Method and apparatus for automatically determining focus of optical device using oct, and recording medium having instruction recorded thereon

Abstract

Disclosed is a technique for automatically determining the focus of an optical device using OCT. An apparatus according to one aspect of the present disclosure comprises: a light source for outputting irradiation light; a beam splitter for separating the irradiation light into first light and second light; a reference mirror for reflecting the first light; and an image sensor for receiving interference light between reflected light of the first light and reflected light of the second light from an object, wherein the apparatus may change the position of the reference mirror, generate an optical coherence tomography (OCT) image of the object on the basis of the interference light, determine one or more positions of the reference mirror at which an OCT pattern is positioned within a predetermined position range of the OCT image, and move the reference mirror to a position at which an average value of intensities of the interference light is maximized.

Description

Method for automatically determining the focus of an optical device using OCT, device and recording medium recording commands

[0001] The present disclosure relates to a technology for automatically determining the focus of an optical device using OCT (Optical Coherence Tomography).

[0002] This study was conducted as part of the "Inter-Ministry Full-cycle Medical Device Research and Development Project," a program co-sponsored by the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health and Welfare, the Ministry of Food and Drug Safety, and the Inter-Ministry Full-cycle Medical Device Research and Development Project Group. [Project Title: Development of a Medical Image-Based Stereotactic Surgery Assistance Robot System and Component Modules, Project Identification Number: 1711138178, Project Number: KMDF_PR_20200901_0103-01]

[0003] To diagnose diseases occurring in the human body, tissue biopsies are utilized, which involve removing and examining tissue from areas suspected of having the disease. OCT technology is a medical imaging technology capable of producing cross-sectional images of biological tissue with a resolution of approximately 10 to 30 um. OCT systems can generate three-dimensional OCT images of a measurement target using interference images formed by the interference between a reference light beam reflected by a reference mirror and the reflected light from the target.

[0004] At least one embodiment of the present disclosure provides a technique for automatically adjusting the focus of an optical device to obtain a clear image of an object.

[0005] At least one embodiment of the present disclosure can automatically determine the positions of the reference mirror and lens based on the intensity of the interference light.

[0006] At least one embodiment of the present disclosure can automatically determine the focus of an optical device based on an OCT image generated using a Fast Fourier Transform (FFT) of data acquired from a Fourier domain OCT.

[0007] A device according to one aspect of the present disclosure comprises: a light source that outputs irradiation light having a wavelength that varies in a predetermined wavelength range; a beam splitter that separates the irradiation light into first light and second light; a reference mirror that reflects the first light incident from the beam splitter; an image sensor that receives interference light of a reflection of the first light on the reference mirror and a reflection of the second light on an object; a first driver that controls the reference mirror; And includes one or more processors, wherein the one or more processors control the first driving unit to change the position of the reference mirror, determine the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, generate an OCT (optical coherence tomography) image of the object based on the interference light, determine one or more positions of the reference mirror so that an OCT pattern corresponding to a measurement object in the object is located within a predetermined position range of the OCT image, determine a position where an average value of the intensity of the interference light is maximum among the one or more positions as a first target position, and control the first driving unit to move the reference mirror to the first target position.

[0008] In one embodiment, the apparatus further comprises an objective lens for irradiating the second light to the target object; and a second driving unit for controlling the objective lens, wherein the one or more processors control the second driving unit to change the position of the objective lens, determine a position among the positions of the objective lens at which the average value of the intensity of the interference light is maximum as a second target position, and control the second driving unit to move the objective lens to the second target position.

[0009] In one embodiment, the device further comprises a liquid lens for irradiating the second light to the target object; and a second driving unit for controlling the liquid lens, wherein the one or more processors control the second driving unit to change the thickness of the liquid lens, determine a thickness among the thicknesses of the liquid lens at which the average value of the intensity of the interference light is maximum as the target thickness, and control the second driving unit to set the liquid lens to the target thickness.

[0010] In one embodiment, the one or more processors can obtain information indicating the intensity of the interference light from the image sensor, and, based on the information indicating the intensity of the interference light, determine the intensity of the interference light according to the position of the reference mirror and the change in the wavelength.

[0011] In one embodiment, the one or more processors can obtain information indicating the intensity of the interference light from the image sensor, and generate the OCT image based on the information indicating the intensity of the interference light.

[0012] In one embodiment, the one or more processors may generate the OCT image using a Fast Fourier Transform (FFT).

[0013] In one embodiment, the one or more processors may be such that each of the one or more positions of the reference mirror is such that a difference between the optical path of the first light and the optical path of the second light is within a predetermined optical path difference.

[0014] According to another aspect of the present disclosure, a method may include the steps of: outputting a probe light having a wavelength that varies in a predetermined range and is split into a first light and a second light by a beam splitter; receiving an interference light of a reflection of the first light on a reference mirror and a reflection of the second light on a target object; changing a position of the reference mirror using a first driving unit that controls the reference mirror; determining an intensity of the interference light according to a change in the position of the reference mirror and the wavelength; generating an OCT image of the target object based on the interference light; determining one or more positions of the reference mirror such that an OCT pattern corresponding to a measurement target within the target object is positioned within a predetermined position range of the OCT image; determining a position at which an average value of the intensity of the interference light is maximized among the one or more positions as a first target position; and using the first driving unit, moving the reference mirror to the first target position.

[0015] In one embodiment, the method may further include a step of changing the position of the objective lens by using a second driving unit that controls the objective lens for irradiating the second light to the target object, a step of determining a position among the positions of the objective lens at which the average value of the intensity of the interference light is maximum as the second target position, and a step of controlling the second driving unit to move the objective lens to the second target position.

[0016] In one embodiment, the method may further include a step of changing the thickness of the liquid lens by using a second driving unit that controls the liquid lens for irradiating the second light to the target object, a step of determining a position in the thickness of the liquid lens where the average value of the intensity of the interference light is maximum as the target thickness, and a step of controlling the second driving unit to set the liquid lens to the target thickness.

[0017] In one embodiment, the step of generating the OCT image may include the step of obtaining information indicating the intensity of the interference light, and the step of determining the intensity of the interference light according to the position of the reference mirror and the change in the wavelength based on the information indicating the intensity of the interference light.

[0018] In one embodiment, the step of generating the OCT image may include the step of generating the OCT image based on information indicating the intensity of the interference light obtained from an image sensor.

[0019] In one embodiment, the step of generating the OCT image may include the step of generating the OCT image using a Fast Fourier Transform (FFT).

[0020] In one embodiment, each of the one or more positions of the reference mirror may be a position such that the difference between the optical path of the first light and the optical path of the second light is within a predetermined optical path difference.

[0021] According to another aspect of the present disclosure, a non-transitory computer-readable recording medium having recorded thereon instructions that, when executed by one or more processors, cause the one or more processors to perform a calculation, the instructions include: a step of causing the one or more processors to output a irradiation light having a wavelength that varies in a predetermined range and is split into a first light and a second light by a beam splitter; a step of receiving an interference light of a reflection of the first light with respect to a reference mirror and a reflection of the second light with respect to a target object; a step of changing a position of the reference mirror using a first driving unit that controls the reference mirror; a step of determining an intensity of the interference light according to a change in the position of the reference mirror and the wavelength; a step of generating an OCT image of the target object based on the interference light; a step of determining one or more positions of the reference mirror such that an OCT pattern corresponding to a measurement target within the target object is located within a predetermined position range of the OCT image; a step of determining a position at which an average value of the intensity of the interference light is maximized among the one or more positions as a first target position; and a step of controlling the reference mirror using the first driving unit. A step can be performed to move to the first target location.

[0022] According to at least one embodiment of the present disclosure, the positions of the reference mirror and lens can be automatically determined based on the intensity of the interference light.

[0023] According to at least one embodiment of the present disclosure, the focus of an optical device can be automatically determined based on an OCT image generated using FFT.

[0024] The effects according to the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the specification.

[0025] FIG. 1A is a block diagram of an electronic device according to one embodiment of the present disclosure.

[0026] FIG. 1b illustrates the principle of generating interference light by reflecting light output from a light source according to one embodiment of the present disclosure on a reference mirror and an object.

[0027] FIGS. 2A and 2B illustrate an objective lens and a liquid lens of a probe according to one embodiment of the present disclosure.

[0028] FIG. 3 illustrates a graph of the intensity of interference light according to a change in the position of a first lens or a change in the thickness of a liquid lens of an electronic device according to one embodiment of the present disclosure.

[0029] FIG. 4a illustrates a graph of the intensity of interference light according to a change in the position of a reference mirror for determining the position of the reference mirror according to one embodiment of the present disclosure.

[0030] FIG. 4b and FIG. 4c are diagrams for explaining the principle of changing an OCT image depending on changes in wavelength and position of a reference mirror according to one embodiment of the present disclosure.

[0031] FIGS. 5A and 5B illustrate intensity graphs of interference light and OCT images generated thereby according to one embodiment of the present disclosure.

[0032] FIG. 6 is a flowchart of a method for automatically determining a focus of an electronic device according to one embodiment of the present disclosure.

[0033] The various embodiments described in this document are exemplified for the purpose of clearly explaining the technical concept of the present disclosure and are not intended to be limited to specific embodiments. The technical concept of the present disclosure includes various modifications, equivalents, alternatives, and embodiments selectively combined from all or part of the embodiments described in this document. Furthermore, the scope of the technical concept of the present disclosure is not limited to the various embodiments presented below or the specific descriptions thereof.

[0034] Terms used in this document, including technical or scientific terms, unless otherwise defined, may have the meaning commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0035] The expressions "includes," "may include," "comprises," "may have," "have," and "may have" used in this document imply the presence of a target feature (e.g., a function, operation, or component), but do not exclude the presence of other additional features. In other words, such expressions should be understood as open-ended terms that imply the possibility of including other embodiments.

[0036] The singular forms used in this document may include the plural form unless the context clearly indicates otherwise, and this also applies to the singular forms set forth in the claims.

[0037] The expressions "first," "second," or "first", "second", etc. used in this document, unless the context indicates otherwise, are used to refer to multiple similar objects and to distinguish one object from another, and do not limit the order or importance among the objects.

[0038] As used herein, the expressions "A, B, and C", "A, B, or C", "A, B, and / or C", or "at least one of A, B, and C", "at least one of A, B, or C", "at least one of A, B, and / or C", etc., may refer to each of the listed items or to all possible combinations of the listed items. For example, "at least one of A or B" may refer to (1) at least one A, (2) at least one B, (3) at least one A and at least one B.

[0039] The term "component" as used herein may refer to software or hardware components such as field-programmable gate arrays (FPGAs) and application specific integrated circuits (ASICs). However, the "component" is not limited to hardware and software. The "component" may be configured to be stored on an addressable storage medium, and may be configured to execute one or more processors. In one embodiment, the "component" may include components such as software components, object-oriented software components, class components, and task components, as well as processors, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

[0040] The expression "based on" as used in this document is used to describe one or more factors that influence the decision, act of judgment, or action described in the phrase or sentence containing the expression, and this expression does not exclude additional factors that influence the decision, act of judgment, or action.

[0041] As used herein, the expression that a component (e.g., a first component) is “connected” or “connected” to another component (e.g., a second component) may mean that the component is directly connected or connected to the other component, as well as connected or connected via a new other component (e.g., a third component).

[0042] The expression "configured to" as used in this document can mean "set to do", "having the ability to do", "modified to do", "made to do", "capable of doing", etc., depending on the context. The expression is not limited to the meaning of "specifically designed in hardware", and for example, a processor configured to perform a specific operation can mean a generic-purpose processor that can perform the specific operation by executing software.

[0043] Hereinafter, various embodiments of the present disclosure will be described with reference to the attached drawings. In the attached drawings and the description of the drawings, identical or substantially equivalent components may be assigned the same reference numerals. Furthermore, in the description of various embodiments below, duplicate descriptions of identical or corresponding components may be omitted, but this does not mean that the corresponding components are not included in the embodiments.

[0044] FIG. 1A is a block diagram of an electronic device (100) according to one embodiment of the present disclosure. According to one embodiment, the electronic device (100) may include a processor (110), a memory (120), and an interferometer (130) including a light source (140), a beam splitter (150), a probe (160), a reference mirror (170), an image sensor (180), and an analog-to-digital converter (190), and may further include a first driving unit, a second driving unit, an objective lens, or a liquid lens. In some embodiments, at least one of these components of the electronic device (100) may be omitted, or other components may be added to the electronic device (100). In some embodiments, additionally or alternatively, some of the components may be implemented in an integrated manner, or implemented as a single or multiple entities.

[0045] The electronic device (100) according to various embodiments of the present disclosure may be a device of various forms. For example, the electronic device (100) may be a portable communication device, a computer device, a portable multimedia device, a wearable device, a home appliance device, or a device according to a combination of one or more of the above-described devices. The electronic device (100) of the present disclosure is not limited to the above-described devices.

[0046] At least some of the components inside and outside the electronic device (100) are connected to each other through a bus, GPIO (general purpose input / output), SPI (serial peripheral interface), or MIPI (mobile industry processor interface), and can exchange data and / or signals.

[0047] The light source (Swept Laser) (140) can emit light having a wavelength corresponding to each wave number by varying the wavelength. According to one embodiment, the wavelength of the light emitted by the light source (140) can be periodically changed within a predetermined range. For example, the wavelength of the light from The wavelength can be periodically varied within a range between 0 and 100 nm. The electronic device (100) can generate an OCT image using optical interference by using light having a periodically varying wavelength output from a light source (140). According to one embodiment, the light output from the light source (140) can travel along a pre-installed optical cable.

[0048] The beam splitter (150) can split the irradiated light into a plurality of lights according to a specified ratio. For example, the light output from the light source (140) can pass through the beam splitter (150) and be split into a first light that is incident on the reference mirror (170) and a second light that is incident on the object (162). For example, the first light may be light that is reflected by the beam splitter (150) among the irradiated light and is incident on the reference mirror (170), and the second light may be light that is transmitted through the beam splitter (150) among the irradiated light and is incident on the object (162). The beam splitter (150) may be a cube beam splitter or a plate beam splitter depending on the structure, and may be a polarizing beam splitter or a non-polarizing beam splitter depending on the polarization tendency. Examples of beam splitters (150) are not limited to those mentioned above.

[0049] The first reflected light, which is the first light reflected on the reference mirror (170), and the second reflected light, which is the second light reflected on the object (162), may travel back to the beam splitter (150) and cause interference between them. For example, a path difference between the two lights may occur due to a difference in the distance between the beam splitter (150) and the reference mirror (170) and a difference in the distance between the beam splitter (150) and the object (162). Interference light of the first reflected light and the second reflected light may be generated due to this optical path difference. The beam splitter (150) may reflect the interference light and transmit it to the image sensor (180).

[0050] The image sensor (180) can receive interference light reflected from the beam splitter (150) and convert the received optical signal into an electrical signal. The image sensor (180) can transmit the electrical signal to an analog-to-digital converter (ADC) (190). The image sensor (180) may be a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS), but is not limited thereto.

[0051] The probe (160) is a component for photographing an object (162) and may further include an objective lens, which is a lens used to form an image of the object (162). According to one embodiment, the objective lens may include a first lens and a second lens positioned closer to the object (162) than the first lens. The electronic device (100) may adjust the distance between the first lens and the second lens by adjusting the position of the first lens, thereby adjusting the position at which the image is formed. According to another embodiment, the probe (160) may include a liquid lens instead of the objective lens. When a liquid lens is used, the electronic device (100) may adjust the thickness of the liquid lens to adjust the position at which the image is formed.

[0052] The first driving unit may be a control circuit that controls the movement of the reference mirror (170), and the second driving unit may be a control circuit that controls the movement of the first lens among the objective lenses. The first driving unit and the second driving unit may adjust the positions of the reference mirror (170) and the first lens within a set range according to commands from the processor (110).

[0053] The processor (110) can control at least one component of an electronic device (100) connected to the processor (110) by executing software (e.g., commands, programs, etc.). In addition, the processor (110) can perform various operations related to the present disclosure, such as calculations, processing, data generation, and processing. In addition, the processor (110) can load data, etc. from the memory (120) or store data, etc. in the memory (120).

[0054] The processor (110) can focus to generate an OCT image based on a digital signal for interference light received from the analog-to-digital converter (190). Hereinafter, focusing means changing the position of the reference mirror (170) and the position of the first lens to a desired position or determining the thickness of the liquid lens. The processor (110) can adjust the position of the reference mirror (170) and the position of the first lens based on the change in the intensity of the interference light, and determine the thickness of the liquid lens. Hereinafter, the intensity of the interference light may refer to the average intensity of the generated OCT image. Even within one OCT image, a difference in brightness may occur for each pixel, and the average intensity refers to the average value of the brightness of all pixels within one OCT image. For example, an OCT image generated in a state where the focus is not well-matched may have a low average intensity because the image is overall blurry and dark, while an OCT image generated in a state where the focus is well-matched may have a clear and bright image and a high average intensity.

[0055] The memory (120) can store various information (data). The information stored in the memory (120) is information acquired, processed, or used by at least one component of the electronic device (100), and may include software (e.g., commands, programs, etc.). The memory (120) may include volatile and / or non-volatile memory. In the present disclosure, the commands or programs are software stored in the memory (120), and may include an operating system for controlling the resources of the electronic device (100), an application, and / or middleware for providing various functions to the application so that the application can utilize the resources of the electronic device (100). In one embodiment, the memory (120) may store commands that, when executed by the processor (110), cause the processor (110) to perform operations.

[0056] In one embodiment, at least one of the components of the electronic device (100) may be omitted, or another component may be added to the electronic device (100). In one embodiment, additionally or alternatively, some of the components may be implemented in an integrated manner or implemented as a single or multiple entities. In the present disclosure, one or more processors may be referred to as processors (110). The expression “processor (110)” may mean a set of one or more processors (110) unless the context clearly indicates otherwise. In the present disclosure, one or more memories may be referred to as memories (120). The expression “memory (120)” may mean a set of one or more memories (120) unless the context clearly indicates otherwise.

[0057] Hereinafter, the operations described as being performed by the electronic device (100) in FIGS. 1b to 7 can be understood as being performed by the processor (110) of the electronic device (100) described in FIG. 1a.

[0058] FIG. 1B illustrates a principle in which light output from a light source (140) according to one embodiment of the present disclosure is reflected by a reference mirror (170) and an object (162) to generate interference light. As illustrated, the electronic device (100) may include a light source (140), a beam splitter (150), a reference mirror (170), an image sensor (180), and an image processing unit. According to one embodiment, the electronic device (100) may generate an OCT image using interference images generated by an interferometer (130) implemented using a light source (140), a beam splitter (150), a probe (160), a reference mirror (170), an image sensor (180), and an analog-to-digital converter (190). The configuration of the interferometer (130) of the electronic device (100) is not limited to the above components and their connection relationships, and the components of the interferometer (130) and their connection relationships can be changed in various ways as long as substantially identical interference images can be generated.

[0059] The light source (140) can output irradiation light having a variable wavelength toward the beam splitter (150). According to one example, the irradiation light output from the light source (140) can be irradiated to the beam splitter (150) through an optical fiber. According to another embodiment, the irradiation light from the light source (140) can be directly transmitted to the beam splitter (150) through free space or the atmosphere. According to one embodiment, the electronic device (100) further includes a lens, and when the irradiation light from the light source (140) is irradiated to the lens, the lens refracts the incident irradiation light, so that irradiation light having a constant irradiation area can be emitted.

[0060] The irradiation light output from the light source (140) can be separated into first light incident on the reference mirror (170) and second light incident on the target object (162) by the beam splitter (150). For example, a portion of the irradiation light (the first light) can be reflected from the surface of the beam splitter (150) and incident on the reference mirror (170), and another portion of the irradiation light (the second light) can pass through the beam splitter (150) and incident on the target object (162). In addition, the beam splitter (150) can transmit the first reflected light reflected from the reference mirror (170) to the image sensor (180) and reflect the second reflected light and transmit it to the image sensor (180).

[0061] The image sensor (180) can receive the first reflected light and the second reflected light from the beam splitter (150). At this time, an interference phenomenon may occur between the first reflected light and the second reflected light received by the image sensor (180) due to a difference in the distance from the beam splitter (150) to the reference mirror (170) and a difference in the distance from the beam splitter (150) to the object (162). The image sensor (180) can receive the interference light of the first reflected light and the second reflected light, convert it into an electric signal, and transmit it to the analog-to-digital converter (190). The analog-to-digital converter (190) can convert the analog electric signal received from the image sensor (180) into a digital signal. The processor (110) can generate a 3D OCT image of the object (162) based on the digital signal generated by the analog-to-digital converter (190).

[0062] According to one embodiment, the processor (110) can generate an OCT image at each time point when the wavelength of the irradiation light output from the light source (140) is sequentially changed. Accordingly, the processor (110) can sequentially generate a plurality of OCT images of the object (162) while sweeping the wavelength of the light source (140). According to one embodiment, the image sensor (180) can be implemented using a camera or a video camera, but is not limited thereto.

[0063] FIGS. 2A and 2B illustrate an objective lens (210) and a liquid lens of a probe (200) according to an embodiment of the present disclosure. Referring to FIGS. 2A and 2B, the probe (200) of the electronic device (100) may include an objective lens (210) or a liquid lens. The probe (200) includes an optical device (e.g., a camera) for photographing an object (162), and in order to obtain a clear image of the object (162), the position of the object and the position of the camera focus (216) must be aligned. A processor (e.g., the processor (110) of FIG. 1A) can adjust the position of the first lens (212) in the objective lens (210) and adjust the thickness of the liquid lens to align the focus (216). Hereinafter, the case where the probe (200) includes the objective lens (210) and the case where the probe (200) includes the liquid lens will be described in turn.

[0064] When the probe (200) includes an objective lens (210), the objective lens (210) may include a first lens (212) and a second lens (214). Referring to FIG. 2A, the first lens (212) is a component whose position within the probe (200) can be adjusted up and down within a predetermined range, and the second lens (214) may be a lens positioned closer to the object (162) than the first lens (212). In this specification, the direction closer to the object (162) is described as the downward direction, and the direction away from the object (162) is described as the upward direction, based on the objective lens (210). Light reflected from the object (162) and incident into the probe (200) may sequentially pass through the second lens (214) and the first lens (212) and then be incident onto the optical fiber (202). At this time, if the position of the focus (216) of the objective lens (210) does not match the position of the target object (162), the image is blurred and it is difficult to obtain a clear OCT image. In order to obtain a clear OCT image, the processor can adjust the position of the focus (216) of the objective lens (210) by adjusting the position of the first lens (212).

[0065] According to one embodiment, the processor can determine the position of the first lens (212) based on the digital signal of the interference light obtained from the analog-to-digital converter (190). The processor can determine the position of the first lens (212) based on the intensity of the interference light according to the position of the first lens (212). For example, the processor can change the position of the first lens (212) over time and check the intensity of the interference light that changes according to the position of the first lens (212). The processor can determine the position of the first lens (212) when the intensity of the interference light is the greatest as the target position.

[0066] According to one embodiment, the processor can control the first driving unit to adjust the position of the first lens (212). The processor can adjust the position of the first lens (212) to move upward to shorten the focal length. Conversely, the processor can adjust the position of the first lens (212) to move downward to lengthen the focal length. For example, the processor can adjust the first lens to a first position (212a), a second position (212b), and a third position (212c). When the first lens is at the first position (212a), the focus is formed at the first focus (216a), when the first lens is at the second position (212b), the focus is formed at the second focus (216b), and when the first lens is at the third position (212c), the focus is formed at the third focus (216c). In each case, the processor can check the intensity of the interference light acquired by the image sensor (180) and determine the position of the first lens when the intensity of the interference light is the greatest as the target position. For example, if the first lens is currently at the second position (212b) and the intensity of the interference light is the greatest when the first lens is at the first position (212a), the processor can control the first driving unit to move the first lens to the first position (212a). At this time, when the first lens (212) is at the target position, the focus (216) of the objective lens can match the position of the object (162).

[0067] When the probe (200) includes a liquid lens (220), the processor can adjust the focal length by adjusting the thickness of the liquid lens (220). When the probe (200) includes the liquid lens (220), light reflected from the object (162) can pass through the liquid lens (220) and be incident on the optical fiber (202). The thicker the liquid lens (220), the more refraction occurs, thus shortening the focal length, and the thinner the liquid lens (220), the longer the focal length. For example, referring to FIG. 2B, the focal position (222b) when the liquid lens has a second thickness (220b) is located lower than the focal position (222a) when the liquid lens has a first thickness (220a). The processor can determine the target thickness of the liquid lens (220) based on the intensity of the interference light according to the thickness of the liquid lens (220). For example, the processor can determine the thickness of the liquid lens (220) as the target thickness when the intensity of the interference light is the greatest. At this time, the focus when the liquid lens (220) is the target thickness can match the position of the object (162).

[0068] FIG. 3 illustrates an intensity graph (300) of interference light according to a change in the position of a first lens or a change in the thickness of a liquid lens of an electronic device (100) according to an embodiment of the present disclosure. Any content overlapping with that described in FIG. 2 will be omitted. A processor (e.g., processor (110) of FIG. 1A) can check a change in the intensity of interference light by adjusting the position of the first lens of the objective lens or the thickness of the liquid lens. The processor can focus based on when the intensity of the interference light is the greatest. For example, the processor can generate an intensity graph (300) of interference light according to a change in the position of the first lens or a change in the thickness of the liquid lens based on a digital signal for interference light received from an analog-to-digital converter (190). Based on the intensity graph (300), the processor can determine the position of the first lens when the intensity of the interference light is the greatest (310) as a target position, or determine the thickness of the liquid lens when the intensity of the interference light is the greatest as a target thickness.

[0069] In one embodiment, if the position of the probe (e.g., probe (160) of FIG. 1A) has changed since the processor determined the position of the first lens or the thickness of the liquid lens, the processor may need to reset the position of the first lens or the thickness of the liquid lens.

[0070] FIG. 4A illustrates a graph of the intensity of interference light according to a change in the position of a reference mirror (e.g., the reference mirror (170) of FIG. 1A) for determining the position of a reference mirror according to one embodiment of the present disclosure. A processor (e.g., the processor (110) of FIG. 1A) may generate a first graph (400) indicating the intensity of interference light according to a change in the position of the reference mirror, based on a digital signal received from an analog-to-digital converter (190). According to one embodiment, the processor may generate the first graph (400) by performing an FFT conversion on the digital signal received from the analog-to-digital converter (190).

[0071] Referring to FIG. 4A, the first graph (400) may be in a form in which high and low points are repeated. The x-axis of the first graph (400) represents the position of a reference mirror (e.g., the reference mirror (170) of FIG. 1A), and the y-axis represents the intensity of interference light. That is, the intensity of interference light may increase and decrease repeatedly as the reference mirror moves. According to one embodiment, the first graph (400) may include a value corresponding to an interference revival image. The interference revival image is a virtual image that appears due to the characteristics of a variable wavelength light source (e.g., the light source (140) of FIG. 1A), and may be an image in which the focus is not precisely aligned, but the intensity of interference light is high.

[0072] The processor can generate a second graph (410) indicating the position of the OCT pattern corresponding to the measurement target within the object within the OCT image according to the position of the reference mirror. Hereinafter, for convenience of explanation, the position of the OCT pattern corresponding to the measurement target within the object within the OCT image will be described as 'depth'. In the second graph (410), the x-axis represents the position of the reference mirror, and the y-axis represents the depth. For example, when photographing a tissue of a mouse, the position of the OCT pattern corresponding to the target tissue within the OCT image may change depending on a change in the position of the reference mirror. The reason why the depth changes depending on a change in the position of the reference mirror will be described in detail with reference to FIGS. 4b to 4c below.

[0073] The processor can determine one or more positions of the reference mirror so that the OCT pattern corresponding to the measurement target within the object is located within a predetermined position range of the OCT image. The processor can determine one or more positions (hereinafter, target position candidates) of the reference mirror corresponding to a desired range of depth in the second graph (410), and determine values ​​corresponding to the target position candidates in the first graph (400). Referring to FIG. 4A, the third graph (420) only displays values ​​corresponding to the target position candidates in the first graph (400). The processor can determine, among the values ​​displayed in the third graph (420), the position (421) of the reference mirror when the intensity of the interference light is the greatest as the target position.

[0074] FIGS. 4B to 4C are diagrams illustrating the principle of how an OCT image changes depending on changes in wavelength and the position of a reference mirror according to one embodiment of the present disclosure. FIG. 4B illustrates a double-slit experiment. A double slit is installed between a light source and a screen, and light output from the light source can pass through the double slit and reach the screen. Even if the light reaching the screen arrives at the same position due to the double slit, a path difference may occur. If the light output from the light source has a single wavelength, an interference pattern may appear on the screen according to the intensity of the light that changes due to the path difference. For example, referring to FIG. 4c, constructive interference (442) may occur due to an optical path difference at a first position (432) of the screen, partial constructive interference (444) may occur due to an optical path difference at a second position (434), and destructive interference (446) may occur due to an optical path difference at a third position (436).

[0075] In FIG. 4B, when the distance from the light source to the screen is adjusted, the optical path difference of the light reaching a point on the screen may change, and thus the generated interference pattern may change. For example, when the reference mirror moves away from the beam splitter (e.g., the beam splitter (150) of FIG. 1A), the optical path of the first reflected light may become longer, and when the reference mirror moves closer to the beam splitter, the optical path of the second reflected light may become longer. When the light source outputs a light whose wavelength periodically changes while there is a difference in the optical path, constructive interference and destructive interference may occur periodically for each wavelength depending on the difference in the optical path, and the frequency at which the constructive interference and destructive interference occur may be proportional to the difference in the optical path. According to one embodiment, as the difference in the optical paths of the first reflected light and the second reflected light increases, the interference frequency may increase, and as the difference in the optical paths decreases, the interference frequency may decrease. The interference frequency may mean the number of times constructive interference (or destructive interference) occurs per unit time. Since the interference frequency in OCT images generated from analog signals is proportional to depth, depth can also change depending on the position of the reference mirror. For example, a large difference in the optical path length can increase the depth, while a small difference in the optical path length can decrease the depth.

[0076] FIGS. 5A and 5B illustrate intensity graphs of interference light and OCT images generated thereby according to one embodiment of the present disclosure. Descriptions of portions overlapping with those described in FIG. 4A will be omitted. Since the wavelength of the irradiating light output from a light source (e.g., the light source (140) of FIG. 1A) is variable, constructive interference and destructive interference may occur depending on changes in the position of a reference mirror (e.g., the reference mirror (170) of FIG. 1A). A processor (e.g., the processor (110) of FIG. 1A) may generate an intensity graph for the interference light in which constructive interference and destructive interference occur periodically. The processor may generate an OCT image by performing FFT transform on the intensity graph for the interference light.

[0077] According to one embodiment, the depth at which the OCT pattern of the measurement target is located in the OCT image may vary depending on the interference frequency of the interference light. According to one embodiment, as the interference frequency increases, the depth may increase (deeper), and as the interference frequency decreases, the depth may decrease (lower). For example, referring to FIGS. 5A and 5B, it can be confirmed that the depth of the OCT image (512) of FIG. 5B is greater than the depth of the OCT image (502) of FIG. 5A because the interference frequency of the interference light shown in the graph (510) of FIG. 5B is greater than the interference frequency of the interference light shown in the graph (500) of FIG. 5A.

[0078] FIG. 6 is a flowchart of a method for automatically determining a focus of an electronic device according to an embodiment of the present disclosure. In step 600, the electronic device (e.g., the electronic device (100) of FIG. 1A) may determine the position of an objective lens or the thickness of a liquid lens based on the intensity of interference light. If the probe (e.g., the probe (160) of FIG. 1A) includes an objective lens, the electronic device may change the position of the first lens (212) over time and determine the intensity of interference light that changes according to the position of the first lens (212). The electronic device may determine the position of the first lens (212) at which the intensity of the interference light is the greatest as the target position. If the probe includes a liquid lens, the electronic device may measure the intensity of interference light according to the thickness of the liquid lens (220) and determine the thickness of the liquid lens (220) at which the intensity of the interference light is the greatest as the target thickness.

[0079] In step 610, the electronic device can measure the intensity of interference light according to the change in the position and wavelength of a reference mirror (e.g., the reference mirror (170) of FIG. 1A). Since the wavelength of the irradiation light output from a light source (e.g., the light source (140) of FIG. 1A) changes periodically over time, constructive interference and destructive interference may occur depending on the position of the reference mirror. The electronic device can measure the intensity of the interference light using an image sensor (e.g., the image sensor (180) of FIG. 1A). In step 620, the electronic device can generate an OCT image of the object based on the interference light.

[0080] The electronic device may determine, in step 630, one or more positions of a reference mirror such that an OCT pattern corresponding to a measurement target within an object is positioned within a predetermined position range of an OCT image. The electronic device may determine one or more positions of the reference mirror using a first graph (e.g., the first graph (400) of FIG. 4A) indicating an intensity of interference light according to a change in the position of the reference mirror, and a second graph (e.g., the second graph (410) of FIG. 4A) indicating a position of an OCT pattern corresponding to a measurement target within an object within an OCT image. The electronic device may generate, from the first graph, a third graph (e.g., the third graph (420) of FIG. 4A) that displays only values ​​corresponding to one or more positions of the reference mirror corresponding to a desired depth range in the second graph.

[0081] The electronic device, in step 640, determines a position where the average value of the intensity of the interference light in the third graph is maximum as a first target position, and controls the first driving unit to move the reference mirror to the first target position.

[0082] Although the steps of the method or algorithm according to the present disclosure are described in a sequential order in the flowchart illustrated in FIG. 6, the steps may be performed in any order that can be arbitrarily combined according to the present disclosure, in addition to being performed sequentially. The description according to this flowchart does not exclude changes or modifications to the method or algorithm, and does not imply that any step is essential or desirable. In one embodiment, at least some of the steps may be performed in parallel, iteratively, or heuristically. In one embodiment, at least some of the steps may be omitted, or other steps may be added.

[0083] Various embodiments of the present disclosure may be implemented as software on a machine-readable storage medium. The software may be software for implementing various embodiments of the present disclosure. The software may be inferred from various embodiments of the present disclosure by programmers skilled in the art to which the present disclosure pertains. For example, the software may be a program including machine-readable instructions (e.g., code or code segments). The device may be a device capable of operating according to instructions called from a storage medium, such as a computer. In one embodiment, the device may be an electronic device (100) according to embodiments of the present disclosure. In one embodiment, the processor of the device may execute the called instructions, causing components of the device to perform functions corresponding to the instructions. In one embodiment, the processor may be a processor (110) according to embodiments of the present disclosure. The storage medium may refer to any type of recording medium that stores data and can be read by the device. The storage medium may include, for example, ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, etc. In one embodiment, the storage medium may be memory (120). In one embodiment, the storage medium may be implemented in a distributed form, such as in a network-connected computer system. The software may be distributed and stored and executed in a computer system, etc. The storage medium may be a non-transitory storage medium. A non-transitory storage medium means a tangible medium regardless of whether data is stored semi-permanently or temporarily, and does not include a signal that is propagated transitorily.

[0084] While the technical concept of the present disclosure has been described through various embodiments, it should be understood that the technical concept of the present disclosure encompasses various substitutions, modifications, and variations that can be made within the scope of those skilled in the art to which the present disclosure pertains. Furthermore, it should be understood that such substitutions, modifications, and variations are encompassed within the scope of the appended claims.

Claims

1. A light source that outputs light having a wavelength that varies within a predetermined wavelength range; A beam splitter that separates the above-mentioned light into first light and second light; A reference mirror that reflects the first light incident from the beam splitter; An image sensor that receives interference light of the reflected light of the first light on the reference mirror and the reflected light of the second light on the object; A first driver controlling the above reference mirror; and Containing one or more processors, One or more of the above processors, Controlling the first driving unit to change the position of the reference mirror, Determine the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, Based on the above interference light, an OCT (Optical Coherence Tomography) image of the object is generated, determining one or more positions of the reference mirror so that an OCT pattern corresponding to a measurement target within the object is positioned within a predetermined position range of the OCT image; Among the above one or more locations, the location where the average value of the intensity of the interference light is maximum is determined as the first target location, A device that controls the first driving unit to move the reference mirror to the first target position.

2. In paragraph 1, An objective lens for irradiating the second light onto the target object; and Further comprising a second driving unit for controlling the objective lens, One or more of the above processors, Controlling the second driving unit to change the position of the objective lens, Among the positions of the objective lens, the position at which the average value of the intensity of the interference light is maximum is determined as the second target position, A device that controls the second driving unit to move the objective lens to the second target position.

3. In paragraph 1, A liquid lens for irradiating the second light to the target object; and Further comprising a second driving unit for controlling the liquid lens, One or more of the above processors, Controlling the second driving unit to change the thickness of the liquid lens, Among the thicknesses of the above liquid lens, the thickness at which the average value of the intensity of the interference light is maximum is determined as the target thickness, A device that controls the second driving unit to set the liquid lens to the target thickness.

4. In paragraph 1, One or more of the above processors, From the image sensor, information indicating the intensity of the interference light is obtained, A device that determines the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, based on information indicating the intensity of the interference light.

5. In paragraph 1, One or more of the above processors, From the image sensor, information indicating the intensity of the interference light is obtained, A device for generating the OCT image based on information indicating the intensity of the interference light.

6. In paragraph 5, A device wherein the one or more processors generate the OCT image using FFT (Fast Fourier Transform).

7. In paragraph 1, One or more of the above processors, A device wherein each of the one or more positions of the reference mirror is a position such that the difference between the optical path of the first light and the optical path of the second light is within a predetermined optical path difference.

8. A step of outputting a light beam having a wavelength that varies within a predetermined range and being separated into a first light beam and a second light beam by a beam splitter; A step of receiving interference light of the reflected light of the first light on the reference mirror and the reflected light of the second light on the object, A step of changing the position of the reference mirror using a first driving unit that controls the reference mirror, A step of determining the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, A step of generating an OCT image of the object based on the interference light, A step of determining one or more positions of the reference mirror so that an OCT pattern corresponding to a measurement target within the object is positioned within a predetermined position range of the OCT image; A step of determining a position where the average value of the intensity of the interference light is maximum among the one or more positions as a first target position, and A method comprising a step of moving the reference mirror to the first target position using the first driving unit.

9. In paragraph 8, A step of changing the position of the objective lens using a second driving unit that controls the objective lens for irradiating the second light to the target object, A step of determining a position among the positions of the objective lens at which the average value of the intensity of the interference light is maximum as a second target position, and A method further comprising the step of controlling the second driving unit to move the objective lens to the second target position.

10. In paragraph 8, A step of changing the thickness of the liquid lens using a second driving unit that controls the liquid lens for irradiating the second light to the target object, A step of determining a position where the average value of the intensity of the interference light is maximum among the thicknesses of the liquid lens as the target thickness, and A method further comprising the step of controlling the second driving unit to set the liquid lens to the target thickness.

11. In paragraph 8, The steps of generating the above OCT image are: A step of obtaining information indicating the intensity of the interference light, and A method comprising a step of determining the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, based on information indicating the intensity of the interference light.

12. In paragraph 8, The steps of generating the above OCT image are: A method comprising the step of generating the OCT image based on information indicating the intensity of the interference light obtained from the image sensor.

13. In paragraph 12, The steps of generating the above OCT image are: A method comprising a step of generating the OCT image using FFT (Fast Fourier Transform).

14. In paragraph 8, A method wherein each of the one or more positions of the reference mirror is a position such that the difference between the optical path of the first light and the optical path of the second light is within a predetermined optical path difference.

15. A non-transitory computer-readable recording medium having recorded thereon a command that, when executed by one or more processors, causes the one or more processors to perform an operation, The above command causes the one or more processors to: A step of outputting an investigation light having a wavelength that varies within a predetermined range and being separated into a first light and a second light by a beam splitter, A step of receiving interference light of the reflected light of the first light on the reference mirror and the reflected light of the second light on the object, A step of changing the position of the reference mirror using a first driving unit that controls the reference mirror, A step of determining the intensity of the interference light according to the position of the reference mirror and the change in the wavelength, A step of generating an OCT image of the object based on the interference light, A step of determining one or more positions of the reference mirror so that an OCT pattern corresponding to a measurement target within the object is positioned within a predetermined position range of the OCT image; A step of determining a position where the average value of the intensity of the interference light is maximum among the one or more positions as a first target position, and A computer-readable recording medium that causes a step of moving the reference mirror to the first target position using the first driving unit.

Images