RU2738314C1 - System, computing device and method of determining optical properties of volume scattering medium using diffuse reflectometry - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used to determine optical properties of a volume-scattering medium. Essence of invention consists in that system for determining optical properties of volume-scattering medium using diffuse reflectometry, comprising: a radiation source configured to provide radiation to the volume-scattering medium in the radiation input region; an optical receiving system configured to receive radiation transmitted through the scattering medium in the radiation receiving region to obtain a radiation intensity distribution, wherein the optical receiving system comprises an array of LC (liquid crystal) cells, an array of microlenses and an array of photodetectors which are aligned such that each LC cell from the array of LC cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; a separator which separates the radiation input region from the radiation receiving region and is configured to prevent radiation incident partially reflected from the surface of the volume-scattering medium in the radiation input region into the radiation receiving region of the optical receiving system; control unit configured to control the optical receiving system, while providing radiation to the volume-scattering medium in the radiation input region, to induce the optical receiving system to serially open each LC cell with simultaneous reception of radiation which has passed through the corresponding open LC cell and a microlens corresponding to the photodetector from the array of photodetectors to obtain said radiation intensity distribution; and a data processing unit configured to determine the optical properties of the volume-scattering medium based on the radiation intensity distribution.

EFFECT: technical result is enabling high accuracy of determining optical properties of a volume scattering medium.

24 cl, 6 dwg

Description

Technology area

[0001] The present invention relates to a method for determining the optical properties of a volume scattering medium without penetration and without destroying the volume scattering medium. More specifically, this application discloses a system, computing device, and method for determining the optical properties of a volume-scattering medium using diffuse reflectometry.

State of the art

[0002] Volume-scattering media such as, for example, biomaterial (blood, skin), wood, pharmacological and other compositions, products and other materials that fall under the definition of a turbid medium, have two main parameters that determine their optical properties: the coefficient scattering and absorption coefficient. To accurately determine the optical properties of the volume scattering medium, it is extremely important that the measurement of these coefficients is accurate.

[0003] Most of the known devices for non-invasive determination of the optical properties of a volume-scattering medium are based on spectrometry and measure this medium only one response, determined by a combination of scattering and absorption coefficients, at a time. Thus, the accuracy of this response is reduced due to the phenomenon of crosstalk, in which radiation that has passed through the measured volume-scattering medium and is characteristic of a certain area on the surface of the volume-scattering medium is simultaneously received by two or more adjacent photodetectors (receivers) from the array photodetectors in the optical receiving system due to the aberrations inherent in this optical receiving system. Thus, the signal-to-noise ratio (SNR) is significantly reduced even with a crosstalk of 1%.

[0004] Patent Document EP1119763 (A1) - 2001-08-01 discloses "METHOD FOR MEASURING LOCALLY AND SUPERFICIALLY THE SCATTERING AND ABSORPTION PROPERTIES OF TURBID MEDIA" . The solution disclosed in the '763 patent is, in the opinion of the Applicant, the closest analogue. In one embodiment of said solution, a collimated or focused radiation source unit, an optical detector unit, which is formed from a one-dimensional or two-dimensional optical detector array, and a signal processing unit are provided. Thus, the '763 solution measures only one response at a time, i.e. this solution still has inherent cross-talk on the photodetector side, which significantly reduces SNR.

The essence of the invention

[0005] To solve the above-described technical problem and achieve the technical result of improving the accuracy of determining the optical properties of the volume-scattering medium by eliminating cross-talk on the side of photodetectors, the following main aspects of the invention disclosed in this application are proposed.

[0006] According to a first aspect of the present invention, there is provided a system for determining optical properties of a volume scattering medium using diffuse reflectometry, comprising: at least one radiation source configured to provide radiation to the volume scattering medium in a radiation input region; an optical receiving system configured to receive radiation that has passed through a volume-scattering medium in the radiation receiving region to obtain a radiation intensity distribution, while the optical receiving system contains an array of LC (liquid crystal) cells, an array of microlenses and an array of photodetectors, which are combined as follows that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; at least one separator separating the radiation input area from the radiation receiving area and configured to prevent the ingress of radiation, partially reflected from the surface of the volume-scattering medium in the radiation input area, into the radiation receiving area of the optical receiving system; a control unit configured to control the optical receiving system, while providing radiation to the volume-scattering medium in the radiation input region, to induce the optical receiving system to sequentially open each LC cell from an array of LCD cells while simultaneously receiving radiation that has passed through the corresponding an open LCD cell and a microlens with a corresponding photodetector from a photodetector array to obtain said radiation intensity distribution; and a data processing unit configured to determine the optical properties of the volume scattering medium based on the radiation intensity distribution.

[0007] According to a second aspect of the present invention, there is provided a user computing device with a function for determining the optical properties of a volume-scattering medium, comprising at least partially installed in a housing of the user computing device: at least one radiation source configured to provide radiation to the volume-scattering medium. environment in the field of radiation input; an optical receiving system configured to receive radiation that has passed through a volume-scattering medium in the radiation receiving region to obtain a radiation intensity distribution, while the optical receiving system contains an array of LCD cells, an array of microlenses and an array of photodetectors, which are aligned so that each An LCD cell from an array of LCD cells corresponds to a corresponding microlens from an array of microlenses and a corresponding photodetector from an array of photodetectors; at least one separator separating the radiation input area from the radiation receiving area and configured to prevent the ingress of radiation, partially reflected from the surface of the volume-scattering medium in the radiation input area, into the radiation receiving area of the optical receiving system; a processor capable of: controlling the optical receiving system, while providing radiation to the volume-scattering medium in the region of radiation input, to induce the optical receiving system to sequentially open each LC cell from an array of LCD cells with simultaneous registration of radiation that has passed through the corresponding an open LCD cell with a corresponding photodetector from the photodetector array to obtain said radiation intensity distribution; and determining the optical properties of the volume scattering medium based on the obtained radiation intensity distribution.

[0008] According to a third aspect of the present invention, there is provided a method for determining the optical properties of a volume-scattering medium, comprising the steps of: introducing radiation into an illumination region on the surface of the volume-scattering medium while preventing the radiation partially reflected from the surface of the volume-scattering medium from entering the backlight area, into the target area of the optical receiving system containing an array of LCD cells, an array of microlenses and an array of photodetectors, which are aligned so that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; by means of an optical receiving system, radiation passed through the volume-scattering medium is received in the target area to obtain the distribution of the radiation intensity, while the said reception of radiation contains substages, in which, simultaneously with the introduction of radiation into the illumination region on the surface of the volume-scattering medium: sequentially open each LCD cell of the array of LCD cells and detecting radiation transmitted through the open LCD cell with a corresponding photodetector from the array of photodetectors to obtain a plurality of radiation intensity values that represent said radiation intensity distribution; and determining the optical properties of the volume scattering medium based on the radiation intensity distribution.

Brief Description of Drawings

[0009] Other aspects, features and advantages of the present invention will become apparent to the person skilled in the art upon reading the following detailed description of embodiments of the present invention with reference to the accompanying drawings, in which:

[FIG. 1] FIG. 1 illustrates a side view of an embodiment of a system 100 for determining the optical properties of a volume scattering medium 20 using diffuse reflectometry at an initial time t _{1 of} the operating time.

[FIG. 2] FIG. 2 illustrates a top view of an embodiment of a system 100 for determining the optical properties of a volume scattering medium 20 using diffuse reflectometry at an initial time t _{1 of} the operating time.

[FIG. 3] FIG. 3 illustrates a side view of an embodiment of a system 100 for determining the optical properties of a volume scattering medium 20 using diffuse reflectometry at a subsequent time t _{2 of} operation.

[FIG. 4] FIG. 4 illustrates an embodiment of a user computing device 300 with a function for determining the optical properties of a volume scattering medium 20.

[FIG. 5] FIG. 5 illustrates an embodiment of a method for determining the optical properties of a volume scattering medium 20.

[FIG. 6] FIG. 6 illustrates the sub-steps of the step of receiving S405 radiation that has passed through the volume scattering medium 20 in the target area for obtaining the radiation intensity distribution according to an embodiment of the method for determining the optical properties of the volume scattering medium 20 shown in FIG. 5.

Detailed description of embodiments of the invention

[0010] FIG. 1 illustrates a side view of an embodiment of a system 100 for determining the optical properties of a volume scattering medium 20 using diffuse reflectometry at an initial time (t ₀ ) of operation. A top view of this embodiment of the system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry at the initial time of operation is illustrated in FIG. 2. The volume scattering medium 20 is shown in FIG. 1-2 as an example of a medium whose optical properties are desired to be determined by the system 100. It should be understood that the medium 20 is not included in the system 100 itself. In addition, it should be understood that the orientation of the environment 20 relative to the components of the system 100 is not necessarily the same as shown in FIG. 1-2. The volume-scattering medium 20 can be, but is not limited to, the following media, biomaterial (for example, blood, skin), wood, pharmacological and other compositions, products, gas, in any transparent vessel, as well as other materials that fall under under the definition of a turbid environment. If the system 100 is intended to be used to determine the optical properties or to analyze the gaseous space-scattering medium 20, the system 100 may further include a chamber (not shown in the figures) of a transparent material (e.g., glass), which is pre-inflated or otherwise filled. gaseous space-scattering medium 20, the optical properties or analysis of which must be determined / carried out.

[0011] The system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry, illustrated in FIG. 1-2, contains at least one radiation source 105 configured to provide radiation to the volume-scattering medium 20 in the radiation input region 10. In a preferred embodiment, the radiation source 105 is, but is not limited to, a coherent radiation source (eg, a laser), light-emitting diode (s) (LED), superluminescent diode (s) (SLD), a lamp (eg, xenon) with a filter. Examples of lasers that can be used: DFB laser, VCSEL, etc. It should be understood that the radiation input region 10 is shown in FIG. 1-2 schematically. The actual size and shape of the radiation input region 10 (i.e., the illumination spot on the surface of the volume scattering medium 20) depends on the type, shape and number of radiation sources 105, as well as on the distance from the radiation sources 105 to the surface of the volume scattering medium 20. When using the radiation source 105 without a transmitting optical system, the source 105 is placed as close as possible to the surface of the volume-scattering medium 20, otherwise the illumination spot on the surface of the volume-scattering medium 20 becomes large, and the accuracy of restoring the optical properties decreases. The specific distance from the radiation source 105 to the surface of the volume-scattering medium 20 can be selected empirically taking into account the design features of the housing (not shown) of the system 100 and the relative position of the components of the system 100 in this housing.

[0012] The system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry, illustrated in FIG. 1-2, contains an optical receiving system 110. The optical receiving system 110 is configured to receive radiation that has passed through the volume-scattering medium 20 in the radiation receiving area 15 to obtain a radiation intensity distribution. It should be understood that the radiation receiving area 15 is shown in FIG. 1-2 schematically. The actual size and shape of the radiation receiving area 15 (i.e., the target area on the surface of the volume scattering medium 20) depends on the type, shape and number of elements in the optical receiving system 110. The specific distance from the surface of the volume scattering medium 20 to the optical receiving system can be selected empirically taking into account the design features of the housing (not shown) of the system 100 and the relative position of the components of the system 100 in this housing. In this case, the optical receiving system 110 contains an array of 110.1 LCD cells, an array of 110.2 microlenses, and an array of photodetectors 110.3, which are aligned so that each LCD cell from an array of LCD cells corresponds to a corresponding microlens from an array of microlenses and a corresponding photodetector from an array of photodetectors (see Fig. 1). In a preferred embodiment of the present invention, an LCD cell array 110.1, a microlens array 110.2, and a photodetector array 110.3 are aligned with each other in this order as they move away from the volume scattering medium 20 and, optionally, can be mounted in the housing of the optical receiving system 110, as shown in FIG. 1-2.

[0013] According to the present invention, an LCD cell array 110.1 may be comprised of two or more LCD cells arranged in at least one row, a microlens array 110.2 may be composed of two or more microlenses arranged in at least one row, and an array 110.3 photodetectors may consist of two or more photodetectors arranged in at least one row. In the specific (illustrative) embodiment shown in FIG. 1-2, the dimension of each of the array of 110.1 LCD cells, the array of 110.2 microlenses and the array of 110.3 photodetectors is 1 × 6 (six elements in each array, lined up in one row). One skilled in the art will appreciate that other dimensions of these arrays may exist, for example 1 × 2, 2 × 6, 6 × 6, and that increasing the number of elements can increase the resolution of the optical receiving system 110. In a preferred embodiment, the array 110.1 LCD cells, microlens array 110.2, photodetector array 110.3 contain the same number of corresponding elements. However, there may be an embodiment of the present invention in which the LCD cell array 110.1, the microlens array 110.2, the photodetector array 110.3 contain different numbers of corresponding elements, for example, the LCD cell array 110.1 contains one LCD cell, the microlens array 110.2 contains one receiver.

[0014] The system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry, illustrated in FIG. 1-2, contains at least one separator 115 separating the radiation input region 10 from the radiation receiving region 15 and is configured to prevent the radiation, partially reflected from the surface of the volume-scattering medium 20 in the radiation input region 10, from entering the radiation receiving region 15 optical receiving system 110. In a preferred embodiment, the optical receiving system 110 is positioned relative to at least one radiation source 105 and at least one separator 115 so that the SDS distance increases between at least one radiation source and each subsequent a photodetector in at least one row of photodetectors as illustrated in FIG. 1. Due to this, it is possible to analyze different regions of the volume-scattering medium 20. In the design of the system 100, at least one radiation source 105 and the optical receiving system 110 are positioned relative to each other so that the radiation input region 10 and the radiation receiving region 15 are not connected to each other. overlapped, as shown, for example, in FIG. one.

[0015] The system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry, illustrated in FIG. 1-2, contains a control unit 120 configured to control the optical receiving system 110 while providing radiation to the volume-scattering medium 20 in the radiation input region 10, to induce the optical receiving system 110 to sequentially open each LCD cell from the array 110.1 LCD cells with the simultaneous reception of radiation passed through the corresponding open LCD cell and microlens, by the corresponding photodetector from the array 110.3 photodetectors to obtain the radiation intensity distribution. With the sequential opening of each LCD cell from the LCD cell array 110.1, the control unit 120 is specifically configured to control the optical receiving system 110 to induce the optical receiving system 110 to sequentially open each LCD cell from the LCD cell array 110.1 starting from that LCD. -cell, which corresponds to the photodetector with the smallest SDS-distance (SDS ₁ in Fig. 1), and continuing until that LCD cell is opened, which corresponds to the photodetector with the largest SDS-distance (SDS _N in Fig. 1 ). In an alternative embodiment of the present invention, the LC cell opening direction may start from the farthest LCD cell with the longest SDS distance (SDS _N in FIG. 1) and continue towards the LCD cell with the smallest SDS distance (SDS ₁ in FIG. . one). In an alternative embodiment, the sequential opening may include opening all even LCD cells, then all odd LCD cells. Specialists will understand other embodiments of sequential opening, in which the condition is met that adjacent LCD cells to the opened LCD cell are closed. Sequential opening of each LCD cell and receiving only the radiation that has passed through it and the corresponding focusing lens eliminates cross-talk between the photodetectors. In other words, this sequence of actions avoids the situation in which radiation from one area on the surface of the volume-scattering medium 20 in the radiation receiving area 15 is simultaneously recorded by two or more adjacent photodetectors.

[0016] To open the corresponding LCD cell, the control unit 120 is configured to apply a control voltage to the corresponding LCD cell. It should be understood that according to the present invention, only one LCD cell is opened at a time, and at the next time, an open LCD cell is closed, and the next LCD cell from the array of LCD cells is opened, etc. If necessary, several measurements can be made with each LCD cell, i.e. There can be several measurement cycles from the first LCD cell in the array to the last LCD cell in the array. The opening of an LC cell is understood to be such a state in which radiation can pass through it. Initially, the LCD cell is closed, i.e. does not transmit radiation. For receiving radiation by the photodetector, the control unit 120 is configured to output a control signal to the photodetector array 110.3 to cause the corresponding photodetector or the entire photodetector array 110.3 to receive radiation. For sequential opening of each LCD cell from the LCD cell array 110.1 while simultaneously receiving radiation, the control unit 120 synchronizes the moment of applying the control voltage to the corresponding LC cell with the moment of issuing the control signal to the corresponding photodetector or photodetector array 110.3. Thus, at the start time (t ₁ ) of the operating time, which is illustrated in FIG. 1-2, the optical receiving system 110 obtains the value of the radiation intensity in the sub-area of the radiation receiving area 15, which corresponds to the distance SDS ₁ (by means of the first elements of the optical receiving system 110, which correspond to the distance SDS ₁ ). At the subsequent time (t ₂ ) of the operating time, which is illustrated in FIG. 3, the optical receiving system 110 obtains the value of the radiation intensity in the sub-area of the radiation receiving area 15, which corresponds to the distance SDS ₂ (by means of the second elements of the optical receiving system 110, which correspond to the distance SDS ₂ ), etc.

[0017] The system 100 for determining the optical properties of the volume scattering medium 20 using diffuse reflectometry, illustrated in FIG. 1-3, contains a data processing unit 125 adapted to determine the optical properties of the volume-scattering medium 20 based on the distribution of the radiation intensity. In a preferred embodiment, for determining the optical properties of the volume scattering medium 20, the data processing unit 125 is particularly adapted to compare the measured values of the radiation intensity from the radiation intensity distribution obtained for the volume scattering medium 20 with the corresponding set of possible values of the radiation intensity for the given type. volume-scattering medium 20 from the set of possible radiation intensity values, pre-simulated by the Monte Carlo method for different optical properties of volume-scattering media of different types, to find a subset of radiation intensity values that minimizes the error E:

where S is the number of photodetectors,

i = 1 ... S - photodetector number,

- измеренное значение интенсивности излучения для фотодетектора i; и

- the measured value of the radiation intensity for the photodetector i; and

- моделированное значение интенсивности излучения для фотодетектора i;

- the simulated value of the radiation intensity for the photodetector i;

[0018] The found subset of values that minimizes the error E indicates specific optical properties (absorption coefficient and scattering coefficient) of the volume scattering medium 20. The specific type (e.g., skin, air, etc.) of the volume scattering medium 20, according to which will be measured can be indicated by a predetermined value (for example, the value “1” corresponds to the skin, the value “2” corresponds to the exhaled air) of the parameter of the type of the volume-scattering medium 20, which can be received by an input unit (not shown), which for this purpose can be included in the system 100. In another embodiment, in which the system 100 is always used only for a certain type of measured volume-scattering medium 20, for example, skin, the system 100 does not need to accept an input of the type of measured volume-scattering medium 20 every time this type will not change from measurement to measurement. In this other embodiment, the data processing unit 125 may be pre-configured by the manufacturer of the system 100 or the user of the system 100 with the required set of possible values of the radiation intensity for a certain type of volume scattering medium 20, which the system 100 always uses when determining the optical properties of the volume scattering medium 20. For this purpose, the data processing unit 125 may have a data storage function for storing a corresponding set of possible radiation intensity values for a particular type of volume scattering medium 20; or a system 100 or other device (an example of such a device will be described in more detail below), in which such a system 100 may be included, may additionally include a memory (not shown) configured to store a corresponding set of possible radiation intensity values for a certain the type of the volume-scattering medium 20, as well as any other data, for example, computer-readable instructions for the system 100 to execute the procedure for determining the optical properties of the volume-scattering medium 20 using diffuse reflectometry, which are necessary for the operation of the system 100.

[0019] The following is a further explanation of Monte Carlo simulations of sets of possible radiation intensity values for a particular type of volume scattering medium 20. A general Monte Carlo simulation algorithm is known in the art. The Monte Carlo simulation in this application is used to solve the problem of direct numerical simulation of radiation propagation in a certain volume-scattering medium. The Monte Carlo simulation of the present invention includes a ray tracing operation. Ray tracing can be done with special software (such as LightTools), or with code that does a ray-traced Monte Carlo simulation written in any suitable programming language, such as the C programming language. -Carlo simulation can be used a two-layer model of a volume-scattering medium 20 with 4 free parameters: the thickness of the upper layer z0 , the absorption coefficient of the upper layer μa, t , the absorption coefficient of the lower layer μa, b , the scattering coefficient μs , which is considered equal for the upper and lower layers.

Additional Features and Alternative Embodiments of System 100

[0020] Optionally, the microlens array 110.2 is an LCD microlens array (not shown) configured to change the focal length under the control of the control unit 120 depending on the amount of control voltage applied thereto. This makes it possible to change the magnification of the system during the measurement. In addition, the system 100 may further comprise a mirror-lens system (not shown) on the side of at least one radiation source 105, configured to form a parallel or converging radiation beam incident on the surface of the volume-scattering medium 20 normally or obliquely, with using one or more lenses (not shown) and / or one or more mirrors (not shown). The mirror-lens system can be calculated and designed in such a way that a region (spot) of illumination of the required size is formed on the surface of the volume-scattering medium 20. As the size of the illumination region decreases, the accuracy of determining the optical properties (i.e., measurement) increases. The specific size of the illumination region can be selected empirically taking into account the design features of the system 100 according to the general rule, the smaller the illumination region, the greater the accuracy of determining the optical properties. By controlling the angle of incidence of radiation on the volume-scattering surface 20 (at the stage of designing the mirror-lens system), one can: (i) obtain the minimum SDS, that is, bring the illumination region as close as possible to the separator by tilting the beam (and thereby increase the power of the radiation recorded on photodetectors), (ii) change the length of the radiation path in the medium 20.

[0021] In another embodiment, the optical receiving system 110 is mounted in a barrel (not shown) and is movable substantially along the surface of the volume scattering medium 20 to allow the optical receiving system 110 to receive radiation at different SDS distances. Thanks to such a movable arrangement, the optical receiving system 110, containing, in an alternative embodiment, a group of stacked one above the other (by analogy with the alignment of such elements in Fig. 1), a single LCD cell, a single microlens and a single photodetector, will still be made with the possibility of obtaining the distribution of the radiation intensity in the area 15 of the radiation receiving by sequentially recording the intensities of the radiation when moving the optical receiving system 110 at different SDS-distances (SDS ₁ -SDS _N ). The movement itself can be carried out by any means known from the prior art (not shown), for example, a stepping electric drive, a piezoelectric micromotor.

[0022] In a further embodiment, the optical receiving system 110 in the system 100 further comprises an additional microlens array (not shown) aligned with an LCD cell array, a microlens array, and a photodetector array, with one of the additional microlens array and microlens array being mounted in the frame (not shown) with the ability to move essentially perpendicular to the surface of the volume-scattering medium 20 relative to the stationary other of the additional array of microlenses and the array of microlenses. The movement itself can be carried out by any means known from the prior art (not shown), for example, a stepping electric drive, a piezoelectric micromotor. Due to this feature, the magnification of the optical receiving system 110 can be varied, i. E. depending on the required task, you can examine a larger or smaller volume of the environment 20.

[0023] System 100 may comprise optical fiber (not shown) associated with at least one radiation source 105 and configured to transmit radiation from at least one radiation source 105 to a volume scattering medium 20 in the radiation input region 10. The use of optical fiber on the side of the radiation source 105 allows flexible installation and free orientation of at least one radiation source 105 and any other components of the mirror lens system to miniaturize the size of the final system 100 or the device into which such system 100 can be installed. When using optical fiber on the side of at least one radiation source 105, the system 100 may further comprise a reference channel configured to divert a portion of the radiation transmitted from at least one radiation source to a reference receiver that is configured to measure the change in power (for example, due to heating) of at least one radiation source 105 based on the intensity of the extracted radiation and the message of the measured change in power to the data processing unit 125 to take this change into account when determining the optical properties of the volume-scattering medium 20 based on the distribution of the radiation intensity. Part of the radiation from the optical fiber to the reference channel can be diverted by means of a beam splitter (not shown). Due to this consideration of the time variation of the power of the radiation source 105, the accuracy of determining the optical properties of the volume-scattering medium 20 does not tend to deteriorate gradually.

[0024] The optical receiving system 110 has a housing, and, optionally, at least one separator 115 is at least part of the housing of the optical receiving system 110. In addition, at least part of the housing of the optical receiving system 110 may be provided with a mirror surface and such an inclination and / or shape, which / which are made with the possibility of redirecting the incident or output radiation on it, for example, from an optical fiber, to the radiation input region 10 on the surface of the volume-scattering medium 20. Using the above features in the practical implementation of the present invention makes it possible to miniaturize the size of the target system 100 or the device into which such system 100 can be installed.

[0025] In a further embodiment, at least one spacer 115 is a wall that hermetically encloses the periphery of the optical receiving system 110 and protrudes with its exposed side for radiation reception towards the radiation receiving region 15 on the surface of the volume scattering medium 20. The protruding part of the wall may be covered by a transparent element such as glass to form a sealed chamber (not shown) that can be filled with an immersion liquid. The formation of a sealed chamber with an immersion liquid in the path of the radiation recorded in the radiation receiving area 15 by the optical receiving system 110 makes it possible to increase the numerical aperture of the receiving optical system, i.e. in this case, the receiving optical system will collect more light on the photodetectors, in other words, the radiation power on the photodetectors will be higher.

[0026] One skilled in the art will understand that the system 100 further comprises a power supply unit (not shown) configured to supply power to at least one radiation source 105, an optical receiving system 110, a control unit 120, and a data processing unit 125. In addition, it should be understood that the power supply, at least one radiation source 105, the optical receiving system 110, at least one separator 115, the control unit 120 and the data processing unit 125 are at least partially located in a housing, which can be the body of the wearable device. FIG. 1-3, the chassis of the system 100 is not illustrated for ease of illustration.

Other aspects of the present invention:

- Computing device 300 user -

[0027] In a second aspect of the present invention, a user computing device 300 is provided with a function for determining the optical properties of a volume scattering medium 20. The computing device 300 is schematically shown in FIG. 4. The user computing device 300 comprises, installed at least partially in the body of the user computing device 300: at least one radiation source 305 configured to provide radiation to the volume scattering medium 20 in the radiation input region 10; an optical receiving system 310 configured to receive radiation that has passed through the volume-scattering medium 20 in the radiation receiving area 15 to obtain a radiation intensity distribution, at least one separator 315 separating the radiation input area 10 from the radiation receiving area 15 and made with the possibility of preventing the ingress of radiation, partially reflected from the surface of the volume-scattering medium 20 in the radiation input area 10, into the radiation receiving area 15 of the optical receiving system 310; and processor 320.

[0028] The optical receiving system 310 comprises an LCD cell array 310.1, a microlens array 310.2, and a photodetector array 310.3, which are aligned such that each LCD cell from the LCD cell array 310.1 corresponds to a corresponding microlens from the microlens array 310.2 and a corresponding photodetector from the array 310.3 photodetectors. The optical receiving system 310 may be similar to the optical receiving system 110 illustrated and described with reference to FIG. 1-3. However, it should be understood that the specific configuration and orientation (relative to radiation sources 105, 305) of both the optical receiving system 110 and the optical receiving system 310 may be anything but outside the scope of the above description. By way of example, the number of elements in each of the arrays contained in the optical receiving systems 110, 310 can be any adequate number starting from 1 (in an embodiment, an optical receiving system that is movable along the air / volume scattering Wednesday 20) and above (6 in each of the arrays in Figs. 1-3). In addition, it should be understood that both in the first aspect (system 100) of the present invention and in the second aspect (device 300) of the present invention, the periphery of the optical receiving system 110, 310 can be surrounded by a spacer and multiple radiation sources can be installed from opposite sides to increase the signal power on the photodetectors. Any other features described above with reference to the system 100 according to the first aspect of the present invention also apply to the user computing device 300 according to the second aspect of the present invention.

[0029] The processor 320 of the user computing device 300 is configured to control the optical receiving system 310 while providing radiation to the volume-scattering medium 20 in the radiation input region 10 to cause the optical receiving system 310 to sequentially open each LCD cell from the array 310.1 LC cells with simultaneous registration of radiation transmitted through the corresponding open LC cell, a corresponding photodetector from the array 310.3 of photodetectors in order to obtain the above-mentioned radiation intensity distribution and determine the optical properties of the volume-scattering medium 20 based on the obtained radiation intensity distribution. The processor 320 of the user computing device 300 according to the second aspect of the present invention may implement the functionality of the control unit 120 and the data processing unit 125 of the first aspect of the present invention. Any of the processor 320, control unit 120, and processing unit 125 may be implemented as a system-on-a-chip (SoC), a system-in-a-package (SVC), a programmable logic integrated circuit (FPGA), a special purpose integrated circuit (ASIC), etc. The user's computing device 300 can be, but is not limited to, any of a smartphone, tablet, smart watch, smart bracelet, etc.

- Method for determining the optical properties of a volume-scattering medium 20 -

[0030] In a third aspect of the present invention, there is provided a method for determining the optical properties of a volume scattering medium 20 illustrated in FIG. 5. The above method comprises the steps of: introducing S400 radiation into the illumination region on the surface of the volume-scattering medium 20 while preventing radiation from entering (by using the separator of the illumination region and the target region) partially reflected from the surface of the volume-scattering medium 20 in the region illumination, to the target area of the optical receiving system containing an array of LCD cells, an array of microlenses and an array of photodetectors, which are aligned so that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; receiving S405 through the optical receiving system, the radiation passed through the volume scattering medium 20 in the target area to obtain a distribution of the radiation intensity; and determining in S410 the optical properties of the volume scattering medium 20 based on the radiation intensity distribution.

[0031] Said radiation reception S405 comprises the illustrated in FIG. 6 sub-stages, in which, simultaneously with the introduction of S400 radiation into the backlight region on the surface of the volume-scattering medium 20: sequentially (one after the other, one or more), each LCD cell from the array of LCD cells is opened S405.1 and S405 is recorded. 2, radiation passed through an open LCD cell by a corresponding photodetector from a photodetector array to obtain a plurality of radiation intensity values that represent said radiation intensity distribution.

- Other possible aspects and other explanations -

[0032] In another aspect, a computer-readable medium may be provided comprising computer-executable instructions for implementing the steps and sub-steps of a method for determining the optical properties of a volume scattering medium 20 by at least a radiation source, a processor, and an optical receiving system.

[0033] The singular mention of any element of this specification does not exclude its possible plurality in the actual implementation. Use of the terms “first”, “second”, etc. should not be interpreted as indicating any priority or preferred order of any of the elements described in this description using such terms. Instead, these terms are used only to distinguish between one or more elements of the same type and, therefore, to simplify their description. The use of the terms "contains" and "includes" throughout this description means an open list. The term "array" used in this description is used to indicate a set of elements of the same type, while the term itself does not imply that such elements are initially assembled as a single component-array, instead, the term "array" can mean a set of similar elements (LCD cells, microlenses, photodetectors), produced as separate elements, which are evenly distributed over a certain area and fixed relative to each other by any means, for example, a fastening element, glue, a common substrate, etc.

Industrial applicability

[0034] The invention disclosed in this application can be used as part of a sensor for non-invasive medical monitoring of various vital signs, for example, blood glucose levels, oxygenation, changes in tissue microstructure (associated, for example, with intraepithelial neoplasia). Such use can take place in a medical facility or at home. In addition, a sensor for non-invasive medical monitoring using the invention disclosed in this application can be used as a wearable device.

[0035] The invention disclosed in this application can be applied as part of a medical gas analyzer for determining the oxygen concentration in exhaled air. Since there is a correlation between oxygen consumption in the lungs and metabolic rate, it is possible to determine: VO2 max for sports medicine, calorie consumption, body response to treatment, hypoxia, etc. The invention disclosed in this application can also be applied to air quality monitoring to determine the presence of harmful substances, particles, etc. in the air. In addition, the invention disclosed in this application can also be applied to quality control of products to determine the freshness of fruits, vegetables, dairy products; determination of the concentration of harmful additives in products; control over the fermentation process of milk when processing milk into various products such as cheese, cream, yoghurt, etc.

[0036] The invention disclosed in this application may also be used in pharmaceuticals, including to characterize the starting material, control the powder production process, control the granulation process, control the tablet production process, and to characterize the final products. Finally, the invention disclosed in this application can be used to determine the characteristics (degree of destruction and inclusions) of archaeological values made of wood without destroying them.

[0037] Upon reading this description, the skilled person will understand other embodiments of the present invention, modifications, equivalent features and features. All such other embodiments of the present invention, modifications, equivalent features and features are intended to be embraced by the following claims.

List of reference positions

10 - Radiation input area

15 - Radiation receiving area

20 - Volume scattering medium

100 - System for determining the optical properties of a volume-scattering medium using diffuse reflectometry

105 - Radiation source

110 - Optical receiving system

110.1 - Array of LCD cells

110.2 - Array of microlenses

110.3 - Array of photodetectors

115 - Separator

120 - Control unit

125 - Data processing unit

300 - Computing device of the user with the function of determining the optical properties of the volume-scattering medium

305 - Radiation source

310 - Optical receiving system 310

310.1 - Array of LCD cells

310.2 - Array of microlenses

310.3 - Array of photodetectors

315 - Separator

320 - Processor.

Claims (46)

1. System (100) for determining the optical properties of a volume-scattering medium (20) using diffuse reflectometry, containing: at least one radiation source (105) configured to provide radiation to the volume-scattering medium in the radiation input area (10); an optical receiving system (110) configured to receive radiation that has passed through a volume-scattering medium in the radiation receiving area (15) to obtain a radiation intensity distribution, while the optical receiving system contains an array (110.1) of LC (liquid crystal) cells, an array (110.2) of microlenses and an array (110.3) of photodetectors, which are aligned so that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; at least one separator (115) separating the radiation input region from the radiation receiving region and configured to prevent the radiation, partially reflected from the surface of the volume-scattering medium in the radiation input region, from entering the radiation receiving region of the optical receiving system; a control unit (120) configured to control the optical receiving system, while providing radiation to the volume-scattering medium in the radiation input region, to induce the optical receiving system to sequentially open each LCD cell from the array of LCD cells while simultaneously receiving radiation, passed through the corresponding open LCD cell and microlens, the corresponding photodetector from the array of photodetectors to obtain the above-mentioned distribution of radiation intensity; and a data processing unit (125) configured to determine the optical properties of the volume-scattering medium based on the distribution of the radiation intensity. 2. The system of claim. 1, in which the array of LCD cells, the array of microlenses and the array of photodetectors are aligned with each other in the specified order as the distance from the volume-scattering medium. 3. The system of claim. 1, in which the array of LCD cells consists of two or more LCD cells located in at least one row, the array of microlenses consists of two or more microlenses placed in at least one row, and the array photodetectors consist of two or more photodetectors arranged in at least one row. 4. The system of claim. 3, in which the optical receiving system is located relative to at least one radiation source and at least one separator so that the distance source-detector (SDS) increases between at least one radiation source and each next photodetector in at least one row of photodetectors, whereby upon sequential opening of each LCD cell from the array of LCD cells, the control unit is in particular configured to control the optical receiving system to induce the optical receiving system to sequentially open each LCD cell from the array of LCD cells, starting with the LCD cell to which the photodetector with the shortest SDS distance corresponds, and continuing until the LCD cell to which the photodetector with the longest SDS distance corresponds. 5. The system according to claim 1, in which, in order to determine the optical properties of the volume-scattering medium, the data processing unit, in particular, is configured to compare the measured values of the radiation intensity from the radiation intensity distribution obtained for the volume-scattering medium with the corresponding set of possible values radiation intensity for a given type of volume scattering medium from the set of radiation intensity values preliminarily simulated by the Monte Carlo method for various optical properties of volume scattering media of different types in order to find a subset of radiation intensity values that minimizes the error E:

S is the number of photodetectors; i = 1… S - photodetector number;

- measured signal value for photodetector i; and

- simulated signal value for photodetector i; the subset of values found, which minimizes the error E, indicates certain optical properties of the volume-scattering medium, while the specific optical properties are the absorption coefficient and the scattering coefficient of the volume-scattering medium. 6. The system of claim. 1, in which the array of microlenses is an array of LCD microlenses made with the ability to change the focal length under the control of the control unit depending on the value of the applied control voltage. 7. The system according to claim 1, further comprising a mirror-lens system on the side of at least one radiation source, configured to form a parallel or converging radiation beam incident on the surface of the volume-scattering medium along the normal or obliquely, using one or more lenses and / or one or more mirrors. 8. The system of claim. 1, in which the optical receiving system is installed in the frame with the ability to move substantially along the surface of the volume-scattering medium to allow the optical receiving system to receive radiation with different SDS-distances. 9. The system according to claim 1, in which the optical receiving system additionally contains an additional array of microlenses, combined with an array of LCD cells, an array of microlenses and an array of photodetectors, wherein one of the additional array of microlenses and an array of microlenses is installed in the frame with the ability to move essentially perpendicular to the surface of the volume-scattering medium relative to the stationary other of the additional microlens array and microlens array to change the resolution provided by the optical receiving system. 10. The system of claim. 1, further comprising an optical fiber associated with at least one radiation source and configured to transmit radiation from at least one radiation source to a volume-scattering medium in the radiation input region. 11. The system of claim 10, further comprising a reference channel configured to divert a portion of the radiation transmitted from at least one radiation source to a reference receiver configured to measure a change in the power of at least one radiation source based on the intensity of the extracted radiation and communicating the measured power change to the data processing unit to account for this change in determining the optical properties of the volume scattering medium based on the radiation intensity distribution. 12. The system of claim. 11, in which the removal of part of the radiation from the optical fiber to the reference channel is provided by means of a beam splitter. 13. The system of claim. 1, in which the optical receiving system is enclosed in a housing, and the at least one separator is the housing of the optical receiving system. 14. The system according to claim. 13, in which at least part of the housing is mirrored and made with the possibility of redirecting the incident radiation to the region of radiation input on the surface of the volume-scattering medium, the system further comprises an optical fiber associated with at least one radiation source and configured to transmit radiation from at least one radiation source to the mirror portion of the optical receiving system housing. 15. The system of claim. 1, in which to open the corresponding LCD cell, the control unit is configured to apply a corresponding control voltage to the corresponding LCD cell. 16. The system of claim 1, wherein said at least one radiation source is a source of coherent radiation. 17. The system of claim. 1, in which at least one separator is a wall, hermetically enclosing the periphery of the optical receiving system and protruding beyond the optical receiving system towards the volume-scattering medium, while the projecting part of the wall is covered with a transparent element to form a sealed chamber that is filled with immersion liquid. 18. The system of claim. 1, in which at least one radiation source and the optical receiving system are located relative to each other so that the radiation input region and the radiation receiving region do not overlap with each other. 19. The system according to claim 1, further comprising a power supply configured to supply power to at least one radiation source, an optical receiving system, a control unit and a data processing unit. 20. The system of claim. 19, in which the power supply, at least one radiation source, optical receiving system, at least one separator, control unit and data processing unit are at least partially located in the housing. 21. The system of claim 20, wherein the housing is a wearable device housing. 22. Computing device (300) of the user with the function of determining the optical properties of the volume-scattering medium, containing installed at least partially in the case of the computing device of the user: at least one radiation source (305) configured to provide radiation to the volume-scattering medium in the radiation input area; an optical receiving system (310), configured to receive radiation that has passed through a volume-scattering medium in the radiation receiving region to obtain a radiation intensity distribution, while the optical receiving system contains an array of LCD cells, an array of microlenses and an array of photodetectors, which are combined so that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; at least one separator (315), separating the radiation input area from the radiation receiving area and configured to prevent the radiation, partially reflected from the surface of the volume-scattering medium in the radiation input area, from entering the radiation receiving area of the optical receiving system; processor (320), configured to: control of the optical receiving system, while providing radiation to the volume-scattering medium in the region of radiation input, to induce the optical receiving system to sequentially open each LC cell from the array of LC cells with simultaneous registration of radiation that passed through the corresponding open LC cell, corresponding a photodetector from an array of photodetectors to obtain said radiation intensity distribution; and determination of the optical properties of the volume-scattering medium based on the obtained distribution of the radiation intensity. 23. The user's computing device according to claim 22, which is one of a smartphone, tablet, smart watch, smart bracelet. 24. A method for determining the optical properties of a volume-scattering medium, comprising the stages at which: injecting (S400) radiation into the illumination region on the surface of the volume-scattering medium while preventing the radiation partially reflected from the surface of the volume-scattering medium in the illumination region from entering the target region of the optical receiving system containing an array of LCD cells, an array of microlenses and an array of photodetectors , which are aligned such that each LCD cell from the array of LCD cells corresponds to a corresponding microlens from the array of microlenses and a corresponding photodetector from the array of photodetectors; receiving (S405) by means of the optical receiving system the radiation passed through the volume-scattering medium in the target area to obtain the radiation intensity distribution, while said receiving (S405) of radiation comprises sub-steps, in which, simultaneously with the input of radiation into the illumination region on the surface, volumetrically - scattering environment: sequentially open (S405.1) each LCD cell from the array of LCD cells and record (S405.2) the radiation transmitted through each open LCD cell by the corresponding photodetector from the photodetector array to obtain a plurality of radiation intensity values that represent said distribution radiation intensity; and determining (S410) the optical properties of the volume scattering medium based on the radiation intensity distribution.

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