CA2050316A1 - Process and device for the contactless testing of areal and spatial test pieces - Google Patents
Process and device for the contactless testing of areal and spatial test piecesInfo
- Publication number
- CA2050316A1 CA2050316A1 CA002050316A CA2050316A CA2050316A1 CA 2050316 A1 CA2050316 A1 CA 2050316A1 CA 002050316 A CA002050316 A CA 002050316A CA 2050316 A CA2050316 A CA 2050316A CA 2050316 A1 CA2050316 A1 CA 2050316A1
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- Prior art keywords
- light
- accordance
- test piece
- opto
- intensity
- Prior art date
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Links
- 238000012360 testing method Methods 0.000 title claims abstract description 74
- 238000000034 method Methods 0.000 title claims abstract description 28
- 230000005693 optoelectronics Effects 0.000 claims abstract description 15
- 230000003287 optical effect Effects 0.000 claims description 15
- 230000001419 dependent effect Effects 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 5
- 230000035945 sensitivity Effects 0.000 claims description 3
- 239000004065 semiconductor Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 description 25
- 238000010586 diagram Methods 0.000 description 7
- 238000007689 inspection Methods 0.000 description 4
- 239000011888 foil Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 230000000149 penetrating effect Effects 0.000 description 3
- 239000006096 absorbing agent Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000004154 testing of material Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
- G01N21/8901—Optical details; Scanning details
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Textile Engineering (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In the process of the invention for the contactless testing of the surface or inner structure of various test pieces, the test piece (1) is illuminated and crossed by a light beam (3). The light from the beam (3) which is reflected or scattered from or allowed through by the test piece (1) is detected and compared with predetermined values. The device for implementing the process has a linear light source (2) to generate a continuous light beam (3) and at least one linear opto-electronic converter arrangement (4,6) to detect reflected, scattered or through-going light.
In the process of the invention for the contactless testing of the surface or inner structure of various test pieces, the test piece (1) is illuminated and crossed by a light beam (3). The light from the beam (3) which is reflected or scattered from or allowed through by the test piece (1) is detected and compared with predetermined values. The device for implementing the process has a linear light source (2) to generate a continuous light beam (3) and at least one linear opto-electronic converter arrangement (4,6) to detect reflected, scattered or through-going light.
Description
2 ~ 3 ~
PROCESS AND DEVICE FOR CONTACTLESS TESTING
OF AREAL AND SPATIAL TEST PIE OES
The present invention relates to a process and a device for contactless testing of different test pieces. This may concern surfaces of test pieces or also their spatial interior. In particular, supposedly smooth or regularly structured surfaces are tested for irregularities in this way, or a transparent, supposedly evenly or regularly structured layer of a material is tested as to its irregularities. Such irregularities may occur because of occlusions. With web materials undergoing a manufacturing process or treatment process, for example a foil web or a textile web, and which display during the run a surface which supposedly is steady, the extent of this quiet running can be determined or possible irregularities in the quiet running can be detected. Such tests are necessary in connection with various treatment processes, such as laminating or vaporizing. On the other hand, in the course of testing three-dimensional structures it is possible to detect and measure positional changes in internal boundary surfaces of the material to be tested. In addition, oscillations of such areas or of occlusions can be tested. Testing of rotating parts as to concentricity and oscillations are also a part of the functional area of such tests.
Systems known so far utilize a laser beam which is deflected with mechanical means (laser scanner) and complicated optical components. Corresponding test devices are therefore expensive, of large size and also subject to wear. Other systems operate with electronic cameras. These are embodied as line cameras, for example, and can simultaneously detect a line of the material passing through which is to be tested. But because such a camera can only be directed vertically on the material at one location in the line, it is necessary to adjust the testing results of surface areas which are recorded at a slant angle 2~;,a3:16 accordingly. Thus complicated corrections of the image are required. If the line is scanned with the camera, however, complicated shift registers are necessary and the test results must be converted to the ruling measuring points by means of extensive transformation calculations. Because of the geometrical requirements and the increasingly diminishing error resolution with increasing inspection width, testing of very long or wide materials is possible to only a limited extent with either system.
A further disadvantage of the systems known so far lies in that the entire scanned information is provided in a serial form.
The measuring device measures line by line and combines the detected data in a series. This series of measured data then must be associated to the individual measuring points by transformation, which requires a very great bandwidth of the evaluation devices and in most cases also makes great demands on the evaluation software. The lack of redundancy of the systems is also disadvantageous. Failure of a single important part, for instance of the laser, leads to failure of the entire installation.
It is therefore the object of the present invention to provide a process and a device which overcome the disadvantages mentioned and which in particular also permit the testing of materials of complicated shapes, where the testing device can be adapted in a pre-determined fashion to the requirements of the testing pieces or can be automatically adapted in the course of testing.
This object is attained by means of a process in accordance with the preamble and the characterizing features of claim 1, and of a device for executing the process with the characteristics of claim 4.
The process in accordance with the invention and the devices for its execution make possible the contactless testing of 2 f~ 3 i ~
a surface or of an interior boundary surface of a material to be tested by means of incident light, which is reflected at the surface or on an interior boundary surface and subsequently detected. It is also possible to test a spatial layer or a spatial section of a material, or its interior structure, by scattering the incident light on it and subsequently detecting it.
The basic functional principle of the process in accordance with the invention will be set forth in the following description with the aid of various drawings. Additionally, some exemplary devices for executing the process will be explained by ~eans of diagrams.
Shown are in:
Fig. 1, the functional principle of the process for testing a surface and the interior structure of a test piece;
Figs. 2 to 5, four basic variants of the process;
Fig. 6, the functional principle of the process for testing a test piece with irregular thickness of the material;
Fig. 7, a diagram of a first exemplary alternative of a device for controlling the light intensity of a light source sector;
Fig. 8, a diagram of a second exemplary alternative of a device for controlling the light intensity of a light source sector;
Fig. 9, a diagram of a first exemplary alternative of a device for determining the light intensity at the light receiver;
Fig. 10, a diagram of a second exemplary alternative of a device for determining the light intensity at the light receiver.
The basic functional principle of the process in accordance with the invention for testing a surface and/or the interior structure of a test piece is shown in Fig. 1 by means of a schematically illustrated device for executing it. The test piece 1 consists of a material which :is, for example, a web material, 20~3~
the surface of which is intended to be tested, or it may be a transparent or translucent material in connection with which the interior structure is to be tested besides the surface. In Fig. 1 the test piece moves with an even movement from right to left in accordance with the drawn in arrow . In accordance with the invention, it is now illuminated by light from a directed, linear light source 2 as indicated by the appropriate drawn in arrows.
The light, impinging o~ the test piece 1 in the form of a light beam 3, is reflected by the test piece 1 to an extent which depends on the material and particularly on the structure of its surface. The reflected portion of the light is again detected as a light beam at a lin~ar opto-electronic converter arrangement 4.
The non-reflected portion of the light penetrates the test piece 1, is scattered and emerges from it on the other, in this case the lower, side of the test piece 1. Further reflection is possible on the lower boundary surface of the test piece 1. Finally, the emerging light is detected by a further linear opto-electronic converter arrangement 5. In accordance with the method the intensity of the light is measured in the individual points of the linear opto-electronic converter arrangements 4, 5. For this purpose these converter arrangements 4, 5 must have as large as possible an optical resolution. For this reason they are constructed of a number of individual optical elements 6 which are embodied such that they together form a linear field of sight.
For special uses, however, the light source 6 is constructed of a type of individual optical elements 7 which are then individually controllable in regard to the light emitted by them. By means of the separate individual control of the light intensity of each point of light and the separate individual determination of the detected intensity at each measuring point it is possible to select a certain light intensity for practically every measuring point, or the values to be detected can be preset as parameters.
PROCESS AND DEVICE FOR CONTACTLESS TESTING
OF AREAL AND SPATIAL TEST PIE OES
The present invention relates to a process and a device for contactless testing of different test pieces. This may concern surfaces of test pieces or also their spatial interior. In particular, supposedly smooth or regularly structured surfaces are tested for irregularities in this way, or a transparent, supposedly evenly or regularly structured layer of a material is tested as to its irregularities. Such irregularities may occur because of occlusions. With web materials undergoing a manufacturing process or treatment process, for example a foil web or a textile web, and which display during the run a surface which supposedly is steady, the extent of this quiet running can be determined or possible irregularities in the quiet running can be detected. Such tests are necessary in connection with various treatment processes, such as laminating or vaporizing. On the other hand, in the course of testing three-dimensional structures it is possible to detect and measure positional changes in internal boundary surfaces of the material to be tested. In addition, oscillations of such areas or of occlusions can be tested. Testing of rotating parts as to concentricity and oscillations are also a part of the functional area of such tests.
Systems known so far utilize a laser beam which is deflected with mechanical means (laser scanner) and complicated optical components. Corresponding test devices are therefore expensive, of large size and also subject to wear. Other systems operate with electronic cameras. These are embodied as line cameras, for example, and can simultaneously detect a line of the material passing through which is to be tested. But because such a camera can only be directed vertically on the material at one location in the line, it is necessary to adjust the testing results of surface areas which are recorded at a slant angle 2~;,a3:16 accordingly. Thus complicated corrections of the image are required. If the line is scanned with the camera, however, complicated shift registers are necessary and the test results must be converted to the ruling measuring points by means of extensive transformation calculations. Because of the geometrical requirements and the increasingly diminishing error resolution with increasing inspection width, testing of very long or wide materials is possible to only a limited extent with either system.
A further disadvantage of the systems known so far lies in that the entire scanned information is provided in a serial form.
The measuring device measures line by line and combines the detected data in a series. This series of measured data then must be associated to the individual measuring points by transformation, which requires a very great bandwidth of the evaluation devices and in most cases also makes great demands on the evaluation software. The lack of redundancy of the systems is also disadvantageous. Failure of a single important part, for instance of the laser, leads to failure of the entire installation.
It is therefore the object of the present invention to provide a process and a device which overcome the disadvantages mentioned and which in particular also permit the testing of materials of complicated shapes, where the testing device can be adapted in a pre-determined fashion to the requirements of the testing pieces or can be automatically adapted in the course of testing.
This object is attained by means of a process in accordance with the preamble and the characterizing features of claim 1, and of a device for executing the process with the characteristics of claim 4.
The process in accordance with the invention and the devices for its execution make possible the contactless testing of 2 f~ 3 i ~
a surface or of an interior boundary surface of a material to be tested by means of incident light, which is reflected at the surface or on an interior boundary surface and subsequently detected. It is also possible to test a spatial layer or a spatial section of a material, or its interior structure, by scattering the incident light on it and subsequently detecting it.
The basic functional principle of the process in accordance with the invention will be set forth in the following description with the aid of various drawings. Additionally, some exemplary devices for executing the process will be explained by ~eans of diagrams.
Shown are in:
Fig. 1, the functional principle of the process for testing a surface and the interior structure of a test piece;
Figs. 2 to 5, four basic variants of the process;
Fig. 6, the functional principle of the process for testing a test piece with irregular thickness of the material;
Fig. 7, a diagram of a first exemplary alternative of a device for controlling the light intensity of a light source sector;
Fig. 8, a diagram of a second exemplary alternative of a device for controlling the light intensity of a light source sector;
Fig. 9, a diagram of a first exemplary alternative of a device for determining the light intensity at the light receiver;
Fig. 10, a diagram of a second exemplary alternative of a device for determining the light intensity at the light receiver.
The basic functional principle of the process in accordance with the invention for testing a surface and/or the interior structure of a test piece is shown in Fig. 1 by means of a schematically illustrated device for executing it. The test piece 1 consists of a material which :is, for example, a web material, 20~3~
the surface of which is intended to be tested, or it may be a transparent or translucent material in connection with which the interior structure is to be tested besides the surface. In Fig. 1 the test piece moves with an even movement from right to left in accordance with the drawn in arrow . In accordance with the invention, it is now illuminated by light from a directed, linear light source 2 as indicated by the appropriate drawn in arrows.
The light, impinging o~ the test piece 1 in the form of a light beam 3, is reflected by the test piece 1 to an extent which depends on the material and particularly on the structure of its surface. The reflected portion of the light is again detected as a light beam at a lin~ar opto-electronic converter arrangement 4.
The non-reflected portion of the light penetrates the test piece 1, is scattered and emerges from it on the other, in this case the lower, side of the test piece 1. Further reflection is possible on the lower boundary surface of the test piece 1. Finally, the emerging light is detected by a further linear opto-electronic converter arrangement 5. In accordance with the method the intensity of the light is measured in the individual points of the linear opto-electronic converter arrangements 4, 5. For this purpose these converter arrangements 4, 5 must have as large as possible an optical resolution. For this reason they are constructed of a number of individual optical elements 6 which are embodied such that they together form a linear field of sight.
For special uses, however, the light source 6 is constructed of a type of individual optical elements 7 which are then individually controllable in regard to the light emitted by them. By means of the separate individual control of the light intensity of each point of light and the separate individual determination of the detected intensity at each measuring point it is possible to select a certain light intensity for practically every measuring point, or the values to be detected can be preset as parameters.
3 :~ ~
It is therefore possible, depending on the resolution of the light beam generated and of the detected light, to preset location-dependent intensity values empirically or mathematically for each point in accGrdance with the movement of scanning of the test piece 1, which are then used a measurement parameters. Means may also be provided with which an empirically or mathematically defined, location-dependent progression of the intensity of the light to be detected can be preset for every point of the light beam in the course o~ scanning the test piece. The values can be fed back or compared. It is possible to perform a moving inspection of the passing surface by means of the identification of a defined progression of intensity.
Figs. 2 to 5 show four different variants of employment of the process in accordance with the invention. The probably simplest variant is shown in Fig. 2, where the light source 2 illuminates an opaque material 1. A portion of the impinging light is reflected at its surface, the rest is absorbed by the material. The reflected portion is detected by the detector 4, the opto-electronic converter arrangement. This arrangement can be used for testing the surface of a foil material, for example, where the foil material passes underneath the light beam 3 in the form of a web. However, the arrangement is also suitable for testing the surface of solid surfaces~ for example auto body parts, shaped metal parts or similar materials with light-reflecting surfaces. In this case it is possible to test widths of up to 10 meters by means of in-line inspection. For holes, so-called "pin holes", in thin rolled surface layers the error resolution is approximately 10 ~m, for example. In connection with scratches and dust particles as interference spots for reflection, a resolution of approximately 50 ~m is attained.
Thus, mainly coating defects, foreign particles (dust), scratches, drag marks, indentations and holes become detectable with the help 2 ~ ~ ~3 3 ~ ~
of this arrangement. Changes in density, color, surface roughness and surface quality can also be detected. The testing process in accordance with the invention permits high testing speeds of up to 17 m/s web speed.
Fig. 3 shows a variant where the test piece 1 is transparent or translucent, i.e. diffusely transparent. A portion of the light emitted by the light source 2 and impinging on the test piece 1 is reflected, the other portion penetrates the test piece 1, except for absorption losses, and is reflected at a mirror 8 after exiting the test piece 1, from where it again penetrates the test piece 1. Finally, the two light beam bundles are detected by means of the photo-electronic converter arrangement 4. This arrangement makes it possible to test the surface and simultaneously the structure of the transparent material. Regarding the structure it is possible, for example, to detect occlusions (bubbles) as well as their size, or it is possible to test the regularity of cross-linkings, the tensile load conn~ctions, on the inside of polymers. Variations in color and transmission can also be determined.
Fig. 4 shows an arrangement for the inspection of surfaces.
A portion of the light is reflected at the surface, while the portion of the light penetrating the test piece 1 is reflected at the opposite surface 9 or on the boundary surface formed by the latter and is detected after again penetrating the test piece 1.
The portion not reflected at the boundary surface is trapped by an absorber 10, for example of black velvetO
An arrangement such as is used for testing the boundary layer 13 between two adjoining materials 11, 12, for example a laminate, is shown in Fig. 5~ The light penetrates the first, here the upper, material 11 and is reflected to a large part at the boundary surface 13 of the second, here lower, material 12.
The reflected light again penetrates the first material 11 and is ~Q~ 3~
detected after it emerges. The light not reflected on the boundary surface 13 penetrates the second material 12 and light emerging from the latter's surface 14 is trapped by an absorber 10. In this case increased penetration light can show defects in the laminate.
Fig. 6 illustrates the functional principle of the process for testing a test piece 1 of uneven material thickness. To obtain an even measuring sensitivity of the measurement of the penetrating light, which is indicated in Fig. 6 by the identical length of the arrows in front of the detectors 4, a band of light having an intensity progression I is generated on the test piece 1, which corresponds to the progression of the weakening of the light in the test piece 1 in such a way that it is compensated.
An opto-electronic converter arrangement 6 and an optical element 7 each form a so-called measuring channel.
Some basic circuits of the arrangement for executing the process of the invention will be described and explained in the following. Fig. 7 shows a diagram of a first exemplary alternative of an arrangement for the location-dependent control in accordance with the program for the light intensity of a light source sector. The linear light source as a whole in this case comprises a plurality of discrete light sources, each one of which here is formed by a light-emitting diode (LED) 15 or a laser.
Each individual one of these light sources forms a light sector which can be individually controlled in its intensity. Control in this case takes place via a control bus 16 connecting all individual light sources. Thus, in the diagram illustrated the circuit of a single light source is illustrated. The circuit is supplied with power ~PWR) via a line 17. The control signals are processed in a logic circuit LOGIC 18 and are forwarded via the digital-analog converter (DAC) 19 to the AC-driver 20. The latter then supplies the light-emitting diode (LED) or a laser. A
3 ~ &
backlight receiver 21 feeds back to the AC-driver 20. This backlight receiver measures the light intensity generated on the test piece so that a control is possible whether it actually corresponds to the desired value. A control circuit i5 formed by the feedback, so that the light intensity can always be adjusted to a preset value.
Fig. 8 shows an alternate circuit to that of Fig. 7. In contrast to the one of Fig. 7, an incandescent lamp 22 is used here as a light source here. The logic circuit LOGIC 18 and the digital-analog converter (DAC) 19 here supply the incandescent lamp 22 via a DC driver 23. An additional AC-driver 24 processes the signals of LOGIC 18 and the digital-analog converter (DAC) 19 as well as of a backlight receiver 21 and then supplies a chopper (shutter) 25. A high frequency is generated by means of the chopper in order to generate light which can be distinguished from the frequencies of ambient light and to ba able to measure regardless of the amkient light. The generated light frequency in this manner serves as carrier frequency for measurement.
Naturally it must be high enough that the scanning or resolution for the moving test piece is sufficient. By means of the described circuit it is possible to control the light intensity of the light emitted by the incandescent lamp sufficiently rapidly and exactly.
Fig. 9 shows a circuit for processing the current values emitted by the light receiver as a light intensity value by means of adjustable measuring amplifiers. By means of this the location-dependent progression of the intensity of the detected light of each individual optical element of the opto-electronic converter arrangement can be amplified to a programmed set value.
In this circuit the light impinges on a photo receiver 26, the electrical signal of which is amplified by a variable amplifier 27. The amplifier 27 is controlled via a logic circuit (LOGIC) 28 9 3 ~ u and a digital-analog converter (DAC) 29. The logic circuit (LOGIC) 28 is supplied with power via the line 30 and is controlled via a line 31 which branches off a common control bus 32.
Fig. 10 shows an alternative circuit. In this case a chopper (shutter) 34 is placed upstream of the photo receiver 33, which is controlled via the logic circuit (LOGIC) 28, the digital-analog converter (DAC) 29 and an AC/DC driver 35. In this circuit the chopper per~its a selective setting to a defined transmitter frequency. On the other hand, the measured intensity can also be arbitrarily reduced with the aid of the chopper.
A number of photo diodes, incandescent lamps, gas-discharge tubes or -lamps can be used as linear light sources on the devices according to the invention. Semiconductor diodes can also be employed. On the other hand, the photo-electronic converter arrangements may consist of photo diodes, photo transistors or photo-electric multipliers. Means for moving the light source and the photo-electronic converter arrangement in relation to the test piece and for detecting the location coordinates of this movement as a parameter for the light source and the opto-electronic converter arrangement are only needed if the test piece is stationary. These means may be, for example, linear units or arbitraLy mechanical driving means from the state of the art. In many cases the test arrangement is stationary and the test pieces are moved along underneath the generated light beams. In some cases the temperature can be a process parameter, which is used a control parameter (guide value). Red-hot metal can be cited as an example, which affects measurement, or the temperature of a test piece must be compensated for because of material expansion. In such cases infrared-pyroelectrical sensors are suitable as opto-electronic elements.
_g _
It is therefore possible, depending on the resolution of the light beam generated and of the detected light, to preset location-dependent intensity values empirically or mathematically for each point in accGrdance with the movement of scanning of the test piece 1, which are then used a measurement parameters. Means may also be provided with which an empirically or mathematically defined, location-dependent progression of the intensity of the light to be detected can be preset for every point of the light beam in the course o~ scanning the test piece. The values can be fed back or compared. It is possible to perform a moving inspection of the passing surface by means of the identification of a defined progression of intensity.
Figs. 2 to 5 show four different variants of employment of the process in accordance with the invention. The probably simplest variant is shown in Fig. 2, where the light source 2 illuminates an opaque material 1. A portion of the impinging light is reflected at its surface, the rest is absorbed by the material. The reflected portion is detected by the detector 4, the opto-electronic converter arrangement. This arrangement can be used for testing the surface of a foil material, for example, where the foil material passes underneath the light beam 3 in the form of a web. However, the arrangement is also suitable for testing the surface of solid surfaces~ for example auto body parts, shaped metal parts or similar materials with light-reflecting surfaces. In this case it is possible to test widths of up to 10 meters by means of in-line inspection. For holes, so-called "pin holes", in thin rolled surface layers the error resolution is approximately 10 ~m, for example. In connection with scratches and dust particles as interference spots for reflection, a resolution of approximately 50 ~m is attained.
Thus, mainly coating defects, foreign particles (dust), scratches, drag marks, indentations and holes become detectable with the help 2 ~ ~ ~3 3 ~ ~
of this arrangement. Changes in density, color, surface roughness and surface quality can also be detected. The testing process in accordance with the invention permits high testing speeds of up to 17 m/s web speed.
Fig. 3 shows a variant where the test piece 1 is transparent or translucent, i.e. diffusely transparent. A portion of the light emitted by the light source 2 and impinging on the test piece 1 is reflected, the other portion penetrates the test piece 1, except for absorption losses, and is reflected at a mirror 8 after exiting the test piece 1, from where it again penetrates the test piece 1. Finally, the two light beam bundles are detected by means of the photo-electronic converter arrangement 4. This arrangement makes it possible to test the surface and simultaneously the structure of the transparent material. Regarding the structure it is possible, for example, to detect occlusions (bubbles) as well as their size, or it is possible to test the regularity of cross-linkings, the tensile load conn~ctions, on the inside of polymers. Variations in color and transmission can also be determined.
Fig. 4 shows an arrangement for the inspection of surfaces.
A portion of the light is reflected at the surface, while the portion of the light penetrating the test piece 1 is reflected at the opposite surface 9 or on the boundary surface formed by the latter and is detected after again penetrating the test piece 1.
The portion not reflected at the boundary surface is trapped by an absorber 10, for example of black velvetO
An arrangement such as is used for testing the boundary layer 13 between two adjoining materials 11, 12, for example a laminate, is shown in Fig. 5~ The light penetrates the first, here the upper, material 11 and is reflected to a large part at the boundary surface 13 of the second, here lower, material 12.
The reflected light again penetrates the first material 11 and is ~Q~ 3~
detected after it emerges. The light not reflected on the boundary surface 13 penetrates the second material 12 and light emerging from the latter's surface 14 is trapped by an absorber 10. In this case increased penetration light can show defects in the laminate.
Fig. 6 illustrates the functional principle of the process for testing a test piece 1 of uneven material thickness. To obtain an even measuring sensitivity of the measurement of the penetrating light, which is indicated in Fig. 6 by the identical length of the arrows in front of the detectors 4, a band of light having an intensity progression I is generated on the test piece 1, which corresponds to the progression of the weakening of the light in the test piece 1 in such a way that it is compensated.
An opto-electronic converter arrangement 6 and an optical element 7 each form a so-called measuring channel.
Some basic circuits of the arrangement for executing the process of the invention will be described and explained in the following. Fig. 7 shows a diagram of a first exemplary alternative of an arrangement for the location-dependent control in accordance with the program for the light intensity of a light source sector. The linear light source as a whole in this case comprises a plurality of discrete light sources, each one of which here is formed by a light-emitting diode (LED) 15 or a laser.
Each individual one of these light sources forms a light sector which can be individually controlled in its intensity. Control in this case takes place via a control bus 16 connecting all individual light sources. Thus, in the diagram illustrated the circuit of a single light source is illustrated. The circuit is supplied with power ~PWR) via a line 17. The control signals are processed in a logic circuit LOGIC 18 and are forwarded via the digital-analog converter (DAC) 19 to the AC-driver 20. The latter then supplies the light-emitting diode (LED) or a laser. A
3 ~ &
backlight receiver 21 feeds back to the AC-driver 20. This backlight receiver measures the light intensity generated on the test piece so that a control is possible whether it actually corresponds to the desired value. A control circuit i5 formed by the feedback, so that the light intensity can always be adjusted to a preset value.
Fig. 8 shows an alternate circuit to that of Fig. 7. In contrast to the one of Fig. 7, an incandescent lamp 22 is used here as a light source here. The logic circuit LOGIC 18 and the digital-analog converter (DAC) 19 here supply the incandescent lamp 22 via a DC driver 23. An additional AC-driver 24 processes the signals of LOGIC 18 and the digital-analog converter (DAC) 19 as well as of a backlight receiver 21 and then supplies a chopper (shutter) 25. A high frequency is generated by means of the chopper in order to generate light which can be distinguished from the frequencies of ambient light and to ba able to measure regardless of the amkient light. The generated light frequency in this manner serves as carrier frequency for measurement.
Naturally it must be high enough that the scanning or resolution for the moving test piece is sufficient. By means of the described circuit it is possible to control the light intensity of the light emitted by the incandescent lamp sufficiently rapidly and exactly.
Fig. 9 shows a circuit for processing the current values emitted by the light receiver as a light intensity value by means of adjustable measuring amplifiers. By means of this the location-dependent progression of the intensity of the detected light of each individual optical element of the opto-electronic converter arrangement can be amplified to a programmed set value.
In this circuit the light impinges on a photo receiver 26, the electrical signal of which is amplified by a variable amplifier 27. The amplifier 27 is controlled via a logic circuit (LOGIC) 28 9 3 ~ u and a digital-analog converter (DAC) 29. The logic circuit (LOGIC) 28 is supplied with power via the line 30 and is controlled via a line 31 which branches off a common control bus 32.
Fig. 10 shows an alternative circuit. In this case a chopper (shutter) 34 is placed upstream of the photo receiver 33, which is controlled via the logic circuit (LOGIC) 28, the digital-analog converter (DAC) 29 and an AC/DC driver 35. In this circuit the chopper per~its a selective setting to a defined transmitter frequency. On the other hand, the measured intensity can also be arbitrarily reduced with the aid of the chopper.
A number of photo diodes, incandescent lamps, gas-discharge tubes or -lamps can be used as linear light sources on the devices according to the invention. Semiconductor diodes can also be employed. On the other hand, the photo-electronic converter arrangements may consist of photo diodes, photo transistors or photo-electric multipliers. Means for moving the light source and the photo-electronic converter arrangement in relation to the test piece and for detecting the location coordinates of this movement as a parameter for the light source and the opto-electronic converter arrangement are only needed if the test piece is stationary. These means may be, for example, linear units or arbitraLy mechanical driving means from the state of the art. In many cases the test arrangement is stationary and the test pieces are moved along underneath the generated light beams. In some cases the temperature can be a process parameter, which is used a control parameter (guide value). Red-hot metal can be cited as an example, which affects measurement, or the temperature of a test piece must be compensated for because of material expansion. In such cases infrared-pyroelectrical sensors are suitable as opto-electronic elements.
_g _
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
[received by the International Bureau on June 3, 1991 (06/03/91);
original claims 1-10 replaced by amended claims 1-10; (4 pages)]
1. A process for contactless testing of the surface or the interior structure of various test pieces, where the test piece (1) is illuminated and scanned by at least one light beam (3), and where the light of the light beam (3), reflected, scattered or passed through the test piece (1) is detected by a two- or three-dimensional sensor arrangement and compared with preset values by presetting location-dependent intensity values for each individual point, which are used as measurement parameters, according to the movement of scanning of the test piece (1) in accordance with the resolution of the generated light beam (3) and of the detected light.
2. A process in accordance with claim 1, where the intensities of the individual points of the light transmitter lines and/or the sensitivity of the individual points of the sensor lines of the sensor device are preset as parameters as a function of the location.
3. A process in accordance with one of the preceding claims, where the intensity or sensitivity values are varied by means of the geometric progression of the light transmitter-and/or the sensor lines as parameters.
4. A device for executing the process in accordance with one of the preceding claims, characterized by a linear light source (2) for the generation of a continuous light beam (3), and by at least one linear opto-electronic converter arrangement (4, 6) for detecting reflected, scattered or passed light, where the linear light source (2) includes optical elements (7), by means of which a linear light beam (3) can be generated on the test piece (1), and that means are provided with which an empirically or mathematically defined, location-dependent progression of the intensity of the light can be preset for every point of the light beam (3) during scanning of the test piece (1).
5. A device in accordance with claim 4, characterized in that the opto-electronic converter arrangement (4) includes optical elements (6) having a linear field of sight, and that means are provided with which an empirically or mathematically defined, location-dependent progression of the intensity of the light to be detected can be preset for every point of the light beam (3) during scanning of the test piece (1).
6. A device in accordance with one of claims 4 to 5, characterized by means for moving the light source (2) and the opto-electronic converter arrangement (4) in relation to the test piece (1) and for detecting the location coordinates of this movement as parameters for the light source (2) and the opto-electronic converter arrangement (4).
7. A device in accordance with one of claims 4 to 6, characterized in that the elements (7) of the light source (2) consist of lasers, incandescent lamps, gas discharge tubes or -lamps or semiconductors and that the opto-electronic converter arrangement (4) consists of photo diodes, photo transistors or photo-electric multipliers.
8. A device in accordance with one of claims 4 to 7, characterized in that the optical elements (7) of the light source (2) and the optical elements (6) of the converter arrangement (4) consist of mirrors, beam splitters, lenses, optical diffraction elements, light choppers, light guides, diffusers and/or collimators.
9. A device in accordance with one of claims 4 to 8, characterized in that the optical elements (7) of the light source (2) include adjustable variable amplifiers and adjustable optical elements, by means of which the location-dependent progression of the intensity of the emitted light of each element (7) can be set, controlled by the program.
10. A device in accordance with one of claims 4 to 9, characterized in that the opto-electronic converter arrangement (4) includes adjustable variable amplifiers (27) and adjustable optical elements, by means of which the location-dependent progression of the intensity of the detected light of each optical element (6) of the opto-electrical converter arrangement (4) can be amplified to a programmable set value.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH91/90-7 | 1990-01-06 | ||
| CH31/90A CH681112A5 (en) | 1990-01-06 | 1990-01-06 | |
| PCT/CH1991/000004 WO1991010891A1 (en) | 1990-01-06 | 1991-01-07 | Process and device for the contactless testing of areal and spatial test pieces |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050316A1 true CA2050316A1 (en) | 1991-07-07 |
Family
ID=4177789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002050316A Abandoned CA2050316A1 (en) | 1990-01-06 | 1991-01-07 | Process and device for the contactless testing of areal and spatial test pieces |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0462240A1 (en) |
| JP (1) | JPH04506411A (en) |
| KR (1) | KR920701784A (en) |
| AU (1) | AU6911891A (en) |
| BR (1) | BR9103915A (en) |
| CA (1) | CA2050316A1 (en) |
| CH (1) | CH681112A5 (en) |
| RU (1) | RU2058546C1 (en) |
| WO (1) | WO1991010891A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7640073B2 (en) | 2005-04-14 | 2009-12-29 | Jeld-Wen, Inc. | Systems and methods of identifying and manipulating objects |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH683293A5 (en) * | 1991-12-20 | 1994-02-15 | Peyer Ag Siegfried | Foreign fiber detection in yarns. |
| AT1797U1 (en) * | 1996-07-23 | 1997-11-25 | Mte Messgeraete Entwicklungs U | OPTOELECTRONIC MEASURING SYSTEM FOR MEASURING AND IDENTIFICATION OF FLAT GLASS PRODUCTS |
| US6100537A (en) * | 1997-07-22 | 2000-08-08 | "MTE" Messgerate, Entwicklungs- und Vertriebsgesellschaft mbH | Measuring system for recognition of surface features |
| DE19801140A1 (en) | 1998-01-14 | 1999-07-15 | Voith Sulzer Papiertech Patent | Device for the direct or indirect application of a liquid to pasty application medium on a running material web and operating method for such a device |
| JP2007039335A (en) * | 1998-11-24 | 2007-02-15 | Nippon Electric Glass Co Ltd | Manufacturing method for ceramic article |
| AU747386B2 (en) | 1998-11-24 | 2002-05-16 | Nippon Electric Glass Company, Limited | Ceramic article |
| FR2817964B1 (en) * | 2000-12-11 | 2003-03-14 | Usinor | DEVICE FOR AUTOMATIC INSPECTION OF THE SURFACE OF A TRAVELING STRIP |
| EP1498723A1 (en) * | 2003-07-17 | 2005-01-19 | Hauni Maschinbau AG | Method for recognizing foreign bodies in a continuous stream of transported products and apparatus for carrying out the method |
| JP4698140B2 (en) * | 2003-11-12 | 2011-06-08 | ザ・ボーイング・カンパニー | System for identifying defects in composite structures |
| RU2319117C1 (en) * | 2006-04-21 | 2008-03-10 | Федеральное государственное унитарное предприятие "Центральный институт авиационного моторостроения имени П.И. Баранова" | Device for determining angular distribution of radiation reflected from object surface being examined |
| RU2540939C2 (en) * | 2013-05-24 | 2015-02-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Сибирская государственная геодезическая академия" (ФГБОУ ВПО "СГГА") | Method of determining coordinates of control point of object using ground-based laser scanner |
| DE102013221334A1 (en) * | 2013-10-21 | 2015-04-23 | Volkswagen Aktiengesellschaft | Method and measuring device for evaluating structural differences of a reflecting surface |
| WO2016158174A1 (en) * | 2015-03-31 | 2016-10-06 | 浜松ホトニクス株式会社 | Projection display device |
| RU178901U1 (en) * | 2017-10-30 | 2018-04-23 | Олег Александрович Продоус | Device for non-contact measurement of surface roughness |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL240616A (en) * | 1958-06-30 | |||
| US3019346A (en) * | 1960-03-28 | 1962-01-30 | Jones & Laughlin Steel Corp | Electronic surface inspection system |
| US3693021A (en) * | 1970-06-29 | 1972-09-19 | Eastman Kodak Co | Web inspection system using interlaced photocells |
| US4594001A (en) * | 1981-07-07 | 1986-06-10 | Robotic Vision Systems, Inc. | Detection of three-dimensional information with a projected plane of light |
| US4650333A (en) * | 1984-04-12 | 1987-03-17 | International Business Machines Corporation | System for measuring and detecting printed circuit wiring defects |
| GB2159271B (en) * | 1984-04-27 | 1988-05-18 | Nissan Motor | Surface flaw detecting method and apparatus |
-
1990
- 1990-01-06 CH CH31/90A patent/CH681112A5/de not_active IP Right Cessation
-
1991
- 1991-01-07 CA CA002050316A patent/CA2050316A1/en not_active Abandoned
- 1991-01-07 JP JP3501170A patent/JPH04506411A/en active Pending
- 1991-01-07 KR KR1019910701040A patent/KR920701784A/en not_active Withdrawn
- 1991-01-07 AU AU69118/91A patent/AU6911891A/en not_active Abandoned
- 1991-01-07 RU SU915001624A patent/RU2058546C1/en active
- 1991-01-07 BR BR919103915A patent/BR9103915A/en not_active IP Right Cessation
- 1991-01-07 EP EP91900711A patent/EP0462240A1/en not_active Withdrawn
- 1991-01-07 WO PCT/CH1991/000004 patent/WO1991010891A1/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7640073B2 (en) | 2005-04-14 | 2009-12-29 | Jeld-Wen, Inc. | Systems and methods of identifying and manipulating objects |
| US7801638B2 (en) | 2005-04-14 | 2010-09-21 | Jeld-Wen, Inc. | Systems and methods of identifying and manipulating objects |
Also Published As
| Publication number | Publication date |
|---|---|
| CH681112A5 (en) | 1993-01-15 |
| RU2058546C1 (en) | 1996-04-20 |
| EP0462240A1 (en) | 1991-12-27 |
| AU6911891A (en) | 1991-08-05 |
| BR9103915A (en) | 1992-03-03 |
| WO1991010891A1 (en) | 1991-07-25 |
| KR920701784A (en) | 1992-08-12 |
| JPH04506411A (en) | 1992-11-05 |
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