Sintered coke powder image acquisition system and method

Abstract

The invention discloses a sintered coke powder image acquisition system and method, and belongs to the field of image acquisition. The collecting system comprises a collecting box, the collecting box is configured to be installed at the tops of belt protection plates on the two sides of a conveying belt, and the collecting box and the belt protection plates jointly define a closed box body arranged above the conveying belt in a covering mode; a light source, a camera and an air blowing pipeline are arranged in the collection box, and the air blowing pipeline is configured to blow towards the lower part of the camera; an air draft pipeline is further arranged in front of the collecting box in the conveying direction of the conveying belt, and the air draft pipeline is configured to be communicated with a cavity defined by the belt protection plates on the two sides of the conveying belt, so that negative pressure adsorption is conducted on the upper portion of the conveying belt. By constructing a negative-pressure long-distance suction and positive-pressure near-field air curtain composite dust removal system, the problem of dust interference caused by high dissipation of coke powder and strong electrostatic adsorption is solved, and the image acquisition quality is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of image acquisition, and more specifically, to a sintered coke powder image acquisition system and method. Background Art

[0002] Both too large or too small particle size of the coke powder for sintering will have a significant impact on sintering production: when the particle size is too large, the combustion speed of the coke powder slows down, the combustion zone widens, resulting in a decrease in the temperature of the high-temperature zone, a decrease in the vertical sintering speed, a deterioration in permeability and a decrease in the utilization coefficient. At the same time, large particle fuels accumulate at the bottom of the material layer, causing over-melting phenomena and an increase in the return ore rate; while when the particle size is too small, due to the too fast combustion speed, the high-temperature holding time is shortened, the liquid-phase reaction is insufficient, resulting in a decrease in the drum strength of the sinter and an increase in the return ore rate, and the fine powder is easily drawn away by the airflow, causing an increase in solid fuel consumption. The ideal particle size should be controlled such that the proportion of 1-3mm accounts for more than 55%. At this time, the fuel is evenly distributed, the combustion efficiency is optimized, the generation amount of calcium ferrite can be increased, the drum strength can be improved, the solid fuel consumption can be reduced, and the reduction degradation index can be improved. Therefore, the particle size control of the coke powder for sintering is very crucial.

[0003] And the prerequisite for realizing accurate control of the particle size of coke powder is to realize precise on-line detection of the particle size of coke powder. At present, the particle size recognition technology based on machine vision is one of the mainstream technologies for on-line particle size detection. However, the coke powder has a small particle size, an irregular porous structure, a large specific surface area, is easy to generate fine dust, the proportion of <0.1mm can reach 30%, the angle of repose of the coke powder reaches 45°, the electrostatic adsorption effect is significant, and the surface static voltage can reach 5kV. Its special physical properties result in a much higher dust emission amount than other metallurgical materials, greatly affecting the quality of the collected images. And the emitted dust is easily aggregated on the surface of the camera due to strong electrostatic adsorption, interfering with the shooting effect. At present, the conventional dust-proof devices on the market are difficult to meet the application requirements of coke powder image acquisition, bringing great obstacles to the application of the particle size recognition technology based on machine vision to coke powder. In addition, the coke powder has a low diffuse reflectance, and the vibration of the conveyor belt is easy to generate multi-directional reflected light, making the coke powder image extremely sensitive to ambient light during the shooting process. Summary of the Invention

[0004] 1. Technical Problems to be Solved by the Invention

[0005] The purpose of the present invention is to provide a sintered coke powder image acquisition system and method capable of effectively improving the quality of graphic acquisition in view of the insufficient accuracy of sintered coke powder image acquisition in the prior art.

[0006] 2. Technical Solutions

[0007] To achieve the above object, the technical solution provided by the present invention is as follows:

[0008] An image acquisition system for sintered coke powder of the present invention includes an acquisition box, which is configured to be installed on the top of the belt protection plates on both sides of the conveyor belt and jointly form a closed box body covering the upper part of the conveyor belt with the belt protection plates; a light source, a camera and a blowing pipeline are arranged in the acquisition box, and the blowing pipeline is configured to blow towards the lower part of the camera; along the conveying direction of the conveyor belt, an exhaust pipeline is further arranged in front of the acquisition box, and the exhaust pipeline is configured to communicate with the chamber formed by the belt protection plates on both sides of the conveyor belt, so as to perform negative pressure adsorption on the upper part of the conveyor belt.

[0009] Furthermore, a protective shell is arranged around the outside of the camera in the acquisition box, the blowing pipelines are arranged on both sides of the camera, and the air outlets of the blowing pipelines face downwards and blow into the inner cavity of the protective shell.

[0010] Furthermore, belt protection plates are arranged along the conveying direction on both sides of the conveyor belt, and the extending height of the belt protection plates exceeds the height of the conveyor belt, forming a protection chamber around the conveyor belt, and the acquisition box and the exhaust pipeline communicate with the protection chamber respectively.

[0011] Furthermore, the camera in the acquisition box is installed on a telescopic bracket, and the telescopic bracket is used to control the height distance between the camera and the conveyor belt.

[0012] Furthermore, a total of four groups of light sources are arranged in the acquisition box, which are symmetrically distributed on both sides of the top and both sides of the middle of the acquisition box.

[0013] Furthermore, it further includes a fixed bracket, which includes a column bracket located outside the belt protection plate and a transverse bracket connected to the tops of the column brackets on both sides, and the acquisition box is installed and extends downward on the transverse bracket.

[0014] The present invention also provides an image acquisition method for sintered coke powder, which uses the above-mentioned acquisition system to acquire images, combines the signal-to-noise ratio SNR and the dynamic range DR to evaluate the image quality, sums the dynamic range DR and the signal-to-noise ratio SNR to obtain an image quality evaluation parameter. The larger this evaluation number is, the clearer the image is, the higher the layering is, and the higher the image quality is; the optimal height distance between the camera and the conveyor belt is determined according to the evaluation parameter, and after determining the optimal position of the camera, the image acquisition is started.

[0015] Furthermore, the height of the camera is adjusted by the telescopic bracket, and the adjustment process is as follows: first, adjust the telescopic bracket to the shortest state and take a photo at this position, calculate the corresponding SNR+DR value, then gradually lower the height of the telescopic bracket, repeat taking photos and calculating the SNR+DR value until the telescopic bracket is fully extended, and take the position when the SNR+DR value reaches the maximum as the optimal height position of the camera. After adjusting the camera position accordingly, then start to acquire images.

[0016] 3. Beneficial effects

[0017] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects:

[0018] (1) For the sintered coke powder image acquisition system of the present invention, by constructing a composite dust removal system of negative pressure remote suction and positive pressure near-field air curtain, it breaks through the problem of dust interference caused by high dust dispersion and strong electrostatic adsorption of coke powder. The negative pressure module realizes efficient capture at the front end of dust diffusion, and the positive pressure module forms a dynamic isolation zone through directional air flow to inhibit pollution caused by electrostatic adsorption; the spatio-temporal coordination of the dual systems extends the lens maintenance cycle from weekly to more than half a year, overcomes the failure bottleneck of the traditional single dust removal mode in the coke powder scenario, and realizes a clean imaging environment with a dust concentration ≤ 5mg / m 3 .

[0019] (2) For the sintered coke powder image acquisition system of the present invention, a closed stainless steel acquisition box is set, and an active gradient light source compensation is added inside the box. The four groups of light sources are stereoscopically arranged to enhance the illuminance uniformity, break through the problem of optical interference caused by low diffuse reflection of coke powder and belt vibration. The rigid-flexible coupling design of the acquisition box and the peripheral fixed bracket improves the vibration suppression efficiency. Combined with the spectral regulation of the neutral light source, it effectively suppresses the multi-directional reflected light noise, improves the signal-to-noise ratio SNR of the coke powder image, and solves the problems of image blurring and detail loss caused by environmental light sensitivity in the traditional open shooting system.

[0020] (2) For the sintered coke powder image acquisition method of the present invention, by constructing a coupling quantization model of dynamic range DR and signal-to-noise ratio SNR, it realizes the collaborative optimization of image clarity SNR and layering DR, overcomes the subjectivity of traditional empirical judgment and the one-sidedness of single indicators; secondly, combined with the step-by-step experimental calibration method, it realizes the precise regulation of the camera installation height in the industrial vision system. This technology breaks through the limitation of traditional single-index optimization, uses the DR+SNR sum as the comprehensive quality evaluation function, reveals the non-linear relationship between the two indicators with the change of distance, provides data support for complex parameter tuning, and avoids sub-optimal solutions caused by index conflicts; forms a quantifiable and replicable calibration process, reduces the dependence on manual experience, is applicable to rapid adaptation to different working conditions such as belt speed and material type changes, and improves the generalization ability of the system. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of the image acquisition system in the embodiment;

[0022] Figure 2 is a schematic side view structural diagram of the image acquisition system in the embodiment;

[0023] Figure 3 is a schematic diagram of the air extraction state at the front end of the belt in the embodiment;

[0024] Figure 4Schematic diagram of the blowing state inside the collection box in the embodiment;

[0025] Figure 5 Trend chart of SNR&DR in the embodiment;

[0026] Figure 6 Trend chart of SNR+DR in the embodiment.

[0027] Explanation of the reference numerals in the schematic diagram:

[0028] 100. Collection box; 101. Light source; 102. Blowing pipeline;

[0029] 200. Camera; 201. Protective shell; 202. Telescopic bracket;

[0030] 300. Conveyor belt; 301. Belt guard; 302. Fixed bracket; 303. Exhaust pipeline; 304. Feeding port. Specific implementation mode

[0031] To further understand the content of the present invention, the present invention will be described in detail with reference to the accompanying drawings.

[0032] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] The present invention will be further described below with reference to the embodiments.

[0034] Embodiment 1

[0035] Combined with Figures 1 - 6As shown in the figure, an image acquisition system for sintered coke powder in this embodiment includes belt guards 301 arranged along the transportation direction on both sides of the conveyor belt 300. The extending height of the belt guards 301 exceeds the height of the conveyor belt 300, forming a protective cavity around the conveyor belt 300. An acquisition box 100 is arranged at the position of the area to be photographed. The acquisition box 100 is installed on the top of the belt guard 301 and communicates with the protective cavity of the belt guard 301, jointly enclosing a closed box body covering the upper part of the conveyor belt 300. The closed box body shown here means that it is closed at the top and around, and the bottom is communicated with the inner cavity of the belt guard 301, so as to effectively isolate the interference of external light; a light source 101, a camera 200 and a blowing pipeline 102 are arranged in the acquisition box 100. The blowing pipeline 102 is configured to blow towards the lower part of the camera 200; along the transportation direction of the conveyor belt 300, an exhaust pipeline 303 is also arranged in front of the acquisition box 100. The exhaust pipeline 303 is configured to communicate with the protective cavity formed by the belt guards 301 on both sides of the conveyor belt 300, so as to perform negative pressure adsorption on the upper part of the conveyor belt 300. A discharge port 304 is correspondingly arranged at the end of the exhaust pipeline 303 for collecting dust.

[0036] In practice, the acquisition box 100 can be made of 316L stainless steel. To solve the problem of image acquisition of sintered coke powder, this system integrates a closed anti-vibration light box, which attenuates the interference of ambient light by more than 90% and reduces the vibration transfer rate to ensure the uniformity of the light field inside the box. In addition, positive and negative pressure combined dust removal is integrated. The front end uses the exhaust pipeline 303 for -200Pa negative pressure pre-dust removal, and the blowing pipeline 102 in the acquisition box 100 is used for +50Pa positive pressure air curtain isolation. Negative pressure is used to prevent diffusion and positive pressure is used to prevent deposition to achieve deep dust prevention and ensure the quality of image acquisition.

[0037] In addition, preferably in practice, there are four groups of light sources 101 in the acquisition box 100, as Figure 1 shown, symmetrically distributed on both sides of the top and both sides of the middle of the acquisition box 100. Specifically, 4500K color temperature LED light sources can be used, with a single lamp of 2000lm and a total illuminance of 8000lux. The top-middle dual-position lighting forms a three-dimensional light cone with a divergence angle of 30°, which improves the effective reflected light flux of the porous surface of the coke powder and enhances the edge contrast of the image. Moreover, the layout of the four groups of light sources 101 also reduces the possibility of dust accumulation in front of the lamps and ensures the uniform distribution of the light intensity. The camera 200 can be a high-definition industrial camera with 24 million pixels, which can still take clear images under severe temperature fluctuations.

[0038] Furthermore, combined with Figure 2, inside the collection box 100, a protective shell 201 is provided around the outside of the camera 200. The blowing ducts 102 are arranged on both sides of the camera 200, and the air outlets of the blowing ducts 102 face downward and blow into the inner cavity of the protective shell 201. The setting of the protective shell 201 can not only protect the camera 200, but also form a limited inner cavity space for blowing, so as to ensure precise blowing in the area near the camera 200 and avoid dust adhering to the camera 200.

[0039] To improve the stability of the overall system, a more optimized design is that, in combination with Figure 1 , it also includes a fixing bracket 302. The fixing bracket 302 includes a column bracket located outside the belt protection plate 301 and a transverse bracket connected to the tops of the column brackets on both sides. The collection box 100 is installed on the transverse bracket and extends downward. The fixing bracket 302 is arranged on the periphery, and the collection box 100 is connected by the top transverse bracket, which can effectively disperse the weight of the box body and avoid damage to the belt protection plate 301. Steel pipes can be further welded on both sides of the column bracket to form a triangular support to further enhance the stability. The fixing bracket 302 is also preferably made of stainless steel to solve the problem of reduced strength caused by rust during long-term use.

[0040] In this embodiment, the exhaust duct 303 first sucks the dust that may affect the imaging quality into the duct through negative pressure adsorption, thus avoiding interference with the shooting process. However, the distance between the exhaust duct 303 and the collection box 100 is crucial for the dust removal effect. If the distance is too close, some dust may not be sucked into the duct in time due to inertia and the pushing effect generated during the belt transportation process, but instead enter the shooting area; if the distance is too far, although effective dust removal can be achieved at the exhaust point, due to the certain distance between the shooting area and the dust removal point, the belt vibration may raise new dust again, reducing the dust removal effect. After many tests, when the exhaust duct 303 is connected to a position 3.5 - 4.5 meters away from the collection box 100, preferably at a position of 4 meters, the dust removal effect is the best, which can not only effectively remove dust but also avoid the generation of new dust.

[0041] In practice, after the camera 200 is used for a long time, a layer of dust often accumulates in front of the lens, and the image quality drops severely. To solve this problem, in this embodiment, a blowing positive pressure dust exhaust structure is designed inside the collection box 100, which consists of two blowing ducts 102 with a diameter of 0.05 meters, connected to the top layer of the collection box 100 for the image, and blows downward from above the protective shell 201 of the camera 200 to form an air flow barrier, effectively preventing dust from contacting the camera lens, ensuring that the lens surface remains clean after long-term use, and thus maintaining the stability of the image quality. The maintenance frequency is significantly reduced, and the operation efficiency and reliability of the equipment are improved.

[0042] In this embodiment, by designing the acquisition box 100, the air extraction negative pressure dust collection and the air blowing positive pressure dust removal structures, and organically integrating the three, the working reliability of the equipment in harsh environments and the consistency of image quality are significantly improved. Among them, the acquisition box 100 effectively isolates the interference of external light and temperature changes on the imaging quality; the air extraction negative pressure dust collection can suck the dust into the pipeline before it reaches the shooting area, thereby eliminating the impact of dust on the image quality; while the air blowing positive pressure dust removal effectively reduces the accumulation of dust in front of the lens through an air flow barrier, avoiding vision problems caused by dust occlusion. Even in a complex and changeable on-site environment, it can ensure the long-term clarity and stability of image acquisition, meet the requirements of high-quality image data, and provide a reliable guarantee for subsequent analysis and applications.

[0043] Furthermore, the camera 200 in the acquisition box 100 is installed on the telescopic bracket 202, and the telescopic bracket 202 is used to control the height distance between the camera 200 and the conveyor belt 300. In practice, the distance between the camera 200 and the conveyor belt 300 has an important impact on the imaging quality and the service life of the camera. If the distance is too far, the proportion of coke powder in the image will become smaller, and the details will be difficult to distinguish. At the same time, due to the limitation of the camera resolution, long-distance shooting will cause details to be lost, and the influence of sensor noise will be more significant, thus reducing the image quality. If the distance is too close, only a local area of the belt can be captured, which may lead to the omission of important information and may also cause defocusing problems. Therefore, it is crucial to adjust the distance between the camera 200 and the conveyor belt 300 to an appropriate range.

[0044] Based on this, in the image acquisition method adopted in this embodiment, the signal-to-noise ratio SNR and the dynamic range DR indicators are comprehensively considered to evaluate the image quality. Among them, the calculation formula of SNR is shown in Equation 1, and it is the ratio of the signal intensity to the noise intensity. The higher the SNR value, the clearer the image and the smaller the noise interference, thus providing a guarantee for the acquisition of high-quality images.

[0045]

[0046] From the dimension of image clarity alone, it is difficult to comprehensively evaluate the quality of the material image. In the process of particle size identification, the layering of the image is equally crucial. Rich layering can provide more detailed information, which helps to improve the accuracy of image recognition. The dynamic range DR is an important indicator used to describe the difference range between the brightest part and the darkest part of the image. The larger the dynamic range, the richer the layering of the image and the stronger the detail expression ability. Its calculation formula is shown in Equation 2.

[0047]

[0048] In order to comprehensively evaluate the image quality in terms of both clarity and layering, the present invention obtains an image quality evaluation parameter by summing the dynamic range DR and the signal-to-noise ratio SNR. The larger this evaluation number is, the clearer the image is, the higher the layering is, and the higher the image quality is. In this embodiment, the camera telescopic bracket 202 is first adjusted to the shortest state. At this time, the distance between the camera 200 and the conveyor belt 300 is 1.7 meters, and a photo is taken at this position to calculate the corresponding SNR+DR value. Subsequently, the telescopic bracket 202 is gradually extended downward by 5 cm, and the photo is taken and the SNR+DR value is calculated repeatedly until the telescopic bracket 202 is fully extended. The calculated results of the SNR and DR values are as Figure 5 shown. As can be seen from Figure 5 , when the initial distance of the camera 200 is 1.7 meters, both the clarity and layering of the image are poor. As the height of the camera 200 gradually decreases, the materials in the image gradually become clearer. When the distance between the camera 200 and the conveyor belt 300 drops to 0.7 meters, the SNR value reaches the highest point of 22.22 dB, indicating that the clarity of the image is the best at this time. At the same time, the changing trend of the dynamic range DR is also worthy of attention: in the initial stage, as the distance of the camera 200 decreases, the DR value changes significantly, and the layering of the image is significantly enhanced; however, when the height of the camera 200 drops to 0.9 meters, the DR value is 21.36 dB, and when the height is further reduced, the change of the DR value tends to be gentle. When the distance is shortened to 0.55 meters, the DR value reaches the maximum value of 22.59 dB, and then begins to gradually decline.

[0049] By analyzing the trend change of the SNR+DR value in Figure 6 , it can be found that the image quality is the worst when the distance is 1.7 meters. After that, as the shooting distance gradually shortens, the image quality gradually improves. When the distance is shortened to 0.7 meters, the SNR+DR value reaches the maximum. At this time, the SNR value is at the highest level, and the DR value is 22.11 dB, close to its peak range, and the image clarity reaches the best state. However, as the distance is further shortened, the SNR+DR value begins to show a downward trend. Considering the clarity and layering of the image comprehensively, the distance between the camera 200 and the conveyor belt 300 is finally set to 0.7 meters. This setting can achieve the best balance of image quality in practical applications.

[0050] In this embodiment, after adjusting the best position of the camera 200 in the above manner, a protective case 201 is installed on the camera to reduce the wear and lens pollution caused by dust, and then the image is collected to ensure the image collection quality. After the image data is converted by photoelectric conversion, it is transmitted to the client for storage and analysis. And by scientifically setting the installation distance, it is possible to avoid local overheating or dust pollution caused by being too close, and sensor noise interference caused by being too far away, and extend the service life of the camera.

[0051] The above has schematically described the present invention and its embodiments. This description is not restrictive and is only one of the embodiments of the present invention. In fact, it is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural modes and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A sintered coke powder image acquisition system, characterized in that: The invention comprises a collection box (100), wherein the collection box (100) is configured to be installed on the top of belt protection plates (301) on both sides of a conveying belt (300), and together with the belt protection plates (301) form a closed box body which is covered above the conveying belt (300); a light source (101), a camera (200) and a blowing duct (102) are arranged in the collection box (100), and the blowing duct (102) is configured to blow towards the bottom of the camera (200); an exhaust duct (303) is also arranged in front of the collection box (100) along the conveying direction of the conveying belt (300), and the exhaust duct (303) is configured to communicate with the chamber surrounded by the belt protection plates (301) on both sides of the conveying belt (300), so as to perform negative pressure adsorption on the top of the conveying belt (300).

2. A sintered coke powder image acquisition system according to claim 1, characterized in that: A protective shell (201) is provided in the collection box (100) surrounding the outside of the camera (200), and an air blowing duct (102) is provided on both sides of the camera (200), and an air blowing port of the air blowing duct (102) blows downward toward the inner cavity of the protective shell (201).

3. The sintered coke powder image acquisition system according to claim 1, characterized in that: Belt protection plates (301) are arranged on both sides of the transport belt (300) along the transport direction. The belt protection plates (301) extend to a height exceeding the height of the transport belt (300), forming a protection cavity around the transport belt (300). The collection box (100) and the exhaust duct (303) are respectively connected to the protection cavity.

4. The sintered coke powder image acquisition system according to claim 1, characterized in that: The camera (200) in the collection box (100) is installed on a telescopic bracket (202), and the telescopic bracket (202) is used to control the height distance between the camera (200) and the transport belt (300).

5. The sintered coke powder image acquisition system according to claim 1, characterized in that: A total of four groups of light sources (101) are arranged in the collection box (100), which are symmetrically distributed on both sides of the top and the middle of the collection box (100).

6. A sintered coke powder image acquisition system according to any one of claims 1 to 5, characterized in that: It also includes a fixed bracket (302), which includes a column bracket located outside the belt protection plate (301) and a transverse bracket connected to the top of the column brackets on both sides. The collection box (100) is installed on the transverse bracket and extends downward.

7. A method for collecting images of sintered coke powder, using the collection system according to any one of claims 1 to 6 to collect images, characterized in that: The image quality is evaluated by combining the signal-to-noise ratio (SNR) and the dynamic range (DR), and the image quality evaluation parameter is obtained by summing the dynamic range (DR) and the signal-to-noise ratio (SNR). The larger the evaluation number, the clearer the image, the higher the layering, and the higher the image quality. The optimal height distance between the camera (200) and the conveyor belt (300) is determined based on the evaluation parameter, and image acquisition begins after the optimal position of the camera (200) is determined.

8. The method for collecting sintered coke powder images according to claim 7, characterized in that: The height of the camera (200) is adjusted by the telescopic bracket (202), and the adjustment process is as follows: first, the telescopic bracket (202) is adjusted to the shortest state and a photo is taken at this position, and the corresponding SNR+DR value is calculated. Then, the height of the telescopic bracket (202) is gradually lowered downward, and the photos are repeatedly taken and the SNR+DR value is calculated until the telescopic bracket (202) is fully extended. The position at which the SNR+DR value reaches the maximum value is the optimal height position of the camera (200). After the position of the camera (200) is adjusted accordingly, image acquisition begins.

Images