US2004090618A1PendingUtilityA1
Process for reading fractions of intervals between contiguous photo-sensitive elements in a linear optical sensor
Est. expiryMay 8, 2021(expired)· nominal 20-yr term from priority
G01D 5/26G01B 11/024
34
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Claims
Abstract
In a process for reading fractions of an interval between contiguous photo-sensitive elements in a linear optical sensor, of a type used in a goniometer, an angle measured is an angle formed with a reference axis of the goniometer, perpendicular to the linear optical sensor, by a light beam which is trained on the optical sensor by an optical device. The process comprises: a reading of a current image constituted by an order totality of intensities of incident radiations read on contiguous photosensitive elements; processing of data taken from the current image by means of a process which converges towards a result defining, with respect to an origin determined by an intersection of the reference axis with an axis of the sensor, a distance d of a point of incidence on the sensor of an ideal optical axis of the light beam.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A process for reading fractions of an interval between contiguous photo-sensitive elements in a linear optical sensor, of a type used in a goniometer, in which an angle measured is an angle formed with a reference axis of the goniometer, perpendicular to the linear optical sensor, by a light beam which is trained on the optical sensor by an optical device, comprising:
reading a current image constituted by an ordered totality of intensities of incident radiations read on contiguous photosensitive elements; and processing data taken from the current image by means of an interpolation process which converges towards a result defining, with respect to an origin determined by an intersection of the reference axis with an axis of the sensor, a distance d of a point of incidence on the sensor of an ideal optical axis of the light beam.
2 . The process of claim 1 , wherein the distance is determined by means of an interpolation process on a measurement of distance based on a comparison of the current image with an image previously acquired which is compared with the current image using a suitable measurement system.
3 . The process of claim 2 , wherein T i , i=1, . . . , n, is the totality of photosensitive elements forming a template, and I i , i=1, . . . , m, m>n, is the totality of photosensitive elements forming the current image, a possible measurement formula is the sum of the distances element by element where the distance can be the Euclidean distance, the distance of the absolute value or other; the distance in element k being:
S
k
=
∑
i
(
I
i
-
T
i
-
k
)
2
with Euclidean measurements; or
S
k
=
∑
i
I
i
-
T
i
-
k
using absolute measurement values; the fraction of interval between two contiguous photosensitive elements being determined using an interpolation obtained considering the local minimum of the interval k+1, k−1 in the curve passing through the distances corresponding to elements k, k+1, k−1, i.e. the fraction of interval being determinable using the ratio:
f
=
d
k
+
1
-
d
k
-
1
2
(
d
k
+
1
-
2
d
k
+
d
k
-
1
)
where f represents the fractional part of the position of the point of incidence of the ideal optical axis of the light beam.
4 . The process of claim 2 , wherein T i , i=1, . . . , n, is the totality of photosensitive elements forming a template, and I i , i=1, . . . , m, m>n, is the totality of photosensitive elements forming the current image, a possible measurement formula is the correlation i.e. the sum of the products element by element between the current image and the pattern determined in calibration with the standard ratio:
S
k
=
∑
i
(
I
i
·
T
i
-
k
)
and, normalised:
S
k
=
∑
i
(
I
i
·
T
i
-
k
)
∑
i
I
i
2
where the fraction of interval between two contiguous photosensitive elements is determined using an interpolation obtained considering the local minimum of the interval k+1, k−1 in the curve passing through the distances corresponding to elements k, k+1, k−1, i.e. the fraction of interval being determinable using the ratio:
f
=
d
k
+
1
-
d
k
-
1
2
(
d
k
+
1
-
2
d
k
+
d
k
-
1
where f represents the fractional part of the position of the point of incidence of the ideal optical axis of the light beam.
5 . The process of claim 1 , wherein the distance is determined by means of a process of interpolation on the current image.
6 . The process of claim 1 , wherein the distance is determined by means of a process of interpolation of a template.
7 . The process of claim 1 , wherein the distance is determined by means of a calculation of symmetries in the current image, or of some details of the image, by determining a position of a centre of symmetry or a centre of mass; the determination being made by means of expressions of the following type:
p
=
∑
i
i
·
I
i
∑
i
I
i
where p is the position of the centre of mass relating to the current image.Join the waitlist — get patent alerts
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