Patent Application
20210270743
Embodiments of the present disclosure generally relate to the field of Raman spectrum detection, and particularly, to a Raman spectrum detection apparatus and a method of monitoring detection security of the Raman spectrum detection apparatus.
Raman spectrum analysis technology is a non-contact spectrum analysis technology based on Raman scattering effect, which can qualitatively and quantitatively analyze the composition of a substance. Raman spectrum is a molecular vibration spectrum that can represent the fingerprint characteristics of molecules, and can be used for the inspection of substance. Raman spectrum detection can inspect and identify the substance by the Raman spectrum generated by the Raman scattering effect of the object to be inspected with respect to exciting light. Raman spectrum detection technology has been widely used in the fields of liquid safety inspection, explosive detection, drug detection, medicine detection and the like.
In applications of the Raman spectrum analysis technologies, there are multifarious objects to be detected, and various substances therein have different physical characteristics and thereby have different thermal sensitivities to laser irradiation used in Raman spectrum analysis technology. Laser having a high power density is generally used as an exciting light source in Raman spectrum detection, for example, near infrared laser light of 785 nm has a stronger thermal effect, thus in case that components of a sample to be detected are not known, a rushed detection made by using such laser light may possibly cause the sample to be burned and damaged by the laser light, or even lead to burning or exploding of a flammable and explosive chemical, resulting in personal and property loss.
The present disclosure is made to at least partly solve or alleviate at least one aspect of the above mentioned and other disadvantages or problems in prior arts.
According to an aspect of the present disclosure, there is provided a method of monitoring detection security of a Raman spectrum detection apparatus, comprising steps of:
emitting excited light by a light source and guiding the excited light to a sample to be detected;
collecting a light signal generated by the sample under irradiation of the excited light and generating spectrum data representing the light signal;
determining a first part of the spectrum data representing an excited light component of the light signal and a second part of the spectrum data representing a Raman scattered component and a fluorescence component of the light signal;
calculating a first parameter, which represents an amplitude of a spectral intensity, and a second parameter, which represents a fluctuation of the spectral intensity, of each of the first part and the second part;
comparing the first parameter of the first part with the first parameter of the second part, and comparing the second parameter of the first part with the second parameter of the second part; and
determining whether or not the sample is a deep-colored substance based on comparison results.
In one embodiment, the step of determining whether or not the sample is a deep-colored substance based on comparison results comprises:
determining the sample is a deep-colored substance, if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is greater than the second parameter of the second part; and
determining the sample is a transparent substance, if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is smaller than the second parameter of the second part.
In one embodiment, the first parameter includes a mean value of spectral intensities, and the second parameter includes a standard deviation of spectral intensities.
In one embodiment, the mean value and the standard deviation are calculated by using following equations:
where, u represents the mean value, σ represents the standard deviation, Xi represents the ith spectrum data, and n represents the number of spectrum data of the first part or the second part.
In one embodiment, the first part represents spectrum data of a portion of the light signal having a Raman shift within a range from −10 cm−1 to 10 cm−1, and the second part represents spectrum data of another portion of the light signal having a Raman shift within a range from 350 cm−1 to 2000 cm−1.
In one embodiment, the method further comprises: stopping irradiation of the excited light to the sample if it is determined that the sample is a deep-colored substance.
In one embodiment, the excited light is emitted by the light source within a preset time duration so as to irradiate the sample.
In one embodiment, the Raman spectrum detection apparatus comprises a spectrometer configured for detecting the light signal generated by the sample under irradiation of the excited light so as to generate the Raman spectrum of the detected sample, and the step of collecting a light signal generated by the sample under irradiation of the excited light and generating spectrum data representing the light signal comprises: collecting by the spectrometer the light signal generated by the sample under irradiation of the excited light so as to generate the spectrum data.
In one embodiment, the excited light component of the light signal from the sample includes a Rayleigh-scattered component.
According to another aspect of the present disclosure, there is provided a Raman spectrum detection apparatus, comprising:
a spectrometer configured to collect a light signal generated by a sample under irradiation of excited light so as to generate spectrum data representing the light signal; and
a data processor configured to:
receive the spectrum data from the spectrometer, and determining a first part of the spectrum data representing an excited light component of the light signal and a second part of the spectrum data representing a Raman scattered component and a fluorescence component of the light signal;
calculate a first parameter, which represents an amplitude of a spectral intensity, and a second parameter, which represents a fluctuation of the spectral intensity, of each of the first part and the second part;
compare the first parameter of the first part with the first parameter of the second part, and compare the second parameter of the first part with the second parameter of the second part; and
determine whether or not the sample is a deep-colored substance based on comparison results.
In one embodiment, the data processor is further configured to:
determine the sample is a deep-colored substance, if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is greater than the second parameter of the second part; and
determine the sample is a transparent substance, if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is smaller than the second parameter of the second part.
In one embodiment, the first parameter includes a mean value of spectral intensities, and the second parameter includes a standard deviation of spectral intensities.
In one embodiment, the data processor is further configured to calculate the mean value and the standard deviation by using following equations:
where, U represents the mean value, σ represents the standard deviation, Xi represents the ith spectrum data, and n represents the number of spectrum data of the first part or the second part.
In one embodiment, the data processor is further configured to: determine a part of the spectrum data corresponding to a portion of the light signal having a Raman shift in a range from −10 cm−1 to 10 cm−1 as the first part, and determine another part of the spectrum data corresponding to another portion of the light signal having a Raman shift in a range from 350 cm−1 to 2000 cm−1 as the second part.
In one embodiment, the Raman spectrum detection apparatus further comprises: a light source for emitting the excited light; and a controller configured to control the light source to stop irradiation of the excited light to the sample when the sample is determined to be the deep-colored substance by the data processor.
In one embodiment, the light source is configured to emit the excited light to irradiate the sample within a preset time duration, and the spectrometer is configured to collect the light signal generated by the sample under irradiation of the excited light so as to generate the spectrum data, based on which the data processor determines whether or not the sample is the deep-colored substance.
In one embodiment, the preset time duration is in a range from 0.5 milliseconds to 5 milliseconds.
In one embodiment, the excited light component of the light signal from the sample includes a Rayleigh-scattered component.
Other objects and advantages of the present disclosure will become apparent from the following description of the present disclosure taken in conjunction with the accompanying drawings, and may give a comprehensive understanding of the present disclosure.
The above and other features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings, which are schematic and should not be interpreted as being limitative to the present disclosure, and in which:
Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein the like reference numerals refer to the like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
During the Raman spectrum detection, it will generally face a security issue where a temperature of the sample is increased due to absorbing heat during irradiation of the laser light onto the sample, which thereby may result in ablation, or even burning or exploding of the detected sample. For a deep-colored substance, especially a non-transparent substance or black substance, a possibility of degradation, ablation, burning or exploding of the substance due to too stronger power density of the laser light will be increased. It will be appreciated that, the expression“deep-colored substance” represents a substance which will absorb heat under irradiation of the excited light during the Raman spectrum detection and thus will be easily ablated, burned or exploded, and which may have a grayscale in a range from 0 to 50, preferably, in a range from 0 to 30. Of course, a specific form of the deep-colored substance may be determined by those skilled in the art according to actual applications, specific detection conditions or historical experiences.
In an embodiment of the present disclosure, as shown in
The excited light emitted from the light source 10, when reaching the sample 1 to be detected, will be reflected and scattered at the sample 1, including diffuse reflection occurring at a surface of the sample 1, and Rayleigh scattering and Raman scattering in the sample 1, and in addition, fluorescent light is also generated from the sample under excitation. In practice, a light intensity for a excited light waveband received by the spectrometer and a light intensity for a Raman scattering waveband received by the spectrometer are also at substantially the same order, because an initial light intensity of the excited light emitted by the light source is significantly larger than the Raman scattering light intensity, and because in the excited light waveband received by the spectrometer, an intensity of backward-Rayleigh scattered light is significantly larger than the intensity of diffusely reflected light.
In some embodiments of the present disclosure, the data processor 50 may determine whether or not the sample 1 is a deep-colored substance (for example, a non-transparent substance or a black substance) based on processing and analysis of a excited light component (mainly including a Rayleigh-scattered component) and a Raman scattered component of the spectrum data from the sample. The deep-colored substance has a stronger absorbing capacity to light and thus will generate a weaker Rayleigh scattering effect, and a Rayleigh scattering spectrum has a different wavelength range from a Raman scattering spectrum.
In an example, the data processor 50 is configured to determine a part of the spectrum data corresponding to a part of the light signal having a Raman shift in a range from −10 cm−1 to 10 cm−1 as the first part P1 for representing the excited light waveband, and to determine another part of the spectrum data corresponding to a part of the light signal having a Raman shift in a range from 350 cm−1 to 2000 cm−1 as the second part P2 for representing the Raman scattered component and the fluorescence component. The excited light wavelength is theoretically a wavelength where a Raman shift is equal to zero; however, since there is no strict single-color light source, even laser light has a very narrow waveband, and since a specific and pre-determined value will be selected as λ0 in the above Raman shift equation, the part of the light signal having a Raman shift in a range from −10 cm−1 to 10 cm−1 will fall within the excited light waveband.
In an example, the data processor 50 may calculate a first parameter (for example, a mean value of spectral intensities), which represents an amplitude of a spectral intensity, and a second parameter (for example, standard deviation, variance or the like), which represents a fluctuation or change of the spectral intensity, of each of the first part P1 and the second part P2, compare the first parameter of the first part P1 with the first parameter of the second part P2, and compare the second parameter of the first part P1 with the second parameter of the second part P2, and determine whether or not the sample is a deep-colored substance based on comparison results.
Exemplarily, if the first parameter of the first part P1 representing the excited light component (mainly including a Rayleigh-scattered component) of the light signal generated by the sample 1 under irradiation of the excited light 11 is smaller than the first parameter of the second part P2 represents the Raman scattered component and the fluorescence component, it shows that a weaker Rayleigh scattering effect occurs at an irradiated position of the sample, and that the sample to be detected may be a deep-colored substance or a transparent substance because the deep-colored substance will absorb much excited light while the transparent substance will transmit therethrough the excited light directly; further, if the second parameter of the first part P1 is greater than the second parameter of the second part P2, it shows that the spectrum data of the second part P2 has a smaller intensity fluctuation, and that there is no obvious spectrum peak in the light signal, thus it may be determined that the sample is a deep-colored substance (illustratively, it has been found by inventors of the present application that it is testified by data measured for known samples that under a shorter irradiation duration of the excited light, most of light initially excited from the deep-colored substance is fluorescent light having an easy or smaller spectral intensity or fluctuation, while the transparent substance may quickly emit stronger Raman scattered light which will generate an obvious spectrum peak), then detection of the sample by the Raman detection apparatus may be terminated; otherwise, it may be determined that the sample is a transparent substance, for example transparent liquid.
In one exemplary embodiment, the data processor 50 is configured to calculate the mean value and the standard deviation by using following equations:
where, u represents the mean value, σ represents the standard deviation, Xi represents the ith spectrum data (for example, the intensity at the ith sampling point, such as a spectral line intensity), and n represents the number of spectrum data of the first part or the second part (for example, the number of sampling points, such as the number of spectral lines).
Exemplarily, u1 and u2 represent mean values of the first part P1 and the second part P2 respectively, and σ1 and σ2 represent standard deviations of the first part P1 and the second part P2, so that the determination may be made in two steps. In the first step, the mean value of the first part P1 is compared with the mean value of the second part P2. In case that u1<u2, if the spectrum data is weaker near 0 cm−1 or in a range from −10 cm−1 to 10 cm−1, it shows that a weaker Rayleigh scattering effect occurs at the sample, and the sample may be a deep-colored substance or a transparent substance, otherwise the sample is other colored substance.
After determining the sample to be detected is a deep-colored substance or a transparent liquid in the first step, a second step is implemented to compare the standard deviation of the first part P1 with the standard deviation of the second part P2. The present disclosure is not limited to the standard deviation, and other characteristic representing a fluctuation of the parameter, such as a variance, may also be adopted. If σ1>σ2, it shows that the spectrum data of the second part P2 has a fluctuation smaller than that of the spectrum data of the first part P1, for example the fluctuation of the spectrum data in a range from 350 cm−1 to 2000 cm−1 is smaller than the fluctuation of the spectrum data near 0 cm−1 or in a range from −10 cm−1 to 10 cm−1, and thus it may be determined that the sample is a deep-colored substance, otherwise it may be determined the sample is a transparent substance, such as a transparent liquid.
After determining the sample is a deep-colored substance, corresponding measures will be taken to ensure detection security because the deep-colored substance has a larger possibility of being degraded, ablated, burned or even exploded under irradiation of the laser light. Exemplarily, the Raman spectrum detection apparatus 100 may further includes a controller 60, which may, when it is determined by the data processor 50 that the sample 1 is a deep-colored substance, send a control signal to the light source 10, so as to reduce power of the light source, or to turn off the light source to stop irradiation of the excited light onto the sample 1, terminating detection of the sample by the Raman spectrum detection apparatus.
In some embodiment, as shown in
In an example, the exemplary Raman spectrum detection apparatus 100 shown in
Embodiments of the present disclosure further provide a method of monitoring security of detecting a sample by a Raman spectrum detection apparatus. Referring to
S1: turning on the Raman spectrum detection apparatus, so that excited light is emitted by a light source 10 within a preset time duration and guided to a sample 1; the preset time duration is shorter than a time duration for a normal or conventional Raman spectrum detection, for example, is 0.5 milliseconds to 5 milliseconds, which may prevent dangerous events from occurring due to violent reaction of the excited light with the sample caused by too large energy of the excited light and avoid the sample from be damaged due to irradiation of the laser light within a longer time period;
S2: collecting a light signal generated by the sample 1 under irradiation of the excited light 11 and generating spectrum data representing the light signal; in an example, the light signal from the sample may be collected within the preset time duration, for example, within a time duration of 5 ms;
S3: determining a first part P1 of the spectrum data representing an excited light component (mainly including a Rayleigh-scattered component) of the light signal and a second part P2 of the spectrum data representing a Raman scattered component and a fluorescence component of the light signal, and calculating a first parameter (for example, a mean value of spectral intensities), which represents an amplitude of a spectral intensity, and a second parameter (for example, standard deviation, variance or the like), which represents a fluctuation or change of the spectral intensity, of each of the first part and the second part; and
S4: comparing the first parameter of the first part with the first parameter of the second part, and comparing the second parameter of the first part with the second parameter of the second part, and determining whether or not the sample is a deep-colored substance based on comparison results.
In some examples, as described above, the method may further include following steps:
S5: when determining the sample is not a deep-colored substance, continuing irradiation of the excited light to the sample, and continuing to collect the Raman spectrum of the sample by the Raman spectrum detection apparatus so as to detect the sample; and
S6: terminating the detection if it is determined that the sample is a deep-colored substance.
In some embodiment, as described above, the step S4 may include:
determining the sample is a deep-colored substance, if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is greater than the second parameter of the second part; and
determining the sample is a transparent substance (for example, transparent liquid), if the first parameter of the first part is smaller than the first parameter of the second part and the second parameter of the first part is smaller than the second parameter of the second part.
Exemplarily, the mean value and the standard deviation may be calculated by using following equations:
where, u represents the mean value, σ represents the standard deviation, Xi represents the ith spectrum data (for example, the intensity at the ith sampling point, such as a spectral line intensity), and n represents the number of spectrum data of the first part or the second part (for example, the number of sampling points, such as the number of spectral lines).
In one embodiment, a part of the obtained spectrum data corresponding to a part of the light signal having a Raman shift in a range from −10 cm−1 to 10 cm−1 may be determined as the first part P1 for representing the excited light waveband (mainly including a Rayleigh-scattered component) from the sample, and another part of the spectrum data corresponding to a part of the light signal having a Raman shift in a range from 350 cm−1 to 2000 cm−1 may be determined as the second part P2 for representing the Raman scattered component and the fluorescence component from the sample.
In embodiments of the present disclosure, the light signal generated by the sample, which is to be detected by the Raman spectrum detection apparatus, under irradiation of the excited light, is collected so as to obtain corresponding spectrum data, the spectrum data is processed and analyzed so as to compare spectral intensities and fluctuations thereof, for example, to calculate and compare mean values an standard deviations of the spectrum data, thereby the type of substance of the sample may be substantially determined based on the Raman scattered component, the fluorescence component and the excited light component (mainly including the Rayleigh-scattered component) of the light signal from the sample, so that degradation, ablation, burning or even exploding of the detected sample caused due to too larger power density of the laser light may be avoided, ensuring security of the sample and a user during use of the Raman spectrometer.
In the above description, illustrative embodiments have been described with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes including routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware. Such existing hardware may include one or more Central Processing Units (CPUs), digital signal processors (DSPs), application-specific-integrated-circuits, field programmable gate arrays (FPGAs) computers or the like.
Here, unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical, electronic quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
Illustrative embodiments have been described above with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes including routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware.
It will be understood by those skilled in the art that the present disclosure includes devices for implementing one or more of methods, steps, operations or functions of modules in the present application. These devices may be specially designed and manufactured for desired purposes, or may include known devices in general-purpose computers. These devices have computer programs stored therein which are selectively activable or reconstructable. Such computer programs may be stored in a device (for example, computer) readable medium or in any kind of medium adapted to store electronic instructions therein and to be coupled with a bus, the computer readable medium includes but is not limited any type of disk (including floppy disk, hard disk, compact disc, CD-ROM and magneto-optical disk), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash, magnetic card or optical card. That is, the readable medium include any medium for storing or transmitting information therein in readable form devices (for example, computer).
Although several exemplary embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made in form and detail in these embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined in the claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201711442673.2 | Dec 2017 | CN | national |
This application is a U.S. national stage application of International Patent Application No. PCT/CN2018/122068, filed on Dec. 19, 2018, which claims the priority benefit of the Chinese Patent Application No. 201711442673.2 filed on Dec. 26, 2017 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2018/122068 | 12/19/2018 | WO | 00 |
