METHOD AND APPARATUS FOR INNER DIAMETER MEASUREMENT OF TRANSPARENT TUBE
First Claim
1. An apparatus for measuring a property of a transparent tubular object having a refractive index, n, and a longitudinal axis, the apparatus comprising:
- a laser beam scanner that scans a laser beam in a scanning direction with a constant scanning speed, vs, along a scanning path at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed in a first laser beam direction to the object at right angles to the scanning direction and at right angles to the longitudinal axis of the object;
a detector assembly that detects an intensity of laser light originating from the object in a first detection direction parallel to the first laser beam direction, and that detects an intensity of laser light originating from the object in a second detection direction at a detection angle, a, greater than zero to the first detection direction;
a processor; and
one or more memories which store an executable set of instructions, which when executed by the processor, cause the processor to execute operations including;
determining a first time, τ
(0), and a second time, τ
(2RD), from the intensity of the laser light detected in the first detection direction by the detector assembly, τ
(0) being representative of the laser beam being tangential to the outer surface of the object at a first point of the object, and τ
(2RD) being representative of the laser beam being tangential to the outer surface of the object at a second point of the object diametrically opposite the first point;
determining a third time, τ
(xD2), and a fourth time, τ
(xd2), from the intensity of the laser light detected in the second detection direction by the detector assembly, τ
(xD2) being representative of the laser beam being reflected at the outer surface of the object at a third point of the object, and τ
(xd2) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fourth point of the object; and
calculating an inner radius, Rd, of the object based on n, vs, α
, τ
(0), τ
(2RD), τ
(xD2), and τ
(xd2), wherein calculating Rd comprises calculating a difference between τ
(2RD) and τ
(0), and a difference between τ
(xd2) and τ
(xD2).
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Accused Products
Abstract
In a method and apparatus for measuring a property of a transparent tubular object, a laser beam scans the object, and laser light originating from the object is detected in a first detection direction parallel to the laser beam direction, or in the first and in a second detection direction at an angle thereto, in particular at 90°. The inner radius of the object may be calculated from the refractive index, scanning speed, outer diameter detected in the first detection direction, and, in the second detection direction, the time difference between laser light reflected from the outer surface of the object and laser light refracted into the object and reflected at the inner surface thereof. If the time of detecting laser light refracted into the object and reflected at the inner surface thereof in the first detection direction is known, the refractive index is not required.
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Citations
16 Claims
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1. An apparatus for measuring a property of a transparent tubular object having a refractive index, n, and a longitudinal axis, the apparatus comprising:
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a laser beam scanner that scans a laser beam in a scanning direction with a constant scanning speed, vs, along a scanning path at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed in a first laser beam direction to the object at right angles to the scanning direction and at right angles to the longitudinal axis of the object; a detector assembly that detects an intensity of laser light originating from the object in a first detection direction parallel to the first laser beam direction, and that detects an intensity of laser light originating from the object in a second detection direction at a detection angle, a, greater than zero to the first detection direction; a processor; and one or more memories which store an executable set of instructions, which when executed by the processor, cause the processor to execute operations including; determining a first time, τ
(0), and a second time, τ
(2RD), from the intensity of the laser light detected in the first detection direction by the detector assembly, τ
(0) being representative of the laser beam being tangential to the outer surface of the object at a first point of the object, and τ
(2RD) being representative of the laser beam being tangential to the outer surface of the object at a second point of the object diametrically opposite the first point;determining a third time, τ
(xD2), and a fourth time, τ
(xd2), from the intensity of the laser light detected in the second detection direction by the detector assembly, τ
(xD2) being representative of the laser beam being reflected at the outer surface of the object at a third point of the object, and τ
(xd2) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fourth point of the object; andcalculating an inner radius, Rd, of the object based on n, vs, α
, τ
(0), τ
(2RD), τ
(xD2), and τ
(xd2), wherein calculating Rd comprises calculating a difference between τ
(2RD) and τ
(0), and a difference between τ
(xd2) and τ
(xD2). - View Dependent Claims (5, 9, 11, 12, 13, 14, 15, 16)
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2. An apparatus for measuring a property of a transparent tubular object having a refractive index, n, and a longitudinal axis, the apparatus comprising:
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a laser beam scanner that scans a laser beam in a scanning direction with a constant scanning speed, vs, along a scanning path at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed in a first laser beam direction to the object at right angles to the scanning direction in a first part of the scanning path, and redirected via a reflector in a second laser beam direction to the object at a scanning angle, β
, greater than zero to the first laser beam direction in a second part of the scanning path;a detector assembly that detects an intensity of laser light originating from the object in a first detection direction parallel to the first laser beam direction, and that detects an intensity of laser light originating from the object in a second detection direction at a detection angle, α
, to the first detection direction;a processor; and one or more memories which store an executable set of instructions, which when executed by the processor, cause the processor to execute operations including; determining a first time, τ
(0), and a second time, τ
(2RD), from the intensity of the laser light detected in the first detection direction, τ
(0) being representative of the laser beam being tangential to the outer surface of the object at a first point of the object, and τ
(2RD) being representative of the laser beam being tangential to the outer surface of the object at a second point of the object diametrically opposite the first point;determining a third time, τ
(xD2), and a fourth time, τ
(xd2), from the intensity of the laser light detected in the second detection direction, τ
(xD2) being representative of the laser beam being reflected at the outer surface of the object at a third point of the object, and τ
(xd2) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fourth point of the object; andcalculating an inner radius, Rd, of the object based on n, vs, α
, β
, τ
(0), τ
(2RD), τ
(xD2) and τ
(xd2), wherein calculating Rd comprises calculating a difference between τ
(2RD) and τ
(0), and a difference between τ
(xd2) and τ
(xD2). - View Dependent Claims (6, 10)
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3. An apparatus for measuring a property of a transparent tubular object having a longitudinal axis, the apparatus comprising:
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a laser beam scanner that scans a laser beam in a scanning direction with a constant scanning speed, vs, along a scanning path at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed in a first laser beam direction to the object at right angles to the scanning direction and at right angles to the longitudinal axis of the object; a detector assembly that detects an intensity of laser light originating from the object in a first detection direction parallel to the first laser beam direction, and that detects an intensity of laser light originating from the object in a second detection direction at a detection angle, a, greater than zero to the first detection direction; a processor; and one or more memories which store an executable set of instructions, which when executed by the processor, cause the processor to execute operations including; determining a first time, τ
(0), and a second time, τ
(2RD), from the intensity of the laser light detected in the first detection direction, τ
(0) being representative of the laser beam being tangential to the outer surface of the object at a first point of the object, and τ
(2RD) being representative of the laser beam being tangential to the outer surface of the object at a second point of the object diametrically opposite the first point;determining a third time, τ
(xD2), and a fourth time, τ
(xd2), from the intensity of the laser light detected in the second detection direction, τ
(xD2) being representative of the laser beam being reflected at the outer surface of the object at a third point of the object, and τ
(xd2) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fourth point of the object;determining a fifth time, τ
(xd1), from the intensity of the laser light detected in the first detection direction, τ
(xd1) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fifth point of the object; andcalculating an inner radius, Rd, of the object based on vs, α
, τ
(0), τ
(2RD), τ
(xD2), τ
(xd2) and τ
(xd1), wherein calculating Rd comprises calculating a difference between τ
(2RD) and τ
(0), and a difference between τ
(xd2) and τ
(xD2). - View Dependent Claims (7)
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4. An apparatus for measuring a property of a transparent tubular object having a longitudinal axis, the apparatus comprising:
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a laser beam scanner that scans a laser beam in a scanning direction with a constant scanning speed, vs, along a scanning path at right angles to the longitudinal axis of the object, wherein the laser beam is directed at right angles to the longitudinal axis of the object, wherein the scanning laser beam is directed in a first laser beam direction to the object at right angles to the scanning direction in a first part of the scanning path, and redirected via a reflector in a second laser beam direction to the object at a scanning angle, β
, greater than zero to the first laser beam direction in a second part of the scanning path;a detector assembly that detects an intensity of laser light originating from the object in a first detection direction parallel to the laser beam direction, and that detects an intensity of laser light originating from the object in a second detection direction at a detection angle, α
, to the first detection direction;a processor; and one or more memories which store an executable set of instructions, which when executed by the processor, cause the processor to execute operations including; determining a first time, τ
(0), and a second time, τ
(2RD), from the intensity of the laser light detected in the first detection direction, τ
(0) being representative of the laser beam being tangential to the outer surface of the object at a first point of the object, and τ
(2RD) being representative of the laser beam being tangential to the outer surface of the object at a second point of the object diametrically opposite the first point;determining a third time, τ
(xD2), and a fourth time, τ
(xd2), from the intensity of the laser light detected in the second detection direction, τ
(xD2) being representative of the laser beam being reflected at the outer surface of the object at a third point of the object, and τ
(xd2) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fourth point of the object;determining a fifth time, τ
(xd1), from the intensity of the laser light detected in the first detection direction, τ
(xd1) being representative of the laser beam being refracted at the outer surface of the object and reflected at the inner surface of the object at a fifth point of the object; andcalculating an inner radius, Rd, of the object based on vs, α
, β
, τ
(0), τ
(2RD), τ
(xD2), τ
(xd2) and τ
(xd1), wherein calculating Rd comprises calculating a difference between τ
(2RD) and τ
(0), and a difference between τ
(xd2) and τ
(xD2). - View Dependent Claims (8)
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Specification