CA2407433A1 - Method for identifying an object - Google Patents
Method for identifying an object Download PDFInfo
- Publication number
- CA2407433A1 CA2407433A1 CA002407433A CA2407433A CA2407433A1 CA 2407433 A1 CA2407433 A1 CA 2407433A1 CA 002407433 A CA002407433 A CA 002407433A CA 2407433 A CA2407433 A CA 2407433A CA 2407433 A1 CA2407433 A1 CA 2407433A1
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- Prior art keywords
- interference pattern
- identification area
- recognized
- interference
- candidate object
- Prior art date
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- Abandoned
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000001427 coherent effect Effects 0.000 claims abstract description 10
- 238000005286 illumination Methods 0.000 claims description 11
- 230000000717 retained effect Effects 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 3
- 238000005305 interferometry Methods 0.000 description 3
- 239000000446 fuel Substances 0.000 description 2
- 239000003758 nuclear fuel Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013475 authorization Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- ORTYMGHCFWKXHO-UHFFFAOYSA-N diethadione Chemical compound CCC1(CC)COC(=O)NC1=O ORTYMGHCFWKXHO-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000002372 labelling Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G07—CHECKING-DEVICES
- G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
- G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
- G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
- G07D7/12—Visible light, infrared or ultraviolet radiation
- G07D7/1205—Testing spectral properties
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V20/00—Scenes; Scene-specific elements
- G06V20/80—Recognising image objects characterised by unique random patterns
Abstract
The invention concerns a method for identifying an object comprising the following steps: (a) selecting an intrinsic surface of an object to be identified; (b) illuminating at least an identification zone in the intrinsic surface of the object to be identified with a coherent light and intercepting at least part of the light reflected by the identification zone, so as to obtain an interference figure in specific illuminating and intercepting conditions; (c) preserving said interference figure as reference interference figure of the object to be identified; (d) placing a candidate object which could possibly be the object to be identified in similar illuminating and intercepting conditions as those used to obtain the reference interference figure and obtain from said candidate object an interference figure; (e) comparing the reference interference figure with the interference figure of the candidate object; and (f) assessing the probability of identity between the object to be identified and the candidate object based on the degree of correspondence between the reference interference figure and the interference figure of the candidate object.
Description
., ;.
r P-CEP-006/WO/GB (as amended) METHOD FOR IDENTIFYING AN OBJECT
Introduction The present invention relates to a method for identifying an object.
State of the art s In order to identify each of the objects of a series of objects with identical appearance, the most standard method consists of fixing an identification plate on each object, each of the identification plates bearing a distinctive mark.
However, if the identification plates are exchanged between several objects of the series, it is no longer possible to identify a particular object of the series with 1 o certainty.
GB-A-2,221,870 relates to a security device for use in an optical method based on the speckle interferometry phenomenon, better known as the "speckle effect". The security device comprises a substrate whereon or wherein there is a structure scattering the radiations. This radiation-scattering structure i5 when it is illuminated by a coherent ray of radiations, causes random scattering;
the scattered rays then interfering to generate an interference pattern. It should be noted that the radiation-scattering structure is formed by stamping with a die bearing a relief pattern. More specifically, a resin layer is stamped by means of said die so as to form the relief pattern therein, which is then covered with an 2 o aluminium reflecting layer. The radiation-scattering structure thereby formed, is then mounted on a support, thereby forming a security device, which in turn is irremovably mounted on an object for which a guarantee of authenticity is desired. The use of the stamping die has the advantage of allowing identical security devices to be manufactured, which will be fixed to objects of identical 25 appearance in order to guarantee their authenticity.
Authentication of an object is performed by checking the security device which is associated with it. The interference pattern of the tested device is compared with the reference interference pattern, obtained under the same irradiation conditions, and the authenticity of the object is confirmed when the interference pattern of the tested device and the reference pattern are identical.
Such a security device provides relatively high security, as it is not conceivable that a potential counterfeiter may make a copy of the radiation-scattering structure capable of generating an interference pattern identical with the reference pattern. However, considering the high sensitivity of the involved physical phenomenon, the possibility of manufacturing by means of the die, a series of identical security devices which generate interference patterns identical with the reference interference pattern, is questionable. Further, if a io counterfeiter would lay hold of the die, he would then be able to readily reproduce the radiation-scattering structure, and therefore also the security device.
Moreover, it should be noted that the security device, which forms an unforgeable identification plate, does not allow a particular object to be identified from a series of objects with an identical appearance. For this, a different security device must be made for each object of the series. However, the aforementioned problem would always remain, i.e. if the security devices were exchanged, it would no longer be possible to identify one object of the series, individually.
2 o Finally, the requirement of fixing an identification plate to the object to be identified or authenticated, may prove to be a problem.
Indeed, it may not be possible to fix the identification plate in a sufficiently secure way. Furthermore, depending on how the object is used, the identification plate may be damaged.
Obiect of the invention (Problem to be solved by the invention) The object of the present invention is to provide a method for identifying an object which does not have the drawbacks of the method using identification plates, and which notably enables an object of a series of objects with identical 3o appearance, to be identified individually. According to the invention, this object is achieved by a method according to claim 1.
r P-CEP-006/WO/GB (as amended) METHOD FOR IDENTIFYING AN OBJECT
Introduction The present invention relates to a method for identifying an object.
State of the art s In order to identify each of the objects of a series of objects with identical appearance, the most standard method consists of fixing an identification plate on each object, each of the identification plates bearing a distinctive mark.
However, if the identification plates are exchanged between several objects of the series, it is no longer possible to identify a particular object of the series with 1 o certainty.
GB-A-2,221,870 relates to a security device for use in an optical method based on the speckle interferometry phenomenon, better known as the "speckle effect". The security device comprises a substrate whereon or wherein there is a structure scattering the radiations. This radiation-scattering structure i5 when it is illuminated by a coherent ray of radiations, causes random scattering;
the scattered rays then interfering to generate an interference pattern. It should be noted that the radiation-scattering structure is formed by stamping with a die bearing a relief pattern. More specifically, a resin layer is stamped by means of said die so as to form the relief pattern therein, which is then covered with an 2 o aluminium reflecting layer. The radiation-scattering structure thereby formed, is then mounted on a support, thereby forming a security device, which in turn is irremovably mounted on an object for which a guarantee of authenticity is desired. The use of the stamping die has the advantage of allowing identical security devices to be manufactured, which will be fixed to objects of identical 25 appearance in order to guarantee their authenticity.
Authentication of an object is performed by checking the security device which is associated with it. The interference pattern of the tested device is compared with the reference interference pattern, obtained under the same irradiation conditions, and the authenticity of the object is confirmed when the interference pattern of the tested device and the reference pattern are identical.
Such a security device provides relatively high security, as it is not conceivable that a potential counterfeiter may make a copy of the radiation-scattering structure capable of generating an interference pattern identical with the reference pattern. However, considering the high sensitivity of the involved physical phenomenon, the possibility of manufacturing by means of the die, a series of identical security devices which generate interference patterns identical with the reference interference pattern, is questionable. Further, if a io counterfeiter would lay hold of the die, he would then be able to readily reproduce the radiation-scattering structure, and therefore also the security device.
Moreover, it should be noted that the security device, which forms an unforgeable identification plate, does not allow a particular object to be identified from a series of objects with an identical appearance. For this, a different security device must be made for each object of the series. However, the aforementioned problem would always remain, i.e. if the security devices were exchanged, it would no longer be possible to identify one object of the series, individually.
2 o Finally, the requirement of fixing an identification plate to the object to be identified or authenticated, may prove to be a problem.
Indeed, it may not be possible to fix the identification plate in a sufficiently secure way. Furthermore, depending on how the object is used, the identification plate may be damaged.
Obiect of the invention (Problem to be solved by the invention) The object of the present invention is to provide a method for identifying an object which does not have the drawbacks of the method using identification plates, and which notably enables an object of a series of objects with identical 3o appearance, to be identified individually. According to the invention, this object is achieved by a method according to claim 1.
General description of the claimed invention with its main advantactes.
A method for identifying an object according to the invention comprises the following steps:
(a) selecting an intrinsic surface of an object to be recognized;
s (b) illuminating at least one identification area in the intrinsic surface of the object to be recognized with coherent light and intercepting at least one portion of the light reflected by the identification area, in order to obtain an interference pattern under determined illumination and interception conditions;
to (c) retaining this interference pattern as a reference interference pattern for the object to be recognized;
(d) placing a candidate object liable to be the object to be recognized under the same illumination and interception conditions as those used for obtaining the reference interference pattern and obtaining is a~n interference pattern from this candidate object;
(e) comparing the reference interference pattern with the interference pattern of the candidate object; and (f) evaluating the probability of identity between the object to be recognized and the candidate object according to the matching 20 level between the reference interference pattern and the candidate object's interference pattern.
By "intrinsic surface" of the object to be recognized, it is meant a surface specific to the object, which is an integral part of it, as opposed to a surtace which would belong to a device fixed on the object for an identification purpose.
2s The method according to the invention uses an optical interference phenomenon, known as "speckle interferometry", for identifying an object.
When an object, which is not an ideal specular reflector is illuminated by a coherent light, microscopic variations on its surface shift the phase of the reflected and scattered light. If this light is intercepted, for example on a screen, 3 o an interference pattern may be observed, or a "speckle" pattern, produced by interferences between the phase-shifted components of this light. In the method according to the invention, an interference pattern obtained under determined illumination and interception conditions is considered as a unique imprint of the surface of the scanned object. Indeed, considering the complexity of the phenomenon involved, sensitive to surface variations on a micron scale, only the same object replaced under the same determined conditions will be s able to produce a substantially identical interference pattern. Thus, in accordance with the method according to the invention, the interference pattern of an object to be recognized is retained as a reference interference pattern, a unique imprint allowing its identification. When it is subsequently desired to identify this object to be recognized, from a plurality of candidate objects liable to to be the object to be recognized, it is sufficient to place each candidate object under the same illumination and interception conditions as those used for obtaining the reference interference pattern and obtain the interference pattern therefrom. A high matching level between an interference pattern obtained for a candidate object and the reference interference pattern will allow the identity of i5 both objects to be confirmed with a high likelihood, i.e. the candidate object is actually the object to be recognized. A first advantage of the present method is its sensitivity, which makes it tamperproof. Indeed, the method is sensitive to surface variations on the micron scale, whereby it is therefore difficult to imagine a replacement of the object to be recognized, with a copy.
2 o A second advantage of the method according to the invention, is that it does not require any labeling, any treatment, of the object to be recognized.
Indeed, the natural surface state of the object to be recognized is preferably used. This means using the actual surface of the object which is therefore an integral part of the latter, and which has not undergone any specific treatment 2s for standardizing the interference pattern which it is susceptible to produce.
From the method according to the invention, it is sufficient to select a portion of the intrinsic surface of the object, i.e. the identification area, in order to obtain the interference pattern from it, and to store this interference pattern as a reference pattern, a unique imprint of the object, allowing its identification 3 o subsequently. The identification of the object may then be performed by obtaining an interference pattern of the same identification area, under the same irradiation conditions and by comparing it with the stored reference pattern. Generally, the surface of the identification area would be a surface machined by a machine tool, subsequently to the shaping of the object, for example. But the resulting surface profile resulting from such shaping is random. Therefore, the surface of the object at the identification area level, has s a random non . standardized profile. Consequently, this identification area is radically different from an identification area which would have undergone a specific treatment, for example die-stamping for standardizing the interference pattern liable to be produced by this identification area. As a result, it is impossible for a potential counterfeiter to reproduce the surface of the to identification area by appropriating a specific treatment technique, as none exist.
In addition, it will be noted that in the present identification method, it is unnecessary to attach an identification device to the object for its subsequent identification, this simplifies implementation of the method. In particular, this eliminates any attachment or deterioration problem of the identification device.
The method according to the invention, therefore provides a secure and unforgeable identification of an object, and in particular enables an object to be identified individually from a series of objects with identical appearance.
Another advantage is that the identification of the object is performed 2 o without any direct contact, which prevents any wear of the identification area and of the surface reading means, which is a light beam here.
Preferably, the coherent light source is a laser beam focused on the identification area. Conventional laser sources may be used, for example of the HeNe type, or a laser diode, the latter providing more flexibility in its use.
Advantageously, the identification area will have a surface from 0.001 to 0.1 mm2, preferably of the order of magnitude of 0.01 m2.
Preferably, the identification area has a peak-to-peak roughness larger than the quarter of the laser's wavelength. The identification area may notably have a peak-to-peak roughness of 0.15 to 0.20 Nm, which is the case for most 3 o unpolished metal surfaces. Lasers which radiate in the red, may thus be used.
Interception of the reflected light by the identification area may simply be performed by a screen. However, the reflected light will preferably be intercepted with a camera or a charge coupled device, which allows the interference patterns to be directly acquired onto computer means. The reference interference pattern may therefore be retained on a computer medium. Moreover, the matching level between the reference interference pattern and the interference pattern of a candidate object, is advantageously determined by image processing computer means which provides more objectivity.
Preferably, the computer means used enable the interference patterns to be stored and compared, comprising an indication of the intensity of the to reflected light, for example by means of gray levels. Indeed, an interference pattern comprising indications of the intensity of the reflected light is more significative than for example a binarized (black and white) image. Such an interference pattern with its gray levels is therefore richer in information on the examined identification area. The number of interference spots required for the identification may therefore be smaller and consequently the dimension of the identification area may be reduced. This also means, that by using interference patterns for example with gray levels, a smaller amount of scattering centers is sufficient, as compared with binarized interference patterns.
Such a method for identifying objects, may advantageously be 2 o developed in order to operate in access control systems, i.e., systems providing the triggering of an action equivalent to an authorization after checking the identity of an object introduced into this system. However, it may also be used for identifying sensitive objects such as nuclear fuel cells. Within this context, it has the advantage of being able to be implemented under water.
Description with the help of the figures Other features and characteristics of the invention will become apparent from the detailed description of an advantageous embodiment discussed below, by way of illustration, with reference to the appended drawings wherein:
3 o Fig. 1 is a diagram illustrating reflection of light on a polished surface;
Fig. 2 is a diagram illustrating reflection of light on a rough surface;
Fig. 3 is a diagram of an assembly for implementing a preferred embodiment of the method according to the invention;
Fig. 4 is a speckle pattern.
The method according to the invention uses an optical interference phenomenon known as speckle interferometry, for identifying objects. When a s surface is illuminated by an optical beam, all the elementary points of this surface reflect the incident light. In the case of a mirror type surface, these points all reflect in the same direction as illustrated in Fig. 1. In the case of a rough surface, which generally is the case, the elementary points reflect in all spatial directions, this is called scattering. If the incident beam is coherent, the to surface reflects and scatters in all spatial directions, elementary beams which may interfere. By intercepting the elementary beams reflected on the screen, for example, an interference pattern or speckle pattern is obtained, consisting of more or less bright spots as shown in Fig. 4. Such an interference pattern is sensitive to surface changes on the micron scale.
15 Thus, according to an important aspect of the invention, it is considered that an interference pattern produced by a given surface portion, under determined illumination and interception conditions is unique. Another surface portion from the same object or from a different object under the same conditions will provide a different interference pattern. Such an interference 2o pattern, therefore forms a unique imprint of a surface and rnay be used for identifying an object.
The method for identifying objects according to the invention was developed on the basis of this observation. An illustration of an assembly for implementing a preferred embodiment of this method, is illustrated in Fig. 3.
2s Reference 10 shows a laser source which is a laser diode Lepton II (Micro Laser System) providing the emission of a monochromatic coherent light beam with a diameter of 6 mm and with insignificant divergence. The light beam emerging from the laser diode is reflected on a separator 12 towards a target object 14. As explained, the incident light beam is reflected and scattered by 3 o the surface of the target object 14. A camera 16 enables a portion of the light reflected by the surface of the target object 14 to be intercepted in order to obtain an interference pattern. A "planar-convex" type lens 18 mounted between the target object 14 and the separator 12, focuses the incident beam on the surface of the target 14 and acts as a diaphragm for collecting the beam reflected by the surface of the target object 14. With a filter 20, placed in front of the camera 16 and only letting through the light with the same wavelength as the laser 10, it is possible to ignore the ambient light conditions. The separator 12 performs the separation of the light sent back by the target object from the incident beam. Its orientation is such that parasitic reflections do not form on the sensor of the camera 16. It will be noted that a compact assembly may be obtained by using the separator 12, as the incident and reflected beams follow 1 o the same optical path between the separator 12 and the target object 14.
By using a camera 16 connected to a computer, it is possible to proceed with direct acquisition of the interference patterns and to retain them as computer files. Further, the analysis of the interference pattern may be performed more objectively by means of data processing software packages. Preferably, the images of the stored interterence patterns comprise an indication of the intensity of the reflected light, materialized by gray levels.
In a first step (step 1 ) of the method according to the invention, the target object 14 of Fig. 3 is an object to be recognized. The object to be recognized is positioned in a determined location, as defined for example by positioning 2 o blocks. One then proceeds with the acquisition of an interference pattern of an intrinsic surface portion of the object to be recognized, called the identification area, under determined conditions for the illumination and interception of reflected light, which are stored. An "intrinsic surface" means a surface specific to the object which is an integral part of it. The interference pattern is then retained (step 2) in the computer as a reference interference pattern of the object to be recognized. It should be noted that the surface of the identification area has not undergone any specific treatment, but that it has its natural (or rough) surface condition, and it therefore has a random surface profile, generally resulting from the machining of the object.
3 o With the present method, this object to be recognized may subsequently be identified among other objects. Thus, according to step 3, a candidate object likely to be the object to be recognized is placed in the same position, while providing the same illumination and interception conditions as those used for obtaining the reference interference pattern, the conditions of step 1. Here, it is a question inter alia . of positioning the object so that it is in the same configuration (distance, orientation, centering) with respect to the optical s instruments of the assembly as during step 1. The obtained interference pattern is then compared (step 4) with the reference interference pattern by means of the image processing software package. A matching level between the interference pattern and the reference interference pattern is thereby determined from which the probability of an identity between the object to be 1 o recognized and the candidate object may be evaluated.
The identification area of the object to be recognized may have a very small surface area of the order of 0.01 mm2. To properly observe the interference phenomenon, the identification area preferably should have peak-to-peak height surface changes larger than a quarter of the laser's wavelength.
15 This is therefore referred to as Rt (peak-to-peak amplitude) roughness and not as Ra roughness. For example, the roughness may have a value of about 0.16 Nm when working with a red laser at 0.633 Nm.
It will be noted that the optical system, i.e., the configuration of the assembly of Fig. 3, as well as the laser's intensity are the most significant 2 o parameters when obtaining an interference pattern. This is why in step 3, the same illumination (laser intensity) and interception (same assembly configuration) conditions as those in step 1 are reproduced. If these conditions are observed and the current candidate object is the object to be recognized, an interference pattern substantially identical with the reference interference 2s pattern will be obtained, obviously subject to the proviso that the observed surface portion is indeed the same as the one in step 1. It is therefore important to properly position the candidate object under the assembly of Fig. 3. For example, when rectangular objects with equal heights are used, an object support may be provided with positioning blocks, positioned at right angles.
All 3 o the samples will then be secured against these blocks, which provides excellent reproducibility in positioning. Thus, if the current candidate object is the object to be recognized, the incident beam will automatically be on the identification area.
to As indicated earlier, the present method may advantageously be applied for identifying nuclear fuel cells. A surface portion of this fuel is then used as an identification area. Within this context, the method has the advantage of being s able to be implemented under water. For example, a base, comprising the laser and the camera at a certain distance from the fuel cells to be identified, may be set up and the latter may be approached by a probe connected to the base by means of optical fibers.
A method for identifying an object according to the invention comprises the following steps:
(a) selecting an intrinsic surface of an object to be recognized;
s (b) illuminating at least one identification area in the intrinsic surface of the object to be recognized with coherent light and intercepting at least one portion of the light reflected by the identification area, in order to obtain an interference pattern under determined illumination and interception conditions;
to (c) retaining this interference pattern as a reference interference pattern for the object to be recognized;
(d) placing a candidate object liable to be the object to be recognized under the same illumination and interception conditions as those used for obtaining the reference interference pattern and obtaining is a~n interference pattern from this candidate object;
(e) comparing the reference interference pattern with the interference pattern of the candidate object; and (f) evaluating the probability of identity between the object to be recognized and the candidate object according to the matching 20 level between the reference interference pattern and the candidate object's interference pattern.
By "intrinsic surface" of the object to be recognized, it is meant a surface specific to the object, which is an integral part of it, as opposed to a surtace which would belong to a device fixed on the object for an identification purpose.
2s The method according to the invention uses an optical interference phenomenon, known as "speckle interferometry", for identifying an object.
When an object, which is not an ideal specular reflector is illuminated by a coherent light, microscopic variations on its surface shift the phase of the reflected and scattered light. If this light is intercepted, for example on a screen, 3 o an interference pattern may be observed, or a "speckle" pattern, produced by interferences between the phase-shifted components of this light. In the method according to the invention, an interference pattern obtained under determined illumination and interception conditions is considered as a unique imprint of the surface of the scanned object. Indeed, considering the complexity of the phenomenon involved, sensitive to surface variations on a micron scale, only the same object replaced under the same determined conditions will be s able to produce a substantially identical interference pattern. Thus, in accordance with the method according to the invention, the interference pattern of an object to be recognized is retained as a reference interference pattern, a unique imprint allowing its identification. When it is subsequently desired to identify this object to be recognized, from a plurality of candidate objects liable to to be the object to be recognized, it is sufficient to place each candidate object under the same illumination and interception conditions as those used for obtaining the reference interference pattern and obtain the interference pattern therefrom. A high matching level between an interference pattern obtained for a candidate object and the reference interference pattern will allow the identity of i5 both objects to be confirmed with a high likelihood, i.e. the candidate object is actually the object to be recognized. A first advantage of the present method is its sensitivity, which makes it tamperproof. Indeed, the method is sensitive to surface variations on the micron scale, whereby it is therefore difficult to imagine a replacement of the object to be recognized, with a copy.
2 o A second advantage of the method according to the invention, is that it does not require any labeling, any treatment, of the object to be recognized.
Indeed, the natural surface state of the object to be recognized is preferably used. This means using the actual surface of the object which is therefore an integral part of the latter, and which has not undergone any specific treatment 2s for standardizing the interference pattern which it is susceptible to produce.
From the method according to the invention, it is sufficient to select a portion of the intrinsic surface of the object, i.e. the identification area, in order to obtain the interference pattern from it, and to store this interference pattern as a reference pattern, a unique imprint of the object, allowing its identification 3 o subsequently. The identification of the object may then be performed by obtaining an interference pattern of the same identification area, under the same irradiation conditions and by comparing it with the stored reference pattern. Generally, the surface of the identification area would be a surface machined by a machine tool, subsequently to the shaping of the object, for example. But the resulting surface profile resulting from such shaping is random. Therefore, the surface of the object at the identification area level, has s a random non . standardized profile. Consequently, this identification area is radically different from an identification area which would have undergone a specific treatment, for example die-stamping for standardizing the interference pattern liable to be produced by this identification area. As a result, it is impossible for a potential counterfeiter to reproduce the surface of the to identification area by appropriating a specific treatment technique, as none exist.
In addition, it will be noted that in the present identification method, it is unnecessary to attach an identification device to the object for its subsequent identification, this simplifies implementation of the method. In particular, this eliminates any attachment or deterioration problem of the identification device.
The method according to the invention, therefore provides a secure and unforgeable identification of an object, and in particular enables an object to be identified individually from a series of objects with identical appearance.
Another advantage is that the identification of the object is performed 2 o without any direct contact, which prevents any wear of the identification area and of the surface reading means, which is a light beam here.
Preferably, the coherent light source is a laser beam focused on the identification area. Conventional laser sources may be used, for example of the HeNe type, or a laser diode, the latter providing more flexibility in its use.
Advantageously, the identification area will have a surface from 0.001 to 0.1 mm2, preferably of the order of magnitude of 0.01 m2.
Preferably, the identification area has a peak-to-peak roughness larger than the quarter of the laser's wavelength. The identification area may notably have a peak-to-peak roughness of 0.15 to 0.20 Nm, which is the case for most 3 o unpolished metal surfaces. Lasers which radiate in the red, may thus be used.
Interception of the reflected light by the identification area may simply be performed by a screen. However, the reflected light will preferably be intercepted with a camera or a charge coupled device, which allows the interference patterns to be directly acquired onto computer means. The reference interference pattern may therefore be retained on a computer medium. Moreover, the matching level between the reference interference pattern and the interference pattern of a candidate object, is advantageously determined by image processing computer means which provides more objectivity.
Preferably, the computer means used enable the interference patterns to be stored and compared, comprising an indication of the intensity of the to reflected light, for example by means of gray levels. Indeed, an interference pattern comprising indications of the intensity of the reflected light is more significative than for example a binarized (black and white) image. Such an interference pattern with its gray levels is therefore richer in information on the examined identification area. The number of interference spots required for the identification may therefore be smaller and consequently the dimension of the identification area may be reduced. This also means, that by using interference patterns for example with gray levels, a smaller amount of scattering centers is sufficient, as compared with binarized interference patterns.
Such a method for identifying objects, may advantageously be 2 o developed in order to operate in access control systems, i.e., systems providing the triggering of an action equivalent to an authorization after checking the identity of an object introduced into this system. However, it may also be used for identifying sensitive objects such as nuclear fuel cells. Within this context, it has the advantage of being able to be implemented under water.
Description with the help of the figures Other features and characteristics of the invention will become apparent from the detailed description of an advantageous embodiment discussed below, by way of illustration, with reference to the appended drawings wherein:
3 o Fig. 1 is a diagram illustrating reflection of light on a polished surface;
Fig. 2 is a diagram illustrating reflection of light on a rough surface;
Fig. 3 is a diagram of an assembly for implementing a preferred embodiment of the method according to the invention;
Fig. 4 is a speckle pattern.
The method according to the invention uses an optical interference phenomenon known as speckle interferometry, for identifying objects. When a s surface is illuminated by an optical beam, all the elementary points of this surface reflect the incident light. In the case of a mirror type surface, these points all reflect in the same direction as illustrated in Fig. 1. In the case of a rough surface, which generally is the case, the elementary points reflect in all spatial directions, this is called scattering. If the incident beam is coherent, the to surface reflects and scatters in all spatial directions, elementary beams which may interfere. By intercepting the elementary beams reflected on the screen, for example, an interference pattern or speckle pattern is obtained, consisting of more or less bright spots as shown in Fig. 4. Such an interference pattern is sensitive to surface changes on the micron scale.
15 Thus, according to an important aspect of the invention, it is considered that an interference pattern produced by a given surface portion, under determined illumination and interception conditions is unique. Another surface portion from the same object or from a different object under the same conditions will provide a different interference pattern. Such an interference 2o pattern, therefore forms a unique imprint of a surface and rnay be used for identifying an object.
The method for identifying objects according to the invention was developed on the basis of this observation. An illustration of an assembly for implementing a preferred embodiment of this method, is illustrated in Fig. 3.
2s Reference 10 shows a laser source which is a laser diode Lepton II (Micro Laser System) providing the emission of a monochromatic coherent light beam with a diameter of 6 mm and with insignificant divergence. The light beam emerging from the laser diode is reflected on a separator 12 towards a target object 14. As explained, the incident light beam is reflected and scattered by 3 o the surface of the target object 14. A camera 16 enables a portion of the light reflected by the surface of the target object 14 to be intercepted in order to obtain an interference pattern. A "planar-convex" type lens 18 mounted between the target object 14 and the separator 12, focuses the incident beam on the surface of the target 14 and acts as a diaphragm for collecting the beam reflected by the surface of the target object 14. With a filter 20, placed in front of the camera 16 and only letting through the light with the same wavelength as the laser 10, it is possible to ignore the ambient light conditions. The separator 12 performs the separation of the light sent back by the target object from the incident beam. Its orientation is such that parasitic reflections do not form on the sensor of the camera 16. It will be noted that a compact assembly may be obtained by using the separator 12, as the incident and reflected beams follow 1 o the same optical path between the separator 12 and the target object 14.
By using a camera 16 connected to a computer, it is possible to proceed with direct acquisition of the interference patterns and to retain them as computer files. Further, the analysis of the interference pattern may be performed more objectively by means of data processing software packages. Preferably, the images of the stored interterence patterns comprise an indication of the intensity of the reflected light, materialized by gray levels.
In a first step (step 1 ) of the method according to the invention, the target object 14 of Fig. 3 is an object to be recognized. The object to be recognized is positioned in a determined location, as defined for example by positioning 2 o blocks. One then proceeds with the acquisition of an interference pattern of an intrinsic surface portion of the object to be recognized, called the identification area, under determined conditions for the illumination and interception of reflected light, which are stored. An "intrinsic surface" means a surface specific to the object which is an integral part of it. The interference pattern is then retained (step 2) in the computer as a reference interference pattern of the object to be recognized. It should be noted that the surface of the identification area has not undergone any specific treatment, but that it has its natural (or rough) surface condition, and it therefore has a random surface profile, generally resulting from the machining of the object.
3 o With the present method, this object to be recognized may subsequently be identified among other objects. Thus, according to step 3, a candidate object likely to be the object to be recognized is placed in the same position, while providing the same illumination and interception conditions as those used for obtaining the reference interference pattern, the conditions of step 1. Here, it is a question inter alia . of positioning the object so that it is in the same configuration (distance, orientation, centering) with respect to the optical s instruments of the assembly as during step 1. The obtained interference pattern is then compared (step 4) with the reference interference pattern by means of the image processing software package. A matching level between the interference pattern and the reference interference pattern is thereby determined from which the probability of an identity between the object to be 1 o recognized and the candidate object may be evaluated.
The identification area of the object to be recognized may have a very small surface area of the order of 0.01 mm2. To properly observe the interference phenomenon, the identification area preferably should have peak-to-peak height surface changes larger than a quarter of the laser's wavelength.
15 This is therefore referred to as Rt (peak-to-peak amplitude) roughness and not as Ra roughness. For example, the roughness may have a value of about 0.16 Nm when working with a red laser at 0.633 Nm.
It will be noted that the optical system, i.e., the configuration of the assembly of Fig. 3, as well as the laser's intensity are the most significant 2 o parameters when obtaining an interference pattern. This is why in step 3, the same illumination (laser intensity) and interception (same assembly configuration) conditions as those in step 1 are reproduced. If these conditions are observed and the current candidate object is the object to be recognized, an interference pattern substantially identical with the reference interference 2s pattern will be obtained, obviously subject to the proviso that the observed surface portion is indeed the same as the one in step 1. It is therefore important to properly position the candidate object under the assembly of Fig. 3. For example, when rectangular objects with equal heights are used, an object support may be provided with positioning blocks, positioned at right angles.
All 3 o the samples will then be secured against these blocks, which provides excellent reproducibility in positioning. Thus, if the current candidate object is the object to be recognized, the incident beam will automatically be on the identification area.
to As indicated earlier, the present method may advantageously be applied for identifying nuclear fuel cells. A surface portion of this fuel is then used as an identification area. Within this context, the method has the advantage of being s able to be implemented under water. For example, a base, comprising the laser and the camera at a certain distance from the fuel cells to be identified, may be set up and the latter may be approached by a probe connected to the base by means of optical fibers.
Claims (11)
1. A method for identifying an object wherein at least one identification area is illuminated with coherent light and at least one portion of the light reflected by said identification area is intercepted, so as to obtain an interference pattern under determined illumination and interception conditions, and then said interference pattern is used for identifying said object, characterized by the following steps:
(a) selecting an intrinsic area of an object to be recognized, which has not undergone any specific treatment for standardizing the interference pattern which it is susceptible to produce;
(b) illuminating at least one identification area in said intrinsic surface of said object to be recognized with a coherent light and intercepting at least one portion of the light reflected by said identification area, in order to obtain an interference pattern under determined illumination and interception conditions;
(c) retaining this interference pattern as a reference interference pattern of the object to be recognized;
(d) placing a candidate object likely to be the object to be recognized under the same illumination and interception conditions as those used for obtaining said reference interference pattern and obtaining an interference pattern from this candidate object;
(e) comparing said reference interference pattern with said interference pattern of the candidate object; and (f) evaluating the probability of identity between the object to be recognized and the candidate object depending on the matching level between said reference interference pattern and said interference pattern of the candidate object.
(a) selecting an intrinsic area of an object to be recognized, which has not undergone any specific treatment for standardizing the interference pattern which it is susceptible to produce;
(b) illuminating at least one identification area in said intrinsic surface of said object to be recognized with a coherent light and intercepting at least one portion of the light reflected by said identification area, in order to obtain an interference pattern under determined illumination and interception conditions;
(c) retaining this interference pattern as a reference interference pattern of the object to be recognized;
(d) placing a candidate object likely to be the object to be recognized under the same illumination and interception conditions as those used for obtaining said reference interference pattern and obtaining an interference pattern from this candidate object;
(e) comparing said reference interference pattern with said interference pattern of the candidate object; and (f) evaluating the probability of identity between the object to be recognized and the candidate object depending on the matching level between said reference interference pattern and said interference pattern of the candidate object.
2. A method according to claim 1, characterized in that the source of coherent light is a laser beam focused on said identification area.
3. A method according to claim 1 or 2, characterized in that said identification area has a surface area from 0.001 to 0.1 mm2.
4. A method according to claim 1, 2 or 3, characterized in that said identification area has a surface of the order of magnitude of 0.01 mm2.
5. A method according to any one of the preceding claims, characterized in that said identification area has a peak-to-peak roughness, which is larger than a quarter of the laser's wavelength.
6. A method according to claim 5, characterized in that said identification area has a peak-to-peak roughness from 0.15 to 0.20 pm.
7. A method according to any one of the preceding claims, characterized in that the reflected light is intercepted by means of a screen, a camera or a charge coupled device.
8. A method according to any one of the preceding claims, characterized in that one proceeds with the acquisition of interference patterns, with computer means and in that the reference interference pattern is retained on a computer medium.
9. A method according to any one of the preceding claims, characterized in that the matching level between said reference interference pattern and said interference pattern of the candidate object is determined by image processing computer means.
10. A method according to claim 8 or 9, characterized in that said computer means allows interterence patterns to be stored and compared, comprising an indication of the intensity of the reflected light.
11. A method according to any one of the preceding claims, characterized in that said intrinsic surface is a machined surface of said object to be recognized.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU90580A LU90580B1 (en) | 2000-05-08 | 2000-05-08 | Method of identifying an object |
| LU90580 | 2000-05-08 | ||
| PCT/EP2001/005147 WO2001086589A1 (en) | 2000-05-08 | 2001-05-07 | Method for identifying an object |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2407433A1 true CA2407433A1 (en) | 2001-11-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002407433A Abandoned CA2407433A1 (en) | 2000-05-08 | 2001-05-07 | Method for identifying an object |
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|---|---|
| US (1) | US6741360B2 (en) |
| EP (1) | EP1281161B1 (en) |
| JP (1) | JP2003534536A (en) |
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| CA (1) | CA2407433A1 (en) |
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| ES (1) | ES2215896T3 (en) |
| LU (1) | LU90580B1 (en) |
| NO (1) | NO20025345L (en) |
| WO (1) | WO2001086589A1 (en) |
Families Citing this family (59)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8171567B1 (en) | 2002-09-04 | 2012-05-01 | Tracer Detection Technology Corp. | Authentication method and system |
| US7869057B2 (en) * | 2002-09-09 | 2011-01-11 | Zygo Corporation | Multiple-angle multiple-wavelength interferometer using high-NA imaging and spectral analysis |
| US7139081B2 (en) * | 2002-09-09 | 2006-11-21 | Zygo Corporation | Interferometry method for ellipsometry, reflectometry, and scatterometry measurements, including characterization of thin film structures |
| FR2849245B1 (en) * | 2002-12-20 | 2006-02-24 | Thales Sa | METHOD FOR AUTHENTICATION AND OPTICAL IDENTIFICATION OF OBJECTS AND DEVICE FOR IMPLEMENTING THE SAME |
| US7106454B2 (en) * | 2003-03-06 | 2006-09-12 | Zygo Corporation | Profiling complex surface structures using scanning interferometry |
| US7324214B2 (en) * | 2003-03-06 | 2008-01-29 | Zygo Corporation | Interferometer and method for measuring characteristics of optically unresolved surface features |
| TWI334921B (en) | 2003-09-15 | 2010-12-21 | Zygo Corp | Surface profiling using an interference pattern matching template |
| GB2411954B (en) * | 2004-03-12 | 2006-08-09 | Ingenia Technology Ltd | Authenticity verification methods,products and apparatuses |
| BRPI0508631A (en) * | 2004-03-12 | 2007-08-07 | Ingenia Technology Ltd | apparatus for determining a signature of an article arranged in a reading volume, use of the apparatus, methods for identifying an article made of paper or cardboard, an article made of plastic, a product by its packaging, a document, a garment or footwear, and a disc, method for tagging an article, and, tagged article |
| WO2005088517A1 (en) | 2004-03-12 | 2005-09-22 | Ingenia Technology Limited | Methods and apparatuses for creating authenticatable printed articles and subsequently verifying them |
| DE102004018856A1 (en) * | 2004-04-19 | 2005-11-03 | Giesecke & Devrient Gmbh | Apparatus for checking banknotes |
| FR2870376B1 (en) | 2004-05-11 | 2006-09-22 | Yann Boutant | METHOD FOR RECOGNIZING FIBROUS MEDIA, AND APPLICATIONS OF SUCH A METHOD IN THE COMPUTER FIELD, IN PARTICULAR |
| WO2005114096A2 (en) * | 2004-05-18 | 2005-12-01 | Zygo Corporation | Methods and systems for determining optical properties using low-coherence interference signals |
| US7667570B1 (en) | 2004-05-19 | 2010-02-23 | Lockheed Martin Corporation | Nanostructured combination key-lock |
| US20060012582A1 (en) * | 2004-07-15 | 2006-01-19 | De Lega Xavier C | Transparent film measurements |
| US7982868B2 (en) * | 2004-07-30 | 2011-07-19 | Eagle Vision Systems B.V. | Apparatus and method for checking of containers |
| GB2417592B (en) * | 2004-08-13 | 2006-07-26 | Ingenia Technology Ltd | Authenticity verification of articles |
| US7884947B2 (en) * | 2005-01-20 | 2011-02-08 | Zygo Corporation | Interferometry for determining characteristics of an object surface, with spatially coherent illumination |
| US7428057B2 (en) | 2005-01-20 | 2008-09-23 | Zygo Corporation | Interferometer for determining characteristics of an object surface, including processing and calibration |
| EP1851678A2 (en) * | 2005-02-08 | 2007-11-07 | Koninklijke Philips Electronics N.V. | Optical speckle pattern investigation |
| GB2426100B (en) * | 2005-05-11 | 2007-08-22 | Ingenia Technology Ltd | Authenticity vertification |
| US20060294583A1 (en) * | 2005-05-11 | 2006-12-28 | Ingenia Holdings (U.K.) Limited | Authenticity Verification |
| GB2429097B (en) * | 2005-07-27 | 2008-10-29 | Ingenia Technology Ltd | Verification |
| WO2007012816A1 (en) * | 2005-07-27 | 2007-02-01 | Ingenia Technology Limited | Verification of authenticity |
| JP2009503976A (en) * | 2005-07-27 | 2009-01-29 | インゲニア・テクノロジー・リミテッド | Verification of article signatures generated from signals obtained from the scattering of coherent light radiation from the surface of the article |
| RU2008107328A (en) * | 2005-07-27 | 2009-09-10 | Инджениа Текнолоджи Лимитед (Gb) | AUTHENTICITY CERTIFICATION |
| GB2428846B (en) * | 2005-07-27 | 2008-08-13 | Ingenia Technology Ltd | Prescription Authentication |
| JP2009503672A (en) * | 2005-07-27 | 2009-01-29 | インゲニア・テクノロジー・リミテッド | Prescription authentication using speckle patterns |
| GB2429095B (en) * | 2005-07-27 | 2008-08-13 | Ingenia Technology Ltd | Verification of authenticity |
| GB2429950B (en) * | 2005-09-08 | 2007-08-22 | Ingenia Holdings | Copying |
| WO2007044786A2 (en) * | 2005-10-11 | 2007-04-19 | Zygo Corporation | Interferometry method and system including spectral decomposition |
| US7624928B2 (en) * | 2005-11-18 | 2009-12-01 | Fuji Xerox Co., Ltd. | Method and apparatus for making tags, tag, and system for managing articles |
| EP1791079A1 (en) * | 2005-11-25 | 2007-05-30 | Fuji Xerox Co., Ltd. | Method and apparatus for making tags, tag, and system for managing articles |
| EP1969525A1 (en) * | 2005-12-23 | 2008-09-17 | Ingenia Holdings (UK)Limited | Optical authentication |
| GB2434442A (en) * | 2006-01-16 | 2007-07-25 | Ingenia Holdings | Verification of performance attributes of packaged integrated circuits |
| GB2440386A (en) * | 2006-06-12 | 2008-01-30 | Ingenia Technology Ltd | Scanner authentication |
| WO2008011510A2 (en) * | 2006-07-21 | 2008-01-24 | Zygo Corporation | Compensation of systematic effects in low coherence interferometry |
| EP1898365A1 (en) * | 2006-08-23 | 2008-03-12 | E.I. Dupont de Nemours and Company | Method and apparatus for verifying the authenticity of an item by detecting encoded luminescent security markers |
| US7643147B2 (en) * | 2006-11-03 | 2010-01-05 | Neuropace, Inc. | Method and system for device identification |
| JP5502491B2 (en) * | 2006-12-22 | 2014-05-28 | ザイゴ コーポレーション | Apparatus and method for characterization of surface features |
| US7889355B2 (en) | 2007-01-31 | 2011-02-15 | Zygo Corporation | Interferometry for lateral metrology |
| GB2450131B (en) * | 2007-06-13 | 2009-05-06 | Ingenia Holdings | Fuzzy Keys |
| US7619746B2 (en) * | 2007-07-19 | 2009-11-17 | Zygo Corporation | Generating model signals for interferometry |
| US8072611B2 (en) * | 2007-10-12 | 2011-12-06 | Zygo Corporation | Interferometric analysis of under-resolved features |
| KR101274517B1 (en) * | 2007-11-13 | 2013-06-13 | 지고 코포레이션 | Interferometer utilizing polarization scanning |
| US8126677B2 (en) | 2007-12-14 | 2012-02-28 | Zygo Corporation | Analyzing surface structure using scanning interferometry |
| GB2460625B (en) * | 2008-05-14 | 2010-05-26 | Ingenia Holdings | Two tier authentication |
| GB2462409A (en) * | 2008-07-11 | 2010-02-10 | Ingenia Holdings | Signature of moulded article |
| US8004688B2 (en) | 2008-11-26 | 2011-08-23 | Zygo Corporation | Scan error correction in low coherence scanning interferometry |
| GB2466311B (en) | 2008-12-19 | 2010-11-03 | Ingenia Holdings | Self-calibration of a matching algorithm for determining authenticity |
| GB2466465B (en) * | 2008-12-19 | 2011-02-16 | Ingenia Holdings | Authentication |
| NL2004539A (en) * | 2009-06-22 | 2010-12-23 | Asml Netherlands Bv | Object inspection systems and methods. |
| GB2476226B (en) | 2009-11-10 | 2012-03-28 | Ingenia Holdings Ltd | Optimisation |
| CN104297260B (en) | 2014-11-04 | 2017-10-10 | 广州广电运通金融电子股份有限公司 | A kind of non-contact type detection method and device of thin-medium |
| IL240872A (en) | 2015-08-27 | 2016-11-30 | Elbit Systems Land & C4I Ltd | System and method for object authenticity detection |
| CN107534553B (en) * | 2015-09-24 | 2021-02-26 | 锡克拜控股有限公司 | Re-authentication of certificates |
| IL245932A (en) | 2016-05-30 | 2017-10-31 | Elbit Systems Land & C4I Ltd | System for object authenticity detection including a reference image acquisition module and a user module and methods therefor |
| US10354963B2 (en) * | 2017-12-12 | 2019-07-16 | Eastman Kodak Company | Decoding information embedded in an electronic element |
| DE102020213161A1 (en) | 2020-10-19 | 2022-04-21 | Robert Bosch Gesellschaft mit beschränkter Haftung | LiDAR system and control method with surface roughness determination |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8812890D0 (en) * | 1988-05-31 | 1988-07-06 | De La Rue Co Plc | Security device & methods & apparatus for verification |
| DE4408226C2 (en) * | 1994-03-11 | 1997-08-28 | Peter Dr Ing Lehmann | Measuring device for the process-related determination of the roughness of technical surfaces by evaluating di- or polychromatic speckle patterns |
| EP0768511A1 (en) * | 1995-10-16 | 1997-04-16 | European Community | Optical three-dimensional profilometry method based on processing speckle images in partially coherent light, and interferometer implementing such a method |
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2000
- 2000-05-08 LU LU90580A patent/LU90580B1/en active
-
2001
- 2001-05-07 ES ES01927944T patent/ES2215896T3/en not_active Expired - Lifetime
- 2001-05-07 US US10/258,233 patent/US6741360B2/en not_active Expired - Fee Related
- 2001-05-07 WO PCT/EP2001/005147 patent/WO2001086589A1/en active IP Right Grant
- 2001-05-07 DK DK01927944T patent/DK1281161T3/en active
- 2001-05-07 DE DE60102150T patent/DE60102150T2/en not_active Expired - Lifetime
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- 2001-05-07 AT AT01927944T patent/ATE260495T1/en not_active IP Right Cessation
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- 2001-05-07 CA CA002407433A patent/CA2407433A1/en not_active Abandoned
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2002
- 2002-11-07 NO NO20025345A patent/NO20025345L/en not_active Application Discontinuation
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| EP1281161B1 (en) | 2004-02-25 |
| ATE260495T1 (en) | 2004-03-15 |
| NO20025345D0 (en) | 2002-11-07 |
| AU5483001A (en) | 2001-11-20 |
| JP2003534536A (en) | 2003-11-18 |
| DK1281161T3 (en) | 2004-07-05 |
| WO2001086589A1 (en) | 2001-11-15 |
| LU90580B1 (en) | 2001-11-09 |
| NO20025345L (en) | 2003-01-08 |
| US6741360B2 (en) | 2004-05-25 |
| DE60102150D1 (en) | 2004-04-01 |
| DE60102150T2 (en) | 2004-08-26 |
| EP1281161A1 (en) | 2003-02-05 |
| ES2215896T3 (en) | 2004-10-16 |
| US20030156294A1 (en) | 2003-08-21 |
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