "preferably", "more preferably", "in particular", "more particularly", "specifically", "more specifically" or similar terms are used in combination with any feature without limiting the alternatives. Thus, the features introduced by these terms are optional features and are not intended to limit the claims in any way. The present invention may be practiced using alternative features, as will be recognized by those skilled in the art. Similarly, features introduced by "in an embodiment of the present invention" or similar expressions are features introduced without any limitation regarding alternative embodiments of the present invention, without any limitation regarding the scope of the present invention, and without any limitation regarding the possibility of combining such introduced features with any other optional or non-optional features of the present invention, and are intended to be any features.

[0086] In summary, the following embodiments are envisioned without further excluding possible embodiments: Embodiment 1: at least one measurement signal S of at least one detector meas from which at least one alternating current (AC) signal S AC is extracted, the method comprising: measuring signal S meas which is the AC signal S AC and at least one direct current (DC) signal S DC wherein the AC signal S AC has at least one predefined frequency f0, the method comprising the following steps: a) monitoring the measurement signal S over time using a detector; (meas)を b) determining the DC signal S using at least one evaluation unit, the determining step comprising evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0; DC meas c) subtracting the DC signal S from the measurement signal S using an evaluation unit to obtain the AC signal S meas DC ACThe step of determining.

[0087] Embodiment 2: The detector includes at least one photodetector including at least one photosensitive region, and step a) includes measuring a measurement signal S using the photosensitive region of the photodetector. meas by measuring, and the measurement signal S meas is the method according to Embodiment 1, which depends on the illumination of the photosensitive region.

[0088] Embodiment 3: The method according to Embodiment 2, wherein the photodetector is configured to detect light radiation having a wavelength of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, more specifically 1400 nm to 2000 nm.

[0089] Embodiment 4: The method according to Embodiment 2 or 3, wherein the photosensitive region includes at least one photoconductive material.

[0090] Embodiment 5: The method according to any one of Embodiments 1 to 3, wherein the photoconductive material is selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, and HgCdTe.

[0091] Embodiment 6: The method includes correcting at least one environmental change that affects the measurement signal S meas The environmental change specifically includes at least one of a temperature change, a change in background light, mechanical stress, a humidity change, and deterioration of at least a part of the detector. The method according to any one of Embodiments 1 to 5.

[0092] Embodiment 7: In step b), the DC signal S DC is determined by further using the phase φ of the measurement signal S meas and the measurement signal S measThe evaluation of the measurement signal S is performed by using at least one of the phase φ, the frequency f0, and at least one of the harmonics of the frequency f0. meas including determining local minima of the measurement signal S DC The method according to any one of Embodiments 1 to 6, wherein the DC signal S is determined by using the local minima.

[0093] Embodiment 8: The evaluation of the measurement signal S meas includes fitting the DC signal S to the local minima of the measurement signal S meas The DC signal S DC is a time-dependent function S(t) including at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter. The method according to the previous embodiment. DC (t) DC (t) is the method according to the previous embodiment.

[0094] Embodiment 9: In step b), the DC signal S DC is determined by converting the measurement signal S meas into the frequency domain. The method according to any one of Embodiments 1 to 8.

[0095] Embodiment 10: The measurement signal S meas is converted into the frequency domain using the Fourier transform. The method according to Embodiment 9.

[0096] Embodiment 11: The evaluation of the measurement signal S meas includes filtering the converted measurement signal S with respect to at least one of the frequency f0 and at least one of the harmonics of the frequency f0. The method according to Embodiment 9 or 10. meas The method according to Embodiment 9 or 10, wherein the evaluation of the measurement signal S includes filtering the converted measurement signal S with respect to at least one of the frequency f0 and at least one of the harmonics of the frequency f0.

[0097] Embodiment 12: The evaluation of the measurement signal S meas is the DC signal SDC The method according to embodiment 11, including using the filtered conversion measurement signal S meas to determine.

[0098] Embodiment 13: The evaluation of the measurement signal S meas includes fitting the DC signal S to the filtered and converted measurement signal S meas where the DC signal S DC is a time-dependent function S(t) including at least one of a polynomial function with at least one fitting parameter, an exponential function with at least one fitting parameter, a square root function with at least one fitting parameter, and a logarithmic function with at least one fitting parameter. DC This is the method according to embodiment 12. DC (t).

[0099] Embodiment 14: The DC signal S DC carries power that is not zero at the frequency f0 and at least one harmonic of the frequency f0. This is the method according to embodiment 13.

[0100] Embodiment 15: The detector comprises an evaluation unit and / or at least one interface for transmitting data from and / or into and / or within the evaluation unit. This is the method according to any one of embodiments 1 to 14.

[0101] Embodiment 16: The evaluation unit is at least partially cloud-based. This is the method according to any one of embodiments 1 to 15.

[0102] Embodiment 17: The method according to any one of embodiments 1 to 16, which is at least partially computer-implemented.

[0103] Embodiment 18: A method for determining at least one information item regarding at least one object to be measured using at least one detector, the method comprising the following steps: i) Using the detector to determine at least one measurement signal S meas ; ii) Determining the AC signal S according to any one of Embodiments 1 to 17, and AC ; iii) Determining an information item regarding the measurement object by evaluating the evaluation unit AC signal S AC .

[0104] Embodiment 19: The detector comprises at least one photodetector comprising at least one photosensitive region, and step i) comprises measuring the measurement signal S using the photosensitive region of the photodetector, the measurement signal S meas ; where the measurement signal S meas depends on the illumination of the photosensitive region, the method according to Embodiment 18.

[0105] Embodiment 20: The method according to Embodiment 18 or 19 referring to a method for determining at least one information item, the method being at least partially computer-implemented.

[0106] Embodiment 21: A non-transitory computer-readable medium that, when executed by one or more processors, causes the one or more processors to execute at least one of the methods according to any one of the embodiments of the method.

[0107] Embodiment 22: A photodetector for measuring light radiation, the photodetector taking at least one alternating current (AC) signal S from at least one measurement signal S meas according to any one of the preceding embodiments referring to a method for extracting at least one alternating current (AC) signal S from at least one measurement signal S AC ; meas from at least one alternating current (AC) signal SAC configured to perform a method for extracting [[ID=]], and / or for determining at least one item of information on a measurement object, according to any one of the preceding embodiments referring to a method for determining at least one item of information on a measurement object, where the photodetector comprises at least one light-receiving region, a photodetector for measuring light radiation.

[0108] Embodiment 23: The photodetector according to embodiment 22, configured to detect light radiation having a wavelength in the range of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, more specifically 1400 nm to 2000 nm.

[0109] Embodiment 24: The photodetector according to any one of the preceding embodiments of the photodetector, wherein the light-receiving region comprises at least one photoconductive material.

[0110] Embodiment 25: The photodetector according to embodiment 24, wherein the photoconductive material is selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, and HgCdTe.

[0111] Embodiment 26: A photodetector, comprising at least one evaluation unit, and / or at least one interface for transmitting data from and / or into and / or within the evaluation unit, the photodetector according to any one of the preceding embodiments referring to a photodetector.

[0112] Embodiment 27: The photodetector according to any one of the preceding embodiments of the photodetector, wherein the evaluation unit is at least partially cloud-based.

[0113] Embodiment 28: A spectrometer for spectroscopically analyzing light radiation supplied from at least one measurement object, hereinafter - at least one radiation source configured to emit light radiation at least partially towards the object to be measured - at least one photodetector according to any one of the embodiments mentioned with reference to the photodetector, A spectrometer comprising:

[0114] Embodiment 29: A spectrometer according to embodiment 28, further comprising at least one evaluation unit, the evaluation unit being further configured to generate at least one item of spectral information regarding the measurement object.

[0115] Embodiment 30: The spectrometer according to embodiment 29, wherein the evaluation unit is further configured to control the radiation source.

[0116] Embodiment 31: The spectrometer according to any one of the embodiments mentioned with reference to the spectrometer, wherein the radiation source is a modulated radiation source.

[0117] Embodiment 32: The spectrometer according to embodiment 31, wherein the radiation source is modulated at a frequency f0.

[0118] Embodiment 33: The spectrometer according to any one of the embodiments mentioned with reference to the spectrometer, wherein the radiation source comprises at least one of a semiconductor-based radiation source, specifically at least one of a light-emitting diode and a laser, and a thermal radiator, specifically at least one of an incandescent lamp.

[0119] Embodiment 34: The spectrometer according to any one of the embodiments mentioned with reference to the spectrometer, further comprising at least one optical filter element.

[0120] Embodiment 35: Use of the spectrometer according to any one of the foregoing embodiments, referring to a spectrometer, for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; thermal exploration applications; flame detection applications; fire detection applications; smoke detection applications; temperature detection applications; spectroscopic applications; exhaust gas monitoring applications; combustion process monitoring applications; pollution monitoring applications; industrial process monitoring applications; chemical process monitoring applications; food processing process monitoring applications; water quality monitoring applications; air quality monitoring applications; quality control applications; temperature control applications; motion control applications; exhaust control applications; gas detection applications; gas analysis applications; motion detection applications; chemical detection applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications such as animal feed applications; cosmetic applications such as cosmetic applications related to hair.

Brief Description of the Drawings

[0121] Further optional features and embodiments are disclosed in more detail in the description of the subsequent embodiments, preferably in conjunction with the dependent claims. There, each optional feature may be implemented not only in any feasible combination, but also in an isolated manner, as will be understood by those skilled in the art. The scope of the present invention is not limited by the preferred embodiments. The embodiments are schematically depicted in the figures. In those figures, the same reference numerals represent the same or functionally equivalent elements.

Figure 1

Figure 2

Figure 3

Figures 4 - 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0122] FIG. 1 schematically shows an exemplary embodiment of a spectrometer 110 according to the present invention. The spectrometer 110 is configured to spectroscopically analyze the optical radiation 112 provided by at least one measurement object 114. The optical radiation 112 may specifically be within at least one of the visible, ultraviolet, or infrared spectral ranges. Preferably, the optical radiation 112 used for typical purposes of the present invention is IR radiation, more preferably NIR radiation, particularly having a wavelength in the range of 760 nm to 3 μm, preferably 1 μm to 3 μm. The optical radiation 112 may be provided by the measurement object 114. This optical radiation may include at least one of reflection, transmission, and radiation. The measurement object 114 may be any object selected from living and non-living bodies. The measurement object 114 may specifically include at least one substance to be investigated. The measurement object 114 generally may represent the object to be measured, for example, the object whose spectrum is recorded, and the measurement object 114 may in principle have any property, for example, any optical property or any shape. The measurement object 114 may include at least one solid sample. However, other measurement objects such as fluids are also feasible.

[0123] The spectrometer 110 may be a device configured to determine spectral information by recording at least one measured value of at least one signal intensity related to at least one corresponding signal wavelength of the optical radiation 112 and evaluating at least one measurement signal related to the signal intensity. The spectrometer 110 comprises at least one radiation source 116 configured to radiate the optical radiation 112 at least partially towards the measurement object 114. The radiation source 116 may be a device configured to emit the optical radiation 112. The radiation source 116 may be configured to emit the optical radiation 112 towards the measurement object 114 in the form of an optical beam 118, for example. The radiation source 116 may be configured to radiate the optical radiation 112 isotropically, for example uniformly in all spatial directions, and only a part of the radiated optical radiation 112 may impinge on the measurement object 114. The radiation source 112 may comprise at least one of a semiconductor-based radiation source or a thermal radiator. The at least one semiconductor-based radiation source may be selected from at least one of a light-emitting diode (LED) or a laser, in particular a laser diode. The LED may comprise at least one fluorescent material and / or phosphorescent material. The thermal radiator may comprise at least one of an incandescent lamp, a black body emitter, and a microelectromechanical system (MEMS) emitter.

[0124] The optical emission 112 may be modulated, for example, by using a modulated radiation source 120. In other words, the radiation source 116 may be a modulated radiation source 120. The radiation source 112 may be modulated at a frequency f0. Accordingly, the frequency f0 and the harmonics of the frequency f0 may be present in the optical emission 112. Modulation may be a process of changing at least one characteristic of the optical emission, specifically, one or both of the intensity or the phase of the optical emission, specifically, changing periodically. The modulation may be a full modulation from a maximum value to zero, or a partial modulation from a maximum value to an intermediate value greater than zero. Modulation may include the use of a modulation element. The modulation element may be configured to mechanically modulate the optical emission, for example, by using a rotating chopper wheel, and / or to electronically modulate the optical emission, for example, by using the electro-optic effect and / or the acousto-optic effect by using a Pockels cell and / or a Kerr cell.

[0125] The spectrometer 110 comprises at least one photodetector 122 according to any one of the embodiments disclosed in more detail below with reference to the above or to the photodetector 122. Exemplary embodiments of the photodetector 122 are also schematically shown separately in FIG. 2. Accordingly, the photodetector 122 can be described with reference to FIGS. 1 and 2 together. Generally, the photodetector 122 is a specific type of detector 124. The detector 124 may be a measuring device such as a sensor configured to generate at least one measurement signal. The detector 124 may be configured to sense or detect or monitor at least one physical quantity. The detector 124 may be an electronic device or an optoelectronic device. The detector 124 may be configured to generate at least one electronic signal such as a current or a voltage or a resistance. The detector 124 may be at least one photodetector 122 or may include at least one photodetector 122. As already shown, in the context of the present invention, multiple types of detectors 124 are basically considered. However, for the sake of explanation, the photodetector 122 is focused on below.

[0126] The photodetector 122 may be a photodetector or photosensor configured to detect light radiation 112, such as for detecting illumination and / or light spots generated by at least one light beam 118. The photodetector 122 receives at least one measurement signal S meas from, as described above, or at least one measurement signal S meas from, to extract at least one alternating current (AC) signal S AC referring to the method for extracting, and is configured to perform the method for extracting at least one alternating current (AC) signal S AC in accordance with the embodiments described in more detail below. And / or referring to the method for performing the method for determining at least one item of information of the measurement object 114 as described above, or in accordance with any one of the embodiments disclosed below, it is configured to perform the method for determining at least one item of information of the measurement object 114. The photodetector 122 includes at least one light-receiving region 126. The photosensitive region 126 may be a unit of the photodetector 122 configured to be illuminated, that is, to receive the light radiation 112, and to generate at least one signal such as an electronic signal in response to the light radiation 112. The photosensitive region 126 may be disposed on the surface of the photodetector 122. The photosensitive region 126 may specifically be a single, closed, uniform photosensitive region 126. The light-receiving region 126 may be referred to as a pixel P. The photodetector 126 may be configured to detect light radiation 112 having a wavelength of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, more specifically 1400 nm to 2000 nm. The photosensitive region 126 may include at least one photoconductive material. The photoconductive material may be selected from at least one of PbS, PbSe, Ge, InGaAs, InSb, and HgCdTe. A photodiode or a thermopile may also be realizable.

[0127] The spectrometer 110 may include at least one evaluation unit 128. The evaluation unit 128 may be configured to generate at least one item of spectral information regarding the measurement object 114. The evaluation unit 128 may be configured to control the radiation source 116. Specifically, the evaluation unit 128 may be configured to control the modulation frequency of the modulated radiation source 120. The photodetector 122 may include at least one interface 130 for transmitting data from and / or to and / or within the evaluation unit 128. The detector 124 may include at least one interface 130 for transmitting data to and / or from and / or within the evaluation unit 128. The evaluation unit 128 may be at least partially cloud-based. In other words, at least one evaluation unit 128 may be at least partially distributed over at least one cloud 132 used for at least one of cloud computing or cloud storage. The cloud 132 may specifically include at least one external device 134, such as a computer or a computer network. The cloud 132 may represent an outsourcing of at least a part of the evaluation unit 128 or the evaluation unit 128 to at least partially interconnected external devices 134, specifically a computer or a computer network having a greater computing power and / or data storage capacity. The external devices 134 may be arbitrarily spatially distributed. The external devices 134 may change over time, especially in response to requests. The external devices 134 may be interconnected by using the Internet and / or at least one intranet.

[0128] The evaluation unit 128 may be a device configured to analyze or interpret data, specifically, a device configured to determine at least one item of qualitative or quantitative information. The information may specifically be at least one signal such as a signal generated by a detector, specifically the measurement signal S meas and may be obtained by evaluating it. The evaluation unit 128 may be or include at least one of an integrated circuit, specifically an application-specific integrated circuit (ASIC), or a data processing device, specifically a digital signal processor (DSP), a field programmable gate array (FPGA), a microcontroller, a microcomputer, a computer, or an electronic communication unit, specifically a smartphone or a tablet. Further components, specifically, at least one preprocessing device or data collection device may be realizable. The evaluation unit 128 may include an interface 130 or a part thereof. The interface 130 may specifically be a wireless interface and / or a wired interface. The evaluation unit 128 may be designed to control or drive further devices such as the detector 124 or the optical detector 122, either completely or partially. The evaluation unit 128 may be designed to execute at least one measurement cycle in which a plurality of measurement signals can be picked up. The evaluation unit 128 may be designed to control the detector 124 or the optical detector 122 in order to execute at least one measurement and / or to generate at least one measurement signal.

[0129] The information determined by the evaluation unit 128 may in particular be provided to at least one further device or the user, preferably in at least one of an electronic, visual, acoustic or tactile manner. The information may be stored in at least one data storage device, in particular in an internal data storage device included in the light detector 122 or the detector 124, in particular in an internal data storage device included in at least one evaluation unit 128, or in a separate storage device to which the information can be transmitted via at least one interface 130. The separate storage device may be included in at least one electronic communication unit. The storage device may in particular be configured to store at least one electronic table, such as at least one look-up table.

[0130] The evaluation unit 128 may be configured to execute at least one computer program, in particular at least one computer program that performs or supports the step of generating at information. As an example, one or more algorithms may be implemented that perform a conversion to a part of the information by using at least one measurement signal as at least one input variable. For this purpose, the evaluation unit 128 may include at least one of at least one data processing device, in particular an electronic data processing device or an optical data processing device that may be designed to generate information by evaluating at least one measurement signal. The evaluation unit 128 may be designed to use at least one measurement signal as at least one input variable and generate information by processing at least one input variable. The processing can be performed in a continuous, parallel or combined manner. The evaluation unit 128 may use any process to generate information, in particular by calculation and / or by using at least one stored and / or known relationship.

[0131] Interface 130 may be an item or element that forms a boundary and is configured to transfer information. Interface 130 may specifically be a communication interface. In particular, Interface 130 may be configured to transfer information, such as transmitting or outputting information from a computing device, e.g., a computer, onto another device, for example. Additionally, or alternatively, Interface 130 may be configured to transfer information, such as receiving information, to a computing device, e.g., a computer. Interface 130 may specifically provide means for transferring or exchanging information. In particular, Interface 130 may provide a data transfer connection such as Bluetooth, NFC, inductive coupling, etc. As an example, Interface 130 may be, or may include, at least one port including one or more of a network or Internet port, a USB port, and a disk drive. Interface 130 may optionally include at least one web interface.

[0132] The spectrometer 110 may include at least one optical filter element 136. The optical filter element 136 may be configured to filter the light emission 112, or more specifically, a selected wavelength of the light emission 112. The at least one filter element 136 may be specifically arranged in the beam path in front of at least one light-receiving region 126 of the photodetector 122. The spectrometer may include a plurality of light-receiving regions 126 and a plurality of optical filter elements 136. The at least one optical filter element 136 may be arranged in the beam path in front of at least one light-receiving region 126, and the plurality of optical filter elements 136 may be configured to at least partially filter different wavelengths. The photodetector 122 may include at least one readout circuit 138. The readout circuit 138 may be configured to read at least one signal generated by the photosensitive region 126. The readout circuit 138 may be connected to further components of the photodetector 122, such as at least one of the evaluation unit 128 or the interface 130, for example, by using at least one wire 140 or at least one trace 142. The spectrometer 110 may include at least one housing 144 that surrounds at least a part of the spectrometer 110, such as at least one of the radiation source 116 and the photodetector 122. At least one external device 134 of the cloud 132 may be arranged outside the housing 144. The housing 144 may include at least one window 146. The window 146 may be at least partially transparent to the light emission 112.

[0133] The exemplary beam path of the optical radiation 112 will be described below with reference to FIG. 1. At least one radiation emitting element 116 may emit the optical radiation 112 as incident optical radiation 148 through the window 146 towards the object under measurement 114. The object under measurement 114 may reflect at least a portion, specifically diffusely, of the incident optical radiation 148 towards at least one light receiving region 126 of the photodetector 122 in the form of reflected optical radiation 150. The object under measurement 114 may absorb at least a portion of the incident optical radiation 148, which may indicate at least one physical property or chemical composition of the object under measurement 114. The reflected optical radiation 150 may pass through the window 146 and the optical filter element 136 before reaching the light sensitive region 126. The light sensitive region 126 may generate a corresponding measurement signal S meas and this may be read out, for example, using the readout circuit 138.

[0134] As already shown, FIG. 2 schematically shows an exemplary embodiment of the photodetector 122 according to the invention. For the description of the photodetector 122, the description of the spectrometer 110 above may be largely referred to. As described above, the photodetector 122 takes at least one measurement signal S meas and extracts at least one alternating current (AC) signal S AC from it according to any one of the embodiments disclosed in more detail below with reference to the method described above or, alternatively, extracts at least one alternating current (AC) signal S meas from at least one measurement signal S AC and is configured to determine at least one item of information about the object under measurement 114 according to any one of the embodiments disclosed in more detail above or below with reference to the method for determining at least one item of information about the object under measurement 114 according to any one of the embodiments disclosed in more detail below with reference to the method described above or, alternatively, extracting at least one alternating current (AC) signal S

[0135] FIG. 3 shows at least one measurement signal S meas from the detector 124 and at least one alternating current (AC) signal S ACA flowchart of an exemplary embodiment of a method for extracting is shown. Measurement signal S meas is an alternating current signal S AC and at least one direct current (DC) signal S DC including. Alternating current signal S AC has at least one predetermined frequency f0. The method includes the following steps; a) Monitoring the measurement signal S over time using a detector 124 (shown by reference numeral 152); meas ; b) Determining the DC signal S using at least one evaluation unit 128 (shown by reference numeral 154), determining including evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0; and DC ; meas ; and c) Using the evaluation unit 128 (shown by reference numeral 156), determining the AC signal S by subtracting the DC signal S from the measurement signal S meas ; DC ; AC .

[0136] The method steps may be performed in the order shown. However, note that different orders are also possible. The method may include additional method steps not listed herein. Further, one or more method steps may be performed once or repeatedly. Further, two or more method steps may be performed simultaneously or in a timely manner and repeatedly. The method steps may be at least partially computer-implemented. As shown, the detector 124 may include a photodetector 122 including at least one light receiving region 126. Step a) may include measuring the measurement signal S using the light receiving region 126 of the photodetector 122. The measurement signal S meas ; meas ;

[0137] The method is the measurement signal S measIt may include correcting at least one environmental change that affects. The environmental change may specifically include at least one of a temperature change, a change in background light, mechanical stress, and a humidity change, and may also include deterioration of at least a part of the detector. The correction may be a correction or readjustment of an entity (real object). The correction is the measurement signal S meas It may also include removing or eliminating perturbations that affect, specifically external perturbations. Specifically, the correction may include removing the contribution to the measurement signal S meas caused by environmental changes such as temperature changes. Such a contribution may represent the DC signal S DC As described above, the detector 124 may be a photodetector 122 of the spectroscope 110 configured to measure the light emission 112. Other external influences other than the measured light emission 112 are not of interest in the measurement and may only interfere with the measurement signal S meas The spectroscope 110 may further include a modulated radiation source 120. Therefore, the signal of interest may be the AC signal S AC External influences, such as temperature, may typically change on a larger time scale compared to the AC signal S AC and may be unidirectional at least during the period to be monitored. External influences usually contribute to the measurement signal S meas in the form of the DC signal S DC By identifying the DC signal S meas in the measurement signal S DC and removing the DC signal S meas from the measurement signal S DC it may be possible to obtain the AC signal S AC which is of particular interest in the measurement.

[0138] The search may be at least one of determining, deriving, and filtering a signal or at least a part of a signal. As described above, the measurement signal S meas includes the AC signal S AC and the DC signal S DC The search is for the AC signal S meas in the measurement signal S ACmay include identifying and / or separating. The search may include removing and / or eliminating the DC signal S meas from the measurement signal S DC . The search may further include providing the AC signal S AC to a further entity, for example, to determine an item of information regarding the measurement object 114 for further processing and / or evaluation.

[0139] The signal may be an observable change in at least one physical quantity. The signal may be a code or function that transmits information regarding at least one physical quantity, or may include these. Specifically, the signal may be at least one of an electronic signal, an optical signal, or an optoelectronic signal, or may include these. The signal may in particular be a variable signal over time. The signal may be an analog signal. The signal may be at least one of a variable voltage, a variable current, a variable charge, a variable resistance, or generally a variable electromagnetic wave, or may include these. The variable electromagnetic wave may include at least one of a variable amplitude, a variable frequency, or a variable phase. The signal may be a digital signal. The signal may include at least one count. Specifically, the signal may be related to at least one measurement. Specifically, the signal may be generated by the detector 124.

[0140] The measurement signal may be a signal related to at least one measurement, more specifically, a signal regarding the measurement object 114. The measurement signal may be a signal generated by the detector 124 upon detection of at least one physical quantity, such as a physical quantity of the measurement object 114. The measurement signal may include at least one electronic signal such as a current, a voltage, or a resistance. The measurement signal may include an analog signal. The measurement signal may include a digital signal such as a count. The measurement signal may be a superposition of two or more signals or sub-signals. The measurement may be subject to multiple influences such as illumination, temperature, humidity, mechanical stress, etc. Each influence may contribute to the measurement signal. The measurement signal may be divided into two or more sub-signals, and the sub-signals may be related to at least partially different influences.

[0141] DC signal S DC may be a signal that continuously increases over time, a signal that continuously decreases over time, or in general a one-directional signal over time or at least an essentially one-directional signal over time. As an example, the DC signal S DC may be a digital signal, and the count may increase continuously with time. The DC signal S DC may include at least one plateau over time. Deviations from a strictly one-directional progression may occur, for example, due to signal noise or external perturbations.

[0142] AC signal S AC may be a signal that, over time, for example, periodically reverses direction and / or changes in magnitude. As an example, the AC signal S AC may be a digital signal, in which the count alternates between increasing and decreasing with time. The AC signal S AC may be a sine wave, a square wave, a pulse width modulation signal, or a combination of the foregoing. The AC signal S AC may be a periodic signal or at least an essentially periodic signal. Deviations from a strictly periodic progression may occur, for example, due to signal noise or external perturbations. As described above, the AC signal S AC has at least one predefined frequency f0. Frequency can generally be defined as the number of occurrences of a repeating event over time. Frequency can be defined as the reciprocal of the period time, such as the period time of a frequency signal. Frequency may be predefined by at least one predefined value, such as at least one predefined value in a measurement setup. The user can set the predefined value or select from a plurality of different predefined values. As described above, the detector 124 may be the optical detector 122 of the spectrometer 110, and the spectrometer 110 may further include a modulated radiation source 120. Accordingly, the AC signal S ACThe frequency may be predefined by setting a specific modulation frequency in the modulation radiation source 120. The harmonic may be a harmonic of a fundamental frequency such as the frequency f0. The harmonic of the frequency f0 may be a positive integer multiple of the frequency f0, such as 2f0, 3f0, 4f0, etc.

[0143] Step a) includes monitoring the measurement signal S over time using the detector 124. Monitoring over time may specifically be at least one of measuring, observing, or recording an entity such as the measurement signal S over time. The monitoring may include recording the progression and / or development of the measurement signal S over time. meas including monitoring the measurement signal S over time. Monitoring over time may specifically be at least one of measuring, observing, or recording an entity such as the measurement signal S over time. meas Monitoring may be at least one of measuring, observing, or recording an entity such as the measurement signal S over time. The monitoring may include recording the progression and / or development of the measurement signal S over time. meas The monitoring may include recording the progression and / or development of the measurement signal S over time.

[0144] Step b) includes determining the DC signal S using the evaluation unit 128, and determining includes evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0. Evaluation may be the processing or analysis or interpretation of an entity such as the measurement signal S. Evaluating may include performing at least one mathematical calculation including the measurement signal S. Evaluating may include converting and / or transforming the measurement signal S. Evaluating may include using at least one relationship, such as a predefined and / or predetermined relationship from a look-up table, or a variable relationship such as a function. Evaluating may include filtering and / or smoothing the measurement signal S. Evaluation includes deriving at least one qualitative or quantitative information item such as the contribution of the measurement signal S to the DC signal S and / or the AC signal S. Different approaches may be possible for such purposes, as outlined in more detail below. DC including determining the DC signal S using the evaluation unit 128, and determining includes evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0. meas Evaluating includes evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0. meas Evaluation may be the processing or analysis or interpretation of an entity such as the measurement signal S. meas Evaluating may include performing at least one mathematical calculation including the measurement signal S. meas Evaluating may include converting and / or transforming the measurement signal S. meas Evaluating may include using at least one relationship, such as a predefined and / or predetermined relationship from a look-up table, or a variable relationship such as a function. meas Evaluating may include filtering and / or smoothing the measurement signal S. DC Evaluation includes deriving at least one qualitative or quantitative information item such as the contribution of the measurement signal S to the DC signal S AC and / or the AC signal S meas from the measurement signal S. Different approaches may be possible for such purposes, as outlined in more detail below.

[0145] Step c) involves determining the alternating current signal S meas by subtracting the direct current signal S DC from the measurement signal S AC . The subtraction may include one or more of removing, removing and subtracting the direct current signal S meas from the measurement signal S DC , and specifically, this is performed over the entire period. The subtraction may include extracting the alternating current signal S meas from the measurement signal S AC . The subtraction may include at least one mathematical calculation. The subtraction may involve specifically subtracting the count of the DC signal S DC , for example the DC signal S DC , from the count of the measurement signal S meas , for example the measurement signal S meas , for each point in time over the entire period individually. Thus, the AC signal S AC may be determined for example for each point in time, thus for each selected time unit, for example for each millisecond, or for each frame number of the photodetector 122.

[0146] Figures 4 to 6B show the experimental results of measurements in an exemplary embodiment of the spectrometer 110 according to the present invention. Figure 4 shows a first approach for determining the DC signal S DC in step b), where the signal S is counted over the frame F. The raw measurement signal is indicated by the reference number 158. The masked measurement signal is indicated by the reference number 160. In Figure 4, the masked measurement signal 160 masks the time at which the AC signal S AC reaches a local minimum, based on at least one of the frequency f0, at least one harmonic of the frequency f0, and the phase φ. The DC signal S DC may be determined using, in addition to the frequency f0, the measurement signal S meas , specifically the phase φ of the AC signal S AC . The measurement signal S measThe evaluation of meas may include determining local minima of the measurement signal S by using at least one of the frequency f0 and the phase φ, and at least one of the frequency f0 and at least one harmonic of the frequency f0. The DC signal S DC may be determined using the local minima. The phase may be an index of position within a periodic signal. Typically, the phase is represented as an angle. The phase may depend on time, the frequency of the signal, and / or a phase offset. Specifically, the phase may indicate when a periodic portion of the entire signal, such as a periodic signal or a periodic sub-signal, reaches an extreme value such as a minimum or maximum value. As an example, the measurement signal S meas may exhibit at least an essentially periodic sub-signal, for example due to using a modulated radiation source as already outlined. This sub-signal may ultimately correspond to the AC signal S AC but at this stage may drift, for example due to environmental changes. The frequency f0 and the phase φ of this sub-signal may be used to identify minima in the sub-signal, which may simultaneously be at least local minima in the overall measurement signal S meas . The local minimum may be the minimum signal value within a signal interval, specifically within the period of a periodic signal. The signal may include multiple local minima. The local minima may have at least partially the same level. The local minima may specifically have at least partially different levels due to external perturbations such as environmental changes affecting the detector and / or the measurement signal. The measurement signal S meas may specifically be recorded as a count number over time. As described above, the measurement signal may include the AC signal S AC and the DC signal S DC . The local minimum may be the minimum count within a time interval related to the period of the AC signal S AC .

[0147] The evaluation of the measurement signal S meas may include fitting the DC signal S DC to the local minima of the measurement signal S meas . The DC signal SDC The function S over time includes at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter (DC) It may be (t). Fitting may include regression analysis for estimating the relationship between at least two variables. Fitting may include at least one of linear regression, partial least squares regression, non-linear regression, interpolation, and extrapolation. Fitting may include at least one regression model (for example, a trained model). Fitting may include using at least one fitting function such as at least one of the above functions. The function S DC (t) may be a fitting function fitted to the local minimum of the measurement signal S meas The fitting function may include at least one fitting parameter. The fitting parameter may be a parameter or coefficient of the fitting function. As an example, the fitting function may be a linear function, and the fitting parameters may be the slope and offset of the linear function

[0148] As specifically shown in FIG. 4, a fourth-degree polynomial function may be fitted to the masked measurement signal 160 th The fitted baseline is indicated by reference numeral 162. The fitted baseline 162 may be subtracted from the raw measurement signal 158 to determine the AC signal S AC The corrected measurement signal based on the masked measurement signal in this way is indicated by reference numeral 164. Additionally, or alternatively, as outlined in more detail below, the measurement signal may be corrected using frequency filtering. The measurement signal corrected using frequency filtering in this way is indicated by reference numeral 166. As shown in FIG. 4, both approaches exhibit equivalent performance

[0149] FIGS. 5A and 5B show the DC signal S in step b DCshows a further approach for determining. Measurement signal S meas In addition to or alternatively to the above-described approach using local minima of, in step b), the DC signal S DC may be determined by converting the measurement signal S meas into the frequency domain. The frequency domain may represent the analysis of the signal with respect to at least one frequency of the signal. The signal may typically be recorded over time in the time domain, meaning that the signal values are associated with specific points in time. However, in various applications, it may be useful to analyze the signal with respect to the frequencies that make up the signal in the frequency domain. As an example, one overall signal may include a plurality of sub-signals, each including a specific frequency. The sub-signals may be distinguishable, for example, for further separated processing, by analyzing the frequencies of the overall signal. In the frequency domain, the signal values may be associated with specific frequencies. Signal values, such as the signal values of the overall signal, may be plotted over a frequency interval in the frequency domain.

[0150] Measurement signal S meas may be converted into the frequency domain using a Fourier transform. FIG. 5A shows such a Fourier-transformed signal obtained using a fast Fourier transform (FFT), with the absolute signal count plotted on a logarithmic scale over the corresponding frequency f. The raw measured signal that has been Fourier-transformed is indicated by reference numeral 168. The first harmonics at frequencies f0 and 2f0 can be recognized as peaks at approximately 15 Hz and 30 Hz, respectively. A distortion approximation is applied to the Fourier-transformed raw measurement signal 168 of FIG. 5A, which is indicated by reference numeral 170. Further, the noise floor is indicated by reference numeral 172. The Fourier transform may be an integral transform for decomposing a space- or time-dependent integrable function into a space-frequency- or time-frequency-dependent function. Specifically, the Fourier transform may be configured to decompose a time-dependent signal into a frequency-dependent signal. The Fourier transform may include at least one of Fourier analysis, continuous Fourier transform, discrete Fourier transform, and Fourier-related transforms such as, for example, Laplace transform. In step b), the DC signal S DCSpecifically, it may be determined by setting at least one of the fundamental frequency f0 and at least one harmonic of the fundamental frequency f0 to zero in the frequency domain, for example, by using an inverse Fourier transform. Therefore, step c) may be specifically executed again in the time domain.

[0151] The evaluation of the measurement signal S as executed in step b) meas may include filtering the transformed measurement signal S for at least one of the fundamental frequency f0 and at least one harmonic of the fundamental frequency f0. Filtering may be, for example, selectively extracting at least a part of the signal, such as a specific signal section, in the frequency domain. Filtering may include extracting a specific frequency or a sub-signal having a specific frequency from the entire signal in the frequency domain. Specifically, filtering may include extracting at least one of the fundamental frequency f0 and at least one harmonic of the fundamental frequency f0 from the measurement signal S. meas The remainder of the original measurement signal S meas may remain as a remainder. The fundamental frequency f0 and the harmonics of the fundamental frequency f meas may represent the AC signal S. (0)の The remainder may represent the DC signal S. AC Filtering may include using at least one electronic filter element, specifically, at least one frequency electronic filter element of a coarse electronic band-pass filter element. The electronic filter element may be an analog electronic filter element or a digital electronic filter element. DC The evaluation of the measurement signal S

[0152] The measurement signal S meas may include using the filtered transformed measurement signal S to determine the DC signal S. Specifically, the evaluation of the measurement signal S DC may include using the remainder of the filtering of the transformed measurement signal S to determine the DC signal S. meas The measurement signal S meas The evaluation of the measurement signal S DC may include using the remainder of the filtering of the transformed measurement signal S to determine the DC signal S. meas The measurement signal Smeas The evaluation of DC DC signal S meas may involve fitting to the filtered and transformed measurement signal S meas , specifically, to the remainder of the filtering of the transformed measurement signal S DC . The DC signal S (DC) may be a function of time S DC (t) that includes at least one of a polynomial function with at least one fitting parameter, an exponential function with at least one fitting parameter, a square root function with at least one fitting parameter, and a logarithmic function with at least one fitting parameter. The DC signal S

[0153] Figures 6A and 6B show application examples of a method for extracting at least one alternating current (AC) signal S meas from at least one measurement signal S AC under different conditions. Figure 6A shows the correction of the signal S when S DC << S (AC)の . The raw fast Fourier transform (FFT) measurement signal is denoted by reference numeral 182. The corrected fast Fourier transform (FFT) measurement signal is denoted by reference numeral 184. Figure 6B shows the signal S when S DC ~ S AC or S DC >> S (AC)の . The raw fast Fourier transform (FFT) measurement signal is denoted by reference numeral 186. The corrected fast Fourier transform (FFT) measurement signal is denoted by reference numeral 188. Clear signal recovery is seen under all conditions.

[0154] FIG. 7 shows a flowchart of an exemplary embodiment of a method for determining at least one information item of a measurement object 114 using a detector 124. This method includes the following steps: i) Using the detector 124 (indicated by reference numeral 190), determining at least one measurement signal S meas ; ii) From at least one measurement signal S meas , using a method according to any one of the embodiments disclosed in more detail above or below with reference to a method for searching for at least one AC signal S AC , determining an AC signal S AC , and iii) Using an evaluation unit 128 (indicated by reference numeral 194), determining an information item regarding the measurement object 114 by evaluating the AC signal S AC .

[0155] The method steps may be executed in the order shown. However, it should be noted that different orders are also possible. The method may include additional method steps not listed herein. Further, one or more method steps may be performed once or repeatedly. Further, two or more method steps may be performed simultaneously or in a timely overlapping manner. The method steps may be at least partially computer-implemented. The information item may be knowledge or evidence providing at least one measurement, specifically a qualitative and / or quantitative description related to at least one measurement object 114. The information item may include at least one of the physical characteristics of the measurement object 114 or the chemical composition of at least one measurement object 114. The physical characteristics may specifically include optical characteristics such as at least one absorbance of the measurement object 114 and / or at least one emissivity of the measurement object 114. The chemical composition may specifically represent qualitative and / or quantitative information regarding at least one material included in the measurement object 114.

Description of Reference Numerals

[0156] 110 Spectrometer 112 Optical emission 114 Object to be measured 116 Radiation source 118 Light beam 120 Modulated radiation source 122 Photodetector 124 Detector 126 Sensitive area 128 Evaluation unit 130 Interface 132 Cloud 134 External device 136 Optical filter element 138 Readout circuit 140 Wire 142 Trace 144 Housing 146 Window 148 Incident optical emission 150 Reflected light 152 Method step a) 154 Method step b) 156 Method step c) 158 Raw measurement signal 160 Masked measurement signal 162 Fitted baseline 164 Measurement signal corrected based on the masked measurement signal 166 Measurement signal corrected using frequency filtering 168 Fourier-transformed raw measurement signal 170 Distortion approximation 172 Noise floor 174 Raw measurement signal 176 Filtered measurement signal 178 Fit correction 180 Corrected measurement signal 182 Fast Fourier-transformed (FFT) raw measurement signal 184 Corrected fast Fourier-transformed (FFT) measurement signal 186 Fast Fourier-transformed (FFT) raw measurement signal 188 Corrected Fast Fourier Transform (FFT) measurement signal 190 Step i) 192 Step ii) 194 Step iii)

Claims

1. At least one measurement signal S of at least one detector (124) meas from which at least one alternating current (AC) signal S AC is extracted, the method comprising: the measurement signal S meas being the AC signal S AC and at least one direct current (DC) signal S DC wherein the AC signal S AC has at least one predefined frequency f 0 and the method comprises the following steps: a) Monitoring the measurement signal S over time using the detector (124); meas and b) determining a DC signal S using at least one evaluation unit (128), wherein the determining comprises evaluating a measurement signal S using at least one of at least one harmonic of a frequency f and a frequency f DC 0 and a frequency f 0 meas ​​​ c) Using the evaluation unit (128), subtracting the DC signal S meas from the measurement signal S DC to determine the AC signal S AC ; A method comprising

2. The detector (124) comprises at least one photodetector (122) including at least one photosensitive region (126), and step a) comprises measuring a measurement signal S using the photosensitive region (126) of the photodetector (122). meas including measuring the measurement signal S meas which depends on the illumination of the photosensitive region (126), according to claim 1.

3. In step b), the DC signal S DC is further determined using the phase φ of the measurement signal S meas , and the evaluation of the measurement signal S meas is performed using at least one of the phase φ and at least one of the harmonics of the frequency f 0 and the frequency f 0 to determine at least one local minimum of the measurement signal S meas , and the DC signal S DC is determined using the local minimum, the method according to claim 1 or 2.

4. Said measurement signal S meas is evaluated by fitting a DC signal S DC to local minima of the measurement signal S meas wherein the DC signal S DC is a function of time S DC (t) including at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter, according to claim 1 or 2.

5. In step b), the DC signal S DC is determined by converting the measurement signal S meas into the frequency domain, and the measurement signal S meas is converted into the frequency domain by using a Fourier transform, according to the method of claim 1 or 2.

6. Measurement signal S meas is evaluated for at least one of the harmonics of the frequency f 0 and the frequency f 0 and the filtered measurement signal S meas converted for at least one of at least one of the harmonics, and the evaluation of the measurement signal S meas is filtered to determine the DC signal S DC using the converted measurement signal S meas The method according to claim 1 or 2, comprising using

7. Measurement signal S meas is evaluated by fitting a DC signal S meas to the filtered and transformed measurement signal S DC where the DC signal S DC is a function of time S(t) that includes at least one of a polynomial function having at least one fitting parameter, an exponential function having at least one fitting parameter, a square root function having at least one fitting parameter, and a logarithmic function having at least one fitting parameter DC The method according to claim 6

8. The method according to claim 1 or 2, wherein the detector (124) comprises at least one interface (130) for transmitting data from and / or to and / or within the evaluation unit (128), and the evaluation unit (128) is at least partially cloud-based.

9. The method according to claim 1 or 2, which is at least partially computer-implemented.

10. A method for determining at least one information item of at least one measurement object (114) using at least one detector (124), the method comprising the following steps: i) Using a detector (124) to determine at least one measurement signal S meas and a step of determining; ii) The step of determining the AC signal S using the method according to claim 1 or 2, and AC ​ iii) A step of determining items of information regarding a measurement target by evaluating an AC signal S using an evaluation unit (128) AC ​ A method comprising

11. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform at least one of the methods according to claim 1 or 2.

12. A photodetector (122) for measuring light emission (112), the photodetector (122) having at least one measurement signal S meas from which at least one alternating current (AC) signal S AC is extracted, referring to the method for implementing the method for extracting at least one alternating current (AC) signal S meas from at least one measurement signal S AC is configured to implement the method for extracting, and / or referring to the method for determining at least one information item regarding the measurement object (114), the photodetector (122) according to claim 10 is configured to implement the method for determining at least one information item regarding the measurement object (114), and the photodetector (122) comprises at least one light-receiving region (126).

13. A spectrometer (110) for spectroscopically analyzing optical radiation provided by at least one measurement object, comprising: - at least one radiation source (116) configured to at least partially emit optical radiation (112) towards the measurement object (114); and - the optical detector (122) according to claim 12. The spectrometer (110) comprising

14. The radiation source (116) is a modulated radiation source (120), and the radiation source (116) is modulated at a frequency f 0 The spectrometer (110) according to claim 13, wherein the spectrometer is modulated at a frequency f

15. The method of using the spectrometer (110) according to claim 13 for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; thermal exploration applications; flame detection applications; fire detection applications; smoke detection applications; temperature detection applications; spectroscopy applications; exhaust gas monitoring applications; combustion process monitoring applications; pollution monitoring applications; industrial process monitoring applications; chemical process monitoring applications; food processing process monitoring applications; water quality monitoring applications; air quality monitoring applications; quality control applications; temperature control applications; motion control applications; exhaust control applications; gas detection applications; gas analysis applications; motion detection applications; chemical detection applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications; cosmetic applications.

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