WO2023023964A1

WO2023023964A1 - Refractometer, smart cup, and refractive index measurement method

Info

Publication number: WO2023023964A1
Application number: PCT/CN2021/114432
Authority: WO
Inventors: 吴泳智
Original assignee: 深圳市流数科技有限公司
Priority date: 2021-08-25
Filing date: 2021-08-25
Publication date: 2023-03-02
Also published as: WO2023024523A1

Abstract

A refractometer, a smart cup, and a refractive index measurement method, which relate to the field of liquid refractive index measurement. The refractometer comprises a light source module (1), a reflective module (2), a lens module (3), a photosensitive area array (4), a control module, and a processor, wherein the reflective module (2) is used to receive a light beam from the light source module (1), the reflective module (2) comprises a total reflection interface (21), and when the incident angle of the light beam from the light source module (1) on the total reflection interface (21) meets a certain condition, the light beam from the light source module (1) is totally reflected on the total reflection interface (21) and is incident to the lens module (3); the lens module (3) is used to converge the light beam from the total reflection interface (21) onto a focal plane of the lens module (3); and the photosensitive area array (4) is located on the focal plane of the lens module (3). The refractometer has the advantages of being low in cost, of a small size, and having a large measurement range and good robustness.

Description

A refractometer, smart cup and method for detecting refractive index

technical field

The invention belongs to the field of liquid refractive index measurement, and in particular relates to a refractometer, a smart cup and a method for detecting the refractive index.

Background technique

A refractometer is a device that measures the refractive index of liquids. Because the solid soluble matter will increase the refractive index of the liquid after dissolving, the measurement of the solid soluble matter content can be achieved by measuring the refractive index, so the refractometer can be used to measure the solid soluble matter content in the liquid. The solid soluble matter in the aqueous solution is usually sugar, so the refractometer is also called a sugar meter when measuring beverages (such as fruit juice, coffee, etc.).

Fig. 1 is a structural schematic diagram of an existing refractometer. The refractometer includes an LED light source 2', a triangular prism 4', a one-dimensional sensitive line array 3' and a processor (not shown). The principle of the refractometer utilizes the fact that the total reflection angle is determined by the refractive index of the two materials at the interface. When the refractometer is placed in the liquid to be measured, if the refractive index of the liquid to be measured is lower than that of the prism 4′, according to the law of refraction sin (α _{refraction angle} )*n _{liquid to be measured} =sin (α _{incident angle} )*n It can be seen from _{the triangular prism} that the incident angle of the light beam on the side 5 ' that is in contact with the liquid in the triangular prism 4 ' satisfies

total reflection occurs. That is to say, among the light beams incident on the surface 5', the part where the incident angle is greater than the total reflection angle undergoes total reflection, and when the incident angle is smaller than the total reflection angle, transmission and reflection coexist, and the brightness of reflection is smaller than that of total reflection. Therefore, in the image formed by the one-dimensional photosensitive line array 3 ′, an obvious brightness change interface can be seen near the incident pixel corresponding to the total reflection angle. The processor can measure the total reflection angle through this interface, and calculate the refractive index n of _{the liquid} to be measured from this.

An existing refractometer is provided with a slit 1' located on the outgoing light path of the LED light source 2', so that the light source is a very small point light source in the direction parallel to the sensitive line array 3', which is very good The angle of each beam of light hitting the sensitive line array 3' is defined. In the case of not using the slit 1', the LED light source 2' is equivalent to multiple point light sources emitting light at the same time, then the light from different point light sources at different angles may be incident on the same point on the sensitive line array 3', As a result, it is impossible to distinguish the angle of these lights, which is very important in determining the total reflection angle. The essence of the slit 1' is to decouple the position and direction of the light, so that the refractometer only needs to detect the direction of the light without being disturbed by the position of the light. However, this design will result in a very large size of the sensitive line array 3 ′, especially in the case where the measurement range of the refractive index is required to be relatively large. The specific reasons are as follows.

As shown in Figure 2, the size of the sensitive line array 3' is 2*tan(α/2)*d, d represents the optical path distance from the LED light source 2' to the sensitive line array 3', and α is the LED light source 2 'The overall opening angle of the outgoing light. In the case where the measurement range of the refractive index is required to be relatively large (for example, to measure liquids with different refractive indices), α needs to have a larger value, so the size of the sensitive line array 3' also needs to be increased accordingly. This is not conducive to miniaturization of the refractometer.

In addition, the sensitive line array 3' generally uses a linear CCD, but the linear CCD is expensive, requires high installation accuracy, and cannot be automatically corrected when the optical path deviates (caused by thermal expansion and contraction, impact or mechanical deformation, etc.), and is easily affected by ambient light. Or the influence of stray light, causing the measurement to be biased.

Contents of the invention

The object of the present invention is to provide a refractometer with low cost, small volume, large measurement range and good robustness, a smart cup with the refractometer and a method for detecting the refractive index to solve the above problems.

In order to achieve the above object, the technical solution adopted by the present invention is: a refractometer, including a light source module, a reflection module, a lens module, a photosensitive array, a control module and a processor, wherein,

The control module is used to control the light beam emitted by the light source module;

The reflection module is used to receive the light beam from the light source module, the reflection module includes a total reflection interface, when the incident angle of the light beam from the light source module on the total reflection interface satisfies a certain condition, the The light beam of the light source module is totally reflected on the total reflection interface, and enters the lens module;

The lens module is used to converge the light beam from the total reflection interface onto the focal plane of the lens module;

The photosensitive surface array is located on the focal plane of the lens module, and the control module is also used to control the photosensitive surface array to detect the received light beam and output a detection image;

A processor, configured to determine a boundary line of a sudden brightness change in the detection image according to the detection image, and determine a side of the total reflection interface facing away from the light source module according to at least one pixel point in the sudden change boundary line of brightness The refractive index of the medium.

The present invention also provides a smart cup, comprising:

Cup lid and cup body;

The above-mentioned refractometer is arranged at the cup cover and is used to detect the refractive index of the liquid in the cup;

a thin film disposed on the bottom of the cup, forming a closed space with the bottom of the cup;

a micro air pressure sensor, arranged in the enclosed space, for detecting the volume of the liquid in the cup;

A calculation module, arranged in the confined space, is used to calculate the calorie of the liquid according to the volume and refractive index of the liquid.

The present invention also provides a method for detecting the refractive index, comprising:

Sending a beam of light towards a total reflection interface within the refractometer;

The light beam reflected by the total reflection interface is converged to the photosensitive array on the focal plane of the lens module through the lens module;

Using the photosensitive array to image the received light beam to generate a detection image;

determining a boundary line of a sudden change in brightness in the detection image according to the detection image;

determining the total reflection angle of the light beam on the total reflection interface according to the position of the brightness mutation boundary line in the detection image;

The refractive index of the medium located outside the total reflection interface is determined according to the total reflection angle.

The refractometer of the present invention arranges the photosensitive surface array on the focal plane of the image side of the lens module, and the lens module adopts the infinity focus imaging method, so that a non-point light source can be used as the light source, so that the photosensitive surface array can be shared by the size of the light source. The size of the photosensitive area makes the size of the photosensitive area very small, which has the advantages of low cost, small size, large measurement range, and good robustness; moreover, the refractometer uses an area array CMOS detection image sensor, which has lower cost and higher accuracy High, reducing installation requirements, and can achieve many things that one-dimensional sensors cannot do, such as improving accuracy, improving anti-interference ability, adding other measurement functions, etc.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is the structural representation of a kind of existing refractometer;

Fig. 2 is a schematic diagram of the side where the photosensitive line array is equivalent to the liquid surface in Fig. 1;

Fig. 3 is a kind of structural representation of the refractometer in the present application;

Fig. 4 is a schematic diagram of the imaging principle of the lens unit using infinity focusing;

Fig. 5 is the detection image formed by the light beam received by the photosensitive surface array when the refractometer detects the liquid to be measured;

Fig. 6 is a schematic diagram of the change of the detection image formed by the light beam received by the photosensitive surface array pair when the refractometer detects three kinds of media to be measured with different refractive indices;

Fig. 7 is the schematic diagram that the photosensitive array in the refractometer shown in Fig. 3 is equivalent to the side of the liquid surface;

FIG. 8 and FIG. 9 are structural schematic diagrams of refractometers using light source modules and lens modules of different sizes in this application, respectively;

The left side of Figure 10 is the pixel value curve of a pixel row on the detection image formed by the photosensitive surface array to the received light beam, and the right side is the pixel value curve obtained after averaging the pixel value of the row and the pixel values of the upper and lower rows .

Fig. 11 is a schematic diagram of an embodiment of the method for detecting the refractive index of the liquid to be measured by using a refractometer in the present application.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with aspects of the invention as recited in the appended claims.

The terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. As used herein and in the appended claims, the singular forms "a", "the", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, the information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another.

Fig. 3 is a structural schematic diagram of a refractometer in the present application. As shown in FIG. 3 , the refractometer includes a light source module 1 , a reflection module 2 , a lens module 3 , a photosensitive array 4 , a control module (not shown in the figure) and a processor (not shown in the figure). Wherein, the control module is used for controlling the light beam emitted by the light source module 1 and for controlling the photosensitive surface array 4 to perform light detection. Optionally, the control module includes a light source controller and a photosensitive controller for controlling the light source module 1 and the photosensitive array 4 respectively. The reflection module 2 is used for receiving the light beam from the light source module 1 . Wherein, the reflection module 2 includes a total reflection interface 21. When the incident angle of the light beam from the light source module 1 on the total reflection interface 21 and the refractive index of the medium on both sides of the total reflection interface 21 meet the conditions of total reflection, the The light beam of the light source module 1 is totally reflected on the total reflection interface 21 and enters the lens module 3 .

In one example, the reflection module 2 includes a prism, and the prism 2 includes a light incident surface 22 , a total reflection interface 21 and a light exit surface 23 . The light beam from the light source module 1 is incident into the prism 2 from the light incident surface 22, and is incident on the total reflection interface 21. When the incident angle above satisfies a certain condition, the light beam is totally reflected on the total reflection interface 21 inside the prism 2, and exits from the light exit surface 23. Optionally, the prism 2 is a triangular prism. Optionally, the prism 2 is an isosceles prism, such as an isosceles rectangular prism, so that the structure of the prism is more compact, making the overall structure smaller. Optionally, anti-reflection coatings are provided on the light incident surface 22 and the light exit surface 23 of the prism 2 to increase the transmittance of light beams. The prism 2 can be made of glass material, or can also be made of other transparent materials such as plastic and resin. Optionally, the size of the total reflection interface 21 of the prism 2 matches the divergence angle of the outgoing light of the light source module 1, so that the light spot formed by the outgoing light on the total reflection interface 21 just covers the total reflection interface 21 or is slightly smaller than The total reflection interface 21 is beneficial to the miniaturization of the refractometer. In other examples, the reflective module 2 may also be other optical elements with a high refractive index, or be made of other media with a high refractive index.

The lens module 3 is used to converge the light beam from the total reflection interface 21 onto the focal plane of the lens module 3 . The lens module 3 may be a lens, and the focal plane of the lens module 3 is the focal plane of the lens. Alternatively, the lens module 3 includes a lens group consisting of at least two lens elements, so that an additional lens can be used to reduce imaging aberration and distortion through optical design. In case the lens module 3 comprises at least two lens elements, the focal plane of the lens module 3 is the equivalent focal plane of the lens group.

The function of the lens module will be explained below by taking the lens module as an example with reference to FIG. 4 . As shown in Figure 4, since the parallel light can be converged on the focal plane after passing through the lens module 3, under ideal conditions, the converging point of the parallel light on the focal plane is unique, extending from the optical center of the lens in the direction of the parallel light Intersection with the focal plane. The convergence point is only related to the direction of the light, not the position of the light. Using this principle, by adding a lens module in front of the photosensitive array, the position and direction of the light can be decoupled without defining a slit or a small hole at the light source for decoupling.

The photosensitive surface array 4 is located on the focal plane of the lens module 3 and is used for detecting the received light beam. When the refractive index of the medium 5 outside the total reflection interface 21 of the reflection module 2 is lower than the refractive index of the reflection module 2, among the light beams incident on the total reflection interface 21 of the reflection module 2, the light beam with an incident angle greater than the total reflection angle It is totally reflected to the lens module 3, and converges to the photosensitive array on the focal plane through the lens module 3; in the light beam whose incident angle is smaller than the total reflection angle, part of the light beam is transmitted through the total reflection interface 21, and part is reflected on the total reflection interface 21 to the lens module 3 , and is converged by the lens module 3 to the photosensitive array on the focal plane.

As shown in Fig. 5, Fig. 5 is a detection image formed by the light beam received by the photosensitive surface array when the refractometer detects a liquid to be measured. The refractometer is placed in the liquid 5 to be tested, so that after the total reflection interface in the reflection module 2 contacts the liquid 5 to be tested, the photosensitive array 4 forms a detection image. As shown in FIG. 5 , the detection image 8 includes a reflective area 81 and a non-reflective area 82 surrounding the reflective area 81 . The reflection area 81 includes a total reflection area 811 and a non-total reflection area 812 . Wherein, the total reflection area 81 refers to the area in the reflection area 81 of the detection image 8 where the light beam totally reflected by the total reflection interface 21 of the reflection module 2 is incident, and the non-total reflection area 812 refers to the area in the detection image 8 that is less than The total reflection angle is the incident area of the reflected light beam when incident on the total reflection interface 21 of the reflection module 2 . Since the reflected part of the non-totally reflected light beam suddenly drops in brightness compared with the fully reflected light beam, an obvious brightness mutation boundary 813 is formed at the junction of the total reflection area 812 and the non-total reflection area 811, and the brightness mutation boundary 813 Corresponding to the incident light beam at the total reflection angle at the total reflection interface 21 .

As shown in FIG. 6 , FIG. 6 is a schematic diagram of changes in detection images formed by the light beams received by the photosensitive surface array when the refractometer detects three kinds of media to be measured with different refractive indices. It can be seen that when corresponding to the medium to be tested with different refractive indices, the brightness mutation boundary in the detection image formed by the photosensitive array has obvious movement. Due to the setting of the lens module, different pixel positions in the detection image correspond to beams emitted from the total reflection interface at different angles, so the processor can determine the brightness mutation boundary by obtaining the position of at least one pixel point in the brightness mutation boundary The corresponding total reflection angle, and then calculate the refractive index of the medium to be measured according to the total reflection angle.

There are a number of ways for the processor to determine the location of the abrupt brightness boundary in the detected image. For example, the processor may separately calculate the brightness gradient change of each pixel row in the reflection area in the detection image, and determine the pixel point with the largest gradient change in each row of pixels as the point on the boundary line of the sudden brightness change. Alternatively, the processor may also acquire the position of the boundary line of sudden brightness changes through methods such as edge detection, template matching, and machine learning. Optionally, in the process of obtaining the position of the sudden brightness change boundary, the processor may also obtain the current temperature and/or the boundary deviation caused by the assembly tolerance, and compare the obtained brightness sudden change boundary according to the current temperature and/or the boundary deviation position to compensate. After determining the boundary line of abrupt change in brightness, the processor can look up the corresponding relationship table between the boundary line of sudden change in brightness and the refractive index that has been calibrated in advance to obtain the corresponding refractive index.

In this application, the viewing angle of the lens is determined by the focal length f and the aperture size d of the lens. However, to achieve a large refractive index detection range for a refractometer not only depends on the viewing angle of the lens, but also needs to ensure that the light within the viewing angle can be reflected by the total reflection interface 21 and enter the lens, so it is necessary to increase the light source accordingly size of. The angle range of the light beam that the final lens can receive is determined by the size of the light source and the size of the lens. A detailed explanation will be given below in conjunction with the equivalent optical system shown in FIG. 7 . In this equivalent optical system, the lens module 3 , the photosensitive surface array 4 and the processor are mirrored on the side of the total reflection interface 21 facing away from the light source module 1 , and the lens module 3 takes a lens as an example.

As shown in Figure 7, the angle range α that can be detected by the photosensitive array 4 is defined by two lines on the edge: the light r1 from the uppermost end of the light-emitting surface of the light source module 1 to the lowermost end of the clear aperture of the lens 3, and the light source r1 Light r2 from the lowermost end of the light-emitting surface of the module 1 to the uppermost end of the clear aperture of the lens. The angle range α is determined by three variables: the size of the light emitting surface of the light source module 1 , the clear aperture of the lens 3 , and the distance between the light emitting surface of the light source module 1 and the lens 3 . Therefore, in the case that the detection angle range α of the photosensitive surface array 4 is the same, compared with the refractometer with a slit design shown in FIG. Shared with the clear aperture of the lens. That is to say, when the detection angle range α of the photosensitive array is the same, the aperture of the photosensitive array in the refractometer shown in FIG. 1 = the aperture of the light emitting surface of the light source module 1 in this application + the clear aperture of the lens.

In an example, the aperture of the light emitting surface of the light source module 1 is greater than or equal to the aperture of the lens module 3 . For example, as shown in FIG. 8 , the diameter of the light-emitting surface of the light source module 1 is the same as the aperture of the lens module 3 or the difference is less than 1/5 of the diameter of the light-emitting surface. Like this, under the same situation that the detection angle range α of photosensitive surface array 4 is the same, the aperture of the photosensitive surface array in the refractometer of the present application is half of the aperture of the photosensitive surface array of the refractometer in the prior art, can reduce the number of refractometers. cost and difficulty in mass production. For another example, as shown in FIG. 9 , the aperture of the light emitting surface of the light source module 1 is larger than twice the aperture of the lens module 3 . In this way, under the condition that the detection angle range α of the photosensitive surface array is the same, the size of the aperture of the photosensitive surface array in the refractometer of the present application can be made very small. The cost and difficulty of mass production required by the size of the array are much lower, and the cost and difficulty of mass production can be reduced to a greater extent by allowing the light source module 1 to bear more dimensions. Moreover, compared to the refractometer shown in Figure 1, the reflection properties of the total reflection surface interface need to be consistent within the range of the liquid surface. Since the light direction can be directly measured in this application, even if there are bubbles or the medium to be measured at the total reflection interface In the case that the total reflection interface is not completely covered, the boundaries of sudden changes in brightness are still clearly distinguishable.

Optionally, the detection angle range α of the photosensitive surface array 4 covers the total reflection angle range of the lens module 3, wherein the total reflection angle range of the lens module 3 refers to the total reflection that can occur on the total reflection interface of the lens module 3 All angles to ensure the large refractive index detection range of the refractometer. Optionally, the reflection module 2 uses a medium with a high refractive index to reduce the total reflection angle range of the lens module 3 . However, due to the serious dispersion of high refractive index glass, this is because when light of different wavelengths passes through the glass, the reflective module with high refractive index will cause a large change in the refractive index of light beams of different wavelengths, which in turn will cause the photosensitive array to obtain The total reflection boundary in the detected detection image will produce blurring, which will reduce the detection accuracy of the total reflection angle. In an example, the refractometer may use a light source module with a narrow wavelength bandwidth, or set a narrow-band filter on the outgoing light path of the light source module to reduce the wavelength bandwidth of the outgoing light from the light source module to reduce dispersion. For example, the outgoing light of the light source module or the outgoing light filtered by the narrow-band filter is a light beam with a full width at half maximum of 5 nm or less.

In this application, since the lens module is added in front of the photosensitive array to decouple the position and direction of the light, the light source module does not need to be small, as long as there is light at a corresponding angle, it can be focused on the corresponding sensor position. Compared with the prior art, the light source module in the present application does not need to bear the function of distinguishing angles and positions. In the prior art, since the divergence angle of the light source module is required to be relatively large, but the divergence angle of the LED light source itself is not very large, it is necessary to find a specially-made LED light source with a large angle and a small light-emitting surface in the solution of the prior art. However, in this application, the requirements for the light source module 1 are much relaxed, and the large-angle light-emitting range can be realized by multiple LEDs+light-diffusing panels. In one example, as shown in FIG. 3 , the light source module 1 further includes a dodging sheet 6 located on one side of the light emitting surface. Since the photosensitive array perceives beams from different directions, the homogenization sheet can improve the uniformity of the beams in each direction, thereby improving the uniformity of the image formed by the photosensitive array, and can also avoid the measurement accuracy caused by inconsistent light intensities at different angles. Lowering the problem.

In one example, the light source module 1 includes an LED light bar, or includes a light source composed of a plurality of LED light beads by patching or packaging. The wavelength of the LED needs to be compatible with the wavelength response of the CMOS photosensitive array. The wavelength can be between 300nm and 1000nm, for example, the wavelength can be between 400nm and 500nm, or between 500nm and 600nm, or between 600nm and 700nm. Either between 700nm and 800nm, or between 800nnm and 900nm. Optionally, the wavelength of the LED is in the green light band, for example, the central wavelength is between 500nm and 600nm. Since a common photosensitive area array on the market is a CMOS sensor with a Bayer pattern of RGGB, this type of photosensitive area array has a higher resolution and is more sensitive to the G channel. Using the green light band can better communicate with the photosensitive surface. array with.

In one example, as shown in FIG. 3 , an optical filter 7 matching the outgoing light of the light source module 1 is provided on the optical path between the total reflection interface 21 of the reflective module 2 and the photosensitive array 4 for transmitting the light from the light source module. 1 and reflected beams of other wavelength bands to reduce the interference of background light on the detection results. Optionally, the output light of the light source module 1 is of a single wavelength, so that it is easier to match a narrow-band filter to eliminate background light.

In one example, the photosensitive surface array 4 may be a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) sensor array. Of course, the photosensitive surface array 4 can also be realized by using other photoelectric sensors such as CCD image sensors. Optionally, after the photosensitive surface array 4 outputs the detection image, the processor counts the brightness of the detection image according to the detection image, and calculates the refractive index according to the detection image only after the brightness of the detection image satisfies a preset condition. There may be various preset conditions. For example, the preset condition includes that the absolute value of the difference between the detected image brightness and the preset target brightness is greater than a threshold.

Compared with the use of linear arrays as photosensitive arrays in the prior art, the use of CMOS sensor area arrays can not only greatly reduce the installation requirements, but also add many things that the previous one-dimensional arrays could not do through the nature of the two-dimensional array. For example, before calculating the refractive index based on a frame of detection image detected by the photosensitive surface array, the processor can perform noise filtering based on the pixel values measured by multiple rows of sensors corresponding to the photosensitive surface array in a frame of detection image to improve the signal-to-noise ratio. Wherein, the processor may perform noise filtering on the frame detection image in the space domain or the transformation domain. When filtering noise, the processor can perform noise filtering based on window sliding average filtering. The width of the filtering window can be a value between 1 and the width of the detected image, and the height can be a value between 1 and the height of the detected image. In a specific example, the processor may perform weighting processing (for example, averaging processing) on the pixel values detected by the multi-row sensors to obtain a noise-filtered result, and then calculate the refractive index of the medium to be detected according to the noise-filtered result. Certainly, the processor may also adopt other noise filtering methods, for example, adopting a machine learning method to filter noise of the frame detection image.

As shown in Figure 10, the left side of Figure 10 is the pixel value curve of a pixel row on the detection image formed by the light beam received by the photosensitive surface array, and the right side is the average of the pixel value of the row and the pixel values of the upper and lower rows From the pixel value curve obtained afterwards, it can be seen that the influence of noise can be reduced after averaging processing with the pixel values of multiple rows. Compared with the prior art where there is only one line of pixel values (that is, only the detection results of the line array sensor), the use of a photosensitive area array in this application can increase the accuracy of measurement.

For another example, when calculating the refractive index of the medium to be measured based on multiple rows of pixel values in the reflection area in the detection image, the processor can eliminate one or more rows of pixel values affected by stray light, or reduce the pixel values affected by stray light. Influence weights for row or rows of pixel values.

A line of measurement results less affected by stray light can be selected from a frame of detection images to calculate the refractive index of the medium to be measured. Stray light is the interference light formed in the optical system due to surface wear, dirt, fog condensation or device position deviation. The presence of stray light will reduce the calculation accuracy of the refractive index. Using the photosensitive area array, the processor can determine the pixel row affected by stray light by comparing and analyzing the brightness of multiple rows of pixel rows. Compared with the linear sensor in the prior art, the photosensitive area array in this application can improve the accuracy of refractive index measurement. Optionally, the processor can also determine the pixel rows affected by stray light by comparing and analyzing multiple frames of detection images. This is more robust for refractive index measurements in the presence of stray light.

In an example, before calculating the refractive index, the processor may also perform noise filtering according to multiple frames of detection images. For example, after the photosensitive array collects multiple frames of detection images, the processor can perform weighted sum processing on the multiple frames of detection images to synthesize a frame of detection images, and then use the synthesized detection images to calculate the refractive index. Optionally, before calculating the refractive index, the processor may also use the single-frame noise filtering method described above to perform further noise filtering on the synthesized detection image.

In one example, the refractometer also has a standby mode and/or a low power mode. In this standby mode, the control module is in a sleep standby state, the light source module and the photosensitive array are both powered off, and the overall power consumption of the refractometer is at the uW level. In the low power consumption mode, the control module is used to control the light source module and the photosensitive array to strobe synchronously, the power-on time is extremely short, and the overall power consumption of the refractometer is at the mW level. Specifically, when the control module controls the light source module 1 and the photosensitive array, it can synchronously trigger a pulse width modulation (PWM, Pulse Width Modulation) signal according to the frame signal of the photosensitive array to realize dimming of the light source module.

In an example, the control module can also obtain brightness information of the current measurement environment, and adjust the detection image quality of the photosensitive area array according to the brightness information, so as to obtain a better measurement quality. Wherein, the control module can adjust at least one of the following items according to the brightness information: the output light intensity of the light source module, the exposure time of the photosensitive array, the analog gain of the photosensitive array, and the digital gain of the photosensitive array. Wherein, the photosensitive surface array can be used to measure the ambient light in a time period other than measuring the total reflected light, or other sensors for measuring the brightness information of the current environment are provided in the detection module.

In one example, the refractometer further includes a first temperature sensor disposed inside the reflective module or on a surface of the reflective module on an area outside the optical path for detecting the temperature of the reflective module. Optionally, the refractometer further includes a second temperature sensor, which is arranged on the surface of the total reflection interface of the reflection module facing the medium to be measured, for detecting the temperature of the medium to be measured. Alternatively, the first temperature sensor and the second temperature sensor may not be in direct contact with the reflective module or the medium to be measured, but through a material with better thermal conductivity as a medium. Since the refractive index of the liquid is related to the temperature of the liquid, and the temperature of the prism determines the ratio of thermal expansion and contraction of the prism, and the temperature of the prism will cause the deviation of the incident and outgoing angles of the beam, therefore, through the pre-established The relationship model between the temperature of the liquid to be measured, the temperature of the reflection module and the refractive index of the liquid to be measured is calculated according to the obtained temperature of the liquid to be measured, the temperature of the reflection module and the relationship model when calculating the refractive index of the liquid to be measured. Measuring the refractive index of liquid can improve the accuracy of refractive index calculation.

In an example, the processor can also calculate the turbidity of the liquid to be tested according to the detection image output by the photosensitive array. Among the outgoing light from the light source module 1, the light beam transmitted from the total reflection interface 21 of the reflection module 2 to the liquid to be measured will be scattered when encountering suspended particles in the liquid to be measured, and part of the scattered light will be transmitted through the total reflection interface 21 Then incident on the photosensitive array. Scattering is divided into Rayleigh scattering, Mie scattering, and refraction with different angular components according to the size of the scattering particles. By analyzing the detection image detected by the photosensitive area array, the processor can obtain the light intensity distribution of the detection image, and obtain the size and properties of the scattering particles according to the light intensity distribution, and then judge the turbidity of the liquid.

For example, as shown in Figure 5, scattering caused by particles in the liquid can cause luminance values to appear on non-reflective areas where luminance should not be present. Thus, the processor can calculate the particle concentration of the liquid from the brightness on this non-reflective area. Specifically, since different pixel positions in the detection image correspond to light beams incident at different angles on the total reflection interface, on the non-reflection area in the detection image, it can be understood that the non-reflection area includes a total reflection area and a non-total reflection area, In FIG. 5 , the total reflection area of the non-reflection area is located on the upper and lower sides of the total reflection area of the reflection area, and the non-total reflection area of the non-reflection area is located on the upper and lower sides of the non-total reflection area of the reflection area. Since the light beam scattered by the particles in the liquid to be measured can only re-enter the reflection module at an angle within the total reflection angle, only the area corresponding to the area smaller than the total reflection angle will appear in the detection image formed by the photosensitive surface array. That is, the scattered light beam will only appear in the non-total reflection area in the detection image.

Therefore, in an example, the processor may calculate the scattered brightness according to the brightness of the non-total reflection area in the non-reflection area on the detection image. Optionally, the processor may also use the brightness of the total reflection area in the non-reflection area as a reference value to calculate the absolute value of the scattering brightness. For example, the processor may subtract the brightness of the total reflection area in the non-reflection area from the brightness of the non-total reflection area in the non-reflection area on the detection image to obtain the absolute value of the scattering brightness. After obtaining the scattering brightness, the processor can obtain the corresponding turbidity of the liquid to be measured according to the pre-established corresponding relationship model between the scattering brightness and the liquid turbidity.

Optionally, when the processor determines the brightness of the total reflection area in the non-reflection area, it may perform weighted average processing on the brightness of at least some pixels in the area to obtain the brightness of the total reflection area. Similarly, when determining the brightness of the non-total reflection area in the non-reflection area, weighted average processing may be performed on the brightness of at least some pixels in the area to obtain the brightness of the non-total reflection area. This reduces calculation errors.

Optionally, a slit is provided on the incident light path of the lens module or on the surface of the lens module. Since the width of the reflection area in the detection image is determined by the width of the light source module and the light aperture of the lens module, by setting a slit on the incident light path of the lens module or on the surface of the lens module, the reflection area and A clearer boundary line is formed between non-reflective areas, which is beneficial to improve the accuracy of turbidity calculation.

For another example, as shown in Figure 5, the scattering caused by particles close to the total reflection interface of the reflection module will cause the boundary line of the brightness change in the reflection area in the detection image to be blurred, so the processor can also obtain the photosensitive surface array detection The degree of fuzziness of the sudden change boundary of brightness on the detected image is determined, and the turbidity in the liquid to be tested is determined according to the degree of fuzziness. Wherein, the processor can look up a table according to the corresponding relationship between the fuzzy degree of the pre-calibrated brightness mutation boundary and the turbidity of the liquid to obtain the corresponding turbidity of the liquid to be measured.

In some examples, the processor is used to calculate the turbidity of the liquid according to the brightness on the non-reflection area in the detection image when the concentration of the liquid to be tested is lower than a preset concentration, and when the concentration of the liquid to be tested is higher than a preset concentration The turbidity of the liquid is calculated according to the fuzzy degree of the boundary line of the sudden change in brightness on the detection image. When the concentration of the liquid to be tested is low, the turbidity of the liquid to be tested has a good linear relationship with the brightness of the non-reflective area in the detection image, and the calculation of turbidity according to the brightness of the non-reflective area can have higher accuracy , when the concentration of the liquid to be measured is high, the linear relationship decreases, and it is more accurate to calculate the turbidity through the fuzziness of the brightness mutation boundary.

Calculating turbidity with a refractometer can have many applications. In some examples, refractometers can be used to perform compositional testing of liquids. For example, a refractometer can simultaneously measure the refractive index and turbidity of a liquid to determine its properties. For another example, a refractometer can measure the refractive index and turbidity of a liquid (such as coffee) at the same time, and judge the sugar content and milk content of the liquid. As another example, a refractometer can simultaneously measure the refractive index and turbidity of a liquid (such as fruit juice) to determine the sugar content and pulp content of the liquid. As another example, a refractometer can measure the refractive index and turbidity in the clear liquid of the sensor, which can be used to determine whether the sensor is dirty. Optionally, the dirty judgment result can be used to decide whether to continue cleaning. In one application scenario, the refractometer can be used for cleaning machines (such as dishwashers, washing machines, etc.), and detect the refractive index and turbidity of the liquid after cleaning the object to judge the cleanliness of the cleaned object. In one application scenario, refractometers can be used for water quality detection. The judgment result of the refractometer can be displayed to the user through the interactive module.

Since the change of the turbidity of the liquid to be measured will also affect the refractive index of the liquid to be measured, in some examples, the processor is also used to calculate the turbidity of the liquid to be measured according to the pre-calibrated turbidity The influence relationship of the refractive index is used to correct the refractive index of the liquid to be measured. For example, in an application scenario, when the refractometer measures the turbidity and sugar content of the liquid to be tested together, the ratio of milk and sugar in the liquid to be tested can be distinguished by measuring the turbidity and sugar content of the liquid to be tested simultaneously to obtain Accurate milk volume and brix values can then more accurately calculate the calorie content of the liquid to be tested.

In some examples, the refractometer further includes at least one of the following: a colorimeter for detecting the color of the liquid to be tested, an impedance meter for detecting the content of ions (such as acid ions) in the liquid to be tested, and an impedance meter for detecting the color of the liquid to be tested. A PH value meter for measuring the acidity value of the liquid, so that the processor can assist in determining the type of the liquid to be tested based on the information.

In one example, the refractometer also includes a wireless communication module, which is used to send at least one of the refractive index, turbidity, and temperature of the liquid to be measured obtained by the processor to other clients (such as small programs in mobile phones, application, computer client, server, etc.), so that the client can display or analyze the collected data from one or more refractometers. In one example, the refractometer further includes an interactive module for displaying the detected data to the user.

The present application also provides a smart cup, the smart cup is provided with the above-mentioned refractometer for detecting the refractive index and/or turbidity of the liquid in the water cup. Optionally, the smart cup is also provided with a micro-pressure sensor and a computing module. The micro-pressure sensor is used to detect the volume of the liquid in the water cup, and the calculation module is used to calculate the calorie of the liquid in the water cup according to the refractive index and/or turbidity of the liquid measured by the refractometer. Optionally, the refractometer is fixed on the lid of the smart level for easy installation. When it is necessary to measure the refractive index of a liquid, the user only needs to invert the water cup covered with the lid to realize the measurement immediately. Optionally, the micro-air pressure sensor is arranged in a closed space formed between the bottom of the cup body and the diaphragm arranged on the bottom.

The present application also provides an intelligent animal urine detector (mat, etc.), which is provided with the above-mentioned refractometer, and the refractive index of animal urine is measured by the refractometer.

The present application also provides a method for detecting the refractive index of the liquid to be measured by using a refractometer. As shown in FIG. 11 , FIG. 11 is a schematic diagram of an embodiment of a method for detecting the refractive index of a liquid to be measured by using a refractometer in the present application. The method includes:

S1101, sending a light beam to a total reflection interface in the refractometer.

S1102. Converge the light beam reflected by the total reflection interface to the photosensitive array located on the focal plane of the lens module through the lens module.

S1103, using the photosensitive array to image the received light beam to generate a detection image.

S1104. Identify a boundary line of a sudden change in brightness on the detection image.

S1105. Determine the total reflection angle of the light beam on the total reflection interface according to the position of the brightness mutation boundary in the detection image.

S1106. Determine the refractive index of the medium outside the total reflection interface according to the total reflection angle.

In an example, before step S1105 determining the boundary line of a sudden change in brightness in the detection image according to the detection image, the method further includes: determining that an absolute value of a difference between the brightness of the detection image and a preset brightness is greater than a threshold.

In one example, before step S1105, determining the boundary line of abrupt brightness change in the detection image according to the detection image further includes: filtering the target pixel row according to at least part of the pixel rows above and below the target pixel row in the detection image noise. Wherein, optionally, performing noise filtering on the target pixel row according to at least part of the upper and lower pixel rows of the target pixel row in the detection image includes: according to the pixel value of the target pixel row and the at least part of the pixel row The weighted average of the pixel values of is used as the noise-filtered pixel value of the target pixel row.

In an example, before step S1105, determining the boundary line of sudden brightness change in the detection image according to the detection image further includes: determining the pixel rows affected by stray light in the detection image, wherein the pixels affected by stray light The row is not used to determine the refractive index of the medium on the side of the total reflection interface facing away from the light source module.

In an example, the detection image is obtained by weighted summation of multiple frames of images acquired by the photosensitive array.

In an example, the method further includes: obtaining the temperature of the medium located outside the total reflection interface and the temperature of the total reflection interface; according to the pre-stored temperature of the medium to be measured, the temperature of the total reflection interface and the temperature The relationship model of the refractive index of the measured medium, and the obtained temperature of the medium outside the total reflection interface and the temperature of the total reflection interface are used to calculate the refractive index of the medium.

In an example, the method further includes: calculating the turbidity of the medium located outside the total reflection interface according to the detection image.

In an example, the detection image includes a non-reflection area; calculating the turbidity of the medium located outside the total reflection interface according to the detection image includes:

Obtaining the scattered brightness of the non-total reflection area in the non-reflection area and/or the blurring degree of the sudden change boundary of the brightness; wherein, the non-total reflection area in the non-reflection area corresponds to the brightness less than the total After the reflection angle is incident on the total reflection interface, it is incident on the area of the photosensitive surface array; the turbidity is calculated according to the scattering brightness of the non-total reflection area in the non-reflection area and/or the fuzziness of the brightness mutation boundary line . Optionally, the non-reflective area further includes a total reflective area located on one side of the non-total reflective area; the acquiring the scattering brightness of the non-total reflective area in the non-reflective area includes: using the non-reflective area The brightness of the total reflection area in is used as a reference value to calculate the scattering brightness of the non-reflection area and the non-total reflection area in the detection image.

In an example, calculating the turbidity according to the brightness distribution of the non-reflective area and/or the fuzziness of the sudden brightness boundary line includes: when the concentration of the liquid to be tested is lower than a preset concentration, according to the Calculate the turbidity of the liquid to be tested according to the scattering brightness of the non-total reflection area on the non-reflective area; when the concentration of the liquid to be tested is higher than the preset concentration, according to the fuzzy degree of the brightness mutation boundary line on the detection image To calculate the turbidity of the liquid to be tested.

In one example, the medium located outside the total reflection interface is the liquid to be tested; the method further includes: obtaining the volume of the liquid to be tested; calculating the Calories of the liquid to be measured.

In one example, the medium located outside the total reflection interface is the liquid to be tested; the method further includes: using auxiliary equipment to obtain auxiliary information, wherein the auxiliary equipment includes a colorimeter, and the auxiliary information includes the measure the color of the liquid; or, the auxiliary equipment includes an impedance meter, and the auxiliary information includes the ion content of the liquid to be tested; or, the auxiliary equipment includes a pH meter, and the auxiliary information includes the liquid to be tested the acidity value; determine the type of the liquid to be tested according to the auxiliary information and the refractive index and/or turbidity of the liquid to be tested.

In an example, before emitting the light beam to the total reflection interface in the refractometer, it also includes: emitting liquid to clean the target object, and the medium located outside the total reflection interface is the liquid after cleaning the target object; the method It also includes: judging the cleanliness of the target object according to the refractive index of the liquid after cleaning the target object.

In an example, the method further includes: judging whether to continue cleaning the target object according to the cleanliness of the target object.

Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Making various changes is within the protection scope of the present invention.

Claims

A refractometer, characterized in that it includes a light source module, a reflection module, a lens module, a photosensitive array, a control module and a processor, wherein,

The control module is used to control the light beam emitted by the light source module;

The reflection module is used to receive the light beam from the light source module, the reflection module includes a total reflection interface, when the incident angle of the light beam from the light source module on the total reflection interface satisfies a certain condition, the The light beam of the light source module is totally reflected on the total reflection interface, and enters the lens module;

The lens module is used to converge the light beam from the total reflection interface onto the focal plane of the lens module;

The photosensitive surface array is located on the focal plane of the lens module, and the control module is also used to control the photosensitive surface array to detect the received light beam and output a detection image;

A processor, configured to determine a boundary line of a sudden brightness change in the detection image according to the detection image, and determine a side of the total reflection interface facing away from the light source module according to at least one pixel point in the sudden change boundary line of brightness The refractive index of the medium.
The refractometer according to claim 1, wherein the divergence angle of the light source module matches the total reflection interface.
The refractometer according to claim 1, wherein the aperture of the light emitting surface of the light source module is the same as the aperture of the lens module or the difference is less than 1/5 of the aperture of the light emitting surface,

Alternatively, the aperture of the light emitting surface of the light source module is greater than twice the light aperture of the lens module.
The refractometer according to claim 1, wherein the detection angle range of the photosensitive surface array covers the total reflection angle range of the lens module.
The refractometer according to claim 1, wherein the half maximum width of the outgoing light of the light source module is less than 5nm, or a narrow-band filter is arranged on the outgoing light path of the light source module, and the light passing through the narrow-band filter The full width at half maximum of the outgoing light after optical sheet filtering is less than 5nm.
The refractometer according to claim 1, wherein a dodging sheet is arranged on the outgoing light path of the light source module.
The refractometer according to claim 1, wherein the emitted light of the light source module is in the green light band, and the photosensitive area array is a CMOS sensor with a Bell pattern of RGGB.
The refractometer according to claim 1, wherein the processor is further configured to determine the brightness of the detection image and the preset brightness before determining the boundary line of a sudden change in brightness in the detection image according to the detection image The absolute value of the difference is greater than the threshold.
The refractometer according to claim 1, wherein the processor is further configured to, before determining the boundary line of a sudden change in brightness in the detection image according to the detection image, according to the target pixel row in the detection image Noise filtering is performed on the target pixel row at least part of the upper and lower pixel rows.
The refractometer according to claim 9, wherein the processor is configured to use the weighted average of the pixel values of the target pixel row and the pixel values of at least some of the pixel rows as the target pixel row for noise filtering After the pixel value.
The refractometer according to claim 1, wherein the processor is further configured to determine pixel rows affected by stray light in the detection image, wherein the pixel rows affected by stray light are not used for determining The refractive index of the medium on the side of the total reflection interface facing away from the light source module.
The refractometer according to claim 11, wherein the processor is further configured to determine the intensity of stray light in the detection image according to the brightness comparison results of multiple rows of pixel rows and/or the brightness comparison results of multiple frames of detection images. The affected pixel row.
The refractometer according to claim 1, wherein the detection image is obtained by weighted summation of multiple frames of images acquired by the photosensitive surface array.
The refractometer according to claim 1, wherein the processor is further configured to calculate the turbidity of the medium on the side of the total reflection interface facing away from the light source module according to the detection image.
The refractometer according to claim 14, wherein the detection image includes a non-reflection area, and the processor is configured to obtain the scattering brightness and/or the sudden change in brightness of a non-total reflection area in the non-reflection area the degree of fuzziness of the boundary line, and calculating the turbidity according to the scattered brightness of the non-total reflection region in the non-reflection region and/or the fuzziness degree of the boundary line of the sudden change in brightness;

Wherein, the non-total reflection area in the non-reflection area corresponds to the area in the non-reflection area that is incident on the total reflection interface at an angle smaller than the total reflection angle and then incident on the photosensitive array.
The refractometer according to claim 15, wherein the non-reflection area further includes a total reflection area located on one side of the non-total reflection area;

The processor is configured to use the brightness of the total reflection area in the non-reflection area as a reference value to calculate the scattering brightness of the non-total reflection area of the non-reflection area in the detection image.
The refractometer according to claim 15, wherein the processor is configured to use the scattering brightness of the non-total reflection area on the non-reflection area in the detection image when the concentration of the liquid to be measured is lower than the preset concentration The turbidity of the liquid to be tested is calculated, and the turbidity of the liquid to be tested is calculated according to the degree of fuzziness of the boundary line of sudden brightness changes on the detection image when the concentration of the liquid to be tested is higher than a preset concentration.
The refractometer according to claim 14, wherein a slit is arranged on the incident light path of the lens module or on the surface of the lens module.
The refractometer according to claim 1, wherein the refractometer has a standby mode;

In the standby mode, the control module is in a dormant standby state, and the light source module and the photosensitive array are in a power-off state.
The refractometer according to claim 1, wherein the refractometer has a low power consumption mode,

In the low power consumption mode, the control module is used to control the light source module and the photosensitive array to flash synchronously.
The refractometer according to claim 20, wherein the control module is configured to synchronously trigger a pulse width modulation signal to control the light source module according to the frame signal of the photosensitive array.
The refractometer according to claim 1, wherein the control module is further configured to obtain brightness information of the current environment, and adjust the detection image quality of the photosensitive surface array according to the brightness information.
The refractometer according to claim 22, wherein the control module is used to adjust the detection image quality of the photosensitive surface array by adjusting at least one of the following:

The emitted light intensity of the light source module, the exposure time of the photosensitive array, the analog gain of the photosensitive array, and the digital gain of the photosensitive array.
The refractometer according to claim 1, wherein the refractometer further comprises a first temperature sensor and a second temperature sensor, and the first temperature sensor is arranged inside the reflection module or on the surface of the reflection module and is located between the optical path The outer area is used to detect the temperature of the reflection module; the second temperature sensor is arranged on the surface of the total reflection interface of the reflection module facing the side of the medium to be measured, and is used to detect the temperature of the medium to be measured;

The temperature of the liquid to be measured, the relationship model between the temperature of the reflection module and the refractive index of the liquid to be measured are pre-stored in the processor, and the processor is also used to The obtained temperature and the relationship model are used to calculate the refractive index of the liquid to be measured.
The refractometer according to any one of claims 1 to 24, wherein the photosensitive area array is an area array CMOS image sensor.
A method for detecting a refractive index, comprising:

Sending a beam of light toward a total reflection interface within the refractometer;

converging the light beam reflected by the total reflection interface to the photosensitive array located on the focal plane of the lens module through the lens module;

Using the photosensitive array to image the received light beam to generate a detection image;

determining a boundary line of a sudden change in brightness in the detection image according to the detection image;

determining the total reflection angle of the light beam on the total reflection interface according to the position of the brightness mutation boundary line in the detection image;

The refractive index of the medium located outside the total reflection interface is determined according to the total reflection angle.
The method according to claim 26, further comprising:

It is determined that the absolute value of the difference between the brightness of the detection image and the preset brightness is greater than a threshold.
The method according to claim 26, further comprising:

Noise filtering is performed on the target pixel row according to at least part of the upper and lower pixel rows of the target pixel row in the detection image.
The method according to claim 26, wherein the noise filtering of the target pixel row according to at least part of the upper and lower pixel rows of the target pixel row in the detection image comprises:

A weighted average of the pixel values of the target pixel row and the pixel values of at least some of the pixel rows is used as the noise-filtered pixel value of the target pixel row.
The method according to claim 26, further comprising:

determining rows of pixels in said probe image that are affected by stray light,

Wherein, the pixel rows affected by stray light are not used to determine the refractive index of the medium located on the side of the total reflection interface facing away from the light source module.
The method according to claim 26, wherein the detection image is obtained by weighted summation of multiple frames of images acquired by the photosensitive array.
The method according to claim 26, wherein the method also includes:

acquiring the temperature of the medium outside the total reflection interface and the temperature of the total reflection interface;

According to the pre-stored temperature of the medium to be measured, the relationship model between the temperature of the total reflection interface and the refractive index of the medium to be measured, and the acquired temperature of the medium outside the total reflection interface and the temperature of the total reflection interface Compute the refractive index of the medium.
The method according to claim 26, further comprising:

Calculating the turbidity of the medium located outside the total reflection interface according to the detection image.
The method of claim 33, wherein the probe image includes non-reflective regions;

Calculating the turbidity of the medium located outside the total reflection interface according to the detection image, including:

Obtaining the scattered brightness of the non-total reflection area in the non-reflection area and/or the blurring degree of the sudden change boundary of the brightness; wherein, the non-total reflection area in the non-reflection area corresponds to the brightness less than the total After the reflection angle is incident on the total reflection interface, it is incident on the area of the photosensitive surface array;

The turbidity is calculated according to the scattering luminance of the non-total reflection area in the non-reflection area and/or the fuzziness of the boundary line of the sudden change in luminance.
The method according to claim 34, wherein the non-reflective area further comprises a total reflection area located on one side of the non-total reflection area;

The acquisition of the scattered brightness of the non-total reflection area in the non-reflection area includes:

The scattering brightness of the non-total reflection area of the non-reflection area in the detection image is calculated by using the brightness of the total reflection area in the non-reflection area as a reference value.
The method according to claim 34, wherein the calculation of the turbidity according to the scattering brightness of the non-total reflection area in the non-reflection area and/or the fuzzy degree of the boundary line of the sudden change in brightness comprises:

calculating the turbidity of the liquid to be tested according to the scattering brightness of the non-total reflection area on the non-reflection area in the detection image when the concentration of the liquid to be tested is lower than the preset concentration;

When the concentration of the liquid to be tested is higher than a preset concentration, the turbidity of the liquid to be tested is calculated according to the fuzzy degree of the boundary line of sudden brightness change on the detection image.
The method according to claim 33, wherein the medium positioned outside the total reflection interface is the liquid to be measured; the method also includes:

Obtain the volume of the liquid to be tested;

The calorie of the liquid to be tested is calculated according to the refractive index, turbidity and volume of the liquid to be tested.
The method according to claim 33, wherein the medium positioned outside the total reflection interface is the liquid to be measured; the method also includes:

Use auxiliary equipment to obtain auxiliary information, wherein, the auxiliary equipment includes a colorimeter, and the auxiliary information includes the color of the liquid to be tested; or, the auxiliary equipment includes an impedance meter, and the auxiliary information includes the color of the liquid to be tested. The ion content of the liquid; or, the auxiliary equipment includes a pH meter, and the auxiliary information includes the acidity value of the liquid to be tested;

The type of the liquid to be tested is determined according to the auxiliary information and the refractive index and/or turbidity of the liquid to be tested.
The method according to claim 1, characterized in that before launching a light beam to the total reflection interface in the refractometer, further comprising:

Emitting liquid to clean the target object, the medium located outside the total reflection interface is the liquid after cleaning the target object;

The method also includes:

The cleanliness of the target object is judged according to the refractive index of the liquid after cleaning the target object.
The method according to claim 39, further comprising;

Whether to continue cleaning the target object is judged according to the cleanliness of the target object.
A smart cup, characterized by comprising:

Cup lid and cup body;

The refractometer according to any one of claims 1 to 25, arranged at the cup cover, for detecting the refractive index of the liquid in the cup;

a thin film disposed on the bottom of the cup, forming a closed space with the bottom of the cup;

a micro air pressure sensor, arranged in the enclosed space, for detecting the volume of the liquid in the cup;

A calculation module, arranged in the confined space, is used to calculate the calorie of the liquid according to the volume and refractive index of the liquid.