JPH0743247B2 - Article dimension measurement method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the dimensions of rocks, ores, and other articles when the dimensions of the articles are measured and the dimensions are controlled such as production, shipment and acceptance.

[0002]

2. Description of the Related Art For example, when shipping or receiving rocks, ores, and other articles, it is necessary to confirm whether or not they have predetermined dimensions, or to select a sieving machine for sorting ores or the like. In order to detect the breakage of the net, it is necessary to measure the size of the ore or the like that has passed through the net and take measures against the breakage of the net when this size exceeds a set value. For such dimension management,
Conventionally, the following measures have been taken as a method for measuring the dimensions of an article.

A. A method in which a person visually monitors b. Method of inferring dimensions from the sound of an article hitting an iron plate c. A method of actually sorting articles using a mechanical vibrating screen d. Method of measuring maximum length, area, etc. by image processing

[0004]

The above-mentioned method a. Has the drawbacks of low reproducibility and large errors due to fatigue.

Method b. Is a large error, noise is generated, failure due to wear, etc.
There are drawbacks such as the possibility of damage to the article.

Method c. Is a measurement time,
There are drawbacks such as failure due to wear.

The above method d. However, depending on the shape of the article, the correlation with the mechanical vibration sieve is small, and is not suitable for the inspection or replacement of the mechanical vibration sieve.

An object of the present invention is to provide a measuring method which eliminates the above-mentioned drawbacks in the conventional dimension measuring method for articles.

[0009]

According to the present invention, an object is photographed by a photographing device, an image signal from the photographing device is sent to an image processing device, and the image processing device uses the image signal. For each image, draw an arbitrary number of straight lines that pass through those points and calculate the lengths of these straight lines that cross the image of the article individually. Remember that as the width at that point,
This is solved by selecting the maximum value from the widths of the arbitrary number of points and outputting it as the dimension of the article for each article.

[0010]

[Function] For an arbitrary number of points in the image of the article displayed on the display screen of the image monitor, an arbitrary number of straight lines passing through those points are drawn, and the lengths of these straight lines crossing the image of the article are individually set. Calculate and store the length of the shortest straight line as the width at that point, calculate such a width for the arbitrary number of points, select the maximum value from those widths, and The size of the article.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an example in which the present invention is applied to detect the breakage of the net of a sieving machine for sorting by the size of ore or the like (hereinafter referred to as stone). Hereinafter, the present invention will be described with reference to these drawings, but the present invention is not limited thereto.

In FIG. 1, a stone 1 carried out from a crusher (not shown) or other processing device falls on a net 2 of a sieving machine, and is subjected to size selection by the net 2. Stones 1a larger than the mesh openings fall on the mesh discharge conveyor 3 without passing through the mesh and are discharged, and stones 1b smaller than the mesh opening pass through the mesh and the mesh discharge conveyor 4 under the mesh. It drops down and is discharged.

The stone 1b on the under-net discharging conveyor 4 is an ITV.
An image is taken by a photographing device 5 such as a surveillance camera or a video camera, and the signal is sent to an image processing device 6, where the size of each stone is measured. An image monitor 7 for inspection and adjustment can be installed in the image processing device 6. The image monitor 7 can be used not only for inspection and adjustment, but also for monitoring the stones 1b on the below-the-mesh discharge conveyor 4 if necessary. 7a is a display screen of the image monitor 7.

The dimensions of the individual stones measured by the image processing device 6 as will be described later are compared with the dimensions preset by the setting value input in the arithmetic device 8. And
If there is a stone larger than the preset size, net 2
When it is determined that the alarm has been broken, a signal is sent to the alarm device 9 to issue an alarm. The setting value may be set by a person in advance, or the setting may be changed by the arithmetic unit 8 itself by some learning function.

A display screen 7a of the image monitor 7 shown in FIG.
The images of several stones A, B,
C and D are displayed. Of these, only the image A of the stone is shown in FIG. 3 to describe the method of measuring the dimensions in the image processing device 6, but the images B, C and D of the other stones displayed on the display screen 7a are also described. The size is measured for each image.

In FIG. 3, the image processing apparatus 6 selects an arbitrary number of points P1, P2, P3 in the image A of the stone shown on the display screen 7a of the image monitor 7, and then the points P1,
An arbitrary number of straight lines P1-1, P1-2 passing through P2, P3,
... P2-1, P2-2, ... P3-1, P3-2, ...
…pull. For each of these straight lines, the length across the stone image A is calculated, and the shortest straight lines P1-2, P2-2,
Find P3-1 and use these as the width at each of the points. A straight line P1-2 having the maximum width is selected from the widths at the respective points thus obtained, and the length value thereof is used as the size of the stone. This dimension measurement is also performed on the images B, C, and D of other stones.

The number of points and the number of straight lines at each point can be appropriately determined according to the size, shape, distribution state, etc. of the stone image.

[0018]

Since the method for measuring the size of an article according to the present invention is non-contact, there is no abrasion of the contact portion with the article or damage to the article, and even if the article has an irregular shape such as ore, The dimensions can be measured reliably. Therefore, it has a large correlation with the mechanical vibrating screen and is suitable for inspection and replacement of the vibrating screen.

Further, when detecting that the net of a sieving machine for sorting by size is broken, the measured value obtained as described above and the maximum value that can be passed when the preset net is not broken. The size of the article is compared, and when the measured value is larger than the set value, it is possible to judge that the net is broken and issue an alarm. Furthermore, it is possible to control the mechanical settings of the crusher, which has great industrial value.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a network breakage detection device of a sieving machine to which the measuring method according to the present invention is applied.

FIG. 2 is a display screen of an image monitor of the apparatus shown in FIG.

FIG. 3 is an explanatory diagram of a stone size measuring method according to the present invention.

[Explanation of symbols] 1 stone 1a stone that did not pass through the net 1b stone that passed through the net 2 net 5 shooting device 6 image processing device 8 computing device 9 alarm device A, B, C, D stone image P1, P2, A point in the image of a P3 stone

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B65G 43/08 F

Claims (1)

[Claims] 1. A method for measuring a dimension of an article when performing dimension management such as production, shipping, and acceptance of the article, wherein the article is photographed by using a photographing device, and an image signal from the photographing device is sent to an image processing device. , This image processing device, for each image of the article, for any number of points in the image, draw an arbitrary number of straight lines passing through those points, and individually determine the lengths of these straight lines that cross the image of the article. Calculate and store the length of the shortest straight line as the width at that point, select the maximum value from the widths for the arbitrary number of points, and output it as the dimension of the article for each article. A dimension measuring method characterized by the above.