JP3214943B2 - Pellet edge inspection 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 inspecting the end face of a pellet, in which the end face of a pellet having a concave portion formed in the center of the end face is imaged and the quality of the end face of the pellet is judged based on the obtained image.

[0002]

2. Description of the Related Art Conventionally, when a parallel light beam is applied to an end surface of a pellet having a spherical concave portion (dish) formed at the center of the end surface and an image is taken, the peripheral portion of the concave portion becomes dark. In the case of a value, it is difficult to distinguish it from a defect such as a chip.

[0003]

In order to solve this problem, Japanese Patent Laid-Open Publication No. 1-136053 proposes a method of detecting defects by adding correction data from a standard image and binarizing the data. ing. This defect inspection method exerts its effect within a range in which the premise that a sample is imaged like a standard image is ensured, but there is a problem that many of them do not actually fall within such a range. is there. Further, since the load on the image processing is large, it takes a long time to perform the processing, and there is a problem that the end face inspection of the pellet cannot be performed at a high speed.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a concave portion on an end face of a pellet.
Uniformity of brightness and uniform brightness of the end face image of the pellet
Another object of the present invention is to provide a pellet end face inspection method capable of performing a smooth and reliable inspection, reducing a load on image processing, and automatically performing a high-speed automatic inspection. Another object of the present invention is to form a concave portion at the center.
Inspection of the pellet end face smoothly and reliably
And reduce the load on image processing.
Edge inspection method that can be automatically inspected by
Is to provide.

[0005]

According to one aspect of the present invention, an image of an end face of a pellet having a concave portion formed in a central portion is taken, and the pellet is formed based on the obtained image. a pellet end face inspection method for determining the quality of the end surface of, when imaging the end face of the pellet, Bae
A parallel light beam is applied to the entire end face of the
Irradiating the part with a focused light beam, including a concave portion
The brightness of the end face image of the pellet is made uniform, a histogram of brightness is obtained for the picked up end face image of the pellet, and the characteristic values of the histogram are extracted. This is to determine the state of the end face of the pellet by comparing with a statistical feature value of a histogram extracted for a typical standard pellet. Further, the second aspect of the present invention is directed to a central portion.
An image of the end face of the pellet having the recess formed therein is obtained.
The quality of the end face of the pellet based on the obtained image
A pellet end face inspection method, wherein
Create a histogram of brightness for the edge image of the
The feature value of the histogram of
Tomograms and a number of typical standard pellets
Statistical feature values of the histogram extracted for
To determine the state of the end face of the pellet,
With respect to the pellets suspended in the determination by the histogram, the captured end face image is binarized with reference to the histogram feature value, connectivity identification and the number of pixels are calculated for the binarized image, and based on the result, This is to determine whether the end faces of the pellets are acceptable or not.

[0006]

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a side view showing an example of a pellet handling unit 10 showing one embodiment of the present invention. In this figure, reference numeral 1 denotes a rotating disk. A large number of V-grooves 2 for accommodating the pellets P are formed on the outer edge of the rotating disk 1, and the pellets P are fed from the loading chute 3 into the V-grooves 2 of the rotating disk 1. Have been. An arcuate guide surface 4 for guiding the pellets P is provided outside the rotary disk 1 and a pellet that is connected to the guide surface 4 and discharges the pellets P determined to be defective by the end face inspection is connected. A sorting section 5 and an unloading chute 6 for unloading the accepted pellets P are provided.
The pellet sorting section 5 discharges the defective pellets P downward by rotating the rotator 7 provided rotatably in the vertical direction downward. Further, a presser 8 that presses the pellets P accommodated in the V-groove 2 is provided above the rotary disk 1 so as to be rotatable in the vertical direction.

As shown in FIG. 2, a pellet end face inspection apparatus 20 of the present invention is provided on both sides of the pellet handling unit 10. The pellet end face inspection apparatus 20 includes an illumination member 22 and an imaging unit 23 provided on a mounting member 21 and the imaging unit 23.
Is connected to an image analysis processing device. And
The illuminating means 22 includes a fiber light source 220, a light source lens 221, a hood 222, a lens barrel 223, and a half mirror box 224 arranged vertically in a line, and the pellet handling side of the half mirror box 224. Hood 22 extending to the end face of pellet P of part 10
5 are arranged. The lens barrel 223 has four cylindrical lens setscrews 223b inside a barrel body 223a.
And one cylindrical tip projection 223c are screwed so as to be movable in the up-down direction, and a plano-convex lens 223d and a perforated lens 22 are screwed into the lens set screws 223b.
3e is pinched. The half mirror box 22
4, a half mirror 224 inclined at 45 degrees with respect to the optical axis of the light beam emitted from the fiber light source 220.
a is stored. Further, the imaging means 23 is provided with a camera lens 230 on the side of the half mirror box 224.
, An intermediate ring 231 and a CCD camera 232.

When inspecting the end face of the pellet P by using the pellet end face inspection apparatus configured as described above,
First, the pellets P are supplied from the loading chute 3 onto the V-grooves 2 of the rotating disk 1 rotating intermittently. Then, the pellet P accommodated in the V-groove 2 of the rotating disk 1 is moved to a predetermined position P
When the temperature reaches 1, P2, images of both end surfaces of the pellet P are captured by the pellet end surface inspection device 20 arranged opposite to both end surfaces of the pellet P. That is, the light beam emitted from the fiber light source 220 is converged by the plano-convex lens 223d of the lens barrel 223 through the light source lens 221 and the inside of the hood 222 to become a parallel light beam. After passing through the inside of the half mirror 224a and the hood 225, both ends of the pellet P accommodated in the V groove 2 of the rotating disk 1 are irradiated. In this case, the parallel light beam that has passed through the central opening of the perforated lens 223e is used as it is for the pellet P.
Is irradiated to the entire end face of the lens, and a perforated lens 223e is provided.
The light beam transmitted through the peripheral portion is focused and applied to the concave portion PA at the center of the end face of the pellet P shown in FIGS. As a result, as shown in FIG. 10, the brightness of the concave portion PA of the pellet P can be made uniform (in FIG. 10, the two-dot chain line indicates the brightness when only the parallel light beam is applied to the entire end face of the pellet P). Is shown).

In this state, the CCD camera 23
By taking an image of the end face of the pellet P with 2, the obtained image is clear and there is no shadow in the concave portion PA on the end face of the pellet P, and only the defect appears black. Next, the obtained image is sent to an image analysis processing device, in which only the inspection area of the multi-valued image is extracted, and a brightness histogram is obtained from the mask image. Then, the characteristic values of this histogram (the brightness with the largest number of pixels, the maximum and minimum brightness based on the brightness, the brightness of the valley and the number of pixels)
Is compared with statistical characteristic values of a large number of typical normal products, defective products, and rejected products extracted in advance to determine pass / fail and suspension. That is, the above-mentioned histogram shows, for example, the state of the end face of the normal pellet P shown in FIG.
In the state where the sintering powder and the like shown in FIG. 2 adhere to the end face of the pellet P, the state where a hardly detectable chip is formed on the end face shown in FIG. 13 (FIG. 14 shows a photographed image in this case) and the like. , Respectively, each has a characteristic waveform, which can be used to determine the end face of the pellet P.

[0011] Further, for a reserved product for which a pass or fail cannot be determined based on the histogram, the image and the histogram characteristic value are transferred to another processing board via a bus line, and in parallel, the image is referred to the histogram characteristic value. The binarized value is calculated and binarized by this value, the outside of the inspection target portion of the binarized image is masked at the same level as the defect, and the connectivity identification of the obtained normal level image (for example,
After the discrimination between “a” and “b” in FIG. 14), the number of pixels of only the normal part “a” is calculated, and the result is passed to the determination unit. Then, in this determination unit, the result of the histogram and the result of the binarized image are combined to determine whether or not the pellet P is acceptable. For the pellets P determined to be rejected, the rotator 7 of the pellet sorting section 5 is rotated and discharged downward.

[0012]

As described above, according to the first aspect of the present invention,
Is an end face of the pellet recesses in the central portion is formed by imaging, a pellet end face inspection method for determining the quality of the end face of the pellet based on the obtained image, the pellet
When imaging the end face of the pellet, the entire surface of the pellet
Along with irradiating the row light beam, the light beam focused on the concave portion is
By irradiating, the end face image of the pellet including the concave
Equalizing the brightness , taking a histogram of the brightness of the captured end face image of the pellet, extracting the characteristic value of this histogram, and extracting the characteristic value of the extracted histogram and a number of typical standard pellets in advance Since the state of the end face of the pellet is determined by comparing the statistical feature value of the extracted histogram, the shadow of the concave portion is prevented from appearing in the end face image of the pellet.
As a result, only the defect can be imaged in black, the image processing can be easily performed, and the end face of the pellet can be inspected smoothly and quickly. Further, claim 2 of the present invention
Is an image of the end face of a pellet with a recess formed in the center.
The quality of the end face of the pellet based on the obtained image
A method for inspecting the end face of a pellet, the method comprising:
Histogram of brightness of the end face image of the pellet
And extract the feature values of this histogram,
The characteristic values of the generated histogram and a number of typical
Histogram statistics extracted for quasi-pellets
And the state of the end face of the pellet
For the pellet suspended in the determination by the histogram , the captured end face image is binarized with reference to the histogram feature value, and the connectivity identification and the number of pixels are calculated for the binarized image. Since the pass / fail of the end face of the pellet is determined based on the result, by performing the determination based on the binarized image only for the suspended pellet, the load on the image processing can be reduced, and high speed processing can be performed. Can be inspected automatically.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a pellet handling unit.

FIG. 2 is a front view showing one embodiment of the present invention.

FIG. 3 is a front view showing one pellet end face inspection apparatus of FIG. 2;

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a bottom view of FIG. 3;

FIG. 6 is an explanatory diagram showing one embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a lighting unit.

FIG. 8 is an explanatory diagram showing a state of a light beam.

FIG. 9 is an explanatory view showing an end face of a pellet.

FIG. 10 is an explanatory diagram showing brightness along AB in FIG. 9;

FIG. 11 is a characteristic diagram showing a histogram of an end face in a normal state.

FIG. 12 is a characteristic diagram showing a histogram of an end face in a state where sintering powder and the like are attached.

FIG. 13 is a characteristic diagram showing a histogram of an end face having a chip;

FIG. 14 is an explanatory diagram showing the end face image of FIG. 13;

[Explanation of symbols]

 P Pellet PA Concave part 1 Rotating disk 2 V groove (accommodation groove) 5 Pellet sorting part 20 Pellet end face inspection device 22 Illumination means 23 Imaging means 223d Plano convex lens 223e Perforated lens

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-94379 (JP, A) JP-A-63-196980 (JP, A) JP-A-1-136053 (JP, A) JP-A-63-196980 18209 (JP, A) JP-A-3-54594 (JP, A) JP-A-4-292324 (JP, A) JP-A 64-57605 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/84-21/958 G21C 17/00-17/14

Claims (2)

(57) [Claims] 1. A by capturing the end face of the pellet recesses in the central portion is formed, a pellet end face inspection method for determining the quality of the end face of the pellet based on the obtained image, the end face of the pellet At the time of imaging, the edge of the pellet
Irradiate the entire surface with parallel rays and focus on the recess.
By irradiating the light beam, the pellet including the concave portion is irradiated.
The brightness of the end face image of the target is equalized, a brightness histogram is obtained for the picked-up end face image of the pellet, the characteristic value of the histogram is extracted, and the characteristic value of the extracted histogram and a number of typical A method for inspecting the end face of a pellet, comprising comparing a statistical feature value of a histogram extracted for a typical standard pellet with the state of the end face of the pellet. 2. A pellet having a recess formed in the center.
The end face of the pellet is imaged, and the pellet is
A pellet end face inspection method for judging the quality of the end face,
The brightness of the image of the edge of the pellet
Take a histogram and extract the feature values of this histogram
The feature values of the extracted histogram
Histog extracted from a typical standard pellet
Compare the statistical characteristics of the ram to the edge of the pellet.
Determines the state of the surface, the pellets suspended in the determination by the histogram, the captured end face image binarized with reference to the histogram feature value, connectivity identification and the number of pixels calculated for this binarized image was carried out, Pere <br/> Tsu preparative edge inspection method characterized by determining the acceptability of the end face of the pellet based on this result.