A specular reflection type liquid surface non-contact detection device and method

Abstract

The present application relates to a kind of mirror surface reflection type liquid level non-contact detection device and method, wherein, detection device includes: lifting mechanism;Rod body, the rod body can be driven by the lifting mechanism and carry out vertical lifting movement, the size of the rod body is set so that the rod body can enter reagent container;Macro camera, the macro camera is centrally fixed on the lower end surface of the rod body and is equipped with at least 4 fill light, at least 4 the fill light surrounds the macro camera and is evenly arranged on the lower end surface of the rod body;And host computer, the host computer is electrically connected with the lifting mechanism and the macro camera.The present application can realize the liquid level of non-contact detection reagent container, improve detection efficiency, and detection accuracy is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of liquid level detection, in particular to a mirror reflection type liquid level non-contact detection device and method. BACKGROUND

[0002] In the field of medical in-vitro diagnostic instruments, there are array type reagent container racks, typically square and disc. The reagent container is usually a test tube or a reagent cup. During the operation of the instrument, the liquid level position of the sample test tube, reagent test tube, reaction test tube, etc. needs to be detected to determine the height of the liquid taking needle, and the liquid taking needle will generally be inserted into the liquid surface to a shallow distance to facilitate the effect of needle cleaning. In order to realize liquid level detection, the typical method is to connect the rear end of the liquid taking needle with a capacitive liquid level detection unit, and the liquid level position is recognized by the change of the capacitive value when the needle head touches the liquid surface.

[0003] The existing capacitive liquid level detection unit is affected by various factors such as changes in air humidity, bubbles in the test tube, and interference of the detection unit, and may have a certain probability of detection error. At the same time, the capacitive value detection method needs to touch the liquid surface, in order to avoid carrying pollution or cross interference, the probe end needs to be cleaned, which increases the workload and cost, especially for array type detection, which increases the cleaning amount. SUMMARY

[0004] The purpose of the present application is to provide a mirror reflection type liquid level non-contact detection device and method to solve the above problems.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] According to one aspect of the present application, a mirror reflection type liquid level non-contact detection device is provided, comprising:

[0007] A lifting mechanism;

[0008] A rod body, which can be driven by the lifting mechanism to vertically lift, and the size of the rod body is set so that the rod body can enter the reagent container;

[0009] A macro camera, which is centrally fixedly installed on the lower end surface of the rod body and is provided with at least 4 fill light lamps, and the at least 4 fill light lamps are evenly arranged on the lower end surface of the rod body around the macro camera; and

[0010] A host computer, which is electrically connected with the lifting mechanism and the macro camera.

[0011] In a preferred embodiment, the lifting mechanism is suspended and installed directly above the reagent container.

[0012] In a preferred embodiment, the lifting mechanism includes a screw rod, a stepping motor and a slider, and the rod body is fixedly connected to the slider.

[0013] In a preferred embodiment, the mirror reflection type liquid level contactless detection device may also include several USB interface boards, the upper ends of the USB interface boards are fixed to the slider and the lower ends are fixedly connected to the rod body, and the USB interface boards are connected to the macro camera and the host.

[0014] In a preferred embodiment, the mirror reflection type liquid level contactless detection device may also include a USB control board, which has a centralized USB interface and multiple branch USB interfaces, the centralized USB interface is connected to the host, and the branch USB interface is connected to the USB interface board.

[0015] In a preferred embodiment, the USB aggregation USB interface and the USB branch interface are both Type-C interfaces.

[0016] In a preferred embodiment, the number of the fill lights is 6.

[0017] In a preferred embodiment, the fill light is an LED.

[0018] According to another aspect of the present invention, a mirror reflection type liquid level contactless detection method is provided, wherein the method comprises the following steps:

[0019] S1. Providing the mirror reflection type liquid level contactless detection device as described above;

[0020] S2, setting the initial position of the macro camera;

[0021] S3, driving the macro camera to gradually descend according to a preset step length by the lifting mechanism, and simultaneously acquiring an image captured by the macro camera at a corresponding position;

[0022] S4, analyzing the captured image to determine whether there are circular light spots with the same number as the fill light. If so, proceed to S5, otherwise return to S3;

[0023] S5. Determine whether the distance between the center of each circular light spot and the common center is equal to a preset value r or the difference between the distance and r is less than a preset error. If so, proceed to S6; otherwise, return to S3.

[0024] S6. Complete the liquid level detection and drive the macro camera to leave the reagent container through the lifting mechanism.

[0025] In a preferred embodiment, the specific process of S4 is:

[0026] S41, convert the image into a grayscale image;

[0027] S42, in a set range A centered on the image center, calculate each pixel point, and the calculation method is to add and average the pixel point values on the circumference line with a radius b around the pixel point to obtain a floating point number K(b);

[0028] S43, find the maximum value K(b)max of K(b) in all pixels;

[0029] S44, the radius is changed from 2 pixels to r pixels, and the maximum value (K(b)max)max of K(b)max under different radius conditions is obtained;

[0030] S45, if K(b)max)max is greater than a preset threshold value K, it is judged that there is a circular light spot with the same number of light supplement lamps.

[0031] The technical scheme of the present application has the beneficial effects that the liquid level of the reagent container can be detected without contact, the detection efficiency is improved, and the detection accuracy is high. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structural schematic diagram of the mirror surface reflection type liquid level non-contact detection device of the present application;

[0033] Figure 2 is a mounting structure schematic diagram of the rod body, camera and light supplement lamp of the mirror surface reflection type liquid level non-contact detection device of the present application;

[0034] Figure 3 is a schematic diagram of the USB interface board of the mirror surface reflection type liquid level non-contact detection device of the present application;

[0035] Figure 4 is a connection topology diagram of the USB control board of the mirror surface reflection type liquid level non-contact detection device of the present application;

[0036] Figure 5 is a flow chart of the mirror surface reflection type liquid level non-contact detection method of the present application;

[0037] Figure 6 is a light circle image detection schematic diagram of the mirror surface reflection type liquid level non-contact detection method of the present application;

[0038] Figure 7 is a principle diagram of the mirror surface reflection type liquid level non-contact detection method of the present application. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the embodiments shown in the drawings are merely intended to illustrate the essential spirit of the present application, and should not be construed to limit the scope of the present application.

[0040] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. It will be appreciated, however, that embodiments can be practiced without one or more of these specific details. In other instances, well-known structures and devices are not shown or described in order to avoid unnecessarily obscuring the description of embodiments.

[0041] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an overly literal sense unless expressly so defined herein.

[0042] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0043] As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the content clearly dictates otherwise. It should be noted that the term "comprising" as used in this specification and the appended claims is inclusive or open and does not exclude other unrecited elements or method steps.

[0044] In the following description, for purposes of explanation and not limitation, specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and devices are not presented in order to avoid obscuring the description of the present application.

[0045] In addition, the terms "horizontal," "vertical," "suspended," and the like, do not mean that the components must be absolutely horizontal or suspended, but can be slightly inclined. For example, "horizontal" merely means that it is more horizontal than "vertical," and does not mean that the structure must be absolutely horizontal, but can be slightly inclined.

[0046] In the description of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] As shown in Figure 1 and 2 , a mirror reflection type liquid surface non-contact detection device, comprising a lifting mechanism 1, a rod body 2, a macro camera 3 and a host computer (not shown), wherein the rod body 2 can be driven by the lifting mechanism 1 to vertically lift, and the size of the rod body 2 is arranged so that the rod body 2 can enter the reagent container (for example, a test tube or a reagent cup, hereinafter taking the test tube as an example for description). Preferably, the rod body 2 is cylindrical. That is, the diameter of the rod body 2 is smaller than the inner diameter of the test tube 100 (see Figure 7 ). The length of the rod body 2 is usually greater than the length (height) of the test tube and matches the stroke of the lifting mechanism 1, to ensure that the detection of each liquid level can be completed. The macro camera 3 is centrally fixedly installed on the lower end face of the rod body 2 and is provided with 6 fill light lamps (for example, LEDs) 4, and the 6 fill light lamps 4 are uniformly arranged on the lower end face of the rod body 2 around the macro camera 3. The host computer (for example, a computer, an industrial computer, etc.) is electrically connected with the lifting mechanism 1 and the macro camera 3, to realize the automatic detection of the liquid surface of the test tube.

[0048] During detection, the lifting mechanism 1 acts to gradually vertically probe the rod body 2 with the macro camera 3 into the test tube containing liquid. When the distance between the camera 3 and the liquid surface approaches the focal length of the macro camera 3, the liquid surface irradiates the LED fill light lamps at a close distance to present a mirror effect, at this time there are 6 obvious circular light spots (hereinafter referred to as light circles) in the image captured by the macro camera 3. As the distance between the macro camera 3 and the liquid surface is closer, the radius of the 6 light circles increases, and the distance between the center of the light circle and the common center position also increases; vice versa, that is, as the distance between the macro camera 3 and the liquid surface is farther, the radius of the 6 light circles decreases, and the distance between the center of the light circle and the common center position also decreases. When the distance between the macro camera 3 and the liquid surface is the close focus focal length d of the macro camera 3, the image is the clearest, at this time the distance between the center of the 6 light circles in the image and the common center position is a specific value r, as shown in Figure 6 .

[0049] Therefore, for the known size (length) of the test tube, the position of the macro camera 3 is gradually lowered from above the test tube opening and images are continuously taken. When the algorithm recognizes 6 light circles and the distance between the 6 light circle centers and the common center is r, the distance between the lower end of the rod body 2 and the liquid surface is the close focus distance d of the macro camera 3. Because the starting position of the movement of the rod body 2 (specifically, the macro camera 3) is at a distance x (x is known) from the bottom of the test tube 100, and the lowering distance of the rod body 2 is y (y is known and can be obtained by the movement stroke of the lifting mechanism 1), the height of the liquid surface in the test tube relative to the bottom of the test tube is x-y-d, as shown in Figure 7

[0050] The mirror surface reflection type liquid surface non-contact detection device of the present application can realize non-contact detection of the liquid surface of the test tube, without the need for cleaning, greatly improving the detection efficiency and having high detection accuracy.

[0051] The lifting mechanism 1 can be composed of a commercially available screw stepper motor. Therefore, the lowering distance y of the rod body 2 can be easily obtained. Specifically, the lifting mechanism 1 can include a stepper motor, a slide rail, a slide block, and a screw rod, etc. The output shaft of the stepper motor is connected to the screw rod, and the slide block is threadedly connected to the screw rod and slidingly engaged on the slide rail. The stepper motor drives the screw rod to rotate, thereby driving the slide block to slide along the slide rail. The lifting mechanism 1 can be suspended above the test tube, so that the rod body 2 is located directly above the test tube, to facilitate the rod body 2 to probe into the test tube for liquid surface detection. Specifically, a row of 2-phase 4-wire small screw stepper motors with a diameter of 8mm-10mm can be suspended on a support platform 7, and the slide block on the screw rod is fixedly connected to the upper end of the rod body 2 by a screw, so that the lifting of the rod body 2 can be controlled by the stepper motor. The rod body 2 can be processed from metal materials such as stainless steel or aluminum alloy, etc. In a specific embodiment, the length of the rod body 2 is 40mm, and the diameter is 3.5mm.

[0052] The macro camera 3 is a commercially available drive-free USB camera, which can be directly connected to the USB interface of a computer and communicate with the computer and acquire images through software. The macro camera 3 and the fill light 4 can usually be integrated together. In a specific embodiment, the macro camera 3 has 300,000 pixels and a focal length of 10mm, and has 6 LED fill lights. It should be understood that the number of LED fill lights 4 is not limited to 6, but can also be 4 or 8, etc.

[0053] Because the camera module (rod body 2 and macro camera 3) needs to be lifted, the liquid surface detection device of the present application further includes a USB interface board 5, which carries a camera module and is fixed to the slide block of the lifting mechanism 1 through a mounting hole 51, as shown in Figure 3 ​As shown. The USB interface board 5 connects to the macro camera 3 via the USB Type-C female connector 52, which provides VCC, D+, D-, and GND terminals. The USB interface board 5 can be connected to a computer via a dual-male Type-C cable. It should be understood that the USB Type-C female connector 52 can also be another type of USB interface.

[0054] Since the liquid level detection unit of the detection device is inserted into the test tube for detection, it will not be affected by the barriers between the various tube positions of the array test tube rack, and it is easy to realize parallel detection of multiple tube positions of the array test tube rack. When performing parallel detection, considering that the test tube rack can usually be designed to be movable in a progressive manner, it is only necessary to perform parallel detection on the liquid level of a row of test tubes. In order to reduce the number of occupied computer USB ports, a USB control board 6 is used to realize the connection of multiple USB interface boards 5 and the aggregation of USB signals. Specifically, as Figure 4 As shown, the USB control board 6 includes a USB hub chip 61 (e.g., USB251X), a centralized USB interface 62, and multiple branch USB interfaces 62. The USB251X chip offers different USB interface options. For example, the USB2517 can connect up to seven USB interface boards 5. To ensure power supply stability, the USB control board 6 receives an external DC power supply (e.g., 12V, 24V, etc.) and converts it to 5V via a DC / DC circuit to power each USB interface board 5. Each USB interface board 5 is connected to the USB Type-C female connector (i.e., branch USB interface 62) of the USB control board 6 via a dual-male Type-C cable. The USB control board 6 is then connected to a computer via a USB Type-C female connector (i.e., centralized USB interface 63) and corresponding cables. This allows the computer to control and acquire image data captured by each macro camera, and then perform image processing. If multiple USB interface boards 5 are to be connected, the USB hub chip's inherent one-to-many functionality can be utilized, allowing multiple USB hub chips to be connected to the computer through a single USB hub chip. The present invention can be easily expanded through the USB interface board 4 and the USB control board 5, and its adaptability is greatly improved.

[0055] Refer to the following Figures 5-7 The present invention describes a non-contact method for detecting liquid level using a mirror reflection method. Driven by a lifting mechanism, the macro camera continuously captures and recognizes images as it moves vertically downward from top to bottom into the test tube 100. Initially, fewer than six light circles are recognized, and then six light circles are gradually recognized (at this time, the distance from the light circle to the center is less than a preset value). Finally, when six light circles are recognized and the distance from the center of the light circle to the common center is equal to or very close to the preset value r (within a predefined error range), the liquid level position detection is completed. Specifically, as Figure 5As shown, the method comprises the following steps:

[0056] S1, providing a mirror reflection type liquid surface non-contact detection device as described above;

[0057] S2, setting the initial position of the macro camera, usually setting the initial position at the mouth of the test tube;

[0058] S3, driving the macro camera to gradually descend by the lifting mechanism according to the preset step (for example, 1mm), while acquiring the images taken by the macro camera at the corresponding position, that is, the macro camera takes pictures while descending;

[0059] S4, analyzing the images taken by the macro camera to determine whether there are the same number of circular light spots as the number of light supplement lamps (i.e., 6 light circles), if yes, go to S5, otherwise return to S3; Specifically, as shown, Figure 6 Based on the phenomenon that the smaller the gray value of the pixel point is, the farther it is from the center of each light circle, the image is converted into a gray image (0-255 gray levels, black is 0 and white is 255); Then in the setting range A with the image center as the center, each pixel point is calculated, the calculation method is to add the pixel point values on the circumference line with a radius b around the pixel point and take the average to get a floating point number K(b); Then find the maximum value K(b)max of K(b) in all pixels; The radius changes from 2 pixels to r pixels, and then the maximum value (K(b)max)max of K(b)max under different radius conditions is compared; If K(b)max)max is greater than the preset threshold value K, it is judged that the 6 light circles exist, otherwise it is judged that the 6 light circles do not exist;

[0060] S5, judging whether the distance between the center of each light circle and the common center meets the requirements, if yes, going to S6, otherwise, returning to S3; Specifically, if it is judged that the 6 light circles exist, and the distance from the corresponding light circle center to the common center is r or the difference from r is less than the preset error, it is judged that the distance between the light circle center and the common center meets the requirements, otherwise it is judged that the distance between the light circle center and the common center does not meet the requirements;

[0061] S6, completing the liquid level detection, and driving the macro camera away from the test tube by the lifting mechanism.

[0062] The application has a common application mode and a reliable application mode. Specifically, the common application mode is to directly use the detection result of the application as the control input of the liquid level detection result. The reliable application mode is combined with the capacitive liquid level detection device, the liquid level position detection result of the application is obtained first, and the capacitive liquid level detection device is used to detect the change of the capacitive detection value when the liquid taking needle is lowered to identify the contact to the liquid level. At this time, the liquid level position obtained by the capacitive liquid level detection device is compared with the liquid level position obtained by the application. If the error exceeds the set range, it is considered abnormal, and the abnormal processing process is entered, for example, the liquid taking needle is raised again and lowered again to identify the liquid level. If it cannot be solved within a certain number of times, it is considered that a fault that must be repaired has occurred, and the instrument stops running and alarms. Through the reliable mode, whether the fault is located in the non-contact detection device of the application or in the capacitive liquid level detection device, or only the sampling needle has encountered a bubble, it can be discovered and responded in time.

[0063] The application is suitable for liquid level detection of various sizes of reagent containers, including narrow-diameter test tubes and wide-diameter reagent cups. In particular, for narrow-diameter test tubes, ultrasonic liquid level detection cannot be used due to the limitation of the current process probe size being too large and the limitation of the emission angle. Therefore, the application can be used instead of the existing ultrasonic liquid level detection technology.

[0064] The preferred embodiments of the application have been described in detail above, but it should be understood that, after reading the above description of the application, those skilled in the art can make various modifications or changes to the application. These equivalent forms also fall within the scope defined by the claims attached hereto.

Claims

1. A mirror reflection type liquid level contactless detection device, characterized in that: include: Lifting mechanism; a rod body, the rod body being driven by the lifting mechanism to perform vertical lifting motion, the rod body being sized so as to be able to enter the reagent container; A macro camera, the macro camera being centrally fixedly mounted on the lower end surface of the rod and provided with at least four fill lights, the at least four fill lights being evenly arranged on the lower end surface of the rod surrounding the macro camera; and A host computer, the host computer being electrically connected to the lifting mechanism and the macro camera to realize automatic detection of the liquid level; During detection, the lifting mechanism is actuated to gradually and vertically insert the rod equipped with the macro camera into the reagent container containing the liquid. When the distance between the camera and the liquid surface is close to the focal length of the macro camera, the liquid surface is illuminated by the fill light at close range to present a mirror effect. At this time, the image captured by the macro camera contains the same number of light circles as the fill light. As the distance between the macro camera and the liquid surface is shortened, the radius of the light circle increases, and the distance between the center of the light circle and the common center position also increases. As the distance between the macro camera and the liquid surface increases, the radius of the light circle increases, and the distance between the center of the light circle and the common center position also increases. As the object is zoomed out, the radius of the light circle decreases, and the distance between the center of the light circle and the common center position also decreases; when the distance between the macro camera and the liquid surface is the near focus focal length d of the macro camera, the image is clearest. At this time, the distance between the centers of the multiple light circles in the image and the common center position is a specific value r, and the height of the liquid surface in the reagent container relative to the bottom of the reagent container is calculated to be xyd; wherein x is the distance between the starting position of the movement of the macro camera and the bottom of the reagent container, and y is the descending distance of the macro camera.

2. The mirror reflection type liquid level contactless detection device according to claim 1, characterized in that: The lifting mechanism is suspended and installed directly above the reagent container.

3. The mirror reflection type liquid level contactless detection device according to claim 1 or 2, characterized in that: The lifting mechanism includes a screw rod, a stepping motor and a slider, and the rod body is fixedly connected to the slider.

4. The mirror reflection type liquid level contactless detection device according to claim 3, characterized in that: It also includes several USB interface boards, the upper ends of the USB interface boards are fixed to the slider and the lower ends are fixedly connected to the rod body, and the USB interface boards are connected to the macro camera and the host.

5. The mirror reflection type liquid level contactless detection device according to claim 4, characterized in that: It also includes a USB control board, which has a summary USB interface and multiple branch USB interfaces. The summary USB interface is connected to the host, and the branch USB interfaces are connected to the USB interface board.

6. The mirror reflection type liquid level contactless detection device according to claim 5, characterized in that: The USB aggregation USB interface and the USB branching interface are both Type-C interfaces.

7. The mirror reflection type liquid level contactless detection device according to claim 1, characterized in that: The number of the fill lights is 6.

8. The mirror reflection type liquid level contactless detection device according to claim 1, characterized in that: The fill light is an LED.

9. A non-contact method for detecting a liquid level by mirror reflection, characterized in that: The method comprises the following steps: S1. Provide a mirror reflection type non-contact liquid level detection device according to any one of claims 1 to 8; S2, setting the initial position of the macro camera; S3, driving the macro camera to gradually descend according to a preset step length by the lifting mechanism, and simultaneously acquiring an image captured by the macro camera at a corresponding position; S4, analyzing the captured image to determine whether there are circular light spots with the same number as the fill light. If so, proceed to S5, otherwise return to S3; S5. Determine whether the distance between the center of each circular light spot and the common center is equal to a preset value r or the difference between the distance and r is less than a preset error. If so, proceed to S6; otherwise, return to S3. S6. Complete the liquid level detection and drive the macro camera to leave the reagent container through the lifting mechanism.

10. The mirror reflection type liquid level contactless detection method according to claim 9, characterized in that: The specific process of S4 is: S41, converting the image into a grayscale image; S42. Calculate each pixel within a set range A centered on the image center by adding and averaging the pixel values ​​on a perimeter line with a set radius b around the pixel to obtain a floating point number K(b). S43, finding the maximum value K(b)max of K(b) among all pixels; S44, the radius changes from 2 pixels to r pixels, and the maximum value of K(b)max under different radius conditions (K(b)max)max is obtained; S45 : If (K(b)max)max is greater than the preset threshold value K, it is determined that there are circular light spots with the same number as the fill light.

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