GB2117898A - Extracting normal incidence signals in surface roughness measurement - Google Patents
Extracting normal incidence signals in surface roughness measurement Download PDFInfo
- Publication number
- GB2117898A GB2117898A GB08307083A GB8307083A GB2117898A GB 2117898 A GB2117898 A GB 2117898A GB 08307083 A GB08307083 A GB 08307083A GB 8307083 A GB8307083 A GB 8307083A GB 2117898 A GB2117898 A GB 2117898A
- Authority
- GB
- United Kingdom
- Prior art keywords
- workpiece
- radiation
- mirror
- signal
- photoelectric sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
- G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
A beam of coherent monochromatic radiation is directed at the surface of a workpiece P to be checked, particularly a workpiece with a cylindrical surface, so as to effect a linear raster scanning cycle along adjacent parallel zones of the workpiece surface. The specular component of the radiation scattered by each point of the workpiece surface examined during the scanning cycle is passed to a photoelectric sensor 21 arranged to provide at its output a signal indicative of the intensity of this component. An electronic processing circuit 32 comprising a microprocessor processes and compares the signal outputs provided by the photoelectrical sensor, identifies the maximum value signal corresponding to the condition in which the beam of incident radiation is perpendicular to the surface of the workpiece, and processes such a signal in order to obtain an indication of the degree of roughness of the workpiece to be checked. The scanning cycle is accomplished using an optical system through which the radiation is directed at the surface of the workpiece P, comprising a cylindrical lens 26 and two mirrors 16, 22 angularly displaceable the first 16 in successive predetermined angular steps and the second 22 in a continuous oscillating manner at a predetermined frequency. <IMAGE>
Description
SPECIFICATION
Extracting normal incidence signals in surface roughness measurement
Field of the Invention
The present invention relates to processes for checking the surface roughness of a workpiece which has undergone mechanical working.
More particularly, the invention relates to a process of the type forming the subject of U.S.
patent number 4,290,698 in the name of the same Applicant. According to this type of process, a beam of coherent, monochromatic radiation is directed at the surface of the workpiece in a direction normal to this surface so as to effect a linear scan over a zone of this surface. The specular component of the radiation scattered by each point of the zones of the surface examined by means of the linear scanning is passed to a photoelectric sensor arranged to provide at its output a signal indicative of the intensity of this component. The signal provided by the photoelectric sensor is processed so as to form a numerical value corresponding to the average level of this signal and is compared with a numerical reference value to form an indication of the degree of surface roughness of the piece being checked.
According to the U.S. patent mentioned above, the scanning of the radiation along the surface of the workpiece is carried out in only one direction.
When pieces to be checked have cylindrical surfaces, this direction is parallel to the generatrix of the cylindrical surface itself.
In order to obtain correct indications with this type of process, it is necessary for the workpiece surface under examination to be aligned exactly perpendicular to the beam of incident radiation.
Although this can be achieved easily in the case of pieces with flat surfaces, the correct alignment of pieces with cylindrical surfaces can present difficulties.
Moreover, in order, for the process to be used industrially, efficiently and with versatility, directly in a workpiece production line, it is necessary for the processing of the signals provided by the photoelectrical sensor to take account both of the working type of the workpieces and the type of working to which the pieces have been subjected.
Object of the Invention
The object of the present invention is to provide an improvement in the subject of U.S. patent number 4,290,698 mentioned above, by virtue of which it will be possible to obtain a correct indication of the degree of roughness of a workpiece to be checked without having to have recourse to accurate preliminary operations for positioning and aligning the zone of the surface to be checked with the incident radiation, even and particularly in the case of pieces with cylindrical surfaces.
A further object of the invention is to provide accurate and precise indications which take account of the material type of the workpieces under examination and the type of working to which these pieces have been subjected.
The Invention
In order to achieve this object, the present invention provides a process of the type specified above, the characteristic of which lies in the fact that the said linear scan is repeated by means of the relative displacement of the beam of incident radiation and the surface of the piece to be checked so as to carry out a linear raster scanning cycle along adjacent parallel zones of the surface of a workpiece, in that the electrical signal provided by the photoelecyric sensor during each scan of the cycle is processed and compared with the signal corresponding to the preceding scan to identify the maximum value signal which corresponds to the condition in which the beam of incident radiation is perpendicular to the surface of the workpiece, in that the signal processed to form an indication of the degree of roughness of the piece to be checked corresponds to the said maximum signal, and in that during the processing of this maximum signal, parameters are used which are indicative of the type of material of the workpiece and of the type of mechanical working to which the piece has been subjected.
By virtue of this characteristic, the indication of the degree of roughness obtained by means of the process according to the invention relates solely to the zone of the surface of the workpiece which is positioned correctly relative to the incident radiation.
In the case of pieces with cylindrical surfaces, the linear scanning cycle is effected along directions parallel to adjacent generatrices of the zone of the cylindrical surfaces of the workpiece the generatrix whereof is intercepted normally by the incident radiation beam. The accuracy of this indication is further ensured by the fact that the process takes account of the characteristics of the material of the workpiece and of the type of mechanical working to which it has been subject.
The invention further relates to an improvement in the device forming the subject of the U.S.
patent cited above, that is, of the type comprising a laser radiation source, a first optical system for directing a beam of radiation emitted by this source at the surface of the workpiece to be checked in a direction normal to this surface, means for relatively displacing the workpiece and the incident radiation in a direction normal to this radiation so as to effect a linear scan along a zone of the surface of the workpiece, a photoelectric sensor, a second optical system for passing the specular component of the radiation scattered by each point of the zone of the surface examined by means of the linear scan to the said photoelectric sensor so as to obtain at the output of the photoelectric sensor an electric signal indicative of the intensity of this component, and an electronic processing circuit fed with the signal at the output of the photoelectric sensor and arranged to form a numerical value corresponding to the average level of this signal and to compare this value with
a numerical reference value.
The device according to the present invenion,
by means of which the process specified above is
carried out, is characterised in that it further
includes means for further relatively displacing the
workpiece and the incident radiation in a direction
perpendicular to the latter and to the said direction
of relative displacement of the workpiece and the
radiation so as to repeat the said linear scan along
adjacent zones of the surface of the workpiece in a
parallel raster scanning cycle, and in that the
electronic processing circuit is arranged to process
the electrical signal output by the photoelectric
sensor during each scan of the cycle, to compare this signal with the signal corresponding to the
preceding scan whereby to identify the maximum signal, and to utilise this maximum signal for the comparison with the reference value with the use of parameters indicative of the type of material of the workpiece and of the type of mechanical
working to which the piece has been subjected.
The device according to the invention is completely reiiable, accurate and easy to use, does not require specific preliminary operations of calibration or alignment of the workpiece and is particularly advantageous for use in the case of pieces with cylindrical surfaces to be checked. The device lends itself to use in a workpiece production line, for carrying out direct quality control of the surface finishing of the pieces themselves.
Description of a Preferred Embodiment of the
Invention
A preferred embodiment of the present invention will now be described with reference to the appended drawings provided purely by way of non-limiting example, in which:
Figure 1 is a schematic, partially sectioned, elevation of a device according to the invention,
Figure 2 is a block schematic diagram illustrating the electronic processing circuit of the device according to the invention, and
Figure 3 illustrates an example of the electrical signal output, in use, from the photoelectric sensor with which the device of Figure 1 is provided.
With reference to Figure 1, a supporting and protecting casing, schematically shown at 10, has a vertical supporting wall 11 for connecting the device to a support structure not illustrated, and, in its lower part, a horizontal transparent wall 12.
The wall 11 supports a laser radiation source 14 of a type known per se arranged to emit a beam of coherent monochromatic light in a direction parallel to the wall 11.
By 16 is indicated a first mirror supported within the casing 10 and arranged to intercept and deflect the radiation emitted by the source 14. The mirror 1 6 is rotatably mounted about a central axis 18 parallel to the supporting wall 11 and can be displaced angularly about this axis 1 8 by means of a conventional device not shown in the drawings, constituted for example by a galvanometer driven by a stepped electrical signal, that is, in successive angular increments. In this manner the beam of radiation striking the mirror 1 6 is reflected thereby according to an angular incremental scanning with predetermined successive angular intervals.
A semi-transparent mirror indicated 20 is supported within the casing 10 in a position underlying the mirror 1 6 and arranged to intercept and deflect the radiation reflected by the latter.
A second mirror 22 is aligned with the semitransparent mirror 20 and can be oscillated about a central axis 24 perpendicular to the supporting wall 11. The oscillation of the mirror 22 about the axis 24 is effected, in the manner described in the following description, by means of a conventional device not illustrated in the drawings, for example similar to that which causes the angular displacement of the mirror 1 6. However, the movement of the mirror 22 is of a continuous oscillatory type with a frequency of oscillation which is preferably between 50 and 100 Hz.
A cylindrical lens 26 is supported within the casing 10 beneath the mirror 22 and facing the transparent portion 12. The focus of the lens 26 is located at the point on the mirror 22 at which the radiation reflected by the semi-transparent mirror 20 is incident in use.
A third mirror 28 is aligned with and parallel to the semi-transparent mirror 20 on the side thereof opposite the mirror 22. The mirror 28 is located beneath the inlet of a photomultiplier 30 supported within the casing 10 by the wall 11.
Associated with the photomultiplier inlet is a spatial filter 31 in the form of a diaphragm with a variable aperture, the function of the diaphragm being to optimise the solid angle through which the photomultiplier inlet 30 receives radiation specularly reflected in use from the surface of the workpiece to be checked.
A photo diode indicated 21 is supported by the wall 11 beneath the semi-transparent mirror 20 and is arranged to intercept the laser radiation, coming from the mirror 1 6 which, in use, passes through the semi-transparent mirror 20. As will be explained further on in the description, the function of the photo diode 21 is to provide an electrical reference signal which is used to render the indications provided by the device independent of fluctuations in intensity of the radiation source 14.
The output of the photomultiplier 30 and the output of the reference photo diode 21 are connected by means of respective electrical conductors 33, 34 to an electronic processing circuit, generally indicated 32, located outside the casing 10.
As illustrated in detail in Figure 2, the electronic processing circuit 32 comprises an amplifier 36 with a high input impedance. The conductors 33, 34 connected respectively to the output of the photoelectric sensor 30 and the output of the reference photo diode 21 terminate at the amplifier 36. The output of the amplifier 36 is connected to an "antialiasing" filter 38 which in its turn is connected to a "sample and hold" type circuit 40 the output of which is connected via an analogue/digital converter 42 to a microprocessor 44.
By 46 is indicated a generator of triangular and step waveform signals which via an output amplifier 48, respectively serve to cause the oscillations of the mirror 22 about the axis 24 and the angular stepped movement of the mirror 1 6 about the axis 1 8. The generator 46 is connected to the microprocessor 44 to indicate the beginning and end of each half period of oscillation of the mirror 22 and to provide the command for the predetermined angular increment for the displacement of the mirror 1 6.
The microprocessor 44 is able to fulfill two types of operation, that is, a preliminary calibrating operation and a measuring operation, During the calibration operation the microprocessor 44 memorises data on the background luminosity (relative to the external and internal environmental conditions of the casing 1 0), a normalisation value coming from the reference photo diode 21 and the values of the luminous intensity of the radiation reflected by a surface of different sample pieces with known roughnesses. These values are fed to the microprocessor 44 through a data input system 50 and an encoder 52 and are normalised with respect to the value provided by the reference photo diode 21.On the basis of this data the microprocessor 44 is able to derive and memorise a voltage correlation curve relating the roughness value "Ra" of the said surface under examination to the values of average voltage provided by the photomultiplier 30 for all those surfaces which are identified separately by each test sample.
The data relating to the calibration of the system (values of background luminosity, normalisation value, correlation curve) are fed to a permanent memory 54 which is powered, not only from the mains voltage, but also by a buffer battery 56 and which has an associated memory address circuit.
Since the correlation curve between the voltage
values derived by the photomultiplier 30 and the roughness values "Ra", is different if the material examined and the type of mechanical working used are varied, the microprocessor 44 contains different correlation curves in its permanent memory 54 which can be selected as required according to the type of material and the type of working, in the manner which will be described below.
In order to recognise the type of material, the device according to the invention has an eddy current sensor 59 which is connected through a drive circuit 61 and a conductor 35 to the analogue/digital converter 42. The sensor 59 is
placed in contact with the surface to be chcked so
as to supply the microprocessor 44 with an
electrical signal from the average level of which the microprocessor 44 recognises the type of
material under examination.
However, in order to recognise the type of
mechanical working to which the surface under
examination has been subjected, the microprocessor 44 uses an internal aigorithm based on the variations in the electrical signal provided by the photomultiplier 30.
By virtue of the measuring operations effected by the processing circuit 32, the device according to the invention can monitor the roughness of workpieces of different materials subjected to different types of mechanical working, in particular pieces with cylindrical surfaces worked by roughing, a finishing grinding process, fine turning and the like.
One the calibrating operations have been carried out as described above, the operation of the device is as set out below.
The first stage of the checking operation consists in positioning the piece to be examined, indicated by P, on a horizontal support S. In the example illustrated, the piece is of cylindrical form and is disposed with its axis parallel to the support
S. Subsequently the casing 10 containing the optical components of the device is placed in a position overlying the support S so that the optical axis of the cylindrical lens 26 is perpendicular to the axis of the piece P.
At this point, the source 14 is activated so as to produce coherent monochromatic radiation directed towards the mirror 1 6. The mirror 16 is made to move about the axis 1 8 by means of the successive angular-step drive signals produced by the generator 46 so as to deflect the radiation towards the semi-transparent mirror 20 according to an incremental angular scan. The radiation is then reflected by the semi-transparent mirror 20 towards the mirror 22 which in its turn is oscillated from the axis 24 by means of the corresponding drive signals from the generator 46.
In this manner, the radiation is deflected onto the cylindrical lens 26 according to a raster scan pattern, constituted by scan lines parallel to each other and spaced apart by an amount dependent on the angular steps of the mirror 1 6. The lens 26 thus allows the radiation passed therethrough to examine the facing surface of the piece P
according to a raster scan pattern constituted by a
combination of parallel linear scans of
predetermined length.
The laser radiation reflected by each point on the surface of the piece P examined during the
scanning cycle, reaches the inlet of the
photomultiplier 30 by passage through the lens
26, reflection by part of the mirror 22, passage
through the semi-transparent mirror 20, reflection
from part of the mirror 28, and passage through
the spatial filter 31.
At the end of the scanning cycle, the
photomultiplier 30 outputs an electrical signal
indicative of the intensity of this scattered
radiation. One possible waveform of the voltage
level V of the electrical signal over the duration ts of a scanning cycle is represented schematically in
Figure 3. As is clearly visible in this Figure, the
signal is at a maximum during a time interval T1 which corresponds to scanning being effected
along the generatrix of the surface of the piece P
when this is aligned perpendicular to the incident
radiation beam.
The signals output by the photomultiplier 30
and the reference photodiode 21 are amplified
and filtered respectively through the amplifier 36
and the filter 38. and are sampled during a slope
(rising or descending) of the triangular wave
produced by the generator 46 which drives the oscillation of the mirror 22, that is, during a scan along the direction of the generatrix of the surface of the piece P. After conversion from analogue to digital, the signals are fed to the microprocessor 44 which is arranged to subtract the background luminosity signal from the signal coming from the photomultiplier 30, to derive the ratio between this signal and the normalisation signal coming from the reference photodiode 21 to average this ratio over the whole slope and to average the signal coming from the photodiode 21 over the whole slope, and finally to divide these average signals.
The value obtained is memorised and the cycle is again repeated.
The value obtained at the end of the subsequent scan is compared with that memorised previously. If the new value is greater than the previous value it is memorised by the microprocessor 44 while if it is less, the previous value is kept in the memory.
This cycle of operations continues during the whole time for which a raster scanning cycle is carried out. Thus of the values associated with the different scans along the generatrices of the piece
P, only the maximum value corresponding to the zone of the surface of the piece P aligned exactly perpendicular to the incident radiation beam, is retained. In practice, the processing circuit 32 in fact calculates the average value of each rectangle of the signal diagram of Figure 3 having side Tj equal to the time required for a single linear scan, and subsequently processes this value in the manner described above.
The value thus obtained is subsequently introduced by the microprocessor 44 into the correlation curve memorised during the calibration cycle and chosen in the manner indicated previously. The microprocessor 44 thus obtains by comparison an indication of the degree of roughness of the surface under examination which takes account of the type of material of the piece
P and of the type of working which the piece P has undergone, and this indication is displayed visually on the screen 64.
From the above it is clear that the device according to the invention is free from errors resulting from incorrect positioning of the optical device relative to the piece under examination, from any fluctuation in the intensity of the laser radiation emitted by the source 14 (due to the presence of the signal provided by the reference photodiode 21), and from different characteristics of material and of mechanical working of the pieces examined. Thus the device is able to provide accurate and reliable indications without requiring specific positioning or preliminary calibrating operations.
Naturally, the principle of the invention remaining the same, the steps of the process and the constructional details of the device may be varied widely with respect to that described and illustrated without thereby departing from the scope of the present invention.
Thus, for example, instead of using the oscillating mirror 1 6 to effect scanning movement of the radiation in a direction transverse to the generatrices of the cylindrical surface of the piece
P, this scanning might be carried out by causing the casing 10 which encloses the optical components of the device, to effect a rectilinear translatory movement in successive linear steps relative to the piece under examination or, alternatively, the piece under examination may be moved in successive linear steps perpendicular to its axis.
Claims (6)
1. A process for checking the surface roughness of a workpiece, particularly a workpiece with a cylindrical surface, which has undergone mechanical working, in which a beam of coherent monochromatic radiation is directed at the surface of the workpiece in a direction normal to this surface so as to effect a linear scan along a zone of this surface, in which the specular component of the radiation scattered by each point of the zone of the said surface examined by means of the said linear scan is passed to a photoelectric sensor arranged to provide at its output a signal indicative of the intensity of this component, and in which the signal provided by this photoelectric sensor is processed and compared with a reference parameter to form an indication of the degree of surface roughness of the piece to be checked, characterised in that the said linear scan is repeated by displacing the beam of incident radiation and the surface of the piece (P) relative to each other so as to effect a linear, raster scanning cycle along adjacent parallel zones of this surface, in that the electrical signal provided by the photoelectric sensor (30) during each scan of the cycle is processed and compared with the signal corresponding to the preceding scan to identify the maximum value signal, corresponding to the condition in which the beam of incident radiation is perfectly perpendicular to the surface of the piece on which it is incident, in that the signal processed to form an indication of the degree of roughness of the workpiece to be checked corresponds to the said maximum value signal, and in that during the processing of this maximum value signal, parameters indicative of the type of material of the workpiece and of the type of mechanical working to which the piece has been subjected are used.
2. A device for checking the surface roughness of a workpiece, particularly a workpiece with a cylindrical surface, which has undergone mechanical working, of a type comprising a laser radiation source, a first optical system for directing a beam of radiation emitted by the source at the surface of the workpiece to be checked in a direction perpendicular to the surface, means for causing relative displacement of the workpiece and of the incident radiation beam in a direction normal to this radiation so as to effect a linear scan along a zone of the surface of the workpiece, a photoelectric sensor, a second optical system for passing to said photoelectric sensor the specular component of the radiation scattered by each point of the zone of the surface examined by means of the linear scan so as to obtain at the output of the photoelectric sensor an electrical signal indicative of the intensity of this component, and an electronic processing circuit fed with the signal output from the photoelectrical sensor and arranged to form a numerical value indicative of the average level of this signal and to compare this value with a numerical reference value, characterised in that it further includes means (16) for relatively displacing the workpiece and the incident radiation beam perpendicular to the latter and to the said direction of relative displacement between the piece (P) and the radiation so as to repeat the said linear scan along parallel, adjacent zones of the surface of the workpiece according to a linear raster scan, and in that the electronic processing circuit (32) is arranged to process the electrical signal provided by the photoelectric sensor (30) during each scan of the cycle, to compare this signal with the signal corresponding to the preceding scan and to identify the maximum value signal, and to utilise this maximum value signal for the comparison with the reference value with the use of parameters indicative of the type of material of the workpiece and of the type of mechanical working which the piece has undergone.
3. A device according to Claim 2, characterised in that the said first and second optical systems comprise: - a first mirror (16) arranged to intercept and deflect the radiation produced by the laser radiation source (14), - a semi-transparent mirror arranged to intercept the radiation deflected by the first mirror (16) and to deflect this radiation, - a second mirror (22) arranged to intercept the radiation deflected by the semi-transparent mirror (20) and to deflect this radiation, - a cylindrical lens (26) having its focal line passing through the point of the second mirror (22) on which the radiation deflected by the semitransparent mirror (20) is incident and having its optical axis perpendicular to the surface of the piece (P) to be checked,
actuator means for angularly displacing the second mirror (22) in a continuous oscillating manner about an axis (24) parallel to the surface of the workpiece (P) to be checked and passing substantially through the focus of the cylindrical lens (26), and for moving the second mirror (16) in successive predetermined angular steps about a respective axis (1 8) so as to deflect the radiation produced by the said source (1 4) towards the semi-transparent mirror (20) according to an incremental scan with successive angular steps, - a third mirror (28) arranged to deflect the specular component of the radiation scattered by each point of the zone of the said surface examined, towards the inlet of the photoelectric sensor (30), the said component reaching the third mirror (28) by passage through the cylindrical lens (26), reflection by the second mirror (22) and passage through the semi-transparent mirror (20).
4. A device according to Claim 2 or Claim 3, characterised in that it further includes an eddy current sensor (59) intended to be placed in contact with the surface of the workpiece (P) to be checked and arranged to provide at its output an electrical signal indicative of the type of material of the workpiece (P), and in that this electrical signal is used by the said electronic processing circuit (32) during the processing of the electrical signal fed to it by the photoelectric sensor (30).
5. A device according to Claim 3 or Claim 4, characterised in that it further includes a reference photosensor (21) arranged to intercept part of the radiation emitted by the said source (14) and to provide at its output an electrical reference signal indicative of the intensity of this radiation, and in that this electrical signal is used by the electronic processing circuit (32) during the processing of the electrical signals fed to it by the photoelectric sensor (30).
6. A device according to any one of Claims 2 to 6, characterised in that the electronic processing circuit (32) includes a microprocessor (44).
The whole substantially as described and illustrated and for the purposes specified.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT67437/82A IT1155486B (en) | 1982-04-02 | 1982-04-02 | PROCEDURE AND DEVICE FOR THE CONTROL OF THE SURFACE ROUGHNESS OF A PIECE IN PARTICULAR OF A CYLINDRICAL SURFACE PIECE WHICH HAS BEEN SUBJECTED TO A MECHANICAL PROCESSING |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8307083D0 GB8307083D0 (en) | 1983-04-20 |
| GB2117898A true GB2117898A (en) | 1983-10-19 |
Family
ID=11302375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08307083A Withdrawn GB2117898A (en) | 1982-04-02 | 1983-03-15 | Extracting normal incidence signals in surface roughness measurement |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2117898A (en) |
| IT (1) | IT1155486B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2248926A (en) * | 1990-10-17 | 1992-04-22 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| EP0787970A2 (en) * | 1996-02-05 | 1997-08-06 | FIRMA F+O ELECTRONIC SYSTEMS GmbH | Wood surface inspection device for determination of surface characteristics and associated method |
| EP1203925A2 (en) * | 2000-11-06 | 2002-05-08 | Tokyo Seimitsu Co.,Ltd. | Roughness measuring method and apparatus |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107063104B (en) * | 2017-04-01 | 2019-06-18 | 清华大学 | Planar motor rotor position measuring system and method based on grating scale and Two-dimensional PSD |
| CN113310439B (en) * | 2021-05-08 | 2022-11-04 | 中国工程物理研究院材料研究所 | Method and system for detecting surface roughness of spherical shell part based on white light confocal sensor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1466303A (en) * | 1973-09-17 | 1977-03-09 | Howell Labor | Glossmeter for and method of measuring the gloss of a surface |
-
1982
- 1982-04-02 IT IT67437/82A patent/IT1155486B/en active
-
1983
- 1983-03-15 GB GB08307083A patent/GB2117898A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1466303A (en) * | 1973-09-17 | 1977-03-09 | Howell Labor | Glossmeter for and method of measuring the gloss of a surface |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2248926A (en) * | 1990-10-17 | 1992-04-22 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| EP0481649A2 (en) * | 1990-10-17 | 1992-04-22 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| EP0481649A3 (en) * | 1990-10-17 | 1993-03-17 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| US5298974A (en) * | 1990-10-17 | 1994-03-29 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| GB2248926B (en) * | 1990-10-17 | 1994-08-31 | Pilkington Plc | Apparatus for determining the surface topography of an article |
| EP0787970A2 (en) * | 1996-02-05 | 1997-08-06 | FIRMA F+O ELECTRONIC SYSTEMS GmbH | Wood surface inspection device for determination of surface characteristics and associated method |
| EP0787970A3 (en) * | 1996-02-05 | 1998-03-04 | FIRMA F+O ELECTRONIC SYSTEMS GmbH | Wood surface inspection device for determination of surface characteristics and associated method |
| EP1203925A2 (en) * | 2000-11-06 | 2002-05-08 | Tokyo Seimitsu Co.,Ltd. | Roughness measuring method and apparatus |
| EP1203925A3 (en) * | 2000-11-06 | 2004-03-31 | Tokyo Seimitsu Co.,Ltd. | Roughness measuring method and apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8307083D0 (en) | 1983-04-20 |
| IT1155486B (en) | 1987-01-28 |
| IT8267437A0 (en) | 1982-04-02 |
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| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |