JPH0789086B2 - Garbage discrimination device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust discriminating apparatus for automatically discriminating the type of dust that is flatly stacked and conveyed on a belt conveyor.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for resource recycling from the viewpoint of environmental protection. In order to recycle resources, it is necessary to separate and collect waste such as aluminum cans, steel cans, bottles, paper and plastics. In the past, such sorting work had to rely almost exclusively on human hands. It has been established that iron dust such as steel cans should be sorted and collected with a magnet, but for other types of dust, it was necessary for humans to visually distinguish the types and sort them.

In the manual sorting work, the collected dust is temporarily stored in a hopper or the like, and a certain amount is cut out from the hopper to a belt conveyor arranged below the hopper, and the dust is flattened on the belt conveyor. After loading it, convey the dust on the belt conveyor,
A person standing by the belt conveyor visually distinguishes the type of dust conveyed and sorts it manually.

[0004]

However, in the sorting work in which a person visually selects, not only does it force the person to work excessively, but it is also dangerous and inefficient. .

It is an object of the present invention to provide a dust discriminating apparatus capable of automatically discriminating the type of dust in place of such human visual discrimination work.

[0006]

The object of the present invention to achieve the above object is to provide a dust discriminating apparatus for automatically discriminating the type of dust according to the thermal characteristics of the dust. An apparatus (2) and an infrared camera that is heated by the heating apparatus (2) and is placed in a dispersed manner on a plane, and photographs dust that has a different surface temperature for each type due to the difference in thermal conductivity of materials. (3) and an image processing device (4) that captures a thermal image of dust captured by the infrared camera (3) and determines the type and position of dust based on the brightness difference of the thermal image caused by the difference in surface temperature of dust. ) And a dust determining device.

[0007]

The dust is heated by the heating device (2) with a predetermined amount of heat under substantially the same conditions for each dust, and then the dust is placed in a planar manner. Dust has different surface temperatures depending on the type due to the difference in the thermal conductivity of the materials, and they are distributed in a plane and are located without overlapping, so each dust is an object in a different position. Is taken by the infrared camera (3).

The image processing device (4) takes in each thermal image of dust captured by the infrared camera (3) and discriminates the type and position of dust from the difference in brightness of each thermal image caused by the difference in surface temperature of dust. To do.

By appropriately setting the heating temperature and the heating time so that the surface temperature of the dust has a difference, the type and position of the dust can be reliably identified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a dust discriminating apparatus which is an embodiment of the present invention.

A dust discriminating device for automatically discriminating the type of dust that is flatly stacked on the belt conveyor 1 and conveyed, and a heating device 2 that faces the belt conveyor 1 and heats the conveyed dust. Is provided, and the infrared camera 3 and the image processing device 4 are provided at positions where the subsequent steps are performed.

The belt conveyor 1 is arranged so as to receive the collected dust such as a hopper (not shown) which is scattered so as to discharge the dust at a fixed amount and spread it in a plane.
Dust is stacked flat on the belt conveyor 1 and conveyed.

The heating device 2 is, for example, an infrared irradiation furnace, and the heating temperature and the heating time are set so that the surface temperature of dust is different. And the infrared camera 3
It is heated by the heating device 2, and due to the difference in the thermal conductivity of the materials,
It is arranged so that dusts having different surface temperatures for each type are photographed as a pattern of dispersed positions on the plane of the conveyor 1.

The image processing device 4 takes in a thermal image of dust captured by the infrared camera 3, discriminates the type and position of the dust based on the difference in brightness between the thermal images of the dust caused by the difference in surface temperature of the dust, and determines the dust. It outputs the upper part.

Next, the operation will be described.

The collected dust is once stored in a hopper (not shown) or the like, and is discharged from the hopper to a belt conveyor 1 arranged at the lower part of the hopper by a fixed amount to be scattered and stacked flat on the belt conveyor 1. And then transported. The transported dust is heated by the heating device 2 and then photographed by the infrared camera 3. A thermal image of dust on the belt conveyor 1 taken by the infrared camera 3 is taken into the image processing device 4. Here, what the thermal image will look like depending on the type of dust will be described below.

Generally, plate thickness l (m) and initial temperature 0 (° C)
Made to insulate the surface of the x = 0 of the plate, the temperature distribution in the plate upon heating hold the other surface of the surface temperature momentarily T ₀ (° C.) of x = l is, x, other off of T ₀ -It is a dimensionless function of the Lie number (at / l ² ). Where a (m ² / s) is the thermal conductivity, and the thermal conductivity (W / (m · K)) is the heat capacity per unit volume.
It is calculated by dividing by (J / (m3 · K)). t
(s) is the heating and holding time. Therefore, it is expected that the temperature of the dust after being heated by the heating device for a certain time is a function of the heating temperature and the heating time, the thermal conductivity of the material of the dust, and the shape of the dust.

Here, the temperature conductivities of the main types of dust are examined as follows. That is, if the thermal conductivity of paper is 1, acrylic is 2, bottle is 4, and
117 cans for aluminum cans and 682 for aluminum cans. If the shape of the dust is the same, the temperature of the dust after heating is proportional to the thermal conductivity.

This relationship will be described with reference to the drawings. FIG. 2 shows the results of measuring the temperature of the surface of aluminum, steel, bottle, acrylic and paper of the same shape after heating for a certain period of time. There is a clear temperature difference depending on the type of dust. In the actual case, since the shapes of dust are not the same, the temperature difference as described above does not occur. However, in general, the shape of dust is often almost fixed depending on its type. For example, when examining the thickness, aluminum cans and steel cans are several hundreds of microns, bottles are several millimeters, and papers such as magazines are several millimeters or more.
It is clear that aluminum cans and steel cans, which have high thermal conductivity, are thin and the temperature tends to rise even more. Therefore, it is expected that the temperature difference after heating will be further increased. Based on this temperature difference, it is possible to accurately determine the type of dust.

A thermal image obtained by photographing dust having such a temperature difference shows a unique form depending on the type of dust. FIG. 3 shows an image of dust taken after heating for a certain period of time. When the metal can 11, the glass bottle 12, and the paper box 13 are dispersed and set on a plane in the photographing area 10 on the belt conveyor 1 after the heating device 2, the thermal image screen 20 indicates that the metal can, which is dust with high temperature, Since the infrared ray output is large in the area 11 and the brightness of the thermal image is high, the thermal image 21 rises high. Since the paper box 13 is dust with a low temperature, the infrared ray output is small and the brightness of the thermal image is low in that part, and the thermal image 31 is almost flat. The thermal image 32 of the glass bottle 12 showing intermediate characteristics is slightly raised.

Therefore, the type of dust can be discriminated by setting the threshold value of the brightness of the thermal image for each type of dust. Further, on the position image screen 30, the thermal image screen 20 is projected in a plane, and the metal can 11 and the glass bottle 1 are projected.
2. The paper box 13 forms the images 31 to 33 at the respective coordinate positions, and by checking the coordinates of the respective images, it is possible to determine which position of the dust has such a brightness.

Next, the procedure of processing a thermal image by the image processing apparatus 4 will be described with reference to the drawings. FIG. 4 is a flow chart showing a processing procedure in the image processing device 4 of a thermal image taken by the infrared camera 3. The activation is repeated every fixed time, for example, every 1/30 seconds. If the apparatus is in a standby state where it can be processed in step 1, a thermal image is captured from the infrared camera 3 in step 2. In step 3, a brightness threshold value for each dust type is determined from the captured thermal image. By this, the image of the dust is cut out. If the brightness difference does not appear on the screen when cut out, the process ends in step 4, and if there is a brightness difference and dust is cut out,
Find the center of gravity of the dust cut out in step 5.

The center of gravity is obtained while scanning the screen. In step 6, it is determined whether the center of gravity of the dust is within the processing area. If there is, the signal of the type of dust and the position of the center of gravity is determined in step 7. Is output, the dust image processed in step 8 is erased, the process is completed, and the process ends. In this procedure, the type and position of dust on the belt conveyor 1 that is continuously conveyed is determined by repeating the processing at regular intervals.

Then, according to the signal of the type of dust and the position of the center of gravity, the dust is automatically sorted by a manipulator or the like installed downstream of the belt conveyor 1 for treating the dust in the processing area. it can.

[0025]

According to the dust discriminating apparatus of the present invention, attention is paid to the temperature difference after heating due to the difference in the temperature conductivity of dust in discriminating the dust. Can be detected. In addition, since dust that is a normal object has a large difference in thermal conductivity, highly accurate detection can be performed. By automatically determining the type of dust in this manner, the work that conventionally had to rely on human labor is automated, and costs such as labor costs can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of a dust discriminating apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing the temperature difference of dust after heating.

FIG. 3 is an explanatory diagram showing an image obtained by photographing dust after heating.

FIG. 4 is a flowchart showing a procedure of image processing.

[Explanation of symbols]

 1 ... Belt conveyor 2 ... Heating furnace 3 ... Infrared camera 4 ... Image processing device

Claims (1)

[Claims] 1. A dust discriminating device for automatically discriminating the type of dust according to its thermal characteristics, which comprises: a heating device for heating the dust;
An infrared camera that captures dust that has generated different surface temperatures for each type due to the difference in thermal conductivity of the material, and captures a thermal image of dust captured by the infrared camera,
An image processing device for determining the type and position of dust based on the difference in brightness of the thermal image caused by the difference in surface temperature of dust, the dust determination device.