KR20220170324A - Sensitivity improvement method using various filters when detecting lateral flow strip signal - Google Patents

Abstract

The present invention proposes a sensitivity improvement method using various filters when detecting a lateral flow strip signal. For example, the various filters may include at least one of a darkfield filter, a Rheinberg filter, an oblique filter, or a Dodt gradient contrast (DGC) filter. The sensitivity improvement method of the present invention can provide users with accurate data by acquiring a plurality of images using the various filters.

Description

Sensitivity improvement method using various filters when detecting lateral flow strip signal {Sensitivity improvement method using various filters when detecting lateral flow strip signal}

The present invention relates to a sensitivity improvement method using various filters when detecting a signal of a lateral flow strip.

Lateral flow assays (LFA) are immunoassays that can be used to detect a variety of analytes in biological samples. A common method of LFA uses capture antibodies immobilized at specific locations on, for example, a nitrocellulose membrane. The advantage of the LFA method is that, unlike ELISA, the membrane allows analysis in one step. Based on the principles of high affinity, sensitivity and selectivity between specific antibody-antigen pairs, immunology-based assays can be more widely used due to the diversity of existing antibodies, reaction reagents available at reasonable prices, and the like. The lateral flow technology is highly suitable for point-of-care disease diagnosis because it does not require cold chain or specialized reagents for storage and transport, and is reliable and inexpensive.

Many LFA devices consist of a porous matrix made of a material capable of absorbing liquid samples and promoting the capillary action of liquid samples, such as nitrocellulose. The matrix can be of any shape or size, but is usually made to the size of a strip that can be held in one hand. In a preferred test mode, a liquid sample, such as a biological sample, is adsorbed onto the sample pad, then migrated by capillary action to a conjugate pad, and a conjugate labeled with a detectable indicator such as a colored label. particles) and mixed with these conjugates. The labeled conjugate undergoes an intermolecular interaction with a specific analyte contained in the liquid sample by affinity and binding force. The labeled conjugate and its specific analyte then migrate towards the test line. A capture agent that captures the analyte is immobilized on the test line. Excess liquid sample is absorbed by an absorbent pad that pulls the sample across the membrane by capillary action.

Optical filter technology changes the characteristics of a beam by controlling the transmission or blocking of light and the phase, so that various optical performance can be obtained without a significant change in the optical system.

Recently, as the 4th industrial revolution has become an issue, technologies such as the Internet of Things (IoT), autonomous driving, and artificial intelligence have developed, and machine learning, hardware equipment, and deep neural networks (DNNs) have developed. With the development of technology, it is widely used to solve problems in various engineering fields. As a result, success stories for machine learning are exploding in most fields of engineering.

The present invention can provide a signal detection method for detecting an accurate signal of a lateral flow strip using various filters.

A pedestal according to an embodiment, a filter disposed under the pedestal, a light source unit for irradiating light with the filter, and a strip movably disposed on an upper surface of the pedestal in one direction and transmitting light filtered by the filter. , A signal detection method performed by a signal detection system including a camera disposed above the strip and a control unit, wherein the control unit moves the strip to one side at a predetermined speed through the camera. acquiring a plurality of images corresponding to the positions of the moved strips at predetermined cycles while moving the strips; The method may include determining, by the controller, a final line displayed on the strip based on the plurality of images.

In the signal detection method, the filter includes at least one of a Darkfield filter, a Rheinberg filter, an Oblique filter, and a Dodt Gradient Contrast (DGC) filter, and the control unit displays a final image displayed on a strip based on the plurality of images. The determining of the line may include determining, by the controller, a final line displayed on the strip from the plurality of images based on a pre-learned line determination model, wherein the plurality of images includes the at least one line determination model. It may include images acquired using each filter.

In the step of determining, by the control unit, the final line displayed on the strip based on the plurality of images, the control unit digitizes the sharpness of the outer image of the line included in the plurality of images, and the digitized sharpness is determined in advance. It may include; determining that the final line is greater than a first threshold.

In the signal detection method, the filter includes the oblique filter and the slit filter, and the control unit, through the camera, moves the strip to one side at a predetermined speed at a position of the moved strip at a predetermined period. Acquiring a plurality of corresponding images may include, by the controller, obtaining an image displayed by irradiating the strip with the first filtering by the oblique filter and the second filtering by the slit filter through the camera steps may be included.

The step of determining, by the control unit, the final line displayed on the strip based on the image, wherein the control unit digitizes the sharpness of the line images included in the plurality of images, and the line image is separated by a predetermined distance or more It may include determining the final line if the difference in sharpness between any two points is equal to or greater than a predetermined second threshold value.

The present invention can provide users with accurate data by acquiring a plurality of images using various filters.

The present invention can acquire a plurality of images while moving the strip, and provide accurate signal data through machine learning using the acquired images as input values.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description to aid understanding of the various embodiments, provide various embodiments and, together with the detailed description, describe technical features of the various embodiments.
1 is a diagram illustrating an operation of a processor according to an embodiment.
2 is a diagram of a signal detection system according to an embodiment.
3 illustrates an operation of acquiring a plurality of images while moving a strip and determining a final line based on the obtained plurality of images, according to an exemplary embodiment.
4 shows the shapes of an oblique filter and a slit filter according to an embodiment.
5 is a diagram illustrating a state observed using an oblique filter according to an embodiment.
6 is a diagram showing an embodiment using a darkfield filter and a Rheinberg filter according to an embodiment.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term “and/or” includes any combination of a plurality of related recited items or any one of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate overall understanding in the description of the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

1 is a diagram illustrating an operation of a processor belonging to a server according to an embodiment. Referring to FIG. 1 in detail, at least one processor 110 is a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated method for performing methods according to embodiments of the present invention. may mean a processor of Each of the memory 120 and the storage device 160 may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 120 may be one of a read only memory (ROM) and a random access memory (RAM), and the storage device 160 may be a flash-memory. , a hard disk drive (HDD), a solid state drive (SSD), or various memory cards (eg, a micro SD card).

In addition, the server 100 may be included in the server and may include a transceiver 130 that performs communication through a wireless network. In addition, the server 100 may further include an input interface device 140, an output interface device 150, a storage device 160, and the like. Each component included in the server 100 may be connected by a bus 170 to communicate with each other.

2 is a diagram of a signal detection system according to an embodiment.

Referring to FIG. 2 in detail, the signal detection system may include a light source unit 1, a filter 2, a pedestal 3, a strip 4, and a camera 5. A strip may mean a lateral flow strip. The lateral flow strip used to diagnose diseases such as infectious diseases uses gold nanoparticles or fluorescent nanoparticles to measure the intensity of color development in the reaction line to diagnose the presence or absence of disease. Adoption of the time-resolved fluorescence technique is also increasing, and this lateral flow test strip is easy to use, inexpensive, and widely used because the result can be seen quickly. Sometimes a false negative may occur in a signal. Darkfield filter, Rheinberg filter, Oblique filter, and Dodt Gradient Contrast (DGC) filter among the principles of the microscope using bottom illumination are applied to increase the contrast of the test line signal reacting finely on the lateral flow strip and detect it with higher sensitivity. It may be an application example for Commonly used lights and cameras can exhibit improved contrast than the same Brightfield illumination system. Since the lateral flow strip for inspection is placed on a movable tray, the contrast can be further deepened by adjusting the angle with the light shining from the lower illumination system. Multiple images acquired at different angles and wavelengths are converted into individual images or aggregated images, and the machine learning engine determines the strength of the signal and the presence or absence of lines to make a positive or negative decision.

3 illustrates an operation of acquiring a plurality of images while moving a strip and determining a final line based on the obtained plurality of images, according to an exemplary embodiment.

Referring to FIG. 3 in detail, the filter may be disposed under the pedestal. At this time, the pedestal may be made of a transparent material through which light may pass, and may be formed of various materials in addition to it. The light source unit may mean LED lighting, and may provide light as various types of devices.

The filter may include at least one of a Darkfield filter, a Rheinberg filter, an Oblique filter, or a Dodt Gradient Contrast (DGC) filter, and may include a SLIT filter.

When using the darkfield filter, the central blocking plate is used to block the light in the center and only the outer light passes through the objective lens, so the background looks black and only the object is illuminated so that the outer part of the object can be seen more clearly. In addition, it is possible to better observe the interface and scratches of samples with high contrast.

When using the Rheinberg filter, a colored translucent material is used in the center of the disk to illuminate the object with a different color of light, with a color in the observation background and a different color around the outer periphery. Therefore, it can be used as one of the methods used to measure objects more clearly by different colored backgrounds and objects, and usually the center can be used in a darker color than the periphery.

The oblique filter can create a shadow on an object by passing light sideways through various shapes on the disk, and creates a shadow on the outer edge of an object that was seen as two-dimensional to observe the object three-dimensionally, making the outer edge of the object clearer. It can be one of the ways to reproduce the function of phase contrast microscopy or DIC by making

The DGC filter may be a method of creating an intensity gradient by using a filter similar to an oblique filter and passing it through a diffuser.

In all cases, a point light source such as an LED may require a condensing lens to create a wide area cone of light, collimated light.

In the immunological inspection of the lateral flow strip, a darkfield filter, a Rheinberg filter, an oblique filter, and a DGC filter can be used to increase contrast and contrast the outer edge of the test line with the background of the strip to observe fine test lines.

The principle of the above microscope can be applied to observe the minute test line in the lateral distribution strip. The three methods can be mainly used when you want to see the outer edge of an object in more detail, when you want to see the particle part clearly, or when you want to observe an object where light reflection and darkening occur due to high contrast contrast. In order to make the exterior of the object visible, we can focus on increasing the contrast. It may be to increase the sensitivity of the test by raising the contrast of the line using the three methods used in the microscope to read the antibody adsorbed on the membrane. The strip can transmit the light filtered by the filter and can mark the final line. The final line may refer to a line displayed on the strip when various reactions occur. At this time, if the line is minute, it may not be easily visible, so the corresponding line can be clearly seen through the corresponding invention. A camera may be placed on top of the strip to acquire an image of the strip.

The control unit may play a role of controlling various devices in the signal detection system by outputting various signals.

The term 'unit, module, member, or block' used in the specification may be implemented as software or hardware, and according to embodiments, a plurality of 'units, modules, members, or blocks' may be implemented as one component, It is also possible that one 'part, module, member, block' includes a plurality of components.

The control unit may obtain a plurality of images corresponding to a position of the moved strip at a predetermined cycle while moving the strip to one side at a predetermined speed through the camera. The strip may move to the right or the left at a predetermined speed, and when the strip moves, an image of the strip corresponding to the position of the strip may be obtained at a predetermined period. The predetermined period may refer to a time for photographing a camera at a regular period when the strip moves. At this time, it may be to obtain a position where a plurality of images are obtained very densely and the image of the strip is most likely to appear. As will be described later, the controller may determine the final line displayed on the strip based on a plurality of images. At this time, the final line may be determined based on an image that comes out most clearly among the plurality of images, and the clearest final line may be derived through machine learning of the plurality of images.

The controller may determine a final line displayed on the strip from a plurality of images based on a pre-learned line determination model. In this case, the plurality of images may include images acquired using at least one of a Darkfield filter, a Rheinberg filter, an Oblique filter, and a Dodt Gradient Contrast (DGC) filter.

This may be to acquire a plurality of images by utilizing a Darkfield filter, a Rheinberg filter, an Oblique filter, or a Dodt Gradient Contrast (DGC) filter and use them as input values to a pre-learned line decision model. This may be to obtain various data sets by controlling light in different ways with each filter.

In this case, the previously learned identification model may use machine learning. At this time, a deep learning model can be used and it can be performed using a machine learning model. In this case, the training data set may include image information through various filters as a learning data set, and a supervised learning method may be used. In this case, the deep learning model module may use a deep neural network (DNN) algorithm. Without being limited to those described, Convolutional Neural Network (CNN), Recurrent Neural Network (RNN), Restricted Boltzmann Machine (RBM), Deep Belief Network (DBN) algorithms It can be used, and since each algorithm is a well-known technique, a description thereof will be omitted.

At this time, the controller digitizes the sharpness of the outer image of the line included in the plurality of images, and may determine the final line if the digitized sharpness is greater than or equal to a predetermined first threshold value. At this time, the outside may be set by the user. As an example, if a line is observed with a thickness of 2CM, 0.2CM at each end of 2CM may be set as a line. This can be set in various ways.

A method of numerically quantifying sharpness may be the same as Equation 1.

S may mean a value obtained by digitizing the sharpness of the outer image of the line included in the plurality of images. b may mean a Darkfield filter, a Rheinberg filter, an Oblique filter, or a Dodt Gradient Contrast (DGC) filter, and d may mean the number of pixels included in the image. That is, images may be acquired according to a filter, and may mean pixel parts of an outer portion of an outer image of a line included in the images. At this time, the pixel portions of the outer portion may be previously set by the user.

X _ac may mean a brightness value of a corresponding c-th pixel included in an image acquired by a corresponding a-th filter. y _ac may mean a weight of a corresponding c-th pixel included in an image obtained by an a-th filter. This is because the part that emphasizes the outer part of the line, that is, the part that contrasts, is different for each filter, so the weight can be set differently for each filter. Through the corresponding equation, the sharpness of the outer image of each line of a plurality of images obtained using multiple filters is obtained for each position of the strip, for example, when shooting using multiple filters in the center, and compares them, final line can be determined. The weights may be tabled in advance.

If the numerical value obtained through Equation 1 is greater than or equal to a first predetermined threshold, the final line may be determined, and the first predetermined threshold may be set by a user.

In one embodiment, the position of the strip where the final line can be obtained most accurately may be determined for each filter. Through Equation 1 above, an image that is the final line can be determined, and the corresponding image can be acquired at the position of the acquired strip. In this case, the most accurate position of the strip may be obtained when the strip is at a different position for each filter. The position of the strip where the most accurate final line can be obtained may be determined and the corresponding position information may be stored.

That is, the server may acquire (301) a plurality of images corresponding to the position of the moved strip at a predetermined cycle while moving the strip to one side at a predetermined speed, and determine the final line displayed on the strip based on the plurality of images. A decision 302 may be made.

The step in which the control unit acquires a plurality of images corresponding to the positions of the strips moved at a predetermined period while moving the strip to one side at a predetermined speed through the camera, wherein the controller performs the first step by the Oblique filter through the camera. It may include obtaining a displayed image by radiating light secondarily filtered by the filtering and slit filter to the strip. This will be described in detail later.

In the step of determining, by the controller, the final line displayed on the strip based on the image, the controller digitizes the sharpness of the line image included in the plurality of images, and selects a line image between any two points separated by a predetermined distance or more. and determining a final line when the digitized sharpness difference is equal to or greater than a predetermined second threshold. This may be by using various filters to highlight the outside of the image through CONTRAST.

In one embodiment, if the thickness of the line is usually 3CM and the line part is 0.5CM above and below 3CM, the end is emphasized a lot based on 0.5CM from the end and is clear, but the inside is not clear. can Therefore, based on the corresponding 0.5CM, points on the inside and outside are compared to compare the brightness of light, and if there is a sharpness difference of more than a predetermined second threshold, it can be determined as the final line. In this case, the predetermined distance may be set by the user. In one embodiment, there will be a difference of about 1.3CM between the center of the 3CM-thick line and the emphasized part, which is a part about 0.2CM away from the end. When the 1.3CM distance is set as a predetermined distance, if the sharpness difference between the two points is equal to or greater than the predetermined second threshold value, this may mean that the boundary is clearly distinguished, and thus the line included in the image may be determined as the final line. The predetermined second threshold may be set by a user.

4 shows the shapes of an oblique filter and a slit filter according to an embodiment.

RGBW lighting may be placed at the bottom of the light source unit, and LED lighting may be disposed thereon. That is, the light source unit may include RGBW lighting and LED lighting. It can be composed of oblique filter (12) and slit filter (11) sequentially on the light source part. Through the shape of the oblique filter (12), contrast can be increased on the test line of the strip. In addition, the slit filter (11) can focus the light on the outer edge of the test line to change the direction of light more suitable for lateral flow strip observation. can This may be to make the contrast suitable for the line through the slit filter 11 since the object to be observed is the line. In the above process, the detection sensitivity can be increased by moving the strip in a straight line and finding a position where the signal of the test line can be read. At this time, Equation 1 may be used to find the detection sensitivity.

5 is a diagram illustrating a state observed using an oblique filter according to an embodiment.

Looking at the picture below, it can be observed that when the oblique filter is used, the outer image looks more prominent than when using the conventional brightfield filter. This may be to contrast the outer image so that the light is more concentrated in the outer area, so that the object can be seen better.

In this embodiment, by using an oblique filter, it can be adjusted to make the lines in the strip more visible even if they are minute.

6 is a diagram showing an embodiment using a darkfield filter and a Rheinberg filter according to an embodiment.

Referring to FIG. 6 in detail, when the darkfield filter and the rheinberg filter are used, it can be observed that the outer image looks more prominent than when the conventional brightfield filter is used. This is achieved by using a darkfield filter to reduce the light in the outside of the object and make it dark, while leaving the light in the outer part as it is, so that the outer part can be observed relatively more prominently. A Rheinberg filter can observe objects in a variety of colors. In particular, by arranging the outer part in a different color from the central part, it is possible to observe the object more accurately.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable medium may be specially designed and configured for the present invention or may be known and usable to those skilled in computer software.

Examples of computer readable media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include not only machine language codes generated by a compiler but also high-level language codes that can be executed by a computer using an interpreter and the like. The hardware device described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

In addition, the above-described method or device may be implemented by combining all or some of its components or functions, or may be implemented separately.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

1: light source
2: filter
3: pedestal
4: strip
5: Camera

Claims (1)

A pedestal, a filter disposed under the pedestal, a light source unit for irradiating light with the filter, a strip disposed on the upper surface of the pedestal to be movable in one direction and transmitting the light filtered by the filter, and an upper portion of the strip In the signal detection method performed by a signal detection system including a camera and a control unit disposed in,
acquiring, by the controller, a plurality of images corresponding to positions of the moved strip at a predetermined cycle while moving the strip to one side at a predetermined speed through the camera; and
determining, by the control unit, a final line displayed on a strip based on the plurality of images;
The step of determining, by the controller, the final line displayed on the strip based on the plurality of images,
Including, by the controller, digitizing the sharpness of the outer image of the line included in the plurality of images, and determining the final line when the digitized sharpness is equal to or greater than a predetermined first threshold,
The filter includes an oblique filter and a slit filter,
The step of obtaining, by the controller, a plurality of images corresponding to the positions of the moved strip at a predetermined cycle while moving the strip to one side at a predetermined speed through the camera,
and obtaining, by the control unit, an image displayed by irradiating the strip with the first-order filtering by the oblique filter and the second-order filtering by the slit filter through the camera.

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