Detector with temperature drift compensation

Abstract

A method for retrieving at least one alternating current (AC) signal (SAC) from at least one measurement signal (Smeas) of at least one detector (124) is proposed. The measurement signal (Smeas) comprises an AC signal (SAC) and at least one direct current (DC) signal (SDC). The AC signal (SAC) has at least one predetermined frequency (f0). The method comprises the steps of: a) monitoring the measurement signal (Smeas) over time using a detector (124); b) determining the DC signal (SDC) using at least one evaluation unit (128), the determining comprising evaluating the measurement signal (Smeas) using at least one of the frequency (f0) and at least one harmonic of the frequency (f0); and c) determining the AC signal (SAC) by subtracting the DC signal (SDC) from the measurement signal (Smeas) using an evaluation unit (128). Further, a method for determining at least one item of information about at least one measurement object (114), a photodetector (122) and a spectrometer (110) are proposed.

Description

Technical Field

[0001] The invention relates to a method for obtaining a measurement signal S from at least one meas Retrieve at least one alternating current (AC) signal S from AC The invention relates to a method for measuring a measurement object, a method for determining at least one item of measurement information about a measurement object, a photodetector and a spectrometer. Such a method and an apparatus can generally be used for research or monitoring purposes, in particular in the infrared (IR) spectral region, in particular in the near infrared (NIR) spectral region, and for detecting heat, flames, fire or smoke. However, other kinds of applications are also possible. Background Art

[0002] Optical spectroscopy methods (particularly in the near infrared spectral range and the mid-infrared spectral range) allow to gain insight into the molecular structure of an object by observing the vibrations of molecular bonds. Such methods can be used, for example, for spectral analysis, gas detection or temperature measurement. Mid-infrared light can be used to excite fundamental vibration modes with high finesse and absorption intensity, while the near infrared spectral range can enable observation of overtones and combination bands at lower absorption intensities. These advantages can make it possible to probe bulk objects and obtain information about molecular composition by using near infrared spectroscopy. Therefore, NIR spectroscopy can be widely used in the life and natural sciences industry, the pharmaceutical industry, the materials science industry, the agricultural industry, the food industry or the pharmaceutical industry, for example, for blood sugar measurement, pulse oximetry, fat content measurement, material classification, product fraud identification, etc.

[0003] However, in contrast to spectrometers operating in the visible, it is generally quite difficult to provide analytical equipment for the NIR wavelength range: silicon-based photodetectors are generally not suitable for light with wavelengths greater than 1.1 μm due to the band structure. However, indium, germanium or lead salts or thermopiles can be applied. These materials may exhibit a strong dependence on temperature. In addition to temperature, other environmental effects may also have an impact, such as background light, stress or humidity. Therefore, the background signal may drift strongly on the time scale when the environment drifts, such as in the form of a direct current (DC) drift. The optical response (such as an alternating current (AC) signal) can be extracted by using signal modulation schemes, Fourier transform schemes and phase-locked amplification schemes. However, the retrieval of AC signals via Fourier analysis is typically also strongly affected by DC drifts, because the DC component has a wide-band Fourier spectrum.

[0004] Typically, NIR detectors in laboratory spectrometers and desktop spectrometers are usually thermoelectrically cooled using multiple stages, in particular to achieve low temperatures, high detection capabilities, and stability against temperature drift. However, thermoelectric cooling typically increases technical complexity, size, and power consumption, which hinders the widespread application of NIR spectroscopy, such as for instant analysis or consumer devices. Therefore, it is desirable to operate an IR spectrometer without cooling, wherein the detector material preferably works over a wide range of operating conditions and ambient temperatures. Therefore, when comparing the measurement results with a reference signal or when repeating measurements, it is necessary to compensate for the drift of the detector material caused by temperature in order to reduce the measurement noise.

[0005] In the prior art, devices and methods are known that apply a temperature correction based on a temperature sensor or on a second optical detector that is identical to the main detector.

[0006] JP H01110225A discloses a stable infrared radiometer without using mechanical parts such as choppers, which is implemented by monitoring the temperature of the optical system to compensate for the temperature drift at the zero point. A detector including a photodiode (such as InSb and HgCdTe) is placed in a vacuum container and cooled by liquid nitrogen. Infrared rays from the measuring point form an image on the light detection surface of the detector. The field of view of the detector is limited by the cold shield. The temperature of the optical system is monitored by a temperature sensor to use its output to compensate for the temperature drift at the zero point of the infrared radiometer.

[0007] CN 2359677 Y discloses an infrared optical fiber temperature measuring device for smelting and casting. The infrared optical fiber temperature measuring device comprises a positioning cylinder, a hemispherical reflector, a focusing lens, an optical fiber bundle, a filter, a detector and a temperature compensation circuit, wherein the positioning cylinder is close to the surface of molten steel, and the hemispherical reflector buckles one end of the positioning cylinder above the surface of the molten steel to be measured; the focusing lens is installed on the top of the hemispherical reflector, one end face of the optical fiber bundle is installed at the focal length position of the focusing lens, and the other end face is connected to the detector through the filter; the output end of the detector is connected to the temperature compensation circuit.

[0008] US 6852966 B1 discloses a method and apparatus for compensating a photodetector, which allows the adjustment and monitoring of the photodetector to be performed using a common digital controller. The controller accepts input of monitored operating parameters, which include received signal strength and temperature. The controller provides a bias control signal as an output, which adjusts the positive or negative side bias voltage supply of the photodetector. The controller maintains the bias voltage of the photodetector at a certain level. The controller includes a corresponding digital signal strength compensator and a temperature compensator, and the outputs of the digital signal strength compensator and the temperature compensator are added using an adder to provide a bias control signal. The digital signal strength compensator also provides a monitoring signal as an output, and the level of the monitoring signal corresponds to the actual signal strength received by the photodetector after compensating for the variable gain of the photodetector caused by the bias voltage level. A transceiver and a method and device for monitoring a photodetector are also disclosed.

[0009] US20110255075 A1 discloses a spectrometric assembly and method for determining the temperature value of a detector of a spectrometer. Conventionally, a thermal temperature sensor is used to record the detector temperature in a photodetector in order to compensate for temperature fluctuations. Due to the limited distance between the detector and the temperature sensor, the accuracy of the temperature detection is limited. In addition to a device for spectrally dividing incident light and an optical detector for spectrally resolving the spectral range of the divided light, a second optical detector for detecting a partial range of the spectral range is provided as a reference detector.

[0010] CN 109307550 A discloses a temperature compensation method for temperature compensation of an optical power meter. The temperature compensation method comprises the following steps: placing the optical power meter in a high and low temperature chamber, adjusting the temperature from -10°C to 40°C in sequence, recording the zero point value of different gears at each temperature point by a CPU module, and calculating the zero drift of the current gear caused by the temperature difference according to the reference temperature; and obtaining the optical power value detected by the photodetector by the CPU module, setting the current optical power detection gear, obtaining the real-time temperature detected by the temperature sensor, and sending the zero drift calibration factor to the secondary amplification circuit through the temperature compensation circuit according to the temperature drift generated by the reference temperature at the current gear by the CPU module for hardware circuit compensation.

[0011] JP S61213650A discloses an optical measuring device. The radiant energy light from the object to be measured is converged by a lens and blocked by a slit, and then becomes parallel light through the lens. Then, the light is spectrally separated by a spectroscope, and the light is incident on each element of the detector as light of different wavelengths. The gradient or function of the rate of change of the spectral sensitivity of the measuring wavelength of each element of the detector is pre-stored in a memory. The temperature T of the detector is detected by a temperature sensor during measurement, 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] CN 103076087 A discloses a mid-infrared photodetector driving circuit, a detector component and a detector component array.

[0013] DE 102009026951 A1 discloses a spectral gas sensor having an infrared source, an absorption chamber, an optical filter and a detector having a detector element, which forms a measurement beam from the infrared source through the absorption chamber and the optical filter to the detector. The detector element is arranged in the measurement beam and generates a measurement signal. The detector is a pyroelectric detector with an internal temperature compensation device, which generates a temperature compensation result signal according to the measurement signal.

[0014] US2019 / 317016 A1 describes an analyzer for identifying or authenticating or otherwise characterizing a liquid-based pharmaceutical sample, the analyzer comprising: an electromagnetic radiation source for emitting electromagnetic radiation in at least one beam at a sample, the electromagnetic radiation comprising at least two different wavelengths; a sample detector for detecting affected electromagnetic radiation caused by the emitted electromagnetic radiation affected by the sample; and a processor for identifying or authenticating the sample from the detected affected electromagnetic radiation, wherein each wavelength or at least two of these wavelengths are between substantially 1300nm and 2000nm, and each wavelength or at least two of these wavelengths are near the wavelength of a spectral characteristic in the liquid spectrum between substantially 1300nm and 2000nm (or within a region spanning the spectral characteristic).

[0015] WO 2014 / 054022 A1 describes an analyzer for characterizing a sample, the analyzer comprising: an integrated laser for emitting electromagnetic radiation in at least one beam along a single mode (SM) and polarization maintaining (PM) channel at the sample, the electromagnetic radiation comprising at least two different wavelengths; a sample detector for detecting affected electromagnetic radiation caused by the emitted electromagnetic radiation affected by the sample and providing an output representing the detected affected radiation; and a processor for characterizing the sample based on the detector output representing the detected affected electromagnetic radiation.

[0016] Despite the advantages implied by the above-described apparatus and methods, there is still a need for improvement. Specifically, additional sensors or detectors are required to compensate for drift of the detector signal (such as drift caused by temperature), which increases cost, complexity, and therefore error sensitivity of the apparatus and method. As an example, the additional detectors may fail or these additional detectors may themselves drift, specifically in a different manner than the main detector.

[0017] Problem to be solved

[0018] Therefore, it is desirable to provide a method and a device for compensating a measurement signal which at least substantially avoids the disadvantages of known methods and devices of this type. In particular, it is desirable to provide a method and a device which ensures accurate and reliable compensation of detector drifts, in particular temperature drifts of photodetectors, in a simple and safe manner, in particular without requiring the installation of additional components. Summary of the invention

[0019] This problem is solved by the invention having the features of the independent claims. Advantageous embodiments which can be realized individually or in any arbitrary combination are listed in the dependent claims as well as in the entire description.

[0020] In a first aspect of the invention, a method for obtaining at least one measurement signal S from at least one detector is disclosed. meas Retrieve at least one alternating current (AC) signal S from AC The measurement signal S meas Including AC signal S AC and at least one direct current (DC) signal S DC AC signal S AC has at least one predetermined frequency f0. The method comprises the following steps:

[0021] a) Using a detector to monitor the measurement signal S over time meas ;

[0022] b) using at least one evaluation unit to determine the DC signal S DC, wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas ;as well as

[0023] c) by using the evaluation unit from the measurement signal S meas Subtract the DC signal S from DC To determine the AC signal S AC .

[0024] The method steps may be performed in the order indicated. However, it should be noted that a different order is also possible. The method may include additional method steps that are not listed. Further, one or more of the method steps may be performed once or repeatedly. Further, two or more of the method steps may be performed simultaneously or in a time-overlapping manner.

[0025] The method may include correcting the influence of the measurement signal S meas At least one environmental change. The environmental change may specifically include at least one of the following: temperature change, background light change, mechanical stress, humidity change, and degradation of at least a portion of the detector. As used herein, the term "correction" (including any grammatical variations thereof) is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, compensating for or re-adjusting an entity. Correction may include removing or eliminating any influence on the measurement signal S meas Specifically, the correction may include removing the disturbance of the measurement signal S caused by environmental changes (such as temperature changes). meas This effect can refer to the DC signal S DC As an example, the detector may be a photodetector of a spectrometer configured to measure optical radiation. Other external influencing factors besides the optical radiation to be measured may not be of concern in the measurement, and these external influencing factors may only interfere with the measurement signal S meas The spectrometer may further comprise a modulated radiation source. Thus, the signal of interest may be an AC signal S AC External influencing factors (e.g. temperature) can typically be present in the AC signal S AC The external influencing factors can typically be expressed as a DC signal S DC The measured signal S meas Therefore, the identification of the measurement signal S meas The DC signal S DC And the DC signal S DC From the measured signal S measRemove the AC signal S that can cause special attention in the measurement AC . Other options are also possible.

[0026] Known methods (such as those described in US2019 / 317016 A1 and WO 2014 / 054022 A1) propose to use reference and sample detectors, Fourier transform and Fourier analysis to remove the dark current component. In contrast, the present invention proposes to use only the measurement signal and to determine 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.

[0027] As used herein, the term "retrieval" (including any grammatical variations thereof) is a broad term and is to be given its ordinary and customary meaning to one of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, at least one of: determining, deriving, and filtering out a signal or at least a portion of a signal. As described above, the measurement signal S meas Including AC signal S AC and DC signal S DC The retrieval may include identifying and / or isolating the measurement signal S meas The AC signal S AC . The search may include converting the DC signal S DC From the measured signal S meas Retrieving may include providing the AC signal S to another entity. AC for further processing and / or evaluation, such as for determining information about at least one measurement object.

[0028] As used herein, the term "signal" is a broad term and will be given its ordinary and conventional meaning for those of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, an observable change in at least one physical quantity. A signal may be or include an identifier or function that conveys information about the at least one physical quantity. A signal may specifically be or include at least one of an electronic signal, an optical signal, or a photoelectric signal. A signal may be a variable signal, specifically a signal that varies over time. A signal may be an analog signal. A signal may be or include at least one of the following: a variable voltage, a variable current, a variable charge, a variable resistance, or generally a variable electromagnetic wave. A variable electromagnetic wave may include at least one of the following: 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. Other options are also feasible. A signal may specifically be associated with at least one measurement. A signal may specifically be generated by at least one detector.

[0029] As used herein, the term "measurement signal" is a broad term and will be given its ordinary and conventional meaning for a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a signal associated with at least one measurement, more specifically a signal associated with at least one measurement object. A measurement signal may be a signal generated by a detector when at least one physical quantity (such as a physical quantity of a measurement object) is detected. The measurement signal may include at least one electronic signal, such as a current or voltage or 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 affected by a variety of influencing factors, such as light, temperature, humidity, or mechanical stress. Each influencing factor may have an effect on the measurement signal. The measurement signal may be divided into two or more sub-signals, wherein these sub-signals may be at least partially related to different influencing factors.

[0030] Measuring signal S meas Including AC signal S AC and at least one direct current (DC) signal S DC As used herein, the term "direct current signal" (abbreviated as DC signal) is a broad term and shall be given its ordinary and customary meaning to those of ordinary skill in the art and shall not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a signal that varies in one direction or at least substantially in one direction over time, such as a signal that increases continuously over time or a signal that decreases continuously over time. As an example, a DC signal S DC It can be a digital signal, where the count can increase continuously over time. DC signal S DC At least one stationary segment may be included within a period of time. Deviations from a strictly unidirectional evolution may occur, for example due to signal noise or external disturbances.

[0031] As used herein, the term "alternating current signal" (abbreviated as AC signal) is a broad term and shall be given its ordinary and customary meaning to one of ordinary skill in the art and shall not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a signal that reverses direction and / or changes (e.g., periodically changes) its magnitude over time. As an example, an AC signal S AC It can be a digital signal where the count increases and decreases in an alternating manner over time. AC signal S AC It can be a sinusoidal signal, a square wave signal, a pulse width modulation signal or a combination of the above signals. AC It can be a periodic signal or at least a substantially periodic signal. For example, due to signal noise or external disturbances, deviations from a strictly periodic evolution may occur. As mentioned above, the AC signal S ACHaving at least one predetermined frequency f0.

[0032] As used herein, the term "frequency" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, the number of occurrences of a repetitive event over time. Frequency may be defined as the reciprocal of a cycle duration (such as the cycle duration of a periodic signal). Frequency may be predefined by at least one default value (such as at least one default value in a measurement setup). A user may be allowed to set a default value or to choose between a plurality of different available default values. As an example, which will also be described in further detail below, the detector may be a photodetector of a spectrometer, wherein the spectrometer may further include a modulated radiation source. Thus, the AC signal S may be predefined by setting a specific modulation frequency at the modulated radiation source. AC Other options are also possible.

[0033] A frequency (such as frequency f0) usually has multiple harmonics. As used herein, the term "harmonic" is a broad term and will be given its ordinary and conventional meaning to those of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a frequency that is a harmonic of a fundamental frequency (such as frequency f0). A harmonic of frequency f0 may be a positive integer multiple of frequency f0, such as 2f0, 3f0, 4f0, etc.

[0034] As used herein, the term "detector" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a measuring device, such as a sensor, configured to generate at least one measurement signal. The detector may be configured to sense or 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 a current or voltage or resistance. The detector may specifically be or include a photodetector, as will be described in further detail below. However, other types of detectors are also feasible.

[0035] The detector may comprise at least one photodetector. The photodetector may comprise at least one photosensitive region. Step a) may comprise measuring the measurement signal S using the photosensitive region of the photodetector meas . Measurement signal S measMay depend on the illumination of the photosensitive area. As used herein, the term "photodetector" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, an optical detector or optical sensor configured to detect optical radiation, such as for detecting illumination and / or a light spot 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 area that generates a physical response to illumination of a given wavelength range.

[0036] The photodetector may include at least one photosensitive area. The photodetector may include multiple photosensitive areas, which may be arranged in at least one of an array or a matrix. As used herein, the term "photosensitive area" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a unit of a photodetector that is configured to illuminate, or in other words receive light radiation, and generate at least one signal (such as an electronic signal) in response to the illumination. The photosensitive area may be located on the surface of the photodetector. The photosensitive area may specifically be a single, closed, uniform photosensitive area. However, other options may also be feasible. The photosensitive area may also be referred to as a pixel.

[0037] As used herein, the term "illumination" is a broad term and will be given its ordinary and conventional meaning for ordinary technicians in the field and is not limited to a special or custom meaning. The term can specifically refer to, but is not limited to, light radiation, specifically light radiation in at least one spectral range of the visible light spectrum, the ultraviolet spectrum, or the infrared spectrum. The term "ultraviolet light" generally refers to electromagnetic radiation with a wavelength of 1nm to 380nm, preferably 100nm to 380nm. Further, the term "visible light" generally refers to a wavelength of 380nm to 760nm. Further, the term "infrared" ("abbreviated as IR") generally refers to a wavelength of 760nm to 1000μm, wherein a wavelength of 760nm to 3μm is generally referred to as "near infrared" (abbreviated as "NIR"). Preferably, the illumination used for the typical purpose of the present invention is IR radiation, more preferably NIR radiation, especially radiation with a wavelength of 760nm to 3μm, preferably 1μm to 3μm. The illumination can specifically be light radiation that illuminates a photodetector or more specifically a photosensitive area. The term "illumination" may also be referred to herein as "optical radiation" or "light".

[0038] Illumination can be provided by at least one measurement object, wherein the provision can include at least one of reflection, transmission and emission. Specifically, before interacting with the measurement object, illumination can be emitted, for example, by at least one radiation source. As used herein, the term "radiation source" is a broad term, and will be given its ordinary and conventional meaning for ordinary technicians in the field and is not limited to special or custom meanings. The term can specifically refer to, but is not limited to, a device configured to emit optical radiation. The radiation source can be configured to emit optical radiation, such as optical radiation in the form of a beam, toward the measurement object. The radiation source can be configured to emit optical radiation isotropically (e.g., uniformly in all spatial directions), wherein only a portion of the emitted optical radiation can illuminate the measurement object. The radiation source can include at least one of a semiconductor-based radiation source or a thermal radiator. At least one semiconductor-based radiation source can be selected from at least one of a light emitting diode (LED) or a laser (specifically, a laser diode). The LED can include at least one fluorescent and / or phosphorescent material. The thermal radiator can include at least one of an incandescent lamp, a black body emitter, and a microelectromechanical system (MEMS) emitter. Other types of radiation sources may also be possible.

[0039] The illumination may be modulated, for example, using a modulated radiation source. The radiation source may be a modulated radiation source. The radiation source may be modulated at a frequency f0. Thus, the frequency f0 and harmonics of the frequency f0 may be present in the optical radiation illuminating the photodetector and subsequently also in the measurement signal S generated by the photodetector. meas Specifically, as mentioned above, the AC signal S AC With frequency f0. As used herein, the term "modulation" (including any grammatical variations thereof) is a broad term and will be given its ordinary and conventional meaning for those of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a process of changing, specifically periodically changing at least one characteristic of optical radiation, specifically one or both of the intensity or phase of the optical radiation. As the technician will know, intensity is also related to the amplitude of the optical radiation. Modulation may be a full modulation from a maximum value to zero, or may be 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, for example, mechanically modulate the optical radiation (e.g., by using a rotating chopper wheel) and / or for electronically modulating the optical radiation (e.g., by using an electro-optic effect and / or an acousto-optic effect, e.g., by using a Pockels box and / or a Kerr box). Additional options are also feasible.

[0040] The photodetector can be 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. 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. Other options (such as photodiodes or thermopiles) may also be feasible. The photodetector can be configured to generate at least one measurement signal (such as a photocurrent), specifically generating at least one measurement signal in response to illumination of the photosensitive region. However, in addition to illumination, the measurement signal may also be affected by other factors, as will be known to the skilled person. Specifically, environmental changes (such as temperature changes) may also affect the measurement signal, and more specifically may cause a drift in the measurement signal.

[0041] Step a) comprises monitoring the measurement signal S over time using a detector meas As used herein, the term "monitoring over time" (including any grammatical variations thereof) is a broad term and is to be given its ordinary and customary meaning to one of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, performing at least one of the following: specifically measuring, observing, or recording an entity (such as measuring a signal S) over time. meas ). Monitoring may include recording the measurement signal S meas Evolution and / or development over time.

[0042] Step b) comprises determining the DC signal S using at least one evaluation unit DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas As used herein, the term "evaluation" (including any grammatical variations thereof) is a broad term and is to be given its ordinary and customary meaning to one of ordinary skill in the art and is not limited to a special or customary meaning. The term may specifically refer to, but is not limited to, a processing or analysis or interpretation entity, such as a measurement signal S meas The evaluation may include performing a process involving measuring the signal S meas The evaluation may include the measurement signal S meas The evaluation may include using at least one relationship, such as a predefined and / or predetermined relationship, for example from a lookup table, or a variable relationship (such as a function). The evaluation may include evaluating the measurement signal S meas The evaluation may include filtering and / or smoothing the measured signal S meas At least one qualitative or quantitative information is derived from DC and / or AC signal SAC For the measurement signal S meas For such purposes, different approaches may be feasible, as will be outlined in further detail below.

[0043] As used herein, the term "evaluation unit" is a broad term and shall be given its ordinary and customary meaning to a person of ordinary skill in the art and shall not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a device configured to analyze or interpret data, specifically to determine at least one item of qualitative or quantitative information. The information may specifically be obtained by evaluating at least one signal (such as a signal generated by a detector, specifically a measurement signal S meas ). The evaluation unit may be or may include at least one of an integrated circuit (in particular an application specific integrated circuit (ASIC)) or a data processing device, in particular at least one of 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 smart phone or a tablet). Other components may be feasible, in particular at least one preprocessing device or a data acquisition device. 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 may be designed to fully or partially control or drive other devices, such as a detector. The evaluation unit may be designed to perform at least one measurement cycle, in which a plurality of measurement signals may be picked up. The evaluation unit may be designed to control the detector to perform at least one measurement and / or generate at least one measurement signal.

[0044] The information as determined by the evaluation unit may be provided to at least one of the other device or the user, in particular preferably in at least one of an electronic, visual, auditory or tactile manner. The information may be stored in at least one data storage unit, in particular in an internal data storage unit such as a photodetector, in particular the at least one evaluation unit comprises, or in a separate storage unit to which the information may be transmitted via at least one interface. The at least one electronic communication unit may comprise the separate storage unit. The storage unit may be particularly configured for storing at least one electronic table, such as at least one look-up table.

[0045] The evaluation unit can be configured to execute at least one computer program, in particular at least one computer program that performs or supports the information generation step. For example, one or more algorithms can be implemented, which can perform a transformation to information by using at least one measurement signal as at least one input variable. For this purpose, the evaluation unit can include at least one data processing device, in particular at least one of an electronic data processing device or an optical data processing device, which can be designed to generate information by evaluating at least one measurement signal. The evaluation unit can be designed to use at least one measurement signal as at least one input variable and generate information by processing the at least one input variable. The processing can be performed in a continuous, parallel or combined manner. The evaluation unit can use an arbitrary process to generate information, in particular by calculating and / or using at least one stored and / or known relationship to generate information.

[0046] The detector may include an evaluation unit and / or at least one interface for transmitting data from and / or to and / or within the evaluation unit. As used herein, the term "interface" is a broad term and will be given its common and conventional meaning for those of ordinary skill in the art and is not limited to special or custom meanings. Specifically, the term may refer to, but is not limited to, an object or element that forms a boundary configured for transmitting information. The interface may be specifically a communication interface. In particular, the interface may be configured to transmit information from a computing device (e.g., a computer) so that information is sent or output to, for example, another device. Additionally or alternatively, the interface may be configured to transmit information to a computing device, such as a computer, so as to receive information. The interface may specifically provide a means for transmitting or exchanging information. In particular, the interface may provide a data transmission connection, such as Bluetooth, NFC, inductive coupling, etc. As an example, the interface may be or may include at least one port, the 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.

[0047] The evaluation unit may be at least partially cloud-based. As used herein, the term "cloud-based" is a broad term and will be given its ordinary and conventional meaning for a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, outsourcing the evaluation unit or part of the evaluation unit to at least partially interconnected external devices, specifically computers or computer networks with greater computing power and / or data storage. The external devices may be arbitrarily distributed in space. The external devices may change over time, specifically according to demand. The external devices may be interconnected using the Internet and / or at least one intranet. The external devices may each include at least one interface, such as a communication interface for transmitting data.

[0048] As indicated, in step b), there may be a variety of specific methods for determining the DC signal S by using at least one of the frequency f0 and at least one harmonic of the frequency f0. DC As an example which will also be outlined in further detail below, the measurement signal S meas can be transformed into the frequency domain for filtering the frequency f0 and / or at least one harmonic of the frequency f0. The filtered transformed measurement signal S meas Can be used to determine the DC signal S DC , for example, by applying the DC signal S DC Fitting to the filtered transformed measurement signal S meas In the following, a method for determining the DC signal S will be presented. DC These methods may be performed alternatively or additionally, such as sequentially. There may be other methods for determining the DC signal S DC .

[0049] Specifically, in addition to the frequency f0, the measurement signal S can be further used meas Specifically, the AC signal S AC Phase To determine the DC signal S DC . Evaluate the measurement signal S meas This can include using frequency f0 and phase and at least one of the frequency f0 and at least one harmonic of the frequency f0 to determine the measurement signal S meas The local minimum of the DC signal S DC It can be determined by using local minima. As used herein, the term "phase" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term can specifically refer to, but is not limited to, a position indicator within a periodic signal. Typically, the phase can be expressed as an angle as the skilled person will know. The phase can depend on time, signal frequency and / or phase offset. In particular, the phase can indicate when a periodic signal or a periodic portion of a total signal (such as a periodic sub-signal) reaches an extreme value (such as a minimum or maximum value). As an example, the measured signal S meas An at least substantially periodic sub-signal may be present, for example due to the use of a modulated radiation source as already outlined. The sub-signal may correspond to the AC signal S AC , which may eventually be of interest, but at this stage may have drifted, for example due to environmental changes. The frequency f0 and phase of this sub-signal It can be used to identify the minimum values ​​in the sub-signals, which can at the same time be at least the minimum value of the entire measurement signal S measThe local minimum in .

[0050] As used herein, the term "local minimum" is a broad term and is to be given its ordinary and customary meaning to one of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, the lowest signal value in a signal interval, specifically within a period of a periodic signal. The measured signal S meas The measurement signal may specifically be recorded as counts over time. As described above, the measurement signal comprises an AC signal S AC and DC signal S DC The local minimum can be the AC signal S AC The global minimum may be the lowest signal value, such as the lowest count, in a time interval associated with a period of the signal. In contrast, as the skilled person will know, the global minimum may be the lowest signal value of the entire signal. The signal may comprise a plurality of local minima. These local minima may at least partially have the same size. These local minima may in particular at least partially have different sizes, in particular due to external disturbances such as environmental changes affecting the detector and / or the measurement signal.

[0051] Evaluation of the measurement signal S meas This may include converting the DC signal S DC Fitting to the measured signal S meas The local minimum of the DC signal S DC It can be 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. As used herein, the term "fitting" (including any grammatical variations thereof) is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a regression analysis for estimating the relationship between at least two variables. Fitting may include at least one of linear regression, partial least squares regression, nonlinear regression, interpolation, and extrapolation. Fitting may include at least one regression model, for example, a training model. Fitting may include using at least one fitting function, such as at least one of the functions listed above. Function S DC (t) can be fitted to the measured signal S measThe fitting function can include at least one fitting parameter. As used herein, the term "fitting parameter" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term specifically may refer to, but is not limited to, a parameter or coefficient of a fitting function. As an example, the fitting function can be a linear function, and the fitting parameters can be the slope and offset of the linear function. Typically, a variety of additional options are feasible and known to the skilled person.

[0052] As mentioned above, the measurement signal S meas In addition or alternative to the method of finding the local minimum of the measured signal S meas Transform to the frequency domain to determine the DC signal S DC . As used herein, the term "frequency domain" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, analyzing a signal for at least one frequency of the signal. A signal can typically be recorded over time in the time domain, which means that the signal value is associated with a specific point in time. However, as the technician will know, for a variety of applications, it can be helpful to analyze the signal for the frequencies that the signal includes in the frequency domain. As an example, a total signal may include multiple sub-signals, each of which includes a specific frequency. Sub-signals can be distinguished by analyzing the frequencies in the total signal, for example for further separate processing. In the frequency domain, signal values ​​can be associated with specific frequencies. Signal values ​​(such as the signal value of the total signal) can be plotted within a frequency interval in the frequency domain.

[0053] The measured signal S can be transformed by using Fourier transform measTransformed to the frequency domain. The frequency domain may also be referred to as Fourier space. As used herein, the term "Fourier transform" is a broad term and will be given its common and conventional meaning for those of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, an integral transform for decomposing an integrable function that depends on space or time into a function that depends on spatial frequency or temporal frequency. Typically, temporal frequency is referred to as frequency in this article. 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 Laplace transform). Other options are also feasible. Typically, there are several common and well-known conventions to define or perform the Fourier transform (such as fast Fourier transform) of a function and also define the corresponding inverse Fourier transform. In addition to the Fourier transform, other transforms may also be applicable to the present invention. In step b), the DC signal S may be determined in particular by setting at least one of the frequency f0 and at least one harmonic of the frequency f0 to zero in the frequency domain before retransforming to the time domain (such as by using an inverse Fourier transform). DC Therefore, step c) may specifically be performed again in the time domain.

[0054] For example, the evaluation of the measurement signal S performed in step b) meas The transformed measurement signal S may include a measurement of at least one of the frequency f0 and at least one harmonic of the frequency f0. meas Filtering. As used herein, the term "filtering" (including any grammatical variations thereof) is a broad term and will be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, 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 the total signal in the frequency domain. Specifically, filtering may include extracting a specific frequency or a sub-signal having a specific frequency from the measured signal S meas At least one of the frequency f0 and at least one harmonic of the frequency f0 is extracted from the original measurement signal S meas The rest of the frequency f0 and the harmonics of the frequency f0 may be referred to as the AC signal S AC The remaining part can be referred to as the DC signal S DC The filtering may comprise using at least one electronic filter element, in particular at least one frequency electronic filter element, such as an electronic bandpass filter element. The electronic filter element may be an analog electronic filter element or a digital electronic filter element. Other options are also possible and are generally known to the skilled person.

[0055] Evaluation of the measurement signal Smeas This may include using the filtered transformed measurement signal S meas To determine the DC signal S DC Specifically, the measurement signal S is evaluated. meas This may include using the transformed measurement signal S meas The remaining part after filtering is used to determine the DC signal S DC . Evaluate the measurement signal S meas This may include converting the DC signal S DC Fitting to the filtered transformed measurement signal S meas , specifically fitted to the transformed measurement signal S meas The remaining part after filtering. DC signal S DC It can be 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. The DC signal S DC Non-zero power may be carried at at least one of the frequency f0 and at least one harmonic of the frequency f0. For further details on fitting, reference may be made to the definition of this term above.

[0056] Step c) comprises obtaining the measurement signal S by using an evaluation unit meas Subtract the DC signal S from DC To determine the AC signal S AC As used herein, the term "subtract" (including any grammatical variations thereof) is a broad term and is to be given its ordinary and customary meaning to one of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, one or more of the following: specifically, reducing the DC signal S over the entire time period DC From the measured signal S meas Subtracting can include removing, eliminating and subtracting from the measured signal S meas Extract the AC signal S AC The subtraction may comprise at least one mathematical calculation. The subtraction may comprise specifically calculating from the measurement signal S individually for each time point over the entire time period meas (For example, the measured signal S meas The DC signal S is subtracted from the count DC (For example, a DC signal S DC In this way, the AC signal S can be determined, for example, for each time point, and thus for each selected time unit (for example, for each millisecond or for each frame number of the photodetector). AC . Other options may be possible.

[0057] For obtaining from at least one measurement signal S meas Retrieve at least one AC signal S from AC The method may be at least partially computer-implemented. As used herein, the term "computer-implemented" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a method involving at least one computer and / or at least one computer network. The computer and / or computer network may include at least one processor that may be configured to perform at least one of the method steps of the method according to the present invention. Specifically, each of these method steps may be performed by a computer and / or a computer network. The method may be performed fully automatically, specifically without user interaction.

[0058] With reference 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 performed using a computer or a computer network. Thus, typically, any of the method steps including the provision and / or manipulation of data may be performed using a computer or a computer network. Typically, these method steps may include any method steps, except for method steps that typically require manual work, such as providing samples and / or performing certain aspects of actual measurements.

[0059] In another aspect of the present invention, a method for determining at least one item of information about at least one measurement object by using at least one detector is disclosed. The method comprises the following steps:

[0060] i) using a detector to determine at least one measurement signal S meas ;

[0061] ii) using a method according to the above or further detailed disclosure below involving a method for obtaining from at least one measurement signal S meas Retrieve at least one AC signal S from AC The method of any one of the embodiments of the method of the embodiment to determine the AC signal S AC ;as well as

[0062] iii) Evaluating the AC signal S by using an evaluation unit AC To determine information about the object being measured.

[0063] The method steps may be performed in the order indicated. However, it should be noted that different orders are also possible. The method may include additional method steps that are not listed. Further, one or more of the method steps may be performed once or repeatedly. Further, two or more of the method steps may be performed simultaneously or in a time-overlapping manner. For further definitions and embodiments of the method for determining at least one item of information, reference may be made to the above description.

[0064] As used herein, the term "information" is a broad term and will be given its ordinary and conventional meaning to a person of ordinary skill in the art and is not limited to a special or custom meaning. The term may specifically refer to, but is not limited to, knowledge or evidence that provides a qualitative and / or quantitative description associated with at least one measurement, specifically at least one measurement object. The information may include at least one of a physical property of the measurement object or a chemical composition of at least one measurement object. The physical property may specifically include an optical property, such as at least one absorbance of the measurement object and / or at least one emissivity of the measurement object. The chemical composition may specifically refer to qualitative and / or quantitative information about at least one material included in the measurement object.

[0065] As used herein, the term "measurement object" is a broad term and will be given its common and conventional meaning for those of ordinary skill in the art and is not limited to special or custom meanings. The term may specifically refer to, but is not limited to, any body selected from living and inanimate objects. The measurement object may specifically include at least one material that is subjected to research. The measurement object may generally refer to an object to be measured (e.g., for which a spectrum is to be recorded), wherein the measurement object may have any characteristic in principle (e.g., any optical characteristic or any shape). The measurement object may include at least one solid sample. However, other measurement objects such as fluids may also be feasible.

[0066] The detector may comprise at least one photodetector. The photodetector may comprise at least one photosensitive region. Step i) may comprise measuring the measurement signal S using the photosensitive region of the photodetector meas . Measurement signal S meas It may depend on the illumination of the photosensitive area. For further definitions and embodiments regarding the photodetector, reference may be made to the above description.

[0067] The method for determining at least one item of information about at least one measurement object can be at least partially computer-implemented. With reference to the computer-implemented aspects of the present invention, one or more method steps or even all method steps in the method steps of the method according to one or more embodiments of the embodiments disclosed herein can be performed using a computer or a computer network. Therefore, generally, any method step in the method steps including the provision and / or manipulation of data can be performed using a computer or a computer network. Generally, these method steps can include any method steps, except for method steps that generally require manual work, such as providing samples and / or performing certain aspects of actual measurement.

[0068] In another aspect of the present invention, a non-transitory computer-readable medium is disclosed. The non-transitory computer-readable medium includes instructions that, when executed by one or more processors, cause the one or more processors to perform at least one of the methods described in any of the method embodiments disclosed in further detail above or below.

[0069] Specifically, the non-transitory computer readable medium includes instructions that, when executed by one or more processors, cause the one or more processors to perform the method according to the present invention for obtaining at least one measurement signal S from at least one detector. meas Retrieve at least one alternating current (AC) signal S from AC The measurement signal S meas Including AC signal S AC and at least one direct current (DC) signal S DC , where the AC signal S AC has at least one predetermined frequency f0. In particular, the non-transitory computer readable medium comprises a detector that monitors the measurement signal S over time. meas In particular, the non-transitory computer readable medium includes instructions for causing the evaluation unit to determine the DC signal S DC Instructions for use wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas In particular, the non-transitory computer-readable medium comprises a method for causing the evaluation unit to generate a signal from the measurement signal S meas Subtract the DC signal S from DC To determine the AC signal S AC Instructions.

[0070] The non-transitory computer-readable medium may include instructions which, when executed by one or more processors, cause the one or more processors to perform the method for determining at least one item of information about at least one measurement object according to the present invention. In particular, the non-transitory computer-readable medium includes instructions that cause the detector to determine at least one measurement signal S measIn particular, the non-transitory computer readable medium includes an instruction to determine the AC signal S by using the method according to the present invention. AC In particular, the non-transitory computer readable medium includes instructions for causing the evaluation unit to evaluate the AC signal S AC Instructions for determining information about a measurement object.

[0071] In another aspect of the present invention, a photodetector for measuring optical radiation is disclosed. The photodetector is configured to perform the method disclosed in further detail above or below involving obtaining a measurement signal S from at least one measurement signal. meas Retrieve at least one alternating current (AC) signal S from AC The method of any one of the embodiments described in the foregoing embodiment for obtaining from at least one measurement signal S meas Retrieve at least one alternating current (AC) signal S from AC The method of the invention is a method for carrying out the method of determining at least one item of information about a measurement object according to any of the embodiments disclosed in further detail above or below relating to a method for determining at least one item of information about a measurement object. The photodetector comprises at least one photosensitive area.

[0072] In particular, the photodetector is configured to perform the method according to the present invention for obtaining at least one measurement signal S meas Retrieve at least one alternating current (AC) signal S from AC In particular, the photodetector is configured to monitor the measurement signal S over time. meas In particular, the photodetector comprises an evaluation unit which is configured for or can be connected to at least one evaluation unit to determine the DC signal S DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas The evaluation unit can be configured to obtain the measured signal S meas Subtract the DC signal S from DC To determine the AC signal S AC .

[0073] In particular, the photodetector is configured to perform the method according to the invention for determining at least one item of information about at least one measurement object. In particular, the photodetector is configured to determine at least one measurement signal S meas In particular, the photodetector is configured to determine the AC signal S by using the method according to the invention. AC In particular, the photodetector comprises an evaluation unit which is configured for or can be connected to at least one evaluation unit to evaluate the AC signal S AC To determine information about the object being measured.

[0074] The photodetector may be 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. 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. Other options (such as photodiodes or thermopiles) may also be feasible. 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 of the photodetector, reference may be made to the above description.

[0075] In another aspect of the present invention, a spectrometer for spectrally analyzing optical radiation provided by at least one measurement object is disclosed. The spectrometer comprises:

[0076] - at least one radiation source configured for emitting optical radiation at least partially towards the measurement object; and

[0077] - at least one photodetector according to any of the embodiments relating to photodetectors disclosed in further detail above or below.

[0078] As used herein, the term "spectrum" (including any grammatical variations thereof) is a broad term and will be given its ordinary and conventional meaning for a person of ordinary skill in the art and will not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a partition of optical radiation, wherein the spectrum consists of optical signals defined by signal wavelengths and corresponding signal intensities. In particular, the spectrum may include spectral information associated with at least one measurement object, such as the type and composition of at least one material forming the at least one measurement object, which spectral information may be determined by recording at least one spectrum associated with the at least one measurement object. As used herein, the term "spectrometer" is a broad term and will be given its ordinary and conventional meaning for a person of ordinary skill in the art and will not be limited to a special or custom meaning. The term may specifically refer to, but is not limited to, a device configured to determine spectral information by recording at least one measurement of at least one signal intensity associated with at least one corresponding signal wavelength of optical radiation and by evaluating at least one measurement signal associated with the signal intensity.

[0079] The spectrometer may further comprise at least one evaluation unit. The evaluation unit may further be configured to generate at least one spectral information about the measurement object. The evaluation unit may further be configured to control the radiation source, such as a modulation frequency of the radiation source. The spectrometer may further comprise at least one optical filter element. The optical filter element may be configured to filter the optical radiation or more specifically a selected wavelength of the optical radiation. The at least one filter element may specifically be positioned in a beam path before at least one photosensitive area of ​​the photodetector. The spectrometer may comprise a plurality of photosensitive areas and a plurality of optical filter elements, wherein the at least one optical filter element may be positioned in a beam path before the at least one photosensitive area, wherein the plurality of optical filter elements may be configured to at least partially filter different wavelengths.

[0080] For further definitions and embodiments regarding the spectrometer, reference may be made to the above description of the method and the device.

[0081] In another aspect of the present invention, there is provided the use of a spectrometer according to any of the embodiments relating to a spectrometer disclosed in further detail above or below for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; heat seeking applications; flame detection applications; fire detection applications; smoke detection applications; temperature sensing 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; emission control applications; gas sensing applications; gas analysis applications; motion sensing applications; chemical sensing applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications, such as animal feed applications; cosmetic applications, such as hair-related cosmetic applications.

[0082] This article further discloses and proposes a computer program, which includes computer executable instructions, which are used to perform the method according to the present invention in one or more of the embodiments included in this article when the program is executed on a computer or a computer network. Specifically, the computer program can be stored on a computer-readable data carrier and / or a computer-readable storage medium.

[0083] As used herein, the terms "computer-readable data carrier" and "computer-readable storage medium" may specifically refer to a non-transitory data storage device, 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 a random access memory (RAM) and / or a read-only memory (ROM).

[0084] Thus, in particular, one, more than one or even all of the method steps as indicated above may be performed by using a computer or a computer network, preferably by using a computer program.

[0085] This document further discloses and proposes a computer program product having program code means so that when the program is executed on a computer or a computer network, the method according to the present invention in one or more of the method embodiments included in this document is performed. Specifically, the program code means can be stored on a computer-readable data carrier and / or a computer-readable storage medium.

[0086] This document further discloses and proposes a data carrier on which a data structure is stored. After the data carrier is loaded into a computer or a computer network (for example, loaded into a working memory or a main memory of the computer or the computer network), the data carrier can execute a method according to one or more method embodiments of the method embodiments disclosed in this document.

[0087] This article further discloses and proposes a computer program product having program code means stored on a machine-readable carrier so that when the program is executed on a computer or computer network, a method according to one or more method embodiments of the method embodiments disclosed herein is performed. As used herein, a computer program product refers to a program that is a tradable product. The product can generally exist in any format, such as in paper format, or on a computer-readable data carrier and / or a computer-readable storage medium. Specifically, the computer program product can be distributed via a data network.

[0088] Finally, a modulated data signal is disclosed and proposed herein, which contains instructions readable by a computer system or a computer network for executing a method according to one or more of the method embodiments disclosed herein.

[0089] With reference 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 method embodiments disclosed herein may be performed using a computer or a computer network. Thus, typically, any of the method steps including the provision and / or manipulation of data may be performed using a computer or a computer network. Typically, these method steps may include any method steps, except for method steps that typically require manual work, such as providing samples and / or performing certain aspects of actual measurements.

[0090] Specifically, this article further discloses:

[0091] - a computer or a computer network comprising at least one processor, wherein the processor is adapted to perform a method according to one of the method embodiments described in this specification,

[0092] - a computer loadable data structure, which is suitable for performing a method according to one of the embodiments described in this specification when the data structure is executed on a computer,

[0093] - a computer program, wherein the computer program is adapted to perform a method according to one of the embodiments described in this specification when the program is executed on a computer,

[0094] - a computer program comprising program means for carrying out the method according to one of the method embodiments described in the present description when the computer program is executed on a computer or on a computer network,

[0095] - a computer program comprising the program means according to the preceding embodiment, wherein the program means is stored on a computer-readable storage medium,

[0096] - a storage medium, on which a data structure is stored and wherein the data structure is suitable for carrying out a method according to one of the method embodiments described in the present description after being loaded into a main storage device and / or a working storage device of a computer or a computer network, and

[0097] A computer program product having program code means, wherein the program code means can be stored or stored on a storage medium for performing a method according to one of the method embodiments described in the present description if the program code means is executed on a computer or a computer network.

[0098] The method and apparatus as disclosed herein have significant advantages over the prior art. Specifically, the method and apparatus disclosed herein can ensure accurate and reliable compensation for the drift of the detector, specifically the temperature drift of the photodetector, in a simple and safe manner. Such a method and apparatus can rely entirely on data analysis, so there is no need to use additional components (such as temperature sensors or other additional detectors) to compensate for the drift, which typically reduces cost and complexity as well as error sensitivity.

[0099] As used herein, the terms "having", "including" or "comprising" or any arbitrary grammatical variant thereof are used in a non-exclusive manner. Thus, these terms may refer to the absence of additional features in the entity described in this context in addition to the features introduced by these terms, or the presence of one or more additional features. As an example, the expressions "A has B", "A includes B" and "A contains B" may refer to the absence of other elements in A in addition to B (i.e., A consists only and solely of B), or the presence of one or more additional elements in entity A in addition to B (such as element C, elements C and D or even additional elements).

[0100] Further, it should be noted that the terms "at least one", "one or more", or similar expressions indicating that a feature or element may occur once or more than once are typically used only once when introducing the corresponding feature or element. In most cases, when referring to the corresponding feature or element, the expression "at least one" or "one or more" is not repeated, although the corresponding feature or element may occur once or more than once.

[0101] Further, as used herein, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with optional features without limiting the possibilities of alternatives. Therefore, the features introduced by these terms are optional features and are not intended to limit the scope of the claims in any way. As the skilled person will recognize, the present invention can be implemented by using alternative features. Similarly, the features introduced by "in an embodiment of the present invention" or similar expressions are intended to be optional features, without any limitation on alternative embodiments of the present invention, without any limitation on the scope of the present invention, and without any limitation on the possibility of combining the features introduced in this manner with other optional or non-optional features of the present invention.

[0102] Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

[0103] Embodiment 1: A method for obtaining at least one measurement signal S from at least one detector meas Retrieve at least one alternating current (AC) signal S from AC The method, wherein the measurement signal S meas Including AC signal S AC and at least one direct current (DC) signal S DC , where the AC signal S AC Having at least one predetermined frequency f0, the method comprises the following steps:

[0104] a) Using a detector to monitor the measurement signal S over time meas ;

[0105] b) using at least one evaluation unit to determine the DC signal S DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas ;as well as

[0106] c) by using the evaluation unit from the measurement signal S meas Subtract the DC signal S from DC To determine the AC signal S AC .

[0107] Embodiment 2: The method according to the preceding embodiment, wherein the detector comprises at least one photodetector, the at least one photodetector comprising at least one photosensitive area, wherein step a) comprises measuring the measurement signal S using the photosensitive area of ​​the photodetector meas , where the measured signal S meas Depends on the lighting of the photosensitive area.

[0108] Embodiment 3: The method according to the preceding embodiment, wherein the photodetector is configured to detect optical radiation having a wavelength of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, more specifically 1400 nm to 2000 nm.

[0109] Embodiment 4: The method according to any one of the two preceding embodiments, wherein the photosensitive area comprises at least one photoconductive material.

[0110] Embodiment 5: The method according to any one of the three preceding embodiments, wherein the photoconductive material is selected from at least one of PbS, PbSe, Ge, InGaAs, InSb and HgCdTe.

[0111] Embodiment 6: The method according to any of the above embodiments, wherein the method comprises correcting the influence of the measurement signal S meas at least one environmental change of the detector, wherein the environmental change specifically includes at least one of the following: temperature change, background light change, mechanical stress, humidity change, and degradation of at least a portion of the detector.

[0112] Embodiment 7: The method according to any one of the preceding embodiments, wherein in step b), by further using the measurement signal S meas Phase To determine the DC signal S DC , where the measurement signal S is evaluated meas including using at least one of the frequency f0 and at least one harmonic of the frequency f0 and the phase To determine the measurement signal S meas The DC signal S is determined by using the local minimum value. DC .

[0113] Embodiment 8: The method according to the preceding embodiment, wherein the measurement signal S is evaluated meas Including the DC signal S DC Fitting to the measured signal S meas The local minimum of 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.

[0114] Embodiment 9: The method according to any one of the preceding embodiments, wherein in step b), the measurement signal S meas Transform to the frequency domain to determine the DC signal S DC .

[0115] Embodiment 10: The method according to the preceding embodiment, wherein the measurement signal S is converted into meas Transform to frequency domain.

[0116] Embodiment 11: The method according to any one of the two preceding embodiments, wherein the measurement signal S is evaluated. meas comprising a transformed measurement signal S for at least one of the frequency f0 and at least one harmonic of the frequency f0 meas Perform filtering.

[0117] Embodiment 12: The method according to the preceding embodiment, wherein the measurement signal S is evaluated meas The use of the filtered transformed measurement signal S meas To determine the DC signal S DC .

[0118] Embodiment 13: The method according to the preceding embodiment, wherein the measurement signal S is evaluated meas Including the DC signal S DC Fitting to the filtered transformed measurement signal S meas , where 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.

[0119] Embodiment 14: The method according to the previous embodiment, wherein the DC signal S DC Carries non-zero power at at least one of frequency f0 and at least one harmonic of frequency f0.

[0120] Embodiment 15: The method according to any of the preceding embodiments, wherein the detector comprises an evaluation unit and / or at least one interface for transmitting data from and / or to and / or within the evaluation unit.

[0121] Embodiment 16: A method according to any of the preceding embodiments, wherein the evaluation unit is at least partially cloud-based.

[0122] Embodiment 17: A method according to any of the method embodiments described above, wherein the method is at least partially computer-implemented.

[0123] Embodiment 18: A method for determining at least one item of information about at least one measurement object by using at least one detector, the method comprising the following steps:

[0124] i) using a detector to determine at least one measurement signal S meas ;

[0125] ii) determining the AC signal S using the method according to any of the preceding embodiments AC ;as well as

[0126] iii) Evaluating the AC signal S by using an evaluation unit AC To determine information about the object being measured.

[0127] Embodiment 19: The method according to the preceding embodiment, wherein the detector comprises at least one photodetector, the at least one photodetector comprising at least one photosensitive area, wherein step i) comprises measuring the measurement signal S using the photosensitive area of ​​the photodetector meas , where the measured signal S meas Depends on the lighting of the photosensitive area.

[0128] Embodiment 20: A method according to any of the preceding embodiments relating to a method for determining at least one item of information, wherein the method is at least partially computer-implemented.

[0129] Embodiment 21: A non-transitory computer-readable medium comprising instructions, which when executed by one or more processors cause the one or more processors to perform at least one of the methods described in any of the method embodiments described above.

[0130] Embodiment 22: A photodetector for measuring optical radiation, the photodetector being configured to perform the method according to the foregoing method involving the method for obtaining at least one measurement signal S meas Retrieve at least one alternating current (AC) signal S from AC The method of any of the embodiments described in any of the embodiments for obtaining a signal S from at least one measurement meas Retrieve at least one alternating current (AC) signal S from AC A method for determining at least one item of information about a measured object, and / or a method for performing a method for determining at least one item of information about a measured object according to any of the aforementioned embodiments relating to a method for determining at least one item of information about a measured object, wherein the photodetector comprises at least one photosensitive area.

[0131] Embodiment 23: The photodetector according to the preceding embodiment, 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.

[0132] Embodiment 24: A photodetector according to any of the preceding embodiments relating to photodetectors, wherein the photosensitive region comprises at least one photoconductive material.

[0133] Embodiment 25: The photodetector according to the preceding embodiment, wherein the photoconductive material is selected from at least one of PbS, PbSe, Ge, InGaAs, InSb and HgCdTe.

[0134] Embodiment 26: A photodetector according to any of the aforementioned embodiments relating to photodetectors, wherein the photodetector comprises at least one evaluation unit and / or at least one interface for transmitting data from the evaluation unit and / or to the evaluation unit and / or within the evaluation unit.

[0135] Embodiment 27: The photodetector according to any of the preceding embodiments relating to photodetectors, wherein the evaluation unit is at least partially cloud-based.

[0136] Embodiment 28: A spectrometer for performing spectral analysis on optical radiation provided by at least one measurement object, the spectrometer comprising:

[0137] - at least one radiation source configured for emitting optical radiation at least partially towards the measurement object; and

[0138] - at least one photodetector according to any of the preceding embodiments relating to photodetectors.

[0139] Embodiment 29: The spectrometer according to the preceding embodiment, wherein the spectrometer further comprises at least one evaluation unit, wherein the evaluation unit is further configured to generate at least one item of spectral information about the measurement object.

[0140] Embodiment 30 The spectrometer according to the preceding embodiment, wherein the evaluation unit is further configured to control the radiation source.

[0141] Embodiment 31: A spectrometer according to any one of the aforementioned embodiments relating to a spectrometer, wherein the radiation source is a modulated radiation source.

[0142] Embodiment 32: The spectrometer according to the preceding embodiment, wherein the radiation source is modulated with a frequency f0.

[0143] Embodiment 33: A spectrometer according to any of the aforementioned embodiments relating to spectrometers, wherein the radiation source comprises at least one of the following: a semiconductor-based radiation source, specifically at least one of a light emitting diode and a laser; and a thermal radiator, specifically an incandescent lamp.

[0144] Embodiment 34: The spectrometer described in any of the aforementioned embodiments related to the spectrometer further includes at least one optical filter element.

[0145] Embodiment 35: Use of the spectrometer described in any of the aforementioned embodiments involving spectrometers for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; heat seeking applications; flame detection applications; fire detection applications; smoke detection applications; temperature sensing 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; emission control applications; gas sensing applications; gas analysis applications; motion sensing applications; chemical sensing applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications, such as animal feed applications; cosmetic applications, such as hair-related cosmetic applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0146] Other optional features and embodiments are preferably disclosed in more detail in the subsequent description of the embodiments in conjunction with the dependent claims. Wherein, as the skilled person will recognize, the corresponding optional features can be implemented in an independent manner and in any arbitrary feasible combination. The scope of the present invention is not limited by the preferred embodiments. The embodiments are schematically depicted in the accompanying drawings. Wherein, the same reference numerals in these drawings represent the same or functionally equivalent elements.

[0147] In the attached picture:

[0148] Figure 1 Schematically illustrates an exemplary embodiment of a spectrometer according to the present invention;

[0149] Figure 2 schematically illustrates an exemplary embodiment of a photodetector according to the present invention;

[0150] Figure 3 A method for obtaining a signal from at least one measurement signal S according to the present invention is shown. meas Retrieve at least one alternating current (AC) signal S from AC A flowchart of an exemplary embodiment of a method of

[0151] Figures 4 to 6B shows experimental results of measuring an exemplary embodiment of a spectrometer according to the present invention; and

[0152] Figure 7 A flow chart of an exemplary embodiment of a method according to the invention for determining at least one item of information about at least one measurement object is shown. DETAILED DESCRIPTION

[0153] Figure 1 An exemplary embodiment of a spectrometer 110 according to the present invention is schematically shown. The spectrometer 110 is configured to perform a spectral analysis on an optical radiation 112 provided by at least one measurement object 114. The optical radiation 112 may be specifically in at least one spectral range of the visible light spectral range, the ultraviolet spectral range or the infrared spectral range. Preferably, the optical radiation 112 used for the typical purpose of the present invention is IR radiation, more preferably NIR radiation, in particular radiation with a wavelength of 760nm to 3μm, preferably 1μm to 3μm. The optical radiation 112 may be provided by the measurement object 114. The provision may include at least one of reflection, transmission and emission. The measurement object 114 may be any body selected from a living body and an inanimate body. The measurement object 114 may specifically include at least one material subjected to investigation. The measurement object 114 may generally refer to an object to be measured (e.g., for an object, a spectrum is to be recorded), wherein the measurement object 114 may have any properties in principle (e.g., any optical properties or any shape). The measurement object 114 may include at least one solid sample. However, other measurement objects such as fluids may also be feasible.

[0154] The spectrometer 110 may be a device configured to determine spectral information by recording at least one measurement value of at least one signal intensity associated with at least one corresponding signal wavelength of the optical radiation 112 and by evaluating at least one measurement signal associated with the signal intensity. The spectrometer 110 includes at least one radiation source 116, which is configured to emit optical radiation 112 at least partially toward the measurement object 114. The radiation source 116 may be a device configured to emit optical radiation 112. The radiation source 116 may be configured to emit optical radiation 112, such as optical radiation in the form of a light beam 118, toward the measurement object 114. The radiation source 116 may be configured to emit optical radiation 112 isotropically (e.g., uniformly in all spatial directions), wherein only a portion of the emitted optical radiation 112 may illuminate the measurement object 114. The radiation source 112 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 and / or phosphorescent material. The thermal radiator may include at least one of an incandescent lamp, a black body emitter, and a micro-electromechanical system (MEMS) emitter.

[0155] The optical radiation 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. Thus, the frequency f0 and harmonics of the frequency f0 may be present in the optical radiation 112. Modulation may be a process of changing, specifically periodically changing, at least one characteristic of the optical radiation, specifically one or both of the intensity or phase of the optical radiation. The modulation may be a full modulation from a maximum value to zero, or may be 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, for example, to mechanically modulate the optical radiation (for example, by using a rotating chopper wheel) and / or to electronically modulate the optical radiation (for example, by using an electro-optic effect and / or an acousto-optic effect, for example, by using a Pockels cell and / or a Kerr cell).

[0156] The spectrometer 110 comprises at least one photodetector 122 according to any of the embodiments concerning the photodetector 122 disclosed in further detail above or below. Figure 2 An exemplary embodiment of the photodetector 122 is also schematically shown separately in FIG. Therefore, regarding the photodetector 122, it can be combined with Figure 1 and Figure 2124. 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 or include at least one photodetector 122. As already noted, in the context of the present invention, in principle, multiple types of detectors 124 may be conceivable. However, for illustrative purposes, the focus will be placed on the photodetector 122 below.

[0157] The photodetector 122 may be an optical detector or an optical sensor configured to detect the optical radiation 112 (e.g., to detect the illumination and / or light spot generated by the at least one light beam 118). The photodetector 122 may be configured to perform the steps described above or in further detail below with respect to the steps for obtaining the at least one measurement signal S from the at least one light beam 118. meas Retrieve at least one alternating current (AC) signal S from AC The method of any one of the embodiments described in the foregoing embodiment for obtaining from at least one measurement signal S meas Retrieve at least one alternating current (AC) signal S from AC The method of the invention is a method for determining at least one item of information about a measurement object 114 according to any of the embodiments of the method for determining at least one item of information about a measurement object 114 disclosed in further detail above or below. The photodetector 122 includes at least one photosensitive area 126. The photosensitive area 126 may be a unit of the photodetector 122 configured to illuminate, or in other words receive, the optical radiation 112, and generate at least one signal (such as an electronic signal) in response to the optical radiation 112. The photosensitive area 126 may be located on the surface of the photodetector 122. The photosensitive area 126 may be specifically a single, closed, uniform photosensitive area 126. The photosensitive area 126 may also be referred to as a pixel P. The photodetector 126 may be configured to detect the optical radiation 112 having a wavelength of 300 nm to 3000 nm, specifically 500 nm to 2500 nm, and more specifically 1400 nm to 2000 nm. The photosensitive area 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. Photodiodes or thermopiles may also be feasible.

[0158] The spectrometer 110 may include at least one evaluation unit 128. The evaluation unit 128 may be configured to generate at least one spectral information about 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 the evaluation unit 128 and / or at least one interface 130 for transmitting data from and / or to and / or within the evaluation unit. The detector 124 may include the evaluation unit 128 and / or at least one interface 130 for transmitting data from and / or to and / or within the evaluation unit. The evaluation unit 128 may be at least partially cloud-based. In other words, the at least one evaluation unit 128 may be at least partially distributed in at least one cloud 132 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 refer to outsourcing the evaluation unit 128 or parts of the evaluation unit 128 to at least partially interconnected external devices 134, in particular computers or computer networks with greater computing power and / or data storage. The external devices 134 may be arbitrarily distributed in space. The external devices 134 may change over time, in particular according to demand. The external devices 134 may be interconnected by using the Internet and / or at least one intranet.

[0159] The evaluation unit 128 may be a device configured to analyze or interpret data, in particular to determine at least one qualitative or quantitative information. The information may be determined by evaluating at least one signal (such as a signal generated by a detector, in particular a measurement signal S meas ) to obtain. The evaluation unit 128 may be or may include at least one of an integrated circuit (in particular an application specific integrated circuit (ASIC)) or a data processing device, in particular at least one of 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). Other components may be feasible, in particular at least one preprocessing device or a data acquisition device. The evaluation unit 128 may include an interface 130 or a part thereof. The interface 130 may in particular be a wireless interface and / or wired. The evaluation unit 128 may be designed to fully or partially control or drive other devices, such as the detector 124 or the photodetector 122. The evaluation unit 128 may be designed to perform at least one measurement cycle, in which multiple measurement signals may be picked up. The evaluation unit 128 may be designed to control the detector 124 or the photodetector 122 to perform at least one measurement and / or generate at least one measurement signal.

[0160] The information as determined by the evaluation unit 128 can particularly preferably be provided to at least one of the other device or the user in at least one of an electronic, visual, acoustic or tactile manner. The information can be stored in at least one data storage unit, in particular in an internal data storage unit as comprised by the photodetector 122 or the detector 124, in particular the at least one evaluation unit 128, or in a separate storage unit to which the information can be transmitted via the at least one interface 130. The at least one electronic communication unit can include the separate storage unit. The storage unit can in particular be configured for storing at least one electronic table, such as at least one look-up table.

[0161] The evaluation unit 128 can be configured to execute at least one computer program, in particular at least one computer program that performs or supports the information generation step. For example, one or more algorithms can be implemented, which can perform a transformation into information by using at least one measurement signal as at least one input variable. For this purpose, the evaluation unit 128 can include at least one data processing device, in particular at least one of an electronic data processing device or an optical data processing device, which can be designed to generate information by evaluating at least one measurement signal. The evaluation unit 128 can be designed to use at least one measurement signal as at least one input variable and generate information by processing the at least one input variable. The processing can be performed in a continuous, parallel or combined manner. The evaluation unit 128 can use an arbitrary process to generate information, in particular by calculating and / or using at least one stored and / or known relationship to generate information.

[0162] The interface 130 may be an object or element that forms a boundary configured for transmitting information. The interface 130 may be specifically a communication interface. In particular, the interface 130 may be configured to transmit information from a computing device (e.g., a computer) so as to send or output the information to, for example, another device. Additionally or alternatively, the interface 130 may be configured to transmit information to a computing device, such as a computer, in order to receive information. The interface 130 may specifically provide a means for transmitting or exchanging information. In particular, the interface 130 may provide a data transmission connection, such as Bluetooth, NFC, inductive coupling, etc. As an example, the interface 130 may be or may include at least one port, the at least one port including one or more of a network or Internet port, a USB port, and a disk drive. The interface 130 may include at least one web interface.

[0163] The spectrometer 110 may include at least one optical filter element 136. The optical filter element 136 may be configured for filtering the optical radiation 112 or more specifically a selected wavelength of the optical radiation 112. The at least one filter element 136 may be specifically positioned in the beam path before at least one photosensitive region 126 of the photodetector 122. The spectrometer may include a plurality of photosensitive regions 126 and a plurality of optical filter elements 136, wherein at least one optical filter element 136 may be positioned in the beam path before at least one photosensitive region 126, wherein the plurality of optical filter elements 136 may be configured for at least partially filtering different wavelengths. The photodetector 122 may include at least one readout circuit 138. The readout circuit 138 may be configured for reading out at least one signal generated by the photosensitive region 126. The readout circuit 138 may be connected to other components of the photodetector 122, such as to at least one of the evaluation unit 128 or the interface 130, for example by using at least one conductor 140 or at least one trace 142. The spectrometer 110 may include at least one housing 144 that surrounds at least a portion 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 optical radiation 112.

[0164] In the following, about Figure 1 An exemplary beam path of the optical radiation 112 is depicted. The at least one radiation emitting element 116 may emit the optical radiation 112 as incident optical radiation 148 through the window 146 towards the measurement object 114. The measurement object 114 may at least partially reflect (particularly diffusely reflect) the incident optical radiation 148 towards at least one photosensitive region 126 of the photodetector 122 in the form of reflected optical radiation 150. The measurement object 114 may at least partially absorb the incident optical radiation 148, which may be indicative of at least one physical property or chemical composition of the measurement object 114. The reflected optical radiation 150 may pass through the window 146 and the optical filter element 136 and then reach the photosensitive region 126. The photosensitive region 126 may generate a corresponding measurement signal S meas , which measurement signal can be read out, for example, by using a readout circuit 138 .

[0165] As already pointed out, Figure 2 An exemplary embodiment of a photodetector 122 according to the present invention is schematically shown. For the description of the photodetector 122, reference may be made to the above description of the spectrometer 110 to a large extent. As described above, the photodetector 122 is configured to perform the method disclosed in further detail above or below involving the step of obtaining at least one measurement signal S measRetrieve at least one alternating current (AC) signal S from AC The method of any one of the embodiments described in the foregoing embodiment for obtaining from at least one measurement signal S meas Retrieve at least one alternating current (AC) signal S from AC A method for determining at least one item of information about a measurement object 114, and / or a method for performing a method for determining at least one item of information about a measurement object 114 according to any of the embodiments disclosed in further detail above or below involving a method for determining at least one item of information about a measurement object 114.

[0166] Figure 3 shows at least one measurement signal S from the detector 124 meas Retrieve at least one alternating current (AC) signal S from AC Flow chart of an exemplary embodiment of a method of measuring a signal S meas Including AC signal S AC and at least one direct current (DC) signal S DC AC signal S AC has at least one predetermined frequency f0. The method comprises the following steps:

[0167] a) (denoted by reference numeral 152) using the detector 124 to monitor the measurement signal S over time meas ;

[0168] b) (indicated by reference numeral 154) using at least one evaluation unit 128 to determine the DC signal S DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas ;as well as

[0169] c) (denoted by reference numeral 156) by using the evaluation unit 128 from the measurement signal S meas Subtract the DC signal S from DC To determine the AC signal S AC .

[0170] The method steps may be performed in the order indicated. However, it should be noted that a different order is also possible. The method may include additional method steps not listed herein. Further, one or more of the method steps may be performed once or repeatedly. Further, two or more of the method steps may be performed simultaneously or in a time-overlapping manner. The method steps may be at least partially computer-implemented. As indicated, the detector 124 may include a photodetector 122 including at least one photosensitive region 126. Step a) may include measuring the measurement signal S using the photosensitive region 126 of the photodetector 122. meas . Measurement signal Smeas It may depend on the illumination of the photosensitive area 126 .

[0171] The method may include correcting the influence of the measurement signal S meas The environmental change may specifically include at least one of the following: temperature change, background light change, mechanical stress, humidity change, and degradation of at least a portion of the detector. The correction may be compensation or readjustment of the entity. The correction may include removing or eliminating the influence of the measurement signal S meas Specifically, the correction may include removing the disturbance of the measurement signal S caused by environmental changes (such as temperature changes). meas This effect can refer to the DC signal S DC As described above, the detector 124 may be a photodetector 122 of a spectrometer 110 configured to measure the optical radiation 112. Other external influencing factors besides the optical radiation 112 to be measured may not be of concern in the measurement and may only interfere with the measurement signal S meas The spectrometer 110 may further include a modulated radiation source 120. Thus, the signal of interest may be an AC signal S AC External influencing factors (e.g. temperature) can typically be present in the AC signal S AC The external influencing factors can typically be expressed as a DC signal S DC The measured signal S meas Therefore, the identification of the measurement signal S meas The DC signal S DC And the DC signal S DC From the measured signal S meas Remove the AC signal S that can cause special attention in the measurement AC .

[0172] Retrieving can be at least one of the following: determining, deriving and filtering out the signal or at least a portion of the signal. As described above, the measurement signal S meas Including AC signal S AC and DC signal S DC The retrieval may include identifying and / or isolating the measurement signal S meas The AC signal S AC . The search may include converting the DC signal S DC From the measured signal S meas Retrieving may include providing the AC signal S to another entity. AC for further processing and / or evaluation, such as for determining information about the measurement object 114 .

[0173] The signal may be an observable change in at least one physical quantity. The signal may be or include an identifier or function that conveys information about the at least one physical quantity. The signal may specifically be or include at least one of an electronic signal, an optical signal, or a photoelectric signal. The signal may be a variable signal, specifically a signal that changes over time. The signal may be an analog signal. The signal may be or include at least one of the following: a variable voltage, a variable current, a variable charge, a variable resistance, or generally a variable electromagnetic wave. The variable electromagnetic wave may include at least one of the following: 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. The signal may specifically be associated with at least one measurement. The signal may specifically be generated by the detector 124.

[0174] The measurement signal may be a signal associated with at least one measurement, more specifically with the measurement object 114. The measurement signal may be a signal generated by the detector 124 when detecting 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 or 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 affected by a variety of influencing factors, such as light, temperature, humidity or mechanical stress. Each influencing factor may have an impact on the measurement signal. The measurement signal may be divided into two or more sub-signals, wherein the sub-signals may be at least partially related to different influencing factors.

[0175] DC signal S DC It can be a signal that changes unidirectionally or at least substantially unidirectionally over time, such as a signal that increases continuously over time or a signal that decreases continuously over time. As an example, the DC signal S DC It can be a digital signal, where the count can increase continuously over time. DC signal S DC At least one stationary segment may be included within a period of time. Deviations from a strictly unidirectional evolution may occur, for example due to signal noise or external disturbances.

[0176] AC signal S AC It can be a signal that reverses direction and / or changes (e.g., periodically) its magnitude over time. As an example, the AC signal S AC It can be a digital signal where the count increases and decreases in an alternating manner over time. AC signal S AC It can be a sinusoidal signal, a square wave signal, a pulse width modulation signal or a combination of the above signals. ACIt can be a periodic signal or at least a substantially periodic signal. For example, due to signal noise or external disturbances, deviations from a strictly periodic evolution may occur. As mentioned above, the AC signal S AC The frequency may be defined as the reciprocal of a period duration (e.g., the period duration of a periodic signal). The frequency may be predefined by at least one default value (e.g., at least one default value in a measurement setup). The user may be allowed to set a default value or select between a plurality of different available default values. As described above, the detector 124 may be a photodetector 122 of the spectrometer 110, wherein the spectrometer 110 may further include a modulated radiation source 120. Thus, the AC signal S may be predefined by setting a specific modulation frequency at the modulated radiation source 120. AC The harmonics may be harmonics of the 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.

[0177] Step a) comprises monitoring the measurement signal S over time using the detector 124 meas Monitoring over time may be at least one of the following: specifically measuring, observing or recording an entity (such as a measurement signal S) over time. meas ). Monitoring may include recording the measurement signal S meas Evolution and / or development over time.

[0178] Step b) comprises using the evaluation unit 128 to determine the DC signal S DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas The evaluation can be done on an entity (e.g. a measurement signal S meas ) for processing or analysis or interpretation. The evaluation may include performing a meas The evaluation may include the measurement signal S meas The evaluation may include using at least one relationship, such as a predefined and / or predetermined relationship, for example from a lookup table, or a variable relationship (such as a function). The evaluation may include evaluating the measurement signal S meas The evaluation may include filtering and / or smoothing the measured signal S meas At least one qualitative or quantitative information is derived from DC and / or AC signal S AC For the measurement signal S meas For such purposes, different approaches may be feasible, as will be outlined in further detail below.

[0179] Step c) comprises obtaining the measurement signal S by using an evaluation unit meas Subtract the DC signal S from DC To determine the AC signal S AC The subtraction may be one or more of the following: specifically, the DC signal S is reduced over the entire time period. DC From the measured signal S meas Subtracting can include removing, eliminating and subtracting from the measured signal S meas Extract the AC signal S AC The subtraction may comprise at least one mathematical calculation. The subtraction may comprise specifically calculating from the measurement signal S individually for each time point over the entire time period meas (For example, the measured signal S meas The DC signal S is subtracted from the count DC (For example, a DC signal S DC In this way, the AC signal S can be determined, for example, for each time point, and thus for each selected time unit (for example, for each millisecond, or for each frame number of the photodetector 122). AC .

[0180] Figures 4 to 6B Experimental results of measuring an exemplary embodiment of the spectrometer 110 according to the present invention are shown. Figure 4 The method for determining the DC signal S in step b) is shown. DC A first method is described in which the signal S is counted over the frame F. The original measurement signal is denoted by reference numeral 158. The masked measurement signal is denoted by reference numeral 160. Figure 4 Specifically, based on the frequency f0, at least one harmonic of the frequency f0, and the phase At least one of the masking measurement signal 160 masks the AC signal S AC The time when the local minimum is reached. Specifically, in addition to the frequency f0, the measurement signal S meas Specifically, the AC signal S AC Phase To determine the DC signal S DC . Evaluate the measurement signal S meas This can include using frequency f0 and phase and at least one of the frequency f0 and at least one harmonic of the frequency f0 to determine the measurement signal S meas The local minimum of the DC signal S DCThe phase can be determined by using local minima. The phase can be an indicator of the position within the periodic signal. Typically, the phase can be expressed as an angle. The phase can depend on time, signal frequency and / or phase offset. In particular, the phase can indicate when a periodic signal or a periodic part of the total signal (such as a periodic sub-signal) reaches an extreme value (such as a minimum or maximum). As an example, the measured signal S meas An at least substantially periodic sub-signal may be present, for example due to the use of a modulated radiation source as already outlined. The sub-signal may correspond to the AC signal S AC , which may eventually be of interest, but at this stage may have drifted, for example due to environmental changes. The frequency f0 and phase of this sub-signal It can be used to identify the minimum values ​​in the sub-signals, which can at the same time be at least the minimum value of the entire measurement signal S meas The local minimum in the measurement signal S may be the lowest signal value in the signal interval, in particular in the period of the periodic signal. The signal may comprise a plurality of local minima. These local minima may at least partially have the same size. These local minima may in particular at least partially have different sizes, in particular due to external disturbances, such as environmental changes affecting the detector and / or the measurement signal. The measurement signal S meas The measurement signal may specifically be recorded as counts over time. As described above, the measurement signal comprises an AC signal S AC and DC signal S DC The local minimum can be the AC signal S AC The lowest count in the time interval associated with the period.

[0181] Evaluation of the measurement signal S meas This may include converting the DC signal S DC Fitting to the measured signal S meas The local minimum of the DC signal S DC It can be 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. Fitting may include regression analysis for estimating a relationship between at least two variables. Fitting may include at least one of linear regression, partial least squares regression, nonlinear regression, interpolation, and extrapolation. Fitting may include at least one regression model, such as a training model. Fitting may include using at least one fitting function, such as at least one of the functions listed above. Function S DC (t) can be fitted to the measured signal S measThe 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 parameter may be a slope and an offset of the linear function.

[0182] like Figure 4 As specifically shown in FIG. 1 , a 4th order polynomial function may be fitted to the masked measurement signal 160. The fitted baseline is indicated by reference numeral 162. The fitted baseline 162 may be subtracted from the original measurement signal 158 to determine the AC signal S AC The corrected measurement signal obtained in this way based on the masked measurement signal is denoted by reference numeral 164. Additionally or alternatively, as will be outlined in further detail below, the measurement signal may be corrected by using frequency filtering. The corrected measurement signal obtained in this way by using frequency filtering is denoted by reference numeral 166. Figure 4 As shown, the two methods have comparable effects.

[0183] Figure 5A and Figure 5B The method for determining the DC signal S in step b) is shown. DC Another method. As mentioned above, using the measured signal S meas In addition or alternative to the method of finding the local minimum of the measured signal S meas Transform to the frequency domain to determine the DC signal S DC . The frequency domain can refer to analyzing a signal with respect to at least one frequency of the signal. A signal can typically be recorded over time in the time domain, which means that the signal value is related to a specific point in time. However, for many applications, it can be helpful to analyze the signal with respect to the frequencies that the signal includes in the frequency domain. As an example, a total signal can include multiple sub-signals, each of which includes a specific frequency. The sub-signals can be distinguished by analyzing the frequencies in the total signal, for example for further separate processing. In the frequency domain, the signal value can be related to a specific frequency. The signal value (such as the signal value of the total signal) can be plotted within a frequency interval in the frequency domain.

[0184] The measured signal S can be transformed by using Fourier transform meas Transform to frequency domain. Figure 5A Such a Fourier transformed signal obtained by using a Fast Fourier Transform (FFT) is shown, where the absolute signal counts are plotted on a logarithmic scale against the corresponding frequency f. The Fourier transformed raw measured signal is denoted by reference numeral 168. The first harmonics at frequencies f0 and 2f0 can be identified as peaks at approximately 15 Hz and 30 Hz, respectively. The distortion is approximately fitted to Figure 5AThe Fourier transformed raw measurement signal 168 in is represented by reference numeral 170. Further, the noise floor is represented by reference numeral 172. The Fourier transform can be an integral transform for decomposing an integrable function that depends on space or time into a function that depends on spatial frequency or temporal frequency. Specifically, the Fourier transform can 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 Laplace transforms). In step b), the DC signal S can be determined specifically by setting at least one of the frequency f0 and at least one harmonic of the frequency f0 to zero in the frequency domain before retransforming to the time domain (such as by using an inverse Fourier transform). DC Therefore, step c) may specifically be performed again in the time domain.

[0185] For example, the evaluation of the measurement signal S performed in step b) meas The transformed measurement signal S may include a measurement of at least one of the frequency f0 and at least one harmonic of the frequency f0. meas Filtering can be, for example, selectively extracting at least a portion of the signal in the frequency domain, such as a specific signal interval. Filtering can include extracting a specific frequency or a sub-signal with a specific frequency from the total signal in the frequency domain. Specifically, filtering can include extracting a specific frequency or a sub-signal with a specific frequency from the measurement signal S meas At least one of the frequency f0 and at least one harmonic of the frequency f0 is extracted from the original measurement signal S meas The rest of the frequency f0 and the harmonics of the frequency f0 may be referred to as the AC signal S AC The remaining part can be referred to as the DC signal S DC The filtering may comprise using at least one electronic filter element, in particular at least one frequency electronic filter element, such as an electronic bandpass filter element. The electronic filter element may be an analog electronic filter element or a digital electronic filter element.

[0186] Evaluation of the measurement signal S meas This may include using the filtered transformed measurement signal S meas To determine the DC signal S DC Specifically, the measurement signal S is evaluated. meas This may include using the transformed measurement signal S meas The remaining part after filtering is used to determine the DC signal S DC . Evaluate the measurement signal S meas This may include converting the DC signal S DC Fitting to the filtered transformed measurement signal S meas , specifically fitted to the transformed measurement signal S measThe remaining part after filtering. DC signal S DC It can be 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. The DC signal S DC Non-zero power may be carried at at least one of frequency f0 and at least one harmonic of frequency f0. Figure 5B The signal S is shown in the time domain counted over a frame F. The original measurement signal is referenced 174. The filtered measurement signal, in which the carrier frequency and harmonics are filtered out, is referenced 176. The fit correction is referenced 178 and the corrected measurement signal is referenced 180.

[0187] Fig. 6A and Figure 6B shows a method for obtaining a measurement signal S from at least one meas Retrieve at least one alternating current (AC) signal S from AC The methods are applied to different conditions. Fig. 6A For 250 pixels P at S DC < AC The original 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 For 250 pixels P at S DC ~S AC or S DC >>S AC The original 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. For all conditions, a clear signal recovery is evident.

[0188] Figure 7 A flow chart of an exemplary embodiment of a method for determining at least one item of information about a measurement object 114 by using a detector 124 is shown. The method comprises the following steps:

[0189] i) (denoted by reference numeral 190) using the detector 124 to determine at least one measurement signal S meas ;

[0190] ii) (indicated by reference numeral 192) using a method according to the above or further detailed disclosure below involving the method for obtaining from at least one measurement signal S meas Retrieve at least one AC signal S from​AC The method of any one of the embodiments of the method of the embodiment to determine the AC signal S AC ;as well as

[0191] iii) (denoted by reference numeral 194) by evaluating the AC signal S using the evaluation unit 128 AC To determine information about the measurement object 114.

[0192] The method steps may be performed in the order indicated. 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 of the method steps may be performed once or repeatedly. Further, two or more of the method steps may be performed simultaneously or in a time-overlapping manner. The method steps may be at least partially computer-implemented. The information may be knowledge or evidence that provides a qualitative and / or quantitative description of at least one measurement, specifically at least one measurement object 114. The information may include at least one of the physical properties of the measurement object 114 or the chemical composition of at least one measurement object 114. The physical properties may specifically include optical properties, 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 refer to qualitative and / or quantitative information about at least one material included in the measurement object 114.

[0193] List of Reference Numerals

[0194] 110 Spectrometer

[0195] 112 Light Radiation

[0196] 114 Measurement Objects

[0197] 116 Radiation Source

[0198] 118 Beam

[0199] 120 Modulated radiation source

[0200] 122 Photodetector

[0201] 124 Detector

[0202] 126 Photosensitive area

[0203] 128 evaluation units

[0204] 130 Interface

[0205] 132 Cloud

[0206] 134 External Devices

[0207] 136 Optical filter elements

[0208] 138 Readout Circuit

[0209] 140 Wire

[0210] 142 traces

[0211] 144 Shell

[0212] 146 Window

[0213] 148 Incident Light Radiation

[0214] 150 Reflected light radiation

[0215] 152 Method step a)

[0216] 154 Method step b)

[0217] 156 Method step c)

[0218] 158 Raw measurement signal

[0219] 160 Masking measurement signal

[0220] 162 Fitting Baseline

[0221] 164 Corrected measurement signal based on masked measurement signal

[0222] 166 Based on the corrected measurement signal using frequency filtering

[0223] 168 Original measurement signal after Fourier transformation

[0224] 170 Distortion Approximation

[0225] 172 Noise Floor

[0226] 174 Raw measurement signal

[0227] 176 Filtered measurement signal

[0228] 178 Fitting Correction

[0229] 180 Corrected measurement signal

[0230] 182 Original Fast Fourier Transform (FFT) measurement signal

[0231] 184 Corrected Fast Fourier Transform (FFT) measurement signal

[0232] 186 Original Fast Fourier Transform (FFT) measurement signal

[0233] 188 Corrected Fast Fourier Transform (FFT) measurement signal

[0234] 190 Method step i)

[0235] 192 Method step ii)

[0236] 194 Method step iii)

Claims

1. A method for obtaining at least one measurement signal S from at least one detector (124) meas Retrieve at least one alternating current (AC) signal S from AC method, in which The measurement signal S meas Including the AC signal S AC and at least one direct current (DC) signal S DC , where the AC signal S AC Having at least one predetermined frequency f0, the method comprises the following steps: a) monitoring the measurement signal S over time using the detector (124) meas ; b) using at least one evaluation unit (128) to determine the DC signal S DC , wherein the determination comprises evaluating the measurement signal S using at least one of the frequency f0 and at least one harmonic of the frequency f0 meas ;as well as c) by using the evaluation unit (128) from the measurement signal S meas Subtract the DC signal S from DC To determine the AC signal S AC .

2. The method according to the preceding claim, wherein: The detector (124) comprises at least one photodetector (122), the at least one photodetector comprising at least one photosensitive area (126), wherein step a) comprises using the photosensitive area (126) of the photodetector (122) to measure the measurement signal S meas , where the measurement signal S meas Depends on the illumination of the photosensitive area (126).

3. A method according to any one of the preceding claims, wherein: In step b), by further using the measurement signal S meas The phase φ of the DC signal S is determined DC , wherein the measurement signal S is evaluated meas comprising using at least one of the frequency f0 and at least one harmonic of the frequency f0 and the phase φ to determine the measurement signal S meas The DC signal S is determined by using these local minima DC .

4. The method according to the preceding claim, wherein: Evaluation of the measurement signal S meas Including the DC signal S DC Fitting to the measured signal S meas The local minimum of 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.

5. A method according to any one of the preceding claims, wherein: In step b), the measurement signal S meas Transform to the frequency domain to determine the DC signal S DC , where the measurement signal S is transformed by using Fourier transform meas Transform to frequency domain.

6. A method according to any one of the preceding claims, wherein: Evaluation of the measurement signal S meas comprising a transformed measurement signal S for at least one of the frequency f0 and at least one harmonic of the frequency f0 meas Filtering is performed, wherein the measurement signal S is evaluated. meas The use of the filtered transformed measurement signal S meas To determine the DC signal S DC .

7. The method according to the preceding claim, wherein: Evaluation of the measurement signal S meas Including the DC signal S DC Fitted to the filtered transformed measurement signal S meas , where 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.

8. A method according to any one of the preceding claims, wherein: The detector (124) comprises the evaluation unit (128) and / or at least one interface (130) for transmitting data from and / or to the evaluation unit and / or within the evaluation unit (128), wherein the evaluation unit (128) is at least partially cloud-based.

9. A method according to any one of the preceding method claims, wherein: The method is at least partially computer-implemented.

10. A method for determining at least one item of information about at least one measurement object (114) by using at least one detector (124), the method comprising the following steps: i) using the detector (124) to determine at least one measurement signal S meas ; ii) determining the AC signal S using a method according to any one of the preceding claims AC ;as well as iii) evaluating the AC signal S by using an evaluation unit (128) AC To determine information about the measurement object.

11. A non-transitory computer readable medium comprising instructions which, when executed by one or more processors, cause the one or more processors to perform at least one of the methods according to any of the preceding method claims.

12. A photodetector (122) for measuring optical radiation (112), the photodetector (122) being configured to perform the method according to the preceding claims relating to the method for obtaining a measurement signal S from at least one measurement signal meas Retrieve at least one alternating current (AC) signal S from AC The method of any one of claims 1 for obtaining a signal S from at least one measurement signal meas Retrieve at least one alternating current (AC) signal S from AC and / or for carrying out a method for determining at least one item of information about a measurement object (114) according to any of the preceding claims relating to a method for determining at least one item of information about a measurement object (114), wherein: The photodetector (122) includes at least one photosensitive region (126).

13. A spectrometer (110) for spectrally analyzing optical radiation provided by at least one measurement object, the spectrometer (110) comprising: at least one radiation source (116) configured to emit optical radiation (112) at least partially towards the measurement object (114); as well as - At least one photodetector (122) according to the preceding claim.

14. The spectrometer (110) according to the preceding claim, wherein The radiation source (116) is a modulated radiation source (120), wherein the radiation source (116) is modulated with a frequency f0.

15. Use of the spectrometer (110) according to any of the preceding claims relating to the spectrometer (110) for a purpose of use selected from the group consisting of: infrared detection applications; thermal detection applications; thermometer applications; heat seeking applications; flame detection applications; fire detection applications; smoke detection applications; temperature sensing 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; emission control applications; gas sensing applications; gas analysis applications; motion sensing applications; chemical sensing applications; mobile applications; medical applications; mobile spectroscopy applications; food analysis applications; agricultural applications; cosmetic applications.

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