JPH03123840A - Device for measuring particle size distribution - Google Patents

Abstract

PURPOSE:To accurately measure particle size distribution from a substance having a small diameter to a substance having a large diameter by accumulating one-dimensional image data in a moving direction of a substance group with resolution which is nearly equal to the resolution of a one-dimensional image sensor camera and obtaining two-dimensional data. CONSTITUTION:The image of the moving substance group is formed in the two-dimensional image data obtained by an image memory 7 by setting the resolution of the one-dimensional image by the one-dimensional image sensor camera 5 and the resolution in the moving direction of the substance group nearly equal. The image of the moving substance group is formed in the two-dimensional image data obtained by a compressed image memory 9 with the resolution in the moving direction of the substance group which is lower than the resolution of the memory 7. The substance having the small diameter is mainly detected from the two-dimensional image data in the memory 7 and the substance having the large diameter is mainly detected from the two-dimensional image data in the memory 9 respectively, and the particle size distribution of the entire substance group is obtained. Thus, probability that one part of the substance having the large diameter protrudes from the image and becomes out of a measured object is drastically made lower than a case that the detection is performed by using only two-dimensional image accumulated by taking the substance having the small diameter as an object.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to iron ore and coke, which are raw materials for blast furnace charging.

This invention relates to a device for measuring particle size distribution of sintered ore, etc.

[Prior art]

The particle size of the various raw materials charged into the blast furnace has a large effect on the air permeability inside the furnace, and knowing the particle size distribution of the raw materials immediately before charging into the blast furnace is important for stabilizing blast furnace operation.

FIG. 4 is a schematic diagram showing the configuration of a particle size distribution measuring device disclosed in Japanese Patent Application Laid-Open No. 54-92389. In the figure, reference numeral 31 denotes a hopper that stores raw materials. After raw materials 32 are continuously discharged from the hopper 31 and conveyed on a conveyor 33, they are received at a certain height from the end of the hopper 32.
falls inside. This falling raw material 32 is the TV camera 3
The TV camera 35 is connected to a computer 37 via a TV camera control device 36.

The TV camera control device 36 includes a monitor 3 that displays a photographed image.
A monitor 39 for displaying the measurement results of the particle size distribution is connected to the computer 37. Further, on the opposite side of the falling path of the raw material 32 from the TV camera 35, a lighting device 40 using a stroboscope or the like is installed to illuminate the raw material 32, and its light emission is controlled by a computer 37.

In the above-mentioned apparatus, the continuously falling raw material 32 is imaged by the TV camera 35 using the light emitted from the illumination device 40,
Capture it as a still image. Then, from this still image, the computer 37 calculates the area, number, particle size, and weight ratio of the particles of the raw material 32, and the particle size distribution is measured based on these calculated values.

Moreover, in the above-mentioned apparatus, an apparatus is known in which, instead of the TV camera 35, a one-dimensional image sensor camera equipped with a lens is used to measure the particle size distribution of the falling raw material 32. FIG. 5 is a schematic diagram showing the main parts of the configuration. The falling area of the raw material 32 falling in the direction of the arrow is illuminated by a rod-shaped light source 51 such as a fluorescent lamp instead of the illumination device 40. It extends horizontally parallel to the width of the area. On the opposite side of the rod-shaped light source 51, a one-dimensional image sensor camera 54 consisting of a lens 52 and a one-dimensional image sensor 53 is arranged so as to face the falling area of the raw material 32. One-dimensional image sensor 53
is disposed parallel to and opposite to the bar-shaped light source 51 across the falling area of the raw material 32, and the light from the bar-shaped light source 51 is focused by the lens 52 and imaged on the one-dimensional image sensor 53. The one-dimensional image sensor 53 is connected to an image memory 55, and the image memory 55 is connected to an image processing bag 256. With the above configuration, when the raw material 32 falls between the rod-shaped light source 51 and the one-dimensional image sensor camera 54, the light from the rod-shaped light fi51 at that part is blocked, so that the one-dimensional image sensor 53 can detect the size of the raw material 32. A dark signal proportional to is output.

FIG. 6 is an explanatory diagram of the photographing operation by the one-dimensional image sensor camera 54. Until the lower end of the raw material 32 reaches the field of view of the camera, the one-dimensional image sensor 53 scans the one-dimensional image as shown at scanning number 0. No dark portion occurs in the output signal of the sensor 53. When the lower end of the raw material 32 reaches the field of view of the camera, a slight dark area appears as shown in scan number 1, and when the center of the raw material 32 enters the field of view of the camera, a large dark area appears as shown in scan number 4. 53 output signal. As the raw material 32 goes out of the field of view of the camera, the dark area also decreases, as shown in scan number 7 (when the raw material 32 completely goes out of the field of view of the camera, the dark part decreases).
Dark areas disappear from the output of the dimensional image sensor 53. By sequentially storing the above changes in the signals of the one-dimensional image sensor 53 in the image memory 55, a two-dimensional image 60 corresponding to the shape of the raw material 32 is obtained. Although this figure shows an extreme mosaic pattern, a smooth image can be obtained by photographing with a high-resolution one-dimensional image sensor.

The image processing device 56 uses the image 60 obtained in this way.
The particle size of the raw material 32 is determined by performing known image processing according to the method, and the particle size distribution is measured.

In this latter device, the field of view of the camera is one-dimensional, and when compared with the former device that captures images in two dimensions, it is possible to suppress non-uniformity of illuminance within the imaging area, resulting in fewer measurement errors and dust-proof This has the advantage that countermeasures are easy.

[Problem to be solved by the invention]

However, the conventional devices as described above have the following problems. Figure 7 is an explanatory diagram of this, and Figure 7 (a) shows a group of raw materials falling continuously in the direction of the arrow, and the image obtained by capturing this moment is Figure 7 (Mountain). . In FIG. 7(b), the raw material 61 at the upper end is not entirely within the imaging area, and determining the particle size of each raw material from this image lacks accuracy. Objects that protrude are excluded from measurement.

However, the larger the diameter of an object, the higher the probability that it will protrude from the edge of the image, and therefore the higher the probability that it will be excluded from the measurement target. On the other hand, for blast furnace raw materials, the larger the diameter, the smaller the quantity, and the weight of even one piece is large. Therefore, the average particle size in terms of weight becomes thicker depending on whether one piece is included in the measurement target or not. There is a problem.

In order to avoid such problems, methods such as using two cameras and taking images alternately so that their fields of view overlap can be considered, but usually it takes more time to process the images than it takes to take the images. Therefore, the capacity of the memory for storing captured images becomes enormous, which is not practical. It is also conceivable to drop the raw material intermittently, but it is difficult to drop the raw material for an extremely short period of time, and the amount to be measured also decreases, which is not preferable.

The present invention has been made in view of the above circumstances, and it suppresses the exclusion of large diameter objects that affect the particle size distribution from the measurement target, and accurately measures the particle size distribution of objects from small to large diameters. The purpose of the present invention is to provide a particle size distribution measuring device that can measure particle size distribution.

[Means to solve the problem]

The particle size distribution measuring device according to the present invention is a two-dimensional image obtained by photographing a group of objects moving in one direction in time series using a one-dimensional image sensor camera extending in a direction orthogonal to the moving direction. In the apparatus for measuring the particle size distribution of the object group from data, a first device for obtaining two-dimensional image data by accumulating one-dimensional image data in the moving direction of the object group at a resolution substantially equal to the resolution of the one-dimensional image sensor camera; a second image data storage means for accumulating one-dimensional image data in the moving direction of the object group at a resolution lower than the resolution of the first image data storage means to obtain two-dimensional image data; , said No. 1. It is characterized by comprising means for determining the particle size distribution of the object group based on the two-dimensional image data respectively stored in the second image data storage means.

[Effect]

The two-dimensional image data obtained by the first image data storage means includes an image of a group of objects being moved, in which the resolution of the one-dimensional image obtained by the one-dimensional image sensor camera and the resolution in the moving direction of the group of objects are approximately equal. Things are formed.

In the two-dimensional image data obtained by the second image data storage means, an image of the moving object group is formed with a lower resolution in the moving direction of the object group than that of the first image data storage means.

As a result, mainly small-diameter objects are detected from the two-dimensional image data of the first image data storage means, and mainly large-diameter objects are detected from the two-dimensional image data of the second image data storage means. The overall particle size distribution is determined.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a schematic block diagram showing the configuration of a particle size distribution measuring device according to the present invention.

The raw material 16 to be measured is stored in a hopper 1 in the same way as in the conventional apparatus shown in FIG. The receiver is dropped from the end at a constant height, collected into the hopper 3, and transported to be charged into a blast furnace (not shown). As in the conventional apparatus shown in FIG. A one-dimensional image sensor camera 5 arranged in parallel with the rod-shaped light source 4 is arranged to take pictures on the side. The one-dimensional image sensor camera 5 is configured such that a photographing period, that is, a scanning period of the image sensor is controlled by a camera control device 6.

The output signal of the one-dimensional image sensor camera 5 is provided to an image memory 7, which is the first image data storage means, and a signal thinning device 8, and the signal thinning device 8 is also applied to the second image data storage device. The output signal is given to the compressed image memory 9 constituting the . Image memory 7 is 1
The signal from the dimensional image sensor camera 5 is accumulated and a two-dimensional image with a horizontal and falling direction ratio of 1:1 is stored.

Here, the scanning period of the image sensor is set in the camera control device 6 so that the resolution in the falling direction of the two-dimensional image is equal to the resolution in the horizontal direction, that is, the resolution of the one-dimensional image sensor camera 5. The image stored in the image memory 7 mainly provides the particle size distribution of small diameter raw materials. In this case, it is impossible to measure all the falling raw materials, but since the number of small-diameter raw materials is significantly larger than that of large-diameter raw materials, the representativeness of the sampling is sufficient.

The signal thinning device 8 thins out the signal from the one-dimensional image sensor camera 5, and has the required accuracy and raw material 16.
The thinning rate can be changed depending on the expected maximum diameter. As a result, the signals from the one-dimensional image sensor camera 5 are thinned out and stored in the compressed image memory 9.
A two-dimensional image compressed in the falling direction and having lower resolution in the falling direction than the image memory 7 is stored. The thinning rate of the signal thinning device 8 is set to a rate that provides a scanning cycle that is usually 2 to 20 times the scanning cycle of the image sensor stored in the image memory 7. The image compressed and stored in the compressed image memory 9 in this manner mainly provides the particle size distribution of the large-diameter raw material. That is, in the compressed image, small-diameter raw materials are difficult to detect, but large-diameter raw materials are detected. This measurement target area is longer in the falling direction than the measurement target area stored in the image memory 7. Therefore, it is possible to measure large-diameter raw materials, which are small in number and have a high probability of being excluded at the upper and lower ends of the image storage area of the image memory 7, without failing to detect them.

Monitors 10 and 11 are connected to the image memory 7 and the compressed image memory 9, respectively, and display images stored in each memory. The image memory 7 and the compressed image memory 9 are connected to an image processing device 12, and the image processing device 12 processes the signals of each memory to determine the area, number, and particle size of small diameter and large diameter raw materials in each image. .

The image processing device 12 is connected to a computer 13,
The computer 13 calculates the weight from the particle size and number obtained by the image processing device 12, determines the weight ratio within a predetermined particle size range, and determines the particle size distribution. This particle size distribution is displayed in the form of a histogram by a CRT 14 connected to a computer 13.

Now, the operation of measuring particle size distribution by the apparatus of the present invention configured as described above will be specifically explained. Usually, the blast furnace raw material has a particle size of about 3 mm to 100 mm. In order to photograph this raw material at a resolution of 0.6 W using, for example, a one-dimensional image sensor camera 5 with 1000 elements, the field of view of the camera may be set to 600 fins.

Next, when the raw material 16 is dropped from a height of 0.5 m, approximately 3
It passes within the field of view of the camera 5 at a speed of m/sec.

In order to photograph the raw material 16 in the falling direction with a resolution of 0.6 tm, it is necessary to photograph each time it falls by 0.6 ta. In other words, 0.6 m÷3000mm/sec=0.
It is necessary to take a picture every 2 msec. When the number of pixels of the image memory 7 is 1000 x 1000, as shown in the explanatory diagram of Fig. 2, the raw material 16 within a 600 mm x 600 area that falls in 0.2 m seconds x 1000 = 0.2 seconds is the measurement target. . For example, for a raw material with a particle size of 100 fl, if the center of the raw material is within 501 m of the upper and lower ends of the image storage area, part of it will protrude from the image storage area, so it is probable that (50+
50) **/600m=1/6 number of objects are excluded as not to be measured. In addition, by appropriately setting the conveyance width of the conveyor 2 in the width direction of the falling area, it is possible to prevent the raw material from protruding from the image storage area.

FIG. 3 is an explanatory diagram of the stored image, and FIG.
．． This is obtained by photographing for 2 seconds.

As mentioned above, since the resolution in the falling direction is set to 0.6 mm, small-diameter raw materials with a particle size of 3 grains can be reliably detected.

On the other hand, FIG. 3Cb) is a compressed image stored in the compressed image memory 9, which is obtained by thinning out the signals taken every 0.2 msec so that they are stored, for example, once every 10 times. be. In this compressed image, 6000 in the falling direction
The probability that a large-diameter raw material with a particle size of 100 mm will protrude from the upper and lower ends of the image storage area is (5
0+50) D/6000+u= 1/60,
Compared to the case of the image memory 7, the rate of exclusion as not being measured is significantly lower.

In this way, the image memory 7 stores mainly small-diameter raw materials, and the compressed image memory 9 stores mainly large-diameter raw materials, and based on the detection results of the raw material particle size obtained from both images, a wide range from small diameter to large diameter is stored. The particle size distribution of the entire raw material can be measured with high precision.

Note that since the compressed image memory 9 compresses the image in the direction in which the raw material 16 falls, even in the case of intermittent operation, there is no need for the raw material 16 to fall for an extremely short period of time, and the amount to be measured does not decrease significantly.

Further, in this embodiment, the second image data storage means is configured to store a signal obtained by thinning out the photographing signal of the one-dimensional image sensor camera 5 by the signal thinning device 8 in the compressed image memory 9. For example, it is also possible to provide a separate one-dimensional image sensor camera that captures the falling material with a longer imaging cycle than that of the one-dimensional image sensor camera 5, and to store its imaging signals directly in the memory. good.

〔effect〕

As described above, in the particle size distribution measuring device according to the present invention,
Small-diameter objects can be detected using a two-dimensional image that accumulates one-dimensional image data in the moving direction of the object group with a resolution that is approximately equal to the resolution of a one-dimensional image sensor camera, and large-diameter objects can be detected using a two-dimensional image that has accumulated one-dimensional image data in the moving direction of the object group. 2 which accumulated one-dimensional image data
Since it is configured to mainly detect each dimensional image, there is a higher probability that a part of a large diameter object will protrude from the image and will not be measured. This is significantly lower than when detecting using only As a result, regardless of whether the diameter is large or small,
Particle size distribution of raw materials etc. can be measured with high accuracy with sufficient representativeness.
The present invention has excellent effects such as improved reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing the configuration of a particle size distribution measuring device according to the present invention, FIG. 2 is an explanatory diagram of an image storage area, and FIG.
Figure 4 is an explanatory diagram of a stored image, Figures 4 and 5 are schematic diagrams showing the configuration of a conventional device, Figure 6 is an explanatory diagram of the photographing operation of a one-dimensional image sensor camera, and Figure 7 is a problem with the conventional device. FIG. 1... Storage hopper 4... Rod-shaped light source 5... One-dimensional image sensor camera 7... Image memory 8...
・Signal thinning device 9...Compressed image memory 12...
Image processing device 16...Raw material

Claims (1)

[Claims] 1. From two-dimensional image data obtained by photographing a group of objects moving in one direction in time series with a one-dimensional image sensor camera extending in a direction perpendicular to the direction of movement, In an apparatus for measuring particle size distribution of a group of objects, first image data is obtained by accumulating one-dimensional image data in the moving direction of the group of objects at a resolution substantially equal to the resolution of the one-dimensional image sensor camera to obtain two-dimensional image data. accumulating means; accumulating one-dimensional image data in the moving direction of the object group at a resolution lower than the resolution of the first image data accumulating means;
A second image data storage means for obtaining dimensional image data; and a means for determining the particle size distribution of the object group based on the two-dimensional image data stored in the first and second image data storage means, respectively. A particle size distribution measuring device characterized by: