JPH0640075B2 - End face inspection device for cylindrical objects - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an end face inspection device for a cylindrical object that inspects the end face of an object having a cylindrical shape such as a nuclear fuel pellet.

[Background of the Invention]

Conventionally, in order to inspect a crack on the end face of a cylindrical object, scattered light is applied to the end face as described in JP-A-55-154442 and JP-A-56-160645, and the reflected light is reflected by a TV camera. Defect determination is performed on a two-dimensional binary pattern in which only a portion corresponding to an end face is extracted from a binarized video signal detected by an imaging device such as the above. The case where there is a crack defect on the end surface of the cylindrical object is shown in FIG. 2 (a), and the case where there is a chip defect extending from the cylindrical surface to the end surface is shown in FIG. 2 (b). Further, FIG. 3 (a) is a binary value showing a crack defect detected by converting an image signal obtained by imaging the end surface of the cylindrical object shown in FIG. 2 (a) with an image pickup device into a binary image signal. 3B shows a binarized pattern signal, and FIG. 3B shows a chip detected by converting an image signal obtained by imaging the end surface of the cylindrical object shown in FIG. 2B with an image pickup device into a binarized image signal. The binary pattern signal which shows a defect is shown. On the other hand, when inspecting the end surface of an object having a cylindrical shape such as uranium pellets for nuclear fuel, crack defects and chip defects are determined by the fact that the judgment criteria of the quality of crack defects and the chip defects extending from the cylindrical surface to the end surface are different. I needed to identify. However, if there is a chip defect extending from the cylindrical surface to the end surface as shown in FIG.
The binarized pattern signal as shown in (b) is detected, and the binarized pattern signal detected from the chip defect is shown in FIG. 2 (a).
The third detected from the crack defect existing on the end face shown in
As in the case of the binarized pattern signal shown in FIG. 3A, there is a problem that a chip defect is erroneously determined like a crack defect, and the chip defect cannot be excluded to inspect only the crack defect. Was there.

[Object of the Invention]

The object of the present invention is to solve the above-mentioned problems of the prior art, in the defect inspection of the end surface of a cylindrical object such as uranium pellets for nuclear fuel, it is possible to identify a crack defect and a crack defect extending from the cylindrical surface to the end surface. An object of the present invention is to provide an end face inspection device for a cylindrical object, which is capable of inspecting only crack defects by excluding defects.

[Outline of Invention]

In order to achieve the above object, the present invention binarizes a two-dimensional image signal from an imaging device for imaging a circular end surface of a cylindrical object and a circular end surface obtained by imaging with the imaging device. Binarizing means for converting into a three-dimensional image signal; storage means for storing a circular binarizing pattern showing the entire circular shape of the end face and a circumferential binarizing pattern showing only the circumferential contour of the end face; The circular shape binarization pattern and the circumferential contour binarization pattern are read from the storage means in synchronization with the binarized two-dimensional image signal obtained by the binarization means and obtained by the binarization means. A binarized pattern signal and a defect indicating the entire defective portion on the end face of the circular shape by gated on the binarized two-dimensional image signal with each of the circular binarized pattern and the circumferential contour binarized pattern. Binary pattern signal showing only the circumferential contour of the part And an overall projection distribution projected in the horizontal and vertical directions on the binarized pattern signal indicating the entire defective portion extracted by the extracting means and the defective portion extracted by the extracting means. Projection distribution creating means for creating the circumferential contour projection distribution projected in the horizontal direction and the vertical direction with respect to the binarized pattern signal indicating only the circumferential contour of the above, and the entire horizontal direction created by the projection distribution creating means. The vertical widths of both the projection distribution and the circumferential contour projection distribution are substantially equal, and the horizontal widths of both the vertical overall projection distribution and the circumferential contour projection distribution created by the projection distribution creating means are An end face inspection apparatus for a cylindrical object, comprising: a determination unit for determining a defect existing on a circular end face when they are substantially equal as a defect defect extending from the cylindrical face to the end face. .

Example of Invention

One embodiment of the present invention is shown in FIG. The two-dimensional image signal obtained by operating and imaging the end surface of the cylindrical object with the image pickup device 1 is converted into a binarized two-dimensional image signal by the binarization circuit 2 to convert the defect into a binarized pattern signal indicated by "1". Convert. Memory 3
Stores a circular binarization pattern (corresponding to a gate signal indicating the entire circular end face) which is a gate signal. The memory 4 is a circular contour binarization pattern which is a gate signal (corresponding to a gate signal indicating only the circumferential contour of the end face).
Is to remember. Gate signals of the circular binarization pattern and the circumferential contour binarization pattern are read from the memories 3 and 4 in synchronization with the scanning of the image pickup apparatus 1, and the binarization circuit 2 in each of the gate circuits 5 and 6. The binarization pattern signal indicating the defect converted by 1 is gated, and the binarization pattern signal indicating the defect on the end face as shown in FIG. 5 is extracted from the gate circuit 5. The gate circuit 6 extracts a binarized pattern signal indicating a defect in the circumferential contour of the end face by "1". Reference numerals 7 and 8 denote horizontal direction peripheral distribution creation circuits projected in the horizontal scanning direction.
Reference numeral 10 is a vertical direction peripheral distribution generation circuit projected in the vertical scanning direction. Reference numeral 11 is a judgment circuit for inputting the horizontal marginal distributions obtained from the horizontal marginal distribution generating circuits 7 and 8 and determining a defect, and 12 is inputting the vertical marginal distributions obtained from the vertical marginal distribution generating circuits 9 and 10. Then, it is a judgment circuit for judging a defect.

Next, FIG. 4 shows a specific configuration of the horizontal direction peripheral distribution generation circuits 7 and 8 and the vertical direction peripheral distribution generation circuits 9 and 10. Fourth
In the figure, 13 is a binary signal, 14 is a horizontal scanning clock, 15 is the number of pulses of the horizontal scanning clock 14,
It is a horizontal scanning coordinate generation circuit that extracts a horizontal scanning position.
16 is the vertical scanning clock, 17 is the vertical scanning clock 16
This is a vertical scanning coordinate generation circuit that counts the number of pulses of and scans the vertical scanning position. Reference numerals 18 and 19 denote memories for reading and writing with the outputs of the horizontal scanning coordinate generation circuit 15 and the vertical scanning coordinate generation circuit 17 as addresses. Reference numerals 20 and 21 denote adder circuits, which respectively include the contents of the memories 18 and 19 and the binary signal 13
Is added, and the addition result is written in the memories 18 and 19 again. In this way, at the end of scanning one screen, the memory 18,1
In Fig. 9, vertical marginal distribution and horizontal marginal distribution are created respectively.

FIG. 5 shows the four peripheral distributions thus obtained for the cylindrical surface chip and the end surface crack. In FIG.
(a) and (b) are examples of cylindrical surface chipping, (d) and (e) are cracks, and X and Y indicate horizontal peripheral distribution of binary pattern corresponding to end face, vertical direction Marginal distribution, X contact,
The Y contact indicates the horizontal and vertical peripheral distributions of the binary pattern corresponding to the circumference of the end face. In these peripheral distributions, area S, width L, and peak P are shown in FIG.
Define as shown in (a) and (b). S, L, and P are obtained for those separated in the peripheral distribution, S is the area of the distribution,
L is the length of the distribution and P is the peak of the distribution. When three parameters are extracted from the marginal distribution in this way, FIG.
In case of (a) and (b), the width L at X-to-X contact or Y-to-Y contact
Are almost equal (for (a) and (b)). On the other hand, in (d) and (e), the above condition is satisfied in the case of Y and Y contact in (d) (width L becomes almost equal), but the condition is not satisfied in other cases. In the case of (d), since the crack information is extracted from X, it does not matter if the Y distribution is ignored as described above. This is because the criterion for cracks in nuclear fuel pellets is the crack width.
This is because it can be determined by comparing with the set value.

FIG. 7 shows an example in which the above-described judgments are made by the judgment circuits 11 and 12. Here, 11 and 12 are assumed to be configured by a microcomputer or the like, and the program flow thereof is shown. In FIG. 7, S, P, and L are the area, peak, and width of the peripheral distribution of the portion corresponding to the end face, and S contact and L contact are the area and width of the peripheral distribution of the portion corresponding to the circumference of the end face. is there. The distribution means the former distribution, and the tangential distribution means the latter distribution. ε ₁ , ε ₂ ,, ε
₃ is a set value.

〔The invention's effect〕

According to the present invention, in the defect inspection of the end surface of a cylindrical object such as uranium pellets for nuclear fuel, it is possible to distinguish between the chip defect and the crack defect extending from the cylinder surface to the end surface, and the chip defect is excluded to inspect only the crack defect. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an end face inspection method for a cylindrical object of the present invention. 2 and 3 are diagrams showing examples of defects according to the present invention, FIG. 4 is a diagram showing a specific example of the marginal distribution creating circuit shown in FIG. 1, and FIG. 5 is an example of marginal distribution of each defect. FIG. 6 is a diagram showing parameters extracted from the marginal distribution, and FIG. 7 is a diagram for explaining the processing flow of the determination circuit. 1 ... Imaging device 2 ... Binarization circuit 3,4 ... Memory 7,8 ... Horizontal peripheral distribution creation circuit 9,10 ... Vertical peripheral distribution creation circuit 11,12 ... Judgment circuit

Front Page Continuation (72) Inventor Yasuo Nakagawa 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Pref., Institute of Industrial Science, Hitachi, Ltd. (72) Inventor Makihira, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock Company Hitachi, Ltd. Production Technology Research Laboratory (72) Inventor Toshiji Nakamura 300 Hisasho, Nakai-cho, Ashigarashami-gun, Kanagawa Hitachi Electronics Engineering Co., Ltd. (72) Nobu Udaka, 2-3-1, Kawasawa, Yokosuka, Kanagawa・ Fuel Co., Ltd. (56) Reference JP-A-55-154442 (JP, A)

Claims (1)

[Claims] 1. An image pickup device for picking up a circular end face of a cylindrical object, and a two-dimensional image signal for converting a two-dimensional image signal from the circular end face picked up by the image pickup device into a binary two-dimensional image signal. A digitizing means, a circular binarization pattern showing the entire circular shape of the end face, and a circle 2 showing only the circumferential contour of the end face.
Storage means for storing the binarization pattern and a circular shape binarization pattern and a circumferential contour binarization pattern from the storage means in synchronization with the binarization two-dimensional image signal obtained by the binarization means. Defective portions on the end face of the circular shape are obtained by gated on the binarized two-dimensional image signal read out and obtained by the binarizing means with each of the circular binarization pattern and the circumferential contour binarization pattern. And a binarization pattern signal indicating only the circumferential contour of the defective portion, and a binarization indicating the entire defective portion extracted by the extracting means. Only the overall projection distribution of the pattern signal projected in the horizontal direction and the vertical direction and the circumferential contour of the defective portion extracted by the extracting means are shown. 2
Projection distribution creating means for creating the circumferential contour projection distribution projected in the horizontal direction and the vertical direction for the binarized pattern signal, and the horizontal overall projection distribution and the circumferential contour projection distribution created by the projection distribution creating means And the vertical widths of both are substantially equal to each other, and the vertical overall projection distribution created by the projection distribution creating means and the circumferential contour projection distribution are substantially equal to each other in the horizontal direction, a circular end face is formed. An end face inspection apparatus for a cylindrical object, comprising: a determining unit that determines an existing defect as a defect defect extending from a cylindrical surface to an end surface.