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Chapter 5
Applications of Fiber Optic Displacement Sensor
5.1 Introduction
As discussed in earlier chapters, fiber-optic displacement sensors (FODS) have many advantages such as low cost, ease of installation and high sensitivity. This sensor facilitates optical multimode plastic bundled fiber as probe in conjunction with intensity modulation technique. The proposed FODSs are capable of providing a large sensing dynamic range, which in turn allows a more accurate displacement measurement. Beside displacement measurement, the FODS can also be used to sense many other parameters such as temperature, pressure, refractive index, strain, mass and etc [1-3]. In this chapter, applications of FODS such as detection of metal surface roughness, liquid refractive index, liquid level, as well as vibration will be discussed.
In the detection of metal surface roughness, a light beam is launched onto the metal surface via a bundled fiber. The reflected light from the surface is collected by the bundled fiber and routed to a photodiode. The output voltage from the photodiode is measured as a function of distance between the bundled fiber output and metal surface to estimate the surface roughness. On the other hand, application of FODSs in liquid refractive index measurement is investigated theoretically and experimentally and a FODS is used for sensing of glucose concentration in distilled water.
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Continuous monitoring of liquid level is also demonstrated using FODS. For vibration measurement, a simple sensor design is proposed using FODS with a bundled fiber probe.
5.2 The Estimation of Metal Surface Roughness
FODS offers the possible development of a variety of sensors for a wide range of applications [4]. One of the applications is to estimate the surface roughness of various materials. Quantitative estimation of surface roughness can be obtained by various mechanical and optical techniques [5]. The advantages of optical technique over their mechanical counterparts include their non-contact nature and in-situ measurement as well as rapid measurement capability [6-7]. Application of FODS as displacement sensor involves a transmitting fiber which incident a laser beam onto the target surface and multiple receiving fibers surrounding the transmitting fiber to collect the reflected light off the target surface. Displacement measurement is based on the comparison of reflected light intensity against that of the launch light. For surface roughness estimation, FODS is based on intensity modulation technique and the object is placed within the linear response range of the displacement curve.
Experimental set-up of the fiber optic sensor is shown in Fig. 5-1. It consists of a light source, chopper, concentric type bundled fiber and a silicon detector connected to a lock-in amplifier and a computer for signal analysis. The bundled fiber is 2m long
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and consists of one transmitting fiber with diameter of 1mm and surrounded by 16 receiving fibers with diameter of 0.25mm. The light source is a He-Ne laser with a peak wavelength at 594nm. The light source is externally modulated by a chopper at 200Hz and is used in conjunction with lock-in amplifier to reduce noise resulting from DC drift and interference of ambient stray light. This sensor uses a real reflecting object as target, which is displaced from the bundled fiber end facet using a translation stage. The stage is driven by a piezoelectric motor to provide a fine movement of the real object.
In this experiment, the lock-in amplifier output voltage resulting from the reflected light is recorded automatically by a computer at various displacement distances from the object using Delphi software via serial port RS232. The piezoelectric picometer used in the experiment provides a precise step of 25-30nm for every positive pulse applied. Displacement measurement is carried out with distance steps of 13µm.
The surface roughness of the real object is estimated from the displacement curve of the sensor. The light beam leaving the transmitting fiber is reflected back in the form of expanding cone of light towards the receiving fiber, which routes the collected light into silicon photo-detector where its intensity is measured. The intensity of the collected light is a function of lateral movement of the object while the surface of metals is maintained perpendicular to the displacement axis. The experiment is then repeated using three different metal; stainless steel, aluminum and copper.
fu
copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light from
would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and
the intensity drops off following roughly an inverse function of
copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light from
would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and
the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
nction of
copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light from the
would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and
the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic nction of
copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light the
would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and
the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
nction of axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light the transmitting fiber would be reflected back into itself and little or no light would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and
the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
measured and is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light would be transferred to
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light would be transferred to the
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
the receiving fiber
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
receiving fiber
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
receiving fiber
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
receiving fiber
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
Fig. 5.2 shows the characteristic
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
receiving fiber
the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
Fig. 5.2 shows the characteristic of
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
receiving fibers. This is the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
of output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
s. This is the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
s. This is the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
s. This is the distance increases, the reflected cone overlaps
the output intensity increases. This relation is continued until the entire face of receiving fiber is illuminated with the reflected light. This is the
is called optical peak. As the gap increases beyond this transition region, the intensity drops off following roughly an inverse-
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
s. This is referred to as with
the output intensity increases. This relation is continued until the entire face of receiving s the
is called optical peak. As the gap increases beyond this transition region, -square law.
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic displacement sensor.
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
referred to as
with the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving s the point
is called optical peak. As the gap increases beyond this transition region, square law.
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
referred to as
the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving point
is called optical peak. As the gap increases beyond this transition region, square law.
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
referred to as
the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving point where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
square law.
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light
referred to as
the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
square law.
Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
output voltage of the lock
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light referred to as the blind region. As
the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region, Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
output voltage of the lock-
axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region, Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
-in amplifier as axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region a
region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As the receiving fiber
the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region, Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
in amplifier as axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat metal surface) indicates three regions: the blind region, the linear region and nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As the receiving fibers
the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region, Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
in amplifier as axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat nd nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As s and hence the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region, Fig.5.1: Schematic diagram of metal surface roughness based on fiber optic
in amplifier as axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat nd nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As and hence the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
in amplifier as axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat nd nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As and hence the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
159
in amplifier as a axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat nd nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As and hence the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
159
a axial displacement for various metal surfaces (stainless steel, aluminum and copper). The sensor output function (i.e. light intensity versus distance to target flat nd nonlinear region. When the gap between the probe tip and the target is very close to zero, light transmitting fiber would be reflected back into itself and little or no light the blind region. As and hence the output intensity increases. This relation is continued until the entire face of receiving where maximum voltage is is called optical peak. As the gap increases beyond this transition region,
shown i back slopes,
sensitivity, as well as the resolution targets, and
front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
shown i back slopes,
sensitivity, as well as the resolution targets, and
Table 5.1: The features of the fiber optic displacement (front slope) fo
front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for
shown i back slopes,
sensitivity, as well as the resolution targets, and
Table 5.1: The features of the fiber optic displacement (front slope) fo
No.
front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity
shown in Fig. 5.2 and discussed in back slopes,
sensitivity, as well as the resolution targets, and
Table 5.1: The features of the fiber optic displacement (front slope) fo
No.
1.
2.
3.
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity
n Fig. 5.2 and discussed in back slopes,
sensitivity, as well as the resolution targets, and the detailed
Table 5.1: The features of the fiber optic displacement (front slope) fo
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity
n Fig. 5.2 and discussed in back slopes, with the
sensitivity, as well as the resolution the detailed
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and
Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity
n Fig. 5.2 and discussed in with the
sensitivity, as well as the resolution the detailed
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity
n Fig. 5.2 and discussed in with the
sensitivity, as well as the resolution the detailed
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for The sensitivity of the sensor is determined by the
n Fig. 5.2 and discussed in with the
sensitivity, as well as the resolution the detailed
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the n Fig. 5.2 and discussed in
with the front slope sensitivity, as well as the resolution
the detailed discussion
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the n Fig. 5.2 and discussed in
front slope sensitivity, as well as the resolution
discussion
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm Copper, 8.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the n Fig. 5.2 and discussed in
front slope sensitivity, as well as the resolution
discussion
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the n Fig. 5.2 and discussed in
front slope sensitivity, as well as the resolution
discussions can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo
Type of metal rod and diameter (mm) Aluminum, 10.0mm Stainless steel, 10.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
n Fig. 5.2 and discussed in earlier chapters, the sensor has two slopes; front and front slope showing a higher sensitivi
sensitivity, as well as the resolution is
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
Type of metal rod and
Stainless steel, 10.0mm
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
is summarized
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
A linear range
559 (221 351 (104
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
summarized
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
A linear range
520 (104 559 (221 351 (104
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
summarized
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
A linear range (µm) 520 (104 559 (221 351 (104
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
summarized
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
A linear range (µm) 520 (104 559 (221 351 (104
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
summarized
s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo surface objects
A linear range (µm) 520 (104-624) 559 (221-780) 351 (104-455)
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
summarized in table 5.1for the different reflect s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo
A linear range
624) 780) 455)
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for of the sensor is determined by the linear
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
in table 5.1for the different reflect s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo
A linear range
624)
455)
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for linear
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
in table 5.1for the different reflect s can be found in section 3.
Table 5.1: The features of the fiber optic displacement (front slope) fo
Sensitivity (mV/µm)
0.0026 0.0019 0.0011
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
Fig. 5.2: Output voltage against object displacements for various real objects.
linear
earlier chapters, the sensor has two slopes; front and showing a higher sensitivi
in table 5.1for the different reflect s can be found in section 3.2.1.2
Table 5.1: The features of the fiber optic displacement (front slope) fo
Sensitivity (mV/µm)
0.0026 0.0019 0.0011
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and
showing a higher sensitivi
in table 5.1for the different reflect 2.1.2
Table 5.1: The features of the fiber optic displacement (front slope) fo
Sensitivity (mV/µm)
0.0026 0.0019 0.0011
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and
showing a higher sensitivity.
in table 5.1for the different reflect 2.1.2.
Table 5.1: The features of the fiber optic displacement (front slope) fo
Sensitivity (mV/µm)
0.0026 0.0019 0.0011
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and
. T
in table 5.1for the different reflect
Table 5.1: The features of the fiber optic displacement (front slope) fo
Sensitivity
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
Table 5.1: The features of the fiber optic displacement (front slope) for various metal
Resolution
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
r various metal
Resolution (µm)
6 7 5
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
r various metal
Resolution (µm)
6 7 5
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
r various metal
Resolution
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample surface. The intensity of the reflected light from the metal surface depends on
various real objects.
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
r various metal
Resolution
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample on the
160
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
r various metal
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample the
160
portion of the curves. As earlier chapters, the sensor has two slopes; front and he linear range, in table 5.1for the different reflect
For roughness measurement, the object is fixed within the linear range of the front slope. Then, the output voltages are measured as a function of lateral movement to estimate the roughness of the surface. The fiber tip is held perpendicular to the sample the
161
surface texture of the metal and stand-off distance between the surface and fiber tip. Fig.
5.3 (a) shows the output voltage as a function of the position of surface aluminum for 5 lines scanning. As shown in the Fig.5.3 (a), the output voltage has an almost constant value for the whole surface of the metal with a small fluctuation. Fig. 5.3(b) shows 3D views of level roughness of the aluminum surface, which was obtained by 28 lines of scanning on the surface at various lateral position. The 5 lines and 28 lines scanning are means vertical and horizontal detection points. Surface roughness is defined as the difference in detected intensity between the smallest and largest displacements between the fiber tip and the metal surface. The level of roughness is obtained at around 27%, which corresponds to distance variation or maximum gap of about 52µm.
The experiment was then repeated for stainless steel with the results shown in Figs. 5.4 (a) and 5.4 (b). As shown in both Figs, the level of roughness is obtained at around 26%, which corresponds to distance variation or maximum gap of about 37µm.
Figs. 5.5 (a) and 5.5 (b) show the results of surface roughness measurements for the copper surface. These results show that the level of roughness is approximately 20%
which corresponds to distance variation or maximum gap of about 37µm. Table 5.2 summarizes the experimental results for all metal surface roughness. The surface roughness parameter used throughout in this work is the average surface roughness (Ra) as it is the most widely used parameter by researchers and in the industry as well. It is
the fro
w
sampling data. The value of Table 5.2. The
70% and 64%, respectively.
the arithmetic average of the absolute value of the height of roughness irregularities from mean value measured, that is:
where
sampling data. The value of Table 5.2. The
70% and 64%, respectively.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
here y
sampling data. The value of Table 5.2. The
70% and 64%, respectively.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
yi is the height of roughness irregularities from mean value and sampling data. The value of
Table 5.2. The
70% and 64%, respectively.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
is the height of roughness irregularities from mean value and sampling data. The value of
Table 5.2. The
70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
R
is the height of roughness irregularities from mean value and sampling data. The value of
Table 5.2. The
70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
Ra
is the height of roughness irregularities from mean value and sampling data. The value of
reflectivity of stainless steel, aluminum and copper is obtained at 74%, 70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
is the height of roughness irregularities from mean value and sampling data. The value of
reflectivity of stainless steel, aluminum and copper is obtained at 74%, 70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
n
i 1
is the height of roughness irregularities from mean value and sampling data. The value of
reflectivity of stainless steel, aluminum and copper is obtained at 74%, 70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
0 0 0.5 1
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
yi
1
is the height of roughness irregularities from mean value and sampling data. The value of
reflectivity of stainless steel, aluminum and copper is obtained at 74%, 70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
0
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
i /
is the height of roughness irregularities from mean value and sampling data. The value of
reflectivity of stainless steel, aluminum and copper is obtained at 74%, 70% and 64%, respectively.
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
5
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
/ n
is the height of roughness irregularities from mean value and sampling data. The value of Ra
reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
10
arithmetic average of the absolute value of the height of roughness irregularities m mean value measured, that is:
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
10
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
15
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
20
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
20
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
25
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
30
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
25 30
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
10 15 20 25
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
0 5 10
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
0
arithmetic average of the absolute value of the height of roughness irregularities
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
arithmetic average of the absolute value of the height of roughness irregularities
(5
is the height of roughness irregularities from mean value and
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
(5-1)
is the height of roughness irregularities from mean value and n
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
1)
n is the number of
of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
(a) Output voltage against position for scanning at various lines.
(b) 3D views of a level of roughness of the aluminum surface profile.
arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%, arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
162
arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
162
arithmetic average of the absolute value of the height of roughness irregularities
is the number of of the metal surface finish samples as summarized in reflectivity of stainless steel, aluminum and copper is obtained at 74%,
