A portable immunochromatographic test strip quantitative detection device with multi-spectral modulation

Abstract

The invention discloses a portable immunochromatographic test strip quantitative detection device with multi-spectral modulation, comprising a power module, a light source driving module, an optical detection module, a multi-spectral detection module, a CPU signal processing module and a display storage and communication module; the light source driving module adopts a current modulation mode to perform intensity modulation on a light source, and the CPU signal processing module adjusts the duty cycle according to different test strip background light reflections to perform light intensity regulation and compensation; the optical detection module incidents the modulated light onto a test strip to be detected, and guides C-line and T-line reflected light or fluorescence to the multi-spectral detection module through a 45° receiving angle; the invention adopts a low-cost Cortex‑M core single-chip microcomputer to complete signal calculation and processing, eliminates a large-pixel image sensor, adopts an integrated filter mode, has a small size and low cost, adopts a measurement wavelength to reference wavelength ratio algorithm to improve the measurement accuracy of the system, and can be applicable to the detection of colloidal gold test strips and immunofluorescence test strips.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical rapid quantitative detection, in particular to a multi-spectral modulated portable immunochromatographic test strip quantitative detection device. Background Art

[0002] Fluorescent immunochromatography and colloidal gold are two commonly used labeling technologies in medicine. Fluorescent immunochromatography is to drop a sample containing the antigen (antibody) to be tested on the sample addition area. The antigen (antibody) in the sample to be tested binds to the antibody (antigen) labeled with fluorescein, rare earth material or quantum dot material with specific excitation wavelength and emission wavelength in the conjugate pad and chromatographs forward through capillary action. The sample to be tested reacts with the fixed antibody (antigen) on the T line to form a particle-antibody-antigen-antibody sandwich complex and is fixed on the T line, while the excess fluorescent tracer continues to chromatograph forward and immunocombines with the secondary antibody fixed on the C control line. After the reaction is completed, the concentration of the object to be tested is tested by the competition method and sandwich method of immunochromatography. This method has the advantages of low cost, high sensitivity, strong specificity and good stability. It has been widely used in food safety inspection, clinical medicine, scientific research, etc. to detect antigens, antibodies, proteins, viruses, microorganisms, drugs, heavy metals, compounds and other occasions. Colloidal gold technology is a new type of immunolabeling technology based on antigen-antibody binding reaction, which uses colloidal gold as a tracer marker. It has the advantages of low cost, high sensitivity, easy operation, strong specificity and good stability. It has been widely used in food safety inspection, clinical medicine, scientific research, etc. to detect antigens, antibodies, proteins, viruses, microorganisms, drugs, heavy metals, compounds and other occasions.

[0003] At present, there are two main methods for quantitative detection of immunochromatographic test strips:

[0004] 1. Detection method based on image processing algorithm: Under the action of a certain light source (such as semiconductor laser, white light LED, ultraviolet LED, etc.), this method makes the colloidal gold tracer reflect visible light or the fluorescent material tracer stimulate fluorescence and other detectable signals. After the image of the immunochromatographic reagent strip is acquired by a CCD camera or a CMOS camera, an advanced image processing hardware support platform is used (such as application numbers CN109900894A, CN107255712A and CN105181959A using a smart phone as a control algorithm platform, and CN110596368A and CN208818644U using a computer platform) to perform denoising, image segmentation, feature extraction, and grayscale calculation on the acquired image. Finally, the antibody or antigen concentration is inverted according to the calibrated grayscale curve relationship. This method mainly relies on scientific light source illumination system, precision optical imaging system design, camera pixel performance, image processing algorithm and processor platform that supports complex image processing. Generally, it chooses DSP processor or general-purpose computer to complete complex image processing calculation. However, it has the disadvantages of high equipment cost, large size, complex algorithm and easy to be affected by ambient light and stray light.

[0005] 2. Detection method based on optical sensor: This method also requires an external light source (such as a laser or LED light source) to excite colloidal gold particles, fluorescein, rare earth elements or quantum dot tracers, and converts light intensity into voltage through a photoelectric sensor or photothermal sensor (such as the use of photomultiplier tubes in the publication number CN 109900892A, and photodiodes or photoresistors in the publication numbers CN109085352A, CN 109752537 A, CN 109765363 A, CN208076398U, etc.), and establishes a quantitative relationship between antigen-antibody concentration and the corresponding voltage or temperature parameters by collecting and analyzing these parameters, thereby realizing quantitative detection of immunochromatographic test strips. This method can achieve high-precision immunochromatographic quantitative detection through low-cost photoelectric detectors, and has low requirements for data processing and computing platforms. It can also interconnect and share data through wired or wireless means, and can achieve low-cost, portable, and high-precision measurements. In order to improve the sensitivity of system detection and suppress the interference of ambient light and stray light, most of them use multiple convex lenses, multiple filters and dichroic mirrors to form a complex optical system. The optical path design is complex and is easily affected by various light sources such as excitation light source, ambient light source and background light. At the same time, the light intensity parameters of a single broad-spectrum detector are used for concentration inversion. There are still certain problems in the stability and sensitivity of the detection results.

[0006] Based on this, the present invention designs a multi-spectral modulation portable immunochromatographic test strip quantitative detection device to solve the above-mentioned problems. Summary of the invention

[0007] The purpose of the present invention is to provide a portable immunochromatographic test strip quantitative detection device with multi-spectral modulation, which solves the technical problems of high cost, complex optical design, difficulty in carrying, complex calculation, susceptibility to interference, and low measurement accuracy in existing immunochromatographic test strip quantitative detection.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solutions: a portable immunochromatographic test strip quantitative detection device with multi-spectral modulation, comprising a power supply module, a light source driving module, an optical detection module, a multi-spectral detection module, a CPU signal processing module, and a display storage and communication module;

[0009] The power supply module supplies power to the light source driving module, the multi-spectral detection module, the CPU signal processing module, the display storage and communication module;

[0010] The light source driving module uses current modulation to modulate the intensity of the light source, and the CPU signal processing module adjusts the duty cycle according to different test strip background light reflections to perform light intensity regulation and compensation;

[0011] The optical detection module incidents the modulated light onto the test paper strip to be detected, and guides the C-line and T-line reflected light to the multi-spectral detection module through a 45° receiving angle;

[0012] The CPU signal processing module is connected to the light source driving module, and is used to generate a modulation signal and obtain the output signal of the multi-spectral detection module, perform digital wavelet filtering, fast Fourier transform, feature extraction, and concentration inversion on the multi-spectral signal, and transmit the result to the display storage and communication module for result display, storage and communication.

[0013] Preferably, the light source driving module is a white light source driving module, and the white light source driving module is a constant current source driving mode, which uses a modulation signal of a certain frequency to modulate the intensity of the constant current source output to drive the light source to emit light, and the modulation signal uses one of a square wave signal, a sine wave signal and a triangle wave signal. Two independent light sources are vertically installed directly above the C line and the T line of the test paper strip to be tested, and the light source uses a low-cost white light LED.

[0014] Preferably, the light source driving module is an excitation light source driving module, and the excitation light source driving module is a constant current source driving mode, and a modulation signal of a certain frequency is used to modulate the intensity of the constant current source output to drive the light source to emit light. The modulation signal uses one of a square wave signal, a sine wave signal and a triangle wave signal. Two independent excitation light sources are vertically installed directly above the C line and the T line of the test paper strip to be tested. The light source uses a low-cost ultraviolet LED with a wavelength between 300-400nm and a divergence angle of 60°.

[0015] Preferably, the optical detection module integrates light emitting and light reflecting light guide holes, the two independent light sources in the light source driving module are vertically installed directly above the C line and T line of the test paper strip to be detected, and the two reflecting light guide holes are respectively at 45° to the incident light.

[0016] Preferably, the multi-spectral detection module is composed of a photodetector array with a plurality of different wavelength anti-reflection characteristics, and adopts a CCD detection array composed of filters with central wavelengths of 465nm, 525nm and 615nm and a bandwidth of 20nm, and each wavelength channel is composed of 3 pixels.

[0017] Preferably, the CPU signal processing module is a Cortex-M core single-chip microcomputer STM32F405, and the CPU signal processing module is connected to the light source driving module to generate a modulation signal. The CPU signal processing module obtains the multi-spectral output signal of the multi-spectral detection module, and after a series of operations in the CPU, transmits the result to the display storage and communication module for result display, storage and communication.

[0018] Preferably, the quantitative detection of the device comprises the following steps:

[0019] Step 1: After inserting the colloidal gold test strip, start the detection, the CPU signal processing module 5 generates a modulation signal to drive the white light source driving module, the modulated outgoing light signal is incident on the C line and T line of the colloidal gold reagent strip, and the reflected light signal is converted into a digital signal by the multi-spectral detection module, and finally read by the CPU to perform internal calculation;

[0020] Step 2: First, simulate the soft threshold filtering process on the multi-spectral signal in MATLAB. After optimizing the filter parameters, the coefficients are saved in the CPU. Secondly, the obtained multi-spectral signal is subjected to block convolution operation with the optimized wavelet filter coefficients to obtain the filtered multi-spectral data. The wavelet filter algorithm can effectively remove the light source noise and the detector noise, improve the detection sensitivity, and the block convolution can reduce the amount of calculation and improve the calculation rate.

[0021] Step 3, digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal, extract the amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component as the characteristic quantity, take the 465nm wavelength signal as the reference wavelength, and obtain the characteristic quantity ratio parameter of the measured wavelength 525nm and 615nm and the reference wavelength;

[0022] Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. The final result of colloidal gold quantitative detection can be obtained according to the relationship between the C line and T line of the test strip;

[0023] Step 5: The CPU transmits the result to the display storage and communication module for result display, storage and communication.

[0024] Preferably, the quantitative detection of the device comprises the following steps:

[0025] Step 1: After inserting the immunofluorescence test strip, start the detection, the CPU signal processing module generates a modulation signal to drive the excitation light source driving module, and after the modulated output light signal is incident on the C line and T line of the fluorescent immunochromatography reagent strip, the markers such as fluorescein, rare earth materials or quantum dots are excited by the excitation light source, and the radiated fluorescence signal is converted into a digital signal by the multi-spectrum detection module, and finally read by the CPU to perform internal calculation; the immunofluorescence test strip is marked with three different fluorescence spectrum wavelengths, wherein the fluorescence wavelength fixed on the C line and T line is 465nm as the reference wavelength, and the excitation wavelengths of 525nm and 615nm are used as antigen or antibody markers;

[0026] Step 2: First, the multi-spectral signal acquired by the CPU is transmitted to the computer through the communication interface, and the multi-spectral signal is simulated with the wavelet filtering algorithm using the MATLAB software for soft threshold filtering. After the filter parameters are optimized, the coefficients are stored in the CPU. Secondly, the obtained multi-spectral signal is subjected to block convolution operation with the optimized wavelet filtering coefficients to obtain the filtered multi-spectral data. The wavelet filtering algorithm can effectively remove the light source noise and the detector noise, improve the detection sensitivity, and the block convolution can reduce the amount of calculation and improve the calculation rate.

[0027] Step 3, digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal, extract the amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component as characteristic quantities, take the 465nm wavelength signal as the reference wavelength, and obtain the characteristic quantity ratio parameter of the measured wavelengths of 525nm and 615nm and the reference wavelength;

[0028] Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. The final result of the quantitative detection of the fluorescent immunochromatographic test strip can be obtained according to the relationship between the C line and the T line of the test strip.

[0029] Step 5: The CPU transmits the result to the display storage and communication module for result display, storage and communication.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. Compared with the existing devices using image processing methods, the technical solution of the present application does not require the support of a CPU or DSP hardware platform with powerful computing performance, and uses a DSP core integrated in a low-cost Cortex-M core microcontroller to complete signal calculation and processing; at the same time, the large-pixel image sensor is omitted and replaced by a multi-spectral detection pixel array sensor, and an integrated filter is used, which is small in size and low in cost, and the reference wavelength and measurement wavelength ratio algorithm is used to improve the measurement accuracy of the system.

[0032] 2. Compared with the existing optical sensor detection method and device, the present invention adopts light modulation and demodulation technology, does not need to add background light collection channels, can effectively suppress the interference of test strips and ambient light background, and adopts digital filtering and multi-feature extraction algorithms to further improve the detection accuracy and stability, and can be applied to both colloidal gold and fluorescence detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0034] Figure 1 It is a structural block diagram of the present invention;

[0035] Figure 2 It is a detection flow chart of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1, please refer to Figure 1-2The present invention provides a technical solution for a portable immunochromatographic test strip quantitative detection device with multi-spectral modulation: comprising a power module 1, a light source driving module 2, an optical detection module 3, a multi-spectral detection module 4, a CPU signal processing module 5 and a display storage and communication module 6;

[0038] The power supply module 1 supplies power to the light source driving module 2, the multi-spectral detection module 4, the CPU signal processing module 5, and the display storage and communication module 6;

[0039] The light source driving module 2 uses current modulation to modulate the light source intensity, and the CPU signal processing module 5 adjusts the duty cycle according to different test strip background light reflections to perform light intensity regulation and compensation;

[0040] The optical detection module 3 injects the modulated light onto the test paper strip to be detected, and guides the C-line and T-line reflected light to the multi-spectral detection module 4 through a 45° receiving angle;

[0041] The CPU signal processing module 5 is connected to the light source driving module 2, and is used to generate a modulation signal and obtain the output signal of the multi-spectral detection module 4, perform digital wavelet filtering, fast Fourier transform, feature extraction, and concentration inversion on the multi-spectral signal, and transmit the result to the display storage and communication module 6 for result display, storage and communication.

[0042] Among them, the light source driving module 2 is a white light source driving module, and the white light source driving module 2 is a constant current source driving mode. A modulation signal of a certain frequency is used to modulate the intensity of the constant current source output to drive the light source to emit light. The modulation signal uses one of a square wave signal, a sine wave signal and a triangle wave signal, but is not limited to this. Two independent light sources are vertically installed directly above the C line and T line of the test paper strip to be tested. The light source uses a low-cost white light LED, but is not limited to this.

[0043] Among them, the optical detection module 3 integrates light emitting and light reflecting light guide holes. In order to improve the detection sensitivity and shorten the detection time, the two independent light sources in the light source driving module 2 are vertically installed just above the C line and T line of the test paper strip to be tested. The two reflecting light guide holes are respectively at 45° to the incident light, which improves the receiving efficiency of the reflected light signal.

[0044] Among them, the multi-spectral detection module 4 is composed of a photoelectric detector array with multiple wavelength anti-reflection characteristics, and adopts a CCD detection array composed of filters with central wavelengths of 465nm, 525nm and 615nm and a bandwidth of 20nm. Each wavelength channel is composed of 3 pixels, but it is not limited to this.

[0045] Among them, the CPU signal processing module 5 is a low-cost on-chip system microcontroller with integrated DSP computing capabilities, such as the Cortex-M core microcontroller STM32F405, but not limited to this. The CPU signal processing module 5 is connected to the light source driving module 2 and is used to generate a modulation signal. The CPU signal processing module 5 obtains the multi-spectral output signal of the multi-spectral detection module 3, and after a series of operations in the CPU, the result is transmitted to the display storage and communication module 6 for result display, storage and communication.

[0046] The quantitative detection of the device includes the following steps:

[0047] Step 1: After inserting the colloidal gold test strip, start the test, the CPU signal processing module 5 generates a modulation signal to drive the white light source driving module 2, the modulated outgoing light signal is incident on the C line and T line of the colloidal gold reagent strip, and the reflected light signal is converted into a digital signal by the multi-spectral detection module 3, and finally read by the CPU to perform internal calculation;

[0048] Step 2: First, simulate the soft threshold filtering process on the multi-spectral signal in MATLAB. After optimizing the filter parameters, the coefficients are saved in the CPU. Secondly, the obtained multi-spectral signal is convolved with the optimized wavelet filter coefficients to obtain the filtered multi-spectral data. The wavelet filter algorithm can effectively remove the light source noise and the detector noise and improve the detection sensitivity.

[0049] Step 3: Digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal. Taking square wave modulation as an example, the modulated square wave signal can be expressed as the superposition of a series of harmonic signals of the base frequency, that is,

[0050]

[0051] Where ω is the fundamental frequency, A is the amplitude constant, I in is the input light intensity,

[0052] The Laplace transform of a square wave signal is:

[0053]

[0054] Then the output signal of the sensor can be expressed by the transfer function as:

[0055]

[0056] Expand the above equation by partial fractions, assume that the transfer function is a negative number, and perform an inverse Laplace transform on the above equation. Then the time domain output can be expressed as:

[0057]

[0058] Among them, |G(i(2n-1)w)| represents the amplitude value of the corresponding frequency, which is the signal characteristic quantity. The spectrum signal can be obtained by using the DSP core to perform fast Fourier transform inside the CPU

[0059] The amplitude values ​​of the fundamental frequency, third harmonic component, fifth harmonic component and seventh harmonic component are extracted as characteristic quantities, and the 465nm wavelength signal is used as the reference wavelength to obtain the characteristic quantity ratio parameter of the measured wavelength 525nm and 615nm and the reference wavelength, that is,

[0060] ;

[0061] Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. According to the relationship between the C line and T line of the test strip, that is,

[0062] I C = constant, through I T / I C The ratio of is used for intensity inversion,

[0063] Among them I C is the average intensity of C line, I T is the average intensity of the T line, and the final result of colloidal gold quantitative detection is obtained;

[0064] Step 5: The CPU transmits the result to the display storage and communication module 6 for result display, storage and communication. The CPU signal processing module 5 is STMicroelectronics STM32F405, and its built-in 12-bit high-speed digital-to-analog converter is used to generate the modulation signal.

[0065] The display storage and communication module 6 uses a liquid crystal display to display the test results, and stores the data in an external SPI port Flash memory. The measurement results are transmitted to a terminal, such as a mobile phone, tablet or other mobile terminal, via Bluetooth, USB port, WIFI or the like. The CPU signal processing module 5 is also connected to the display storage and communication module 6 for sending the detection information to the receiving terminal.

[0066] Example 2, please refer to Figure 1-2 The present invention provides a technical solution for a portable immunochromatographic test strip quantitative detection device with multi-spectral modulation: comprising a power module 1, a light source driving module 2, an optical detection module 3, a multi-spectral detection module 4, a CPU signal processing module 5 and a display storage and communication module 6;

[0067] The power supply module 1 supplies power to the light source driving module 2, the multi-spectral detection module 4, the CPU signal processing module 5, and the display storage and communication module 6;

[0068] The light source driving module 2 uses current modulation to modulate the light source intensity, and the CPU signal processing module 5 adjusts the duty cycle according to different test strip background light reflections to perform light intensity regulation and compensation;

[0069] The optical detection module 3 injects the modulated light onto the test paper strip to be detected, and guides the C-line and T-line reflected light to the multi-spectral detection module 4 through a 45° receiving angle;

[0070] The CPU signal processing module 5 is connected to the light source driving module 2, and is used to generate a modulation signal and obtain the output signal of the multi-spectral detection module 4, perform digital wavelet filtering, fast Fourier transform, feature extraction, and concentration inversion on the multi-spectral signal, and transmit the result to the display storage and communication module 6 for result display, storage and communication.

[0071] Among them, the light source driving module 2 is an excitation light source driving module, and the excitation light source driving module 2 is a constant current source driving mode. A modulation signal of a certain frequency is used to modulate the intensity of the constant current source output to drive the light source to emit light. The modulation signal uses one of a square wave signal, a sine wave signal and a triangle wave signal, but is not limited to this. Two independent excitation light sources are vertically installed directly above the C line and T line of the test paper strip to be tested. The light source uses a low-cost ultraviolet LED with a wavelength between 300-400nm and a divergence angle of 60°, but is not limited to this.

[0072] Among them, the optical detection module 3 integrates light emitting and light reflecting light guide holes. In order to improve the detection sensitivity and shorten the detection time, the two independent light sources in the light source driving module 2 are vertically installed just above the C line and T line of the test paper strip to be tested. The two reflecting light guide holes are respectively at 45° to the incident light, which improves the receiving efficiency of the reflected light signal.

[0073] Among them, the multi-spectral detection module 4 is composed of a photoelectric detector array with a variety of different wavelength transmittance enhancement characteristics, and adopts a CCD detection array composed of filters with central wavelengths of 465nm, 525nm and 615nm and a bandwidth of 20nm. In order to improve the detection efficiency, each channel is composed of 3 pixels, totaling 3×3 pixels. Multi-spectral detection is more than 3 narrow-band detection spectral regions, but is not limited to this.

[0074] Among them, the CPU signal processing module 5 is a low-cost on-chip system microcontroller with integrated DSP computing capabilities, such as the Cortex-M core microcontroller STM32F405, but not limited to this. The CPU signal processing module 5 is connected to the light source driving module 2 and is used to generate a modulation signal. The CPU signal processing module 5 obtains the multi-spectral output signal of the multi-spectral detection module 3, and after a series of operations in the CPU, the result is transmitted to the display storage and communication module 6 for result display, storage and communication.

[0075] The quantitative detection of the device includes the following steps:

[0076] Step 1: After inserting the immunofluorescence test strip, start the detection, the CPU signal processing module 5 generates a modulation signal to drive the excitation light source driving module 2, and the modulated output light signal is incident on the C line and T line of the fluorescent immunochromatography reagent strip, and the markers such as fluorescein, rare earth materials or quantum dots are excited by the excitation light source, and the radiated fluorescence signal is converted into a digital signal by the multi-spectrum detection module 3, and finally read by the CPU to perform internal calculation; the immunofluorescence test strip is marked with three different fluorescence spectrum wavelengths, among which the fluorescence wavelength fixed on the C line and T line is 465nm as the reference wavelength, and the excitation wavelengths of 525nm and 615nm are used as antigen or antibody markers;

[0077] Step 2: First, the multi-spectral signal acquired by the CPU is transmitted to the computer through the communication interface. The multi-spectral signal is simulated with the wavelet filtering algorithm using MATLAB software for soft threshold filtering. After the filter parameters are optimized, the coefficients are stored in the CPU. Secondly, the obtained multi-spectral signal is subjected to block convolution operation with the optimized wavelet filtering coefficients to obtain the filtered multi-spectral data. The wavelet filtering algorithm can effectively remove the light source noise and the detector noise and improve the detection sensitivity.

[0078] Step 3: Digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal. Taking square wave modulation as an example, the modulated square wave signal can be expressed as the superposition of a series of harmonic signals of the base frequency, that is,

[0079]

[0080] Where ω is the fundamental frequency, A is the amplitude constant, I in is the input light intensity,

[0081] The Laplace transform of a square wave signal is:

[0082]

[0083] Then the output signal of the sensor can be expressed by the transfer function as:

[0084]

[0085] Expand the above equation by partial fractions, assume that the transfer function is a negative number, and perform an inverse Laplace transform on the above equation. Then the time domain output can be expressed as:

[0086]

[0087] Among them, |G(i(2n-1)w)| represents the amplitude value of the corresponding frequency, which is the signal characteristic quantity. The spectrum signal can be obtained by using the DSP core to perform fast Fourier transform inside the CPU

[0088] The amplitude values ​​of the fundamental frequency, third harmonic component, fifth harmonic component and seventh harmonic component are extracted as characteristic quantities, and the 465nm wavelength signal is used as the reference wavelength to obtain the characteristic quantity ratio parameter of the measured wavelength 525nm and 615nm and the reference wavelength, that is,

[0089] ;

[0090] The amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component are extracted as characteristic quantities, and the 465nm wavelength signal is used as the reference wavelength to obtain the characteristic quantity ratio parameter of the measured wavelengths of 525nm and 615nm and the reference wavelength;

[0091] Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. According to the relationship between the C line and T line of the test strip, that is,

[0092] I C = constant, through I T / I C The ratio of is used for intensity inversion,

[0093] Among them I C is the average intensity of C line, I T is the average intensity of the T line, and the final result of the fluorescent immunochromatography quantitative test is obtained;

[0094] Step 5, the CPU transmits the result to the display storage and communication module 6 for result display, storage and communication. The CPU signal processing module 5 is STMicroelectronics STM32F405, which uses an integrated DSP core to implement convolution operations and fast Fourier transform operations of wavelet filtering, and uses its own 12-bit high-speed digital-to-analog converter to generate modulation signals.

[0095] The display storage and communication module 6 uses an OLED liquid crystal display to display the test results, and stores the data in an external SPI port Flash memory. At the same time, the measurement results are transmitted to terminals such as mobile phones, tablets, etc. through Bluetooth, USB port, WIFI, etc.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A portable immunochromatographic test strip quantitative detection device with multi-spectral modulation, Features: It is suitable for both fluorescence and colloidal gold detection, and includes a power module (1), a light source driving module (2), an optical detection module (3), a multi-spectral detection module (4), a CPU signal processing module (5), and a display storage and communication module (6); The power supply module (1) supplies power to the light source driving module (2), the multi-spectral detection module (4), the CPU signal processing module (5), and the display storage and communication module (6); The light source driving module (2) uses a current modulation method to modulate the intensity of the light source, and the CPU signal processing module (5) adjusts the duty cycle according to different test strip background light reflections to perform light intensity regulation and compensation; The optical detection module (3) incidents the modulated light onto the test paper strip to be detected, and guides the C-line and T-line reflected light or fluorescence to the multi-spectral detection module (4) through a 45° receiving angle; The CPU signal processing module (5) is connected to the light source driving module (2) and is used to generate a modulation signal and obtain the output signal of the multi-spectral detection module (4), and perform digital wavelet filtering, fast Fourier transform, feature extraction, and concentration inversion on the multi-spectral signal. The method comprises the following steps: firstly, performing simulated soft threshold filtering on the multispectral signal in MATLAB, optimizing the filter parameters, and then saving the coefficients in the CPU; secondly, performing block convolution operation on the obtained multispectral signal and the optimized wavelet filter coefficients to obtain filtered multispectral data; the wavelet filter algorithm can effectively remove light source noise and detector noise, and improve detection sensitivity; The filtered multi-spectral signal is digitally demodulated, that is, the spectrum of the multi-spectral signal is obtained by fast Fourier transform, the amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component are extracted as characteristic quantities, and the 465nm wavelength signal is used as the reference wavelength to obtain the characteristic quantity ratio parameter of the measured wavelength 525nm and 615nm and the reference wavelength; Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. The final quantitative detection result should be obtained according to the relationship between the C line and the T line of the test strip, and the result should be transmitted to the display storage and communication module (6) for result display, storage and communication; The light source driving module (2) is a white light source driving module or an excitation light source driving module. The light source driving module (2) is in a constant current source driving mode, and uses a modulation signal of a certain frequency to modulate the intensity of the constant current source output to drive the light source to emit light. The modulation signal uses one of a square wave signal, a sine wave signal and a triangle wave signal. Two independent light sources are vertically installed directly above the C line and the T line of the test paper strip to be tested. The light source uses a low-cost white light LED or a low-cost ultraviolet LED with a wavelength between 300 and 400 nm, and its divergence angle is 60°. The multi-spectral detection module (4) is composed of a photoelectric detector array with multiple different wavelength anti-reflection characteristics, using a CCD detection array composed of filters with central wavelengths of 465nm, 525nm and 615nm and a bandwidth of 20nm, and each wavelength channel is composed of 3 pixels; The CPU signal processing module (5) is a Cortex-M core single chip microcomputer STM32F405. The CPU signal processing module (5) is connected to the light source driving module (2) and is used to generate a modulation signal. The CPU signal processing module (5) obtains the multi-spectral output signal of the multi-spectral detection module (4), and after a series of operations in the CPU, transmits the result to the display storage and communication module (6) for result display, storage and communication.

2. A portable immunochromatographic test strip quantitative detection device with multi-spectral modulation according to claim 1, Features: The optical detection module (3) integrates light emitting and light reflecting light guide holes, and the two independent light sources in the light source driving module (2) are vertically mounted directly above the C line and the T line of the test paper strip to be detected, and the two reflecting light guide holes are respectively at 45 degrees to the incident light.

3. A portable immunochromatographic test strip quantitative detection device with multi-spectral modulation according to claim 1, It is characterized in that The quantitative detection comprises the following steps: Step 1: After inserting the colloidal gold test strip, start the detection, the CPU signal processing module 5 generates a modulation signal to drive the white light source driving module, the modulated outgoing light signal is incident on the C line and T line of the colloidal gold reagent strip, and the reflected light signal is converted into a digital signal by the multi-spectral detection module, and finally read by the CPU to perform internal calculation; Step 2: First, simulate the soft threshold filtering process on the multi-spectral signal in MATLAB. After optimizing the filter parameters, the coefficients are saved in the CPU. Secondly, the obtained multi-spectral signal is subjected to block convolution operation with the optimized wavelet filter coefficients to obtain the filtered multi-spectral data. The wavelet filter algorithm can effectively remove the light source noise and the detector noise, improve the detection sensitivity, and the block convolution can reduce the amount of calculation and improve the calculation rate. Step 3, digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal, extract the amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component as the characteristic quantity, take the 465nm wavelength signal as the reference wavelength, and obtain the characteristic quantity ratio parameter of the measured wavelength 525nm and 615nm and the reference wavelength; Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. The final result of colloidal gold quantitative detection can be obtained according to the relationship between the C line and T line of the test strip; Step 5: The CPU transmits the result to the display storage and communication module for result display, storage and communication.

4. A portable immunochromatographic test strip quantitative detection device with multi-spectral modulation according to claim 1, It is characterized in that The quantitative detection comprises the following steps: Step 1: After inserting the immunofluorescence test strip, the detection is started, and the CPU signal processing module (5) generates a modulation signal to drive the excitation light source driving module (2). After the modulated output light signal is incident on the C line and T line of the fluorescent immunochromatographic reagent strip, the fluorescein, rare earth material or quantum dot marker is excited by the excitation light source, and the radiated fluorescence signal is converted into a digital signal by the multi-spectral detection module (4), and finally read by the CPU for internal calculation; the immunofluorescence test strip is marked with three different fluorescence spectrum wavelengths, wherein the fluorescence wavelength fixed on the C line and T line is 465nm as a reference wavelength, and the excitation wavelengths of 525nm and 615nm are used as antigen or antibody markers; Step 2: First, the multi-spectral signal acquired by the CPU is transmitted to the computer through the communication interface. The multi-spectral signal is simulated with the wavelet filtering algorithm using MATLAB software for soft threshold filtering. After the filter parameters are optimized, the coefficients are stored in the CPU. Secondly, the obtained multi-spectral signal is subjected to block convolution operation with the optimized wavelet filtering coefficients to obtain the filtered multi-spectral data. The wavelet filtering algorithm can effectively remove the light source noise and the detector noise and improve the detection sensitivity. Step 3, digitally demodulate the filtered multi-spectral signal, that is, use fast Fourier transform to obtain the spectrum of the multi-spectral signal, extract the amplitude values ​​of the fundamental frequency, the third harmonic component, the fifth harmonic component and the seventh harmonic component as characteristic quantities, take the 465nm wavelength signal as the reference wavelength, and obtain the characteristic quantity ratio parameter of the measured wavelengths of 525nm and 615nm and the reference wavelength; Step 4. Before the experiment, the relationship between the characteristic quantity ratio parameter and the concentration curve should be calibrated, and the calibration coefficient should be stored in the internal Flash. The actual measured characteristic quantity ratio parameter should be substituted into the calibration coefficient, and the harmonic results should be averaged to obtain the C line and T line intensity parameters respectively. The final result of the quantitative detection of the fluorescent immunochromatographic test strip can be obtained according to the relationship between the C line and the T line of the test strip. Step 5: The CPU transmits the result to the display storage and communication module (6) for result display, storage and communication.

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