A method for measuring spectrum by equivalently collecting forward and reverse spectroscopic scanning signals simultaneously

Abstract

The present invention relates to a method for measuring a spectrum that is equivalent to and simultaneously collects forward and reverse spectroscopic scanning signals. Based on the original measuring method of a portable scanning spectrometer, this method adds a reverse scan in reverse order of the measurement in each measurement scan to obtain the collected digital quantity of each wavelength spectroscopic signal of the forward and reverse bidirectional scanning, and takes the average of the collected digital quantities of the same wavelength to collect data at the same time, and calculates the spectrum in the same way as the original spectrum calculation method of the equivalent simultaneous data collection. The collection control circuit of the portable scanning spectrometer is respectively connected to the light source system, the photoelectric conversion and amplification conditioning circuit, the spectroscopic system, the sampling system and the host computer; the portable scanning spectrometer includes two types: the filter type and the grating scanning type. Although the time of the spectrum measurement is increased, the influence of the light intensity of the light source and the instability of the circuit conversion characteristics on the spectrum data can be effectively eliminated, and the accuracy and stability of the spectrum measurement of the portable scanning spectrometer are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of spectrum measurement, and specifically relates to a spectrum measurement method of a portable scanning spectrum instrument, and in particular to a spectrum measurement method of a spectrum instrument capable of realizing forward and reverse spectroscopic scanning. Background Art

[0002] The structure of the portable scanning spectrometer includes a light source system, a spectroscopic system, a sampling system, a photoelectric conversion and amplification conditioning circuit, an acquisition control circuit, and a host computer. The composite light emitted by the light source system is converted into monochromatic light of a specific wavelength by the spectroscopic system; after the monochromatic light signal reacts with the sample in the sampling system, it is converted into an analog electrical signal by the photoelectric conversion and amplification conditioning circuit; it is then converted into a digital quantity by sampling by the acquisition control circuit - acquisition data, and uploaded to the host computer. At the same time, the acquisition control circuit controls the spectroscopic system to scan the sample, background, and reference in sequence, and obtains the digital quantity of the scanned monochromatic light intensity after different wavelengths interact with the sample, background, and reference. The host computer calculates the spectral data of each scanning wavelength based on the acquisition data of each wavelength obtained in one scan.

[0003] Portable scanning spectrometers are widely used because of their easy control, simple optical path, stable performance, fast measurement, and high cost performance. However, due to the requirement for rapid use, this instrument cannot use long-term preheating and complex optical paths and circuit systems. Therefore, during the use of the instrument, the light intensity of the light source system and the conversion characteristics of the circuit system are unstable and change over time. During each scanning measurement of the same sample, the changes in the light intensity of the instrument light source and the circuit conversion characteristics have different effects on the collected digital quantity of each wavelength, which in turn leads to instability in the spectral data.

[0004] In view of the influence of the instability of the light source and circuit system of portable scanning spectrometers, it is necessary to adopt an effective measurement method to eliminate the influence and obtain stable spectral data without changing the original structure of the instrument as much as possible. Summary of the invention

[0005] The purpose of the present invention is to provide a spectral measurement method based on the equivalent simultaneous acquisition of forward and reverse spectroscopic scanning signals to solve the problem of unstable spectral data caused by changes in light source intensity and circuit conversion characteristics over time in portable scanning spectral instruments. It can effectively eliminate the influence of unstable light source intensity and circuit conversion characteristics on spectral data during a single spectral measurement process.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for measuring spectrum by equivalently collecting forward and reverse spectral scanning signals simultaneously adopts a portable scanning spectrometer for measurement. On the basis of the original measurement method of the portable scanning spectrometer, a step of performing reverse scanning in reverse order of measurement is added in each measurement scan to obtain the collected digital quantity d in the forward and reverse directions. k and d' k (k = 1, 2, ..., m, m is the number of splitting signals output by the splitting system), the two are averaged at the same wavelength position, that is, d k and d' m-k+1 After taking the average, we get D k , with D k is the amount of spectroscopic signal collected, and the spectrum value S is obtained by calculating the original spectrum calculation method;

[0008] The portable scanning spectrometer includes an acquisition control circuit consisting of a microprocessor unit and an ADC acquisition unit, a motor drive unit and a serial communication unit connected thereto. The acquisition control circuit is respectively connected to a light source system, a photoelectric conversion and amplification conditioning circuit, a spectroscopic system, a sampling system and a host computer. The portable scanning spectrometer is divided into two types: a portable grating scanning spectrometer and a portable filter type spectrometer.

[0009] Furthermore, the ADC acquisition unit is connected to the photoelectric conversion and amplification conditioning circuit, the microprocessor unit is connected to the light source system, the serial communication unit is connected to the host computer, and the motor drive unit is connected to the spectroscopic system and the sampling system respectively; the ADC acquisition unit is used to acquire analog signals and convert them into digital quantities; the microprocessor unit is used to control the operation of the light source system, control the scanning stepping motor and the sampling system through the motor drive and detection circuit, and receive the photoelectric switch signal and the collected digital quantity of the ADC acquisition unit; the serial communication unit is used to realize two-way communication between the microprocessor unit and the host computer.

[0010] Furthermore, the spectroscopic system of the portable filter-type spectrometer is connected to a transmission mechanism by a stepper motor Ⅰ2, and the stepper motor Ⅰ2 is coaxially connected to the filter disk 3 to receive the control signal of the acquisition control circuit. A plurality of filter holes 5 and a zero-position baffle 6 are distributed on the filter disk 3, and the photoelectric switch 4 is connected to the acquisition control circuit. The photoelectric switch 4 detects the zero-position baffle 6 on the filter disk 3 and generates a zero-position signal which is received by the acquisition control circuit and is used to determine the initial position of the filter disk 3; the filter holes 5 can be sequentially transferred into the system optical path 7 to acquire the signal of the required measurement filter.

[0011] Furthermore, when a background filter, n c Characteristic filters, n rWhen three filters such as a reference filter are used, the sampling system only has a sampler 12, and its forward and reverse spectroscopic scanning signals are equivalent to the spectrum collected at the same time. When the host computer sends a measurement instruction, the acquisition control circuit controls the stepper motor to drive the filter disc to rotate for forward and reverse scanning to obtain the collected digital quantity D k and D' k , calculate the spectrum value S, the measurement method includes the following steps:

[0012] A. The host computer sends a measurement command, and the microprocessor unit of the acquisition control circuit receives the command and performs a spectrum measurement scan and acquisition, and executes in sequence:

[0013] a. Control the light source system to light up the light source;

[0014] b. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0015] c. Control the stepper motor I2 to scan forward and rotate to each filter position in turn. At the same time, control the ADC sampling to obtain the collected data of m filter positions. d k , k = 1, 2, ..., m; m is the number of all filters on the filter disk 3,

[0016] d. Control the stepper motor I2 to scan in reverse, and turn to each filter position in reverse order. At the same time, control the ADC sampling to obtain the collected data d' of m filter positions. k ;

[0017] e. After the forward and reverse scanning acquisition is completed, the microprocessor sends all the acquired digital quantities to the host computer in order;

[0018] B. The host computer receives the collected data and calculates the spectral value of a measurement.

[0019] a. Calculate the equivalent scanning data collected by each filter at the same time: average the forward and reverse scanning digital data of the same filter, then:

[0020]

[0021] b. Calculate the spectrum value according to a characteristic wavelength λ ci Scanning data at, and characteristic wavelength λ ci The corresponding reference wavelength λ rij Scanning data, calculate λ ci Spectral data S ci :

[0022]

[0023] Among them, D ciis the characteristic wavelength λ ci The corresponding equivalent scanning data collected simultaneously, the subscript ci represents the characteristic wavelength λ ci The position number of the corresponding filter on the filter disk 3; i = 1, 2, ..., n c ;n c is the number of characteristic filters on the filter disk 3;

[0024] T λci is the characteristic wavelength λ ci The transmittance of the corresponding filter;

[0025] D b is the equivalent and simultaneously collected scanning data corresponding to the background filter 8;

[0026] D rij is the characteristic wavelength λ ci The reference wavelength λ rij The corresponding equivalent scanning data collected simultaneously, the subscript rij represents the reference wavelength λ rij The position number of the corresponding filter on the filter disk 3; j = 1, 2, ..., n ri ;n ri is the characteristic wavelength λ on filter disk 3 ci The number of corresponding reference wavelength filters; and

[0027] T rij is the characteristic wavelength λ ci The reference wavelength λ rij Corresponding to the transmittance of the filter.

[0028] ρ rij is the reference wavelength λ rij The signal calculation weight is related to each characteristic wavelength λ ci and the reference wavelength λ selected rij are related, and the sum is 1. When n ri =2,

[0029]

[0030] C. Repeat steps A and B L times, perform L spectral measurements, and obtain L sets of spectral data S. cil , take each characteristic wavelength λ ci The corresponding average value of the spectral data is:

[0031]

[0032] D. End.

[0033] Furthermore, the spectroscopic system of the portable grating scanning spectrometer is coaxially connected by a stepper motor II 22 and a lead screw 23, and the lead screw 23 and the nut 24 form a lead screw nut mechanism, which drives the scanning grating 26 fixed on the rocker 25 to rotate, so that monochromatic light of different wavelengths enters the sampling system in sequence; the two photoelectric switches 27 of the spectroscopic system are respectively fixed at the scanning start position and the end position and are connected to the acquisition control circuit, and after detecting the position of the zero position baffle 28, the position signal is sent to the acquisition control circuit.

[0034] Furthermore, the sampling system is connected to the rotating shaft of the sample tray 14 and the collection control circuit by a sampling transposition motor 13, and the sampler 12 is fixed at the outlet of the spectroscopic system, and the sampling position is aligned with the sampling position of the sample tray 14.

[0035] Furthermore, when there is only one type of m characteristic filters on the filter disk 3 of the portable filter-type spectrometer or when the forward and reverse spectroscopic scanning signals of the portable grating scanning spectrometer are equivalently collected for spectrum measurement at the same time, the measurement method includes the following steps:

[0036] A. The host computer sends a measurement command, and the acquisition control circuit controls the light source system to work and light up the light source;

[0037] B. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0038] C. Reference forward scan:

[0039] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor II22 of the spectroscopic system to perform forward scanning, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. rk , k = 1, 2, ..., m; m is the number of spectroscopic signals output by the spectroscopic system; after the scan is completed, the data d is collected rk Send to the host computer in order;

[0040] D. Background reverse scanning:

[0041] The acquisition control circuit controls the sampling system to sample the background, controls the stepper motor II22 of the spectroscopic system to perform reverse scanning, and controls the ADC acquisition unit to sample, thereby obtaining the reverse scanning acquisition data d' of m wavelength positions. bk ; After scanning, collect data d' bk Send to the host computer in order;

[0042] If the background is 0, this step can be omitted;

[0043] E. Scan the sample in forward and reverse directions:

[0044] a. The acquisition control circuit controls the sampling system to take samples;

[0045] b. Control the stepper motor II22 to scan forward and move to each splitting position in turn, and control the ADC sampling at the same time to obtain the forward scanning data of m wavelength positions. sk ; After the forward scan is completed, d sk Send to the host computer in order;

[0046] c. Control the stepper motor II22 to scan in reverse, and rotate in reverse to each splitting position in turn, and control the ADC sampling at the same time to obtain the reverse scanning data d' of m wavelength positions sk ; After the reverse scan is completed, d' sk Send to the host computer in order;

[0047] F. Background forward scanning:

[0048] The acquisition control circuit controls the sampling system to sample the background, controls the stepper motor II22 to scan forward, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. bk ; After scanning, collect data d bk Send to the host computer in order;

[0049] If the background is 0, this step can be omitted;

[0050] G. Reference reverse scan:

[0051] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor II22 to perform reverse scanning, and controls the ADC sampling to obtain the acquisition data d' at m wavelength positions. rk ; After scanning, collect data d' rk Send to the host computer in order;

[0052] H. After receiving all collected data, the host computer calculates the spectrum value:

[0053] a. Calculate the scan data of reference, background and sample collected at each wavelength at the same time:

[0054]

[0055] b. Calculate the spectrum value S for each wavelength k :

[0056]

[0057] I. A spectrum measurement is completed.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The spectral measurement method for equivalent simultaneous collection of forward and reverse spectral scanning signals provided by the present invention controls the spectral system of a portable scanning spectral instrument to perform forward and reverse scanning at a uniform speed and intervals, collects the collected digital quantities of spectral signals of each wavelength obtained by the forward and reverse bidirectional scanning, and takes the average of the collected digital quantities of the same wavelength as equivalent simultaneous collection data; the spectral value is calculated by the equivalent simultaneous collection data, although the spectral measurement time is increased, the influence of the instability of the light source intensity and the circuit conversion characteristics on the spectral data can be effectively eliminated, thereby improving the accuracy and stability of the spectral measurement of the portable scanning spectral instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0061] Figure 1 Portable scanning spectrometer structure diagram;

[0062] Figure 2a Right view of the filter disc structure diagram;

[0063] Figure 2b The front view of the filter disc structure diagram;

[0064] Figure 3 Acquisition control circuit block diagram;

[0065] Figure 4a A top view of the sampling system structure diagram;

[0066] Figure 4b The main view of the sampling system structure diagram;

[0067] Figure 5 Structural diagram of the spectral system of the grating scanning spectrometer;

[0068] Figure 6 Flow chart of the spectrum measurement method for equivalent simultaneous acquisition of spectroscopic scanning signals of a grating scanning spectrum instrument;

[0069] Figure 7 Flow chart of the method for equivalently and simultaneously collecting spectrum measurement of the spectroscopic scanning signal of a filter-type spectral instrument. DETAILED DESCRIPTION

[0070] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0071] The present invention discloses a method for measuring spectrum by equivalently collecting forward and reverse spectral scanning signals at the same time, adopts a portable scanning spectrometer for measurement, and improves on the original measurement method of the portable scanning spectrometer. In each measurement scan, a step of performing reverse scanning in reverse order of measurement is added to obtain the collected digital quantities d in the forward and reverse directions. k and d' k (k = 1, 2, ..., m, m is the number of splitting signals output by the splitting system), the two are averaged at the same wavelength position, that is, d k and d' m-k+1 After taking the average, we get D k , with D k The spectrum value S is calculated by the original spectrum calculation method to obtain the collected amount of spectroscopic signals. Although this method increases the time of spectrum measurement, it can effectively eliminate the influence of light source intensity and circuit conversion characteristics on spectrum data, and improve the accuracy and stability of spectrum measurement of portable scanning spectrometer.

[0072] The portable scanning spectrometer comprises a light source system, a photoelectric conversion and amplification conditioning circuit, a collection control circuit, a spectroscopic system, a sampling system and a host computer. The collection control circuit is respectively connected to the light source system, the photoelectric conversion and amplification conditioning circuit, the spectroscopic system, the sampling system and the host computer.

[0073] The acquisition control circuit block diagram is as follows Figure 3 As shown, it includes an ADC acquisition unit, a microprocessor unit, a serial communication unit and a motor drive unit. The microprocessor unit is connected to the ADC acquisition unit, the motor drive unit and the serial communication unit respectively. The ADC acquisition unit, the microprocessor unit, the serial communication unit and the motor drive unit are connected to the light source system, the photoelectric conversion and amplification conditioning circuit, the spectroscopic system, the sampling system and the host computer respectively. Specifically, the ADC acquisition unit is connected to the photoelectric conversion and amplification conditioning circuit, the microprocessor unit is connected to the light source system, the serial communication unit is connected to the host computer, and the motor drive unit is connected to the spectroscopic system and the sampling system.

[0074] The ADC acquisition unit is used to collect analog signals and convert them into digital quantities. The microprocessor unit is used to control the operation of the light source system, control the scanning stepper motor and the sampling system through the motor drive and detection circuit, and receive the photoelectric switch signal and the collected digital quantity of the ADC acquisition unit. The serial communication unit is used to realize two-way communication between the microprocessor unit and the host computer.

[0075] The spectroscopic system is mainly composed of three parts: stepper motor Ⅰ 2, spectroscopic component and photoelectric switch 4. Commonly used portable scanning spectrometers include filter type and grating scanning type.

[0076] For a portable filter-type spectrometer, as shown in FIG2 , the stepper motor I2 of the spectroscopic system is connected to the transmission mechanism, and the stepper motor I2 is coaxially connected to the spectroscopic components, specifically the filter disc 3, and is connected to the motor drive unit of the acquisition control circuit. The filter disc 3 is provided with a plurality of filter holes and a zero-position baffle 6. The photoelectric switch 4 is connected to the acquisition control circuit.

[0077] Specifically, the stepper motor I2 is fixed on the fixed bracket 1, coaxially connected with the filter disc 3, and receives the control signal of the acquisition control circuit. There are multiple filter holes 5 distributed on the filter disc 3, and the required measurement filters are installed in each filter hole 5 in sequence. The filters include a background filter, n c Characteristic filters, n r Reference filter. As shown in FIG2 , four filters are installed on the filter disc 3, which are: background filter 8, characteristic filter 9, first reference filter 10 and second reference filter 11. The number and order of installation are for reference only. A zero-position baffle 6 is installed on the filter disc 3. The photoelectric switch 4 detects the zero-position baffle 6 on the filter disc 3 and generates a zero-position signal which is received by the acquisition control circuit and is used to determine the initial position of the filter disc 3. When the spectroscopic system is working, the acquisition control circuit controls the filter holes 5 on the filter disc 3 to be transferred into the system optical path 7 in turn to collect the signals of the required measurement filters.

[0078] When the filter disk 3 of the portable filter-type spectrometer has only one type of m characteristic filters, its sampling system structure and measurement method are consistent with those of the grating scanning type spectrometer and its measurement method.

[0079] When a background filter, n c Characteristic filters, n r When there are three filters such as a reference filter, the sampling system only has a sampler 12, and its forward and reverse spectroscopic scanning signals are equivalent to the spectrum measurement method collected simultaneously. The host computer sends a measurement instruction, and the acquisition control circuit controls the stepper motor to drive the filter disc to rotate for forward and reverse scanning to obtain the collected digital quantity D k and D' k , calculate the spectrum value S, the measurement method includes the following steps:

[0080] 1. The host computer sends a measurement command, and the microprocessor unit of the acquisition control circuit receives the command and performs a spectrum measurement scan and acquisition, and executes in sequence:

[0081] a. Control the light source system to light up the light source;

[0082] b. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0083] c. Control the stepper motor I2 to scan forward and rotate to each filter position in turn. At the same time, control the ADC sampling to obtain the collected data of m filter positions. d k , k = 1, 2, ..., m; m is the number of all filters on the filter disk 3,

[0084] d. Control the stepper motor I2 to scan in reverse, and turn to each filter position in reverse order. At the same time, control the ADC sampling to obtain the collected data d' of m filter positions. k ;

[0085] e. After the forward and reverse scanning acquisition is completed, the microprocessor sends all the acquired digital quantities to the host computer in order;

[0086] 2. The host computer receives the collected data and calculates the spectral value of a measurement.

[0087] a. Calculate the equivalent scanning data collected by each filter at the same time: average the forward and reverse scanning digital data of the same filter, then:

[0088]

[0089] b. Calculate the spectrum value according to a characteristic wavelength λ ci Scanning data at, and characteristic wavelength λ ci Corresponding reference wavelength λ rij Scanning data, calculate λ ci Spectral data S ci :

[0090]

[0091] Among them, D ci is the characteristic wavelength λ ci The corresponding equivalent scanning data collected simultaneously, the subscript ci represents the characteristic wavelength λ ci The position number of the corresponding filter on the filter disk 3; i = 1, 2, ..., n c ;n c is the number of characteristic filters on the filter disk 3;

[0092] T λci is the characteristic wavelength λ ci The transmittance of the corresponding filter;

[0093] D b is the equivalent and simultaneously collected scanning data corresponding to the background filter 8;

[0094] D rij is the characteristic wavelength λ ci The reference wavelength λ rijThe corresponding equivalent scanning data collected simultaneously, the subscript rij represents the reference wavelength λ rij The position number of the corresponding filter on the filter disk 3; j = 1, 2, ..., n ri ;n ri is the characteristic wavelength λ on filter disk 3 ci The number of corresponding reference wavelength filters; and

[0095] T rij is the characteristic wavelength λ ci The reference wavelength λ rij Corresponding to the transmittance of the filter.

[0096] ρ rij is the reference wavelength λ rij The signal calculation weight is related to each characteristic wavelength λ ci and the reference wavelength λ selected rij are related, and the sum is 1. When n ri =2,

[0097]

[0098] 3. Repeat steps 1 and 2 L times, perform L spectral measurements, and obtain L sets of spectral data S cil , take each characteristic wavelength λ ci The corresponding average value of the spectral data is:

[0099]

[0100] 4. End.

[0101] The spectroscopic system of the portable grating scanning spectrometer is coaxially connected with a stepper motor II 22 and a lead screw 23. The lead screw 23 and a nut 24 form a lead screw nut mechanism, which drives the scanning grating 26 fixed on the swing rod 25 to rotate, so that monochromatic light of different wavelengths enters the sampling system in sequence; the two photoelectric switches 27 of the spectroscopic system are respectively fixed at the scanning start position and the end position and connected to the acquisition control circuit, and the position signal is sent to the acquisition control circuit after detecting the position of the zero-position baffle 28. The sampling system is connected to the rotating shaft of the sample disk 14 and the acquisition control circuit by the sampling transposition motor 13, and the sampler 12 is fixed at the exit of the spectroscopic system, and the sampling position 16 is aligned with the sampling position of the sample disk 14. A zero-position baffle 6 is installed in the transmission mechanism, and the photoelectric switch detects the zero-position baffle 6 and generates a zero-position signal. The acquisition control circuit receives the zero-position signal to determine the initial position.

[0102] A spectrum measurement method for equivalently and simultaneously collecting forward and reverse spectroscopic scanning signals of a grating scanning spectrum instrument comprises the following steps:

[0103] 1. The host computer sends a measurement command, and the acquisition control circuit controls the light source system to work and light up the light source;

[0104] 2. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0105] 3. Reference forward scan:

[0106] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor of the spectroscopic system to perform forward scanning, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. rk , k = 1, 2, ..., m; m is the number of spectroscopic signals output by the spectroscopic system; after the scan is completed, the data d is collected rk Send to the host computer in order;

[0107] 4. Background reverse scanning:

[0108] The acquisition control circuit controls the sampling system to sample the background, controls the scanning stepper motor of the spectroscopic system to perform reverse scanning, and controls the ADC acquisition unit to sample, and obtains the reverse scanning acquisition data d' of m wavelength positions. bk ; After scanning, collect data d' bk Send to the host computer in order;

[0109] If the background is 0, this step can be omitted;

[0110] 5. The samples are scanned forward and reversely in sequence:

[0111] a. The acquisition control circuit controls the sampling system to take samples;

[0112] b. Control the scanning stepper motor to scan forward and move to each splitting position in turn. At the same time, control the ADC sampling to obtain the forward scanning data of m wavelength positions. d sk ; After the forward scan is completed, d sk Send to the host computer in order;

[0113] c. Control the stepper motor II22 to scan in reverse, and rotate in reverse to each splitting position in turn, and control the ADC sampling at the same time to obtain the reverse scanning data d' of m wavelength positions sk ; After the reverse scan is completed, d' sk Send to the host computer in order;

[0114] 6. Background forward scanning:

[0115] The acquisition control circuit controls the sampling system to sample the background, controls the stepper motor II22 to scan forward, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. bk ; After scanning, collect data dbk Send to the host computer in order;

[0116] If the background is 0, this step can be omitted;

[0117] 7. Reference reverse scan:

[0118] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor II22 to perform reverse scanning, and controls the ADC sampling to obtain the acquisition data d' at m wavelength positions. rk ; After scanning, collect data d' rk Send to the host computer in order;

[0119] 8. After receiving all collected data, the host computer calculates the spectrum value.

[0120] a. Calculate the scan data of reference, background and sample collected at each wavelength at the same time:

[0121]

[0122] b. Calculate the spectrum value S for each wavelength k :

[0123]

[0124] 9. A spectrum measurement is completed.

[0125] The structure diagram of the sampling system is shown in FIG4 , and the sampler structure is different under different sampling modes. Taking the sampling mode of diffuse reflection of an integrating sphere as an example, the sampling system includes a sampler 12, a sampling transposition motor 13, a sample tray 14, and a photoelectric positioning 21. The sampling transposition motor 13 is connected to the sample tray shaft 18 and the acquisition control circuit. The acquisition control circuit controls the sampling transposition motor 13 to drive the sample tray 14 to rotate, so as to switch between three types of objects to be tested: reference, background, and sample. Align the sampling position 16 with the sampling position 19 of the sample tray; in the sampler, monochromatic light enters the sampler from the light inlet 15 of the sampler 12, reacts with the object to be tested, and the reacted light signal is received by the photoelectric conversion and amplification conditioning circuit at the light outlet 17. The photoelectric positioning 21 detects the position of the zero position slot 20 of the sample tray 14 and sends the position information to the acquisition control circuit.

[0126] Example 1

[0127] The spectral measurement of the portable filter-type spectral instrument with equivalent simultaneous acquisition of forward and reverse spectral scanning signals includes the following steps:

[0128] When the filter disc includes three kinds of filters, the sampling system structure has only the sampler 12, the light inlet is aligned with the outlet of the spectroscopic system, and the light outlet is aligned with the photoelectric sensor of the photoelectric conversion and amplification conditioning circuit; the spectrum measurement method of the forward and reverse spectroscopic scanning signals being equivalently collected at the same time is different from that described in Example 2. The host computer sends a measurement instruction, and the collection control circuit controls the stepping motor I2 to drive the filter disc 3 to rotate and perform forward and reverse scanning to obtain the collected digital quantity D k and D' k , calculate the spectrum value S, the measurement flow chart is as follows Figure 6 As shown, the following steps are included:

[0129] 1. The host computer sends a measurement command, and the microprocessor unit of the acquisition control circuit receives the command and performs a spectrum measurement scan and acquisition, and executes in sequence:

[0130] a. Control the light source system to light up the light source;

[0131] b. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0132] c. Control the stepper motor I2 to scan forward and rotate to each filter position in turn. At the same time, control the ADC sampling to obtain the collected data of m filter positions. d k , k = 1, 2, ..., m; m is the number of all filters on the filter disc,

[0133] d. Control the stepper motor to scan in reverse, and turn to each filter position in turn. At the same time, control the ADC sampling to obtain the collected data d' of m filter positions k ;

[0134] e. After the forward and reverse scanning acquisition is completed, the microprocessor sends all the acquired digital quantities to the host computer in order;

[0135] 2. The host computer receives the collected data and calculates the spectral value of a measurement

[0136] a. Calculate the equivalent scanning data collected by each filter at the same time: average the forward and reverse scanning digital data of the same filter, then:

[0137]

[0138] b. Calculate the spectrum value according to a characteristic wavelength λ ci Scanning data at, and characteristic wavelength λ ci Corresponding reference wavelength λ rij Scanning data, calculate λ ci Spectral data S ci :

[0139]

[0140] Among them, D ci is the characteristic wavelength λ ci The corresponding equivalent scanning data collected simultaneously, the subscript ci represents the characteristic wavelength λ ci The position number of the corresponding filter on the filter disk 3; i = 1, 2, ..., n c ;n c is the number of characteristic filters on the filter disk 3;

[0141] T λci is the characteristic wavelength λ ci The transmittance of the corresponding filter;

[0142] D b is the equivalent and simultaneously collected scanning data corresponding to the background filter 8;

[0143] D rij is the characteristic wavelength λ ci The reference wavelength λ rij The corresponding equivalent scanning data collected simultaneously, the subscript rij represents the reference wavelength λ rij The position number of the corresponding filter on the filter disk; j = 1, 2, ..., n ri ;n ri is the characteristic wavelength λ on the filter disc ci The number of corresponding reference wavelength filters; and

[0144] T rij is the characteristic wavelength λ ci The reference wavelength λ rij Corresponding to the transmittance of the filter.

[0145] ρ rij is the reference wavelength λ rij The signal calculation weight is related to each characteristic wavelength λ ci and the reference wavelength λ selected rij are related, and the sum is 1. When n ri =2,

[0146]

[0147] 3. Repeat steps 1 and 2 for L times, perform L spectral measurements, and obtain L sets of spectral data S cil , take each characteristic wavelength λ ci The corresponding average value of the spectral data is:

[0148]

[0149] 4. End.

[0150] Example 2

[0151] Portable grating scanning spectrometer is a spectral measurement that collects the forward and reverse spectroscopic scanning signals equivalently and simultaneously, such as Figure 6 As shown, the following steps are included:

[0152] 1. The host computer sends a measurement command, and the acquisition control circuit controls the light source system to work and light up the light source;

[0153] 2. Receive the photoelectric switch signal of the spectroscopic system and determine whether it is a zero signal. If yes, continue; if no, repeat this step;

[0154] 3. Reference forward scan:

[0155] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor II22 of the spectroscopic system to perform forward scanning, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. rk , k = 1, 2, ..., m; m is the number of spectroscopic signals output by the spectroscopic system; after the scan is completed, the data d is collected rk Send to the host computer in order;

[0156] 4. Background reverse scanning:

[0157] The acquisition control circuit controls the sampling system to sample the background, controls the stepper motor II22 of the spectroscopic system to perform reverse scanning, and controls the ADC acquisition unit to sample, thereby obtaining the reverse scanning acquisition data d' of m wavelength positions. bk ; After scanning, collect data d' bk Send to the host computer in order;

[0158] If the background is 0, this step can be omitted;

[0159] 5. The samples are scanned forward and reversely in sequence:

[0160] a. The acquisition control circuit controls the sampling system to take samples;

[0161] b. Control the stepper motor II22 to scan forward and move to each splitting position in turn, and control the ADC sampling at the same time to obtain the forward scanning data of m wavelength positions. sk ; After the forward scan is completed, d sk Send to the host computer in order;

[0162] c. Control the stepper motor II22 to scan in reverse, and rotate in reverse to each splitting position in turn, and control the ADC sampling at the same time to obtain the reverse scanning data d' of m wavelength positions sk ; After the reverse scan is completed, d' sk Send to the host computer in order;

[0163] 6. Background forward scanning:

[0164] The acquisition control circuit controls the sampling system to sample the background, controls the stepper motor II22 to scan forward, and controls the ADC sampling to obtain the acquisition data d at m wavelength positions. bk ; After scanning, collect data d bk Send to the host computer in order;

[0165] If the background is 0, this step can be omitted;

[0166] 7. Reference reverse scan:

[0167] The acquisition control circuit controls the sampling system to sample the reference, controls the stepper motor II22 to perform reverse scanning, and controls the ADC sampling to obtain the acquisition data d' at m wavelength positions. rk ; After scanning, collect data d' rk Send to the host computer in order;

[0168] 8. After receiving all collected data, the host computer calculates the spectrum value.

[0169] a. Calculate the scan data of reference, background and sample collected at each wavelength at the same time:

[0170]

[0171] b. Calculate the spectrum value S for each wavelength k :

[0172]

[0173] 9. A spectrum measurement is completed.

[0174] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for measuring spectrum by equivalently collecting forward and reverse spectral scanning signals simultaneously, characterized in that: A portable scanning spectrometer is used for measurement. Based on the original measurement method of the portable scanning spectrometer, a reverse scanning step is added in the reverse order of the measurement in each measurement scan to obtain the forward and reverse collected digital quantities d k and d' k , k = 1, 2, ..., m, where m is the number of split signals output by the splitting system, and the two are averaged at the same wavelength position, that is, d k and d' m-k+1 After taking the average, we get D k , with D k is the amount of spectroscopic signal collected, and the spectrum value S is obtained by calculating the original spectrum calculation method; The portable scanning spectrometer includes an acquisition control circuit composed of a microprocessor unit and an ADC acquisition unit, a motor drive unit and a serial communication unit connected thereto, and the acquisition control circuit is respectively connected to a light source system, a photoelectric conversion and amplification conditioning circuit, a spectroscopic system, a sampling system and a host computer; The portable scanning spectrometer is a portable filter-type spectrometer. The filter disc of the portable filter-type spectrometer is equipped with a background filter, n c Characteristic filters, n r A reference filter, the spectrum value calculation method includes the following steps: According to a characteristic wavelength λ ci Scanning data at, and characteristic wavelength λ ci Corresponding reference wavelength λ rij Scanning data, calculate λ ci Spectral data S ci : Among them, D ci is the characteristic wavelength λ ci The corresponding equivalent scanning data collected simultaneously, the subscript ci represents the characteristic wavelength λ ci The position number of the corresponding filter on the filter disk (3); i=1, 2, ..., n c ;n c is the number of characteristic filters on the filter disc; T λci is the characteristic wavelength λ ci The transmittance of the corresponding filter; D b is the equivalent scanning data collected simultaneously corresponding to the background filter; D rij is the reference wavelength λ rij The corresponding equivalent scanning data collected simultaneously, the subscript rij represents the reference wavelength λ rij The position number of the corresponding filter on the filter disk (3); j = 1, 2, ..., n ri ;n ri is the characteristic wavelength λ on the filter disk (3) ci The number of corresponding reference wavelength filters; and T rij is the reference wavelength λ rij The transmittance of the corresponding filter; ρ rij is the reference wavelength λ rij The signal calculation weight is related to each characteristic wavelength λ ci and the reference wavelength λ selected rij are related, and the sum is 1.

2. A method for measuring spectrum by equivalently collecting forward and reverse spectral scanning signals simultaneously, characterized in that: A portable scanning spectrometer is used for measurement. Based on the original measurement method of the portable scanning spectrometer, a reverse scanning step is added in the reverse order of the measurement in each measurement scan to obtain the forward and reverse collected digital quantities d k and d' k , k = 1, 2, ..., m, where m is the number of split signals output by the splitting system, and the two are averaged at the same wavelength position, that is, d k and d' m-k+1 After taking the average, we get D k , with D k is the amount of spectroscopic signal collected, and the spectrum value S is obtained by calculating the original spectrum calculation method; The portable scanning spectrometer includes an acquisition control circuit composed of a microprocessor unit and an ADC acquisition unit, a motor drive unit and a serial communication unit connected thereto, and the acquisition control circuit is respectively connected to a light source system, a photoelectric conversion and amplification conditioning circuit, a spectroscopic system, a sampling system and a host computer; The portable scanning spectrometer is a portable filter-type spectrometer, and the filter disk (3) of the portable filter-type spectrometer is equipped with m characteristic filters, or the portable scanning spectrometer is a portable grating scanning spectrometer, and the calculation of the spectrum value includes the following steps: a. Calculate the scan data of reference, background and sample collected at each wavelength at the same time: b. Calculate the spectrum value S for each wavelength k :

3. A method for measuring spectrum of forward and reverse spectral scanning signals by equivalently collecting spectrum simultaneously according to claim 1 or 2, characterized in that: The ADC acquisition unit is connected to the photoelectric conversion and amplification conditioning circuit, the microprocessor unit is connected to the light source system, the serial communication unit is connected to the host computer, and the motor drive unit is connected to the spectroscopic system and the sampling system respectively; the ADC acquisition unit is used to acquire analog signals and convert them into digital quantities; the microprocessor unit is used to control the operation of the light source system, control the scanning stepping motor and the sampling system through the motor drive and detection circuit, and receive the photoelectric switch signal and the collected digital quantity of the ADC acquisition unit; the serial communication unit is used to realize two-way communication between the microprocessor unit and the host computer.

4. A method for measuring spectrum by equivalently collecting forward and reverse spectral scanning signals simultaneously according to claim 1 or 2, characterized in that: The spectroscopic system of the portable filter-type spectrometer comprises a stepper motor (2) connected to a transmission mechanism, the stepper motors (2) are respectively coaxially connected to the filter disc (3) to receive control signals from a collection control circuit, a plurality of filter holes (5) and a zero-position baffle (6) are distributed on the filter disc (3), a photoelectric switch (4) is connected to the collection control circuit, the photoelectric switch (4) detects the zero-position baffle (6) on the filter disc (3) and generates a zero-position signal which is received by the collection control circuit and is used to determine the initial position of the filter disc (3); The filter holes (5) can be sequentially transferred into the system optical path (7) to collect signals of the required measurement filters.

5. The method for measuring spectrum of forward and reverse spectral scanning signals by equivalently collecting spectrum simultaneously according to claim 1, characterized in that: The sampling system only has a sampler (12), and its forward and reverse spectroscopic scanning signals are equivalent to the spectrum measurement collected at the same time. When the host computer sends a measurement instruction, the collection control circuit controls the stepping motor to drive the filter disc to rotate and perform forward and reverse scanning to obtain the collected digital quantity D k and D' k , calculate the spectral value S.

6. The method for measuring spectrum of forward and reverse spectral scanning signals by equivalently collecting spectrum simultaneously according to claim 2, characterized in that: The spectroscopic system of the portable grating scanning spectrometer is composed of a stepper motor II (22) and a lead screw (23) coaxially connected, and the lead screw (23) and a nut (24) form a lead screw nut mechanism, which drives the scanning grating (26) fixed on the swing rod (25) to rotate, so that monochromatic light of different wavelengths enters the sampling system in sequence; two photoelectric switches (27) of the spectroscopic system are respectively fixed at the scanning start position and the end position and connected to the acquisition control circuit, and after detecting the position of the zero position baffle (28), the position signal is sent to the acquisition control circuit.

7. The method for measuring spectrum of forward and reverse spectral scanning signals by equivalently collecting spectrum simultaneously according to claim 6, characterized in that: The sampling system comprises a sampling transposition motor (13) connected to the rotating shaft of the sample disk (14) and a collection control circuit respectively; the sampler (12) is fixed at the exit of the spectroscopic system, and the sampling position is aligned with the sampling position of the sample disk (14).

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