Alignment apparatus and alignment method
An alignment apparatus that can efficiently align an optical fiber, and an alignment method will be provided. According to the embodiments, the alignment apparatus that aligns an optical fiber comprises an acquisition unit, a calculation unit, and a rotation processing unit. The acquisition unit acquires one or more side images of the optical fiber. The calculation unit calculates correlation coefficients between the luminances of the one or more side images and those of one or more reference side images. The rotation processing unit rotates the optical fiber in the axis direction of the optical fiber so that the correlation coefficients peak.
1. An alignment apparatus that aligns a multi-core optical fiber whose cross section has a marker, comprising:
an acquisition unit that acquires one or more side images of the multi-core optical fiber;
a calculation unit that averages luminances of the side image in an axis direction of the multi-core optical fiber, averaging luminances of each of one or more reference side images in an axis direction of the multi-core optical fiber, and calculates coefficients between averaged luminances of the side image and averaged luminances of the reference side image; and
a rotation processing unit that rotates the multi-core optical fiber in an axis direction of the multi-core optical fiber so that the correlation coefficients peak,
wherein the calculation unit calculates correlation coefficients according to
Z
N
C
C
=
∑
i
=
0
M
-
1
{
(
L
(
i
)
-
L
_
)
(
R
(
i
)
-
R
_
)
}
∑
i
=
0
M
-
1
(
L
(
i
)
-
L
_
)
2
×
∑
i
=
0
M
-
1
(
R
(
i
)
-
R
_
)
2
where L(i) indicates the i-th average luminance of the multi-core optical fiber;
R(i) indicates the i-th average luminance of another optical fiber;
L indicates the average value of L(i);
R indicates the average value of R(i);
M is the total number of pixels; and
i indicates positions in a cross-section direction of the multi-core optical fiber.
2. The alignment apparatus according to claim 1 , wherein
the acquisition unit acquires a first side image photographed in a first direction of the multi-core optical fiber, and a second side image photographed in a second direction different from the first direction,
the reference side image is comprised by a first reference side image corresponding to the first side image, and a second reference side image corresponding to the second side image, and
the calculation unit averages luminances of the first side image and luminances of the first reference side image in an axis direction of the multi-core optical fiber, calculates a first correlation coefficient from averaged luminances of the first side image and averaged luminances of the first reference side image, averages luminances of the second side image and luminances of the second reference side image in an axis direction of the multi-core optical fiber, and calculates a second correlation coefficient from averaged luminances of the second side image and averaged luminances of the second reference side image, as the correlation coefficients.
3. The alignment apparatus according to claim 2 , wherein the rotation processing unit rotates the multi-core optical fiber so that the first correlation coefficient and the second correlation coefficient peak within a scope of the first correlation coefficient and the second correlation coefficient each of which is equal to or greater than 0.964.
4. The alignment apparatus according to claim 3 , wherein the reference side image is a side image of a multi-core optical fiber aligning with the multi-core optical fiber.
5. The alignment apparatus according to claim 3 , wherein the reference side image is a side image of a multi-core optical fiber at a predetermined angle.
6. The alignment apparatus according to claim 2 , wherein the second direction is orthogonal to the first direction.
7. The alignment apparatus according to claim 6 , wherein the reference side image is a side image of a multi-core optical fiber aligning with the multi-core optical fiber.
8. The alignment apparatus according to claim 6 , wherein the reference side image is a side image of a multi-core optical fiber at a predetermined angle.
9. The alignment apparatus according to claim 2 , wherein the reference side image is a side image of a multi-core optical fiber aligning with the multi-core optical fiber.
10. The alignment apparatus according to claim 2 , wherein the reference side image is a side image of a multi-core optical fiber at a predetermined angle.
11. The alignment apparatus according to claim 1 , wherein the reference side image is a side image of a multi-core optical fiber aligning with the multi-core optical fiber.
12. The alignment apparatus according to claim 11 , wherein the reference side image is a side image of a multi-core optical fiber at a predetermined angle.
13. The alignment apparatus according to claim 1 , wherein the reference side image is a side image of a multi-core optical fiber at a predetermined angle.
14. An alignment method that aligns a multi-core optical fiber whose cross section has a marker, comprising:
acquiring one or more side images of the multi-core optical fiber;
averaging luminances of the side images of the multi-core optical fiber;
averaging luminances of each of one or more reference side images in an axis direction of the multi-core optical fiber;
calculating coefficients between averaged luminances of the side image and averaged luminances of the reference side image; and
rotating the multi-core optical fiber in an axis direction of the multi-core optical fiber so that the correlation coefficients peak;
wherein the correlation coefficients are calculated according to
Z
N
C
C
=
∑
i
=
0
M
-
1
{
(
L
(
i
)
-
L
_
)
(
R
(
i
)
-
R
_
)
}
∑
i
=
0
M
-
1
(
L
(
i
)
-
L
_
)
2
×
∑
i
=
0
M
-
1
(
R
(
i
)
-
R
_
)
2
where L(i) indicates the i-th average luminance of the multi-core optical fiber;
R(i) indicates the i-th average luminance of another optical fiber;
L indicates the average value of L(i);
R indicates the average value of R(i);
M is the total number of pixels; and
i indicates positions in a cross-section direction of the multi-core optical fiber.