Area ratio-based mechanism sand free mica detection device and method

Abstract

This invention discloses a rapid detection device and method for free mica in manufactured sand based on area ratio, belonging to the field of concrete raw material testing technology. The device includes a frame, a motor-driven horizontal moving mechanism, an industrial camera, a ring light, multiple sets of thickness-matched support bars, a photoelectric positioning component, and a servo motor, enabling automatic camera positioning and multi-angle shooting. The method first grades the manufactured sand according to particle size, lays it in a single layer of corresponding thickness, and sprays a developer to enhance contrast. Then, multi-angle images are acquired, and the mica contour is extracted through multi-depth-of-field fusion and HSV color space processing. The total content is calculated using area ratio weighting. This invention features a high degree of automation throughout the process, significantly improving detection efficiency, reducing human error, and effectively addressing the problems of low efficiency and unstable accuracy in traditional detection methods. It is easy to operate, highly adaptable, and can meet the needs for rapid and stable detection of mica content in manufactured sand.

Description

Technical Field

[0001] This invention relates to the field of concrete raw material testing technology, specifically to a device and method for detecting free mica in manufactured sand based on area ratio. Background Technology

[0002] Manufactured sand, as a crucial source of fine aggregate for concrete, directly impacts the workability, mechanical properties, and durability of concrete. Mica, a common harmful mineral in manufactured sand, is flaky with a smooth surface and poor adhesion to cementitious materials. When its content exceeds the limit, it significantly reduces the strength and durability of concrete. Currently, the detection of free mica content in manufactured sand faces two main technical challenges: First, traditional manual testing is inefficient and prone to error. Current standards employ manual mica selection under a magnifying glass, requiring personnel to identify and remove mica particles one by one. This method is not only time-consuming and labor-intensive with extremely low efficiency but also highly susceptible to the experience and subjective factors of the testing personnel, resulting in poor repeatability of the test results. Second, existing image detection methods lack sufficient accuracy. Some existing image detection methods do not consider the optimal testing conditions for manufactured sand of different particle sizes, employing uniform sampling quality and sand layer thickness. This leads to excessively thick accumulation of fine-grained sand and overlapping of coarse-grained sand particles, affecting image recognition accuracy. Furthermore, the problems of reflection and projection errors are not effectively addressed, further reducing detection accuracy. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rapid detection device and method for free mica in manufactured sand based on area ratio, which can realize automated, high-precision and rapid detection of free mica content in manufactured sand.

[0004] To solve the above problems, the technical solution of the present invention is as follows: A device for detecting free mica in manufactured sand based on area ratio includes a frame with a base plate mounted on the upper end. A motor, a first guide rail, and a synchronous belt drive mechanism are mounted on the base plate. The first guide rail is horizontally positioned, and a first slider is mounted on it. A support plate is fixedly connected to the first slider. The motor is connected to the support plate via the synchronous belt drive mechanism. An industrial camera and a supplementary light are mounted on the support plate. A panel is located on the frame below the industrial camera, and multiple pairs of support bars of different thicknesses are fixedly connected to the panel, arranged sequentially. The device also includes a controller. The motor and supplementary light are connected to the controller's output. Both the controller and the industrial camera are connected to a computer.

[0005] Furthermore, it also includes a camera height fine-tuning mechanism, which includes a second guide rail vertically mounted on a support plate, a perforated angle plate fixedly connected to the support plate above the second guide rail, a second slider mounted on the second guide rail, a screw mounted on the second slider, the upper end of the screw passing through the perforated angle plate and connected to a nut, and the industrial camera and fill light mounted on the second slider.

[0006] Furthermore, it also includes a U-shaped cable tray connected to the support plate, with two adjustment seats installed inside the U-shaped cable tray. The industrial camera and the fill light are respectively installed on the two adjustment seats.

[0007] Furthermore, the fill light is a ring fill light, and the industrial camera is located directly above the fill light.

[0008] Furthermore, a sand-sweeping port is provided on the panel.

[0009] Furthermore, the panel is provided with four pairs of support strips, the thicknesses of which are 1mm, 1.5mm, 3mm and 5mm respectively. Furthermore, a contact piece is fixedly connected to the support plate, and multiple photoelectric switches are arranged sequentially on the base plate. The support plate, along with the contact piece, triggers each photoelectric switch in sequence. Each photoelectric switch corresponds to a pair of support bars, and each photoelectric switch is connected to the input terminal of the controller.

[0010] Furthermore, a servo motor is mounted on the support plate, and an industrial camera and a fill light are connected to the output end of the servo motor, which is connected to the output end of the controller.

[0011] A method for detecting free mica in manufactured sand by area percentage includes the following steps: S1: A certain mass of manufactured sand is sieved into multiple grades, and then each grade of manufactured sand is spread between each pair of support strips. Then, a scraper is used to scrape off the excess manufactured sand along the support strips to ensure that the thickness of the manufactured sand left between the support strips is consistent with the thickness of the support strips. S2: Spray atomized developer evenly onto the surface of each layer of laid-out machine sand; S3: Adjust the height of the industrial camera and the fill light using the camera height fine-tuning mechanism, and adjust the relative distance between the industrial camera and the fill light using the adjustment mount; S4: Start the motor. The motor drives the support plate to move horizontally along the first guide rail through the synchronous belt transmission mechanism. When the contact piece triggers the photoelectric switch above the corresponding support bar, the controller controls the motor to stop running and starts the industrial camera to take pictures at the same time. S5: The controller controls the servo motor to drive the industrial camera and fill light to rotate at multiple angles, taking pictures of the same grade of manufactured sand from multiple angles; S6: Repeat steps S4 and S5 to complete the image acquisition of the four grades of manufactured sand in sequence, and transfer all images to the computer; S7: The computer processes the collected images, calculates the area ratio of mica in each grade of manufactured sand, and then performs a weighted summation based on the mass ratio of each grade of manufactured sand to obtain the total content of free mica in the manufactured sand.

[0012] Furthermore, the method for determining the mica content by processing the photos using a computer in step S7 includes: S71: Perform multi-depth-of-field image fusion on multi-angle images of the same grade of manufactured sand to construct a virtual reference plane and eliminate projection errors caused by differences in the accumulation morphology of manufactured sand; S72: Convert the fused image to the HSV color space, pre-set the HSV color gamut range of mica based on the color difference between mica and sand particles, create a mask and extract the mica outline; S73: Calculate the total area ratio of the extracted mica contour within the effective area of ​​the image, which is the mica area ratio of the manufactured sand in this grade. S74: According to the formula Calculate the total mica content, where The total free mica content in manufactured sand. For the first The proportion of mica area in manufactured sand. For the first The mass percentage of manufactured sand.

[0013] The beneficial effects of this invention are as follows: 1. High detection efficiency: It realizes full automation from sample placement to image acquisition and data analysis, which greatly shortens the detection time of a single batch and improves detection efficiency.

[0014] 2. High detection accuracy: Different sampling quality and sand layering thickness are adopted for manufactured sand of different particle sizes to ensure that the sand sample is laid flat in a single layer without overlap; projection error is eliminated by multi-angle shooting and multi-depth of field image fusion; HSV color space recognition technology is used to accurately distinguish mica from sand particles, and the accuracy and repeatability of detection results are significantly improved.

[0015] 3. Easy to operate: No professional testing personnel are required. Ordinary operators can complete the testing after simple training, which reduces the testing threshold and labor costs. Attached Figure Description

[0016] The invention will be further described below with reference to the accompanying drawings: Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the present invention; Figure 3 This is a partial three-dimensional structural diagram of the present invention; Figure 4 This is a schematic diagram showing the connection relationship between the various electrical components of the present invention.

[0017] In the diagram: 1. Motor; 2. Support plate; 3. Servo motor; 4. First guide rail; 5. Photoelectric switch; 6. Synchronous belt drive mechanism; 7. Support bar; 8. Panel; 9. Fill light; 10. Industrial camera; 11. Frame; 12. Sand sweeping port; 13. Adjustment seat; 14. U-shaped bridge; 15. Second guide rail; 16. Second slider; 17. Perforated corner plate; 18. Screw; 19. Contact plate. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figures 1 to 4 As shown, this invention discloses a rapid detection device for free mica in manufactured sand based on area ratio, comprising a frame 11, with a base plate horizontally mounted on the upper end of the frame 11. A first guide rail 4 is fixedly mounted on the upper surface of the base plate, and a first slider is slidably mounted on the first guide rail 4. A vertically arranged support plate 2 is fixedly connected to the first slider. A motor 1 (a stepper motor 1) is mounted on one end of the base plate. The output shaft of the motor 1 is connected to a synchronous belt transmission mechanism 6, and the synchronous belt of the synchronous belt transmission mechanism 6 is fixedly connected to the support plate 2. The motor 1 drives the support plate 2 to move horizontally along the first guide rail 4 through the synchronous belt transmission mechanism 6.

[0020] A camera height fine-tuning mechanism is installed on the support plate 2. This mechanism includes a second guide rail 15 vertically fixed to the support plate 2, and a perforated angle plate 17 fixedly connected to the support plate 2 above the second guide rail 15. A second slider 16 is slidably mounted on the second guide rail 15, and a screw 18 is vertically mounted on the second slider 16. The upper end of the screw 18 passes through a through hole in the perforated angle plate 17 and is threadedly connected to an adjusting nut. By rotating the adjusting nut, the second slider 16 can be moved up and down along the second guide rail 15, thereby adjusting the height of the industrial camera 10 and the supplementary light 9. By fine-tuning the camera height, the focal length of the industrial camera 10 can be accurately aligned with the sand sample surface, obtaining the clearest image and improving recognition accuracy.

[0021] A U-shaped bridge 14 is fixedly connected to the second slider 16. Two sliding adjustment seats 13 are installed inside the U-shaped bridge 14, and the industrial camera 10 and the ring light 9 are respectively mounted on the two adjustment seats 13. The industrial camera 10 is equipped with a CPL polarizing filter. By sliding the adjustment seats 13, the relative distance between the industrial camera 10 and the ring light 9 can be adjusted. The distance between the ring light 9 and the camera directly affects the uniformity of illumination on the sand sample surface. Too close a distance will lead to localized overexposure, while too far a distance will result in insufficient illumination. By fine-tuning the distance, the sand sample surface can obtain uniform and soft illumination, eliminating shadows and improving the contrast between mica and sand particles.

[0022] The industrial camera 10 is positioned directly above the ring light 9, with its shooting direction passing through the central hole of the ring light 9. The ring light 9 provides uniform illumination, effectively preventing shadows from sand particles, and, in conjunction with a polarizing filter, suppresses specular reflections on the mica surface, resulting in clearer images.

[0023] A panel 8 is fixedly mounted on the frame 11 below the industrial camera 10. The panel 8 has a sand-sweeping port 12, and a sand-filling basin can be placed below the sand-sweeping port 12. After the test is completed, the sand sample on the panel 8 can be swept into the sand-filling basin through the sand-sweeping port 12 for easy cleaning and recycling.

[0024] Four pairs of support strips 7 are fixedly connected to the panel 8. The thicknesses of the four pairs of support strips 7 are 1mm, 1.5mm, 3mm, and 5mm, respectively, and are arranged sequentially. These four thicknesses correspond to the optimal sand spreading thickness for four particle size grades of manufactured sand: 0.3-0.6mm, 0.6-1.18mm, 1.18-2.36mm, and 2.36-4.75mm. The sand spreading thickness should be slightly less than the minimum value of the particle size grade to ensure that the sand sample is spread in a single layer and avoid particle overlap affecting the test results. Specifically, the corresponding relationships are as follows: 1mm thick support strip 7 for 0.3-0.6mm particle size sand, 1.5mm thick support strip 7 for 0.6-1.18mm particle size sand, 3mm thick support strip 7 for 1.18-2.36mm particle size sand, and 5mm thick support strip 7 for 2.36-4.75mm particle size sand.

[0025] A downwardly extending contact piece 19 is fixedly connected to the support plate 2, and four photoelectric switches 5 are sequentially installed on the base plate corresponding to the four pairs of support bars 7. When the support plate 2 moves above a certain pair of support bars 7, the contact piece 19 triggers the corresponding photoelectric switch 5, and the photoelectric switch 5 sends a signal to the controller. The controller controls the motor 1 to stop running and simultaneously starts the industrial camera 10 to take pictures, realizing precise positioning and automatic shooting of the camera.

[0026] A servo motor 3 is also mounted on the support plate 2. The industrial camera 10 and the ring light 9 are connected to the output end of the servo motor 3. The controller controls the servo motor 3 to rotate the industrial camera 10 and the ring light 9 to three angles: -45°, 0°, and 45°, to take pictures of the same grade of sand sample from different angles and obtain multi-angle images. Mica is in the form of thin flakes, and different angles of light will show different reflection characteristics. By taking pictures from multiple angles, more mica features can be captured, avoiding missed detections due to the tilt of the mica flakes.

[0027] It also includes a controller and a computer. Motor 1, fill light 9, and servo motor 3 are all connected to the output of the controller (the controller is a PLC controller). Photoelectric switch 5 is connected to the input of the controller. The controller and industrial camera 10 are both connected to the computer.

[0028] The specific steps for detecting free mica in manufactured sand using the above-mentioned apparatus are as follows: S1: Sample preparation and placement: Take at least 1000g of manufactured sand sample, dry it in an oven at 105℃±5℃ to constant weight, cool it to room temperature, and then sieve it into four grades: 0.3-0.6mm, 0.6-1.18mm, 1.18-2.36mm, and 2.36-4.75mm. Weigh the sand sample of each grade and calculate the mass percentage of each grade of manufactured sand. .

[0029] According to the sampling quality specified in Table 1, take sand samples of each grade and spread them between the support strips 7 of the corresponding thickness. Use a scraper to scrape off the excess sand sample along the upper surface of the support strip 7, ensuring that the thickness of the sand sample remaining between the support strips 7 is consistent with the thickness of the support strip 7, thus achieving a single-layer flat laying. Excess sand sample can be swept into the sand container through the sand sweeping port 12.

[0030] Table 1. Selection of sampling mass and spreading thickness for different particle sizes

[0031] S2: Development process: Evenly spray the atomized developer onto the surface of each laid-out sand sample. The developer can enhance the edge contrast between mica and sand particles, making the mica outline clearer and facilitating subsequent image recognition.

[0032] S3: Equipment debugging: By rotating the adjusting nut of the camera height fine-tuning mechanism, the height of the industrial camera 10 and the supplementary light 9 are adjusted so that the focal length of the industrial camera 10 is accurately aligned with the surface of the sand sample. By sliding the adjusting seat 13 on the U-shaped bridge 14, the relative distance between the industrial camera 10 and the ring supplementary light 9 is adjusted so that the surface of the sand sample is evenly illuminated without obvious shadows or overexposed areas.

[0033] S4: Automatic positioning and shooting: Start motor 1, which drives support plate 2 to move horizontally along first guide rail 4 via synchronous belt drive mechanism 6. When contact piece 19 on support plate 2 triggers first photoelectric switch 5, controller stops motor 1. At this time, industrial camera 10 is directly above the 70.3-0.6mm particle size sand sample of the first pair of support bars.

[0034] S5: Multi-angle image acquisition: The controller controls the servo motor 3 to rotate the industrial camera 10 and the ring light 9 to a -45° position, activating the industrial camera 10 to capture the first image; then it rotates sequentially to 0° and 45° positions to capture the second and third images respectively. By capturing images from multiple angles, the reflective characteristics of mica sheets in different postures can be obtained, improving the recognition accuracy.

[0035] S6: Sequential data collection across multiple ranges: After the image acquisition of the first sand sample is completed, the controller controls motor 1 to continue driving the support plate 2 to move. When the contact piece 19 triggers the second photoelectric switch 5, the process stops and multi-angle imaging of the second sand sample with a particle size of 0.6-1.18mm is performed. This process is repeated to complete the image acquisition of four sand samples in sequence, and all images are automatically transmitted to the computer.

[0036] S7: Image Processing and Content Calculation: The computer processes the acquired images as follows: S71. Multi-depth-of-field image fusion: Multi-depth-of-field image fusion is performed on three multi-angle images of the same sand sample to construct a virtual reference plane, eliminate the projection error caused by the unevenness of sand particles, and make all particles perform area calculation on the same reference plane.

[0037] S72. Color Space Conversion: Converts the merged image from the RGB color space to the HSV color space. The HSV color space is more suitable for color-based image segmentation and can effectively distinguish the color differences between mica and sand particles.

[0038] S73. Mica Contour Extraction: Based on the pre-calibrated mica HSV color gamut range H: 0-30, S: 0-50, V: 200-255, create a binarized mask to extract the contours of mica particles.

[0039] S74. Area Proportion Calculation: Calculate the total area of ​​all extracted mica contours, divide it by the total area of ​​the effective image region, and obtain the mica area proportion of this grade of manufactured sand. .

[0040] S75. Weighted Summation: According to the formula The total content of free mica in computer-generated sand, of which For total content, For the first The proportion of mica area in the archives For the first The percentage of quality in the document.

[0041] This invention achieves rapid, accurate, and automated detection of free mica content in manufactured sand by using differentiated sand-laying thicknesses for manufactured sand of different particle sizes, combined with multi-angle shooting, multi-depth-of-field image fusion, and HSV color recognition technology. It effectively solves the problems of low efficiency and large error in traditional methods and has significant engineering application value.

[0042] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this invention should not be considered as limited to the specific forms stated in the embodiments. The scope of protection of this invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A device for detecting free mica in manufactured sand based on area ratio, characterized in that: The system includes a frame with a base plate mounted on top. A motor, a first guide rail, and a synchronous belt drive mechanism are mounted on the base plate. The first guide rail is horizontally positioned, and a first slider is mounted on it. A support plate is fixedly connected to the first slider. The motor is connected to the support plate via the synchronous belt drive mechanism. An industrial camera and a fill light are mounted on the support plate. A panel is located on the frame below the industrial camera, and multiple pairs of support bars of different thicknesses are fixedly connected to the panel, arranged sequentially. The system also includes a controller, with the motor and fill light connected to the controller's output. Both the controller and the industrial camera are connected to a computer.

2. The device for detecting free mica in manufactured sand based on area ratio according to claim 1, characterized in that: It also includes a camera height fine-tuning mechanism, which includes a second guide rail vertically mounted on a support plate. A perforated corner plate is fixedly connected to the support plate above the second guide rail. A second slider is mounted on the second guide rail. A screw is mounted on the second slider. The upper end of the screw passes through the perforated corner plate and is connected to a nut. The industrial camera and the fill light are mounted on the second slider.

3. The device for detecting free mica in manufactured sand based on area ratio according to claim 1, characterized in that: It also includes a U-shaped cable tray connected to the support plate, with two adjustment seats installed inside the U-shaped cable tray. The industrial camera and the fill light are respectively installed on the two adjustment seats.

4. The device for detecting free mica in manufactured sand based on area ratio according to claim 1, characterized in that: The fill light is a ring light, and the industrial camera is located directly above the fill light.

5. The device for detecting free mica in manufactured sand based on area ratio according to claim 1, characterized in that: A sand-sweeping port is provided on the panel.

6. The device for detecting free mica in manufactured sand based on area ratio according to claim 1, characterized in that: The panel has four pairs of support strips with thicknesses of 1mm, 1.5mm, 3mm and 5mm respectively.

7. A device for detecting free mica in manufactured sand based on area ratio according to any one of claims 1 to 6, characterized in that: A contact piece is fixedly connected to the support plate, and multiple photoelectric switches are arranged in sequence on the base plate. The support plate, along with the contact piece, triggers each photoelectric switch in sequence. Each photoelectric switch corresponds to a pair of support bars, and each photoelectric switch is connected to the input terminal of the controller.

8. The device for detecting free mica in manufactured sand based on area ratio according to claim 7, characterized in that: A servo motor is mounted on the support plate. An industrial camera and a fill light are connected to the output of the servo motor, which is connected to the output of the controller.

9. A method for detecting mica using the area ratio detection device for manufactured sand free mica as described in claim 8, characterized in that: Includes the following steps, S1: A certain mass of manufactured sand is sieved into multiple grades, and then each grade of manufactured sand is spread between each pair of support strips. Then, a scraper is used to scrape off the excess manufactured sand along the support strips to ensure that the thickness of the manufactured sand left between the support strips is consistent with the thickness of the support strips. S2: Spray atomized developer evenly onto the surface of each layer of laid-out machine sand; S3: Adjust the height of the industrial camera and the fill light using the camera height fine-tuning mechanism, and adjust the relative distance between the industrial camera and the fill light using the adjustment mount; S4: Start the motor. The motor drives the support plate to move horizontally along the first guide rail through the synchronous belt transmission mechanism. When the contact piece triggers the photoelectric switch above the corresponding support bar, the controller controls the motor to stop running and starts the industrial camera to take pictures at the same time. S5: The controller controls the servo motor to drive the industrial camera and fill light to rotate at multiple angles, taking pictures of the same grade of manufactured sand from multiple angles; S6: Repeat steps S4 and S5 to complete the image acquisition of the four grades of manufactured sand in sequence, and transfer all images to the computer; S7: The computer processes the collected images, calculates the area ratio of mica in each grade of manufactured sand, and then performs a weighted summation based on the mass ratio of each grade of manufactured sand to obtain the total content of free mica in the manufactured sand.

10. The rapid detection method for free mica in manufactured sand based on area ratio according to claim 9, characterized in that: The methods used in step S7 to process photos and determine mica content include: S71: Perform multi-depth-of-field image fusion on multi-angle images of the same grade of manufactured sand to construct a virtual reference plane and eliminate projection errors caused by differences in the accumulation morphology of manufactured sand; S72: Convert the fused image to the HSV color space, pre-set the HSV color gamut range of mica based on the color difference between mica and sand particles, create a mask and extract the mica outline; S73: Calculate the total area ratio of the extracted mica contour within the effective area of ​​the image, which is the mica area ratio of the manufactured sand in this grade. S74: According to the formula Calculate the total mica content, where The total free mica content in manufactured sand. For the first The proportion of mica area in manufactured sand. For the first The mass percentage of manufactured sand.

Images