Contactless determination of coating characteristics

Abstract

Contactless determination of coating characteristics. A system for contactless determination of characteristics of a layered coating is provided. The system comprises a determiner unit and a measuring unit having a coating scanner, a vibration detector and an optical arrangement. The coating scanner comprises a protection-level transmitter that emits scanning radiation and a protection-level receiver that senses interaction radiation formed by the interaction of the scanning radiation with a layer of the coating. The vibration detector comprises a protection-level transmitter that emits detection radiation and a protection-level sensor that senses reflected radiation formed by reflection of the detection radiation on the coating to detect vibrations of the coating based on the reflected radiation. The optical arrangement directs the scanning radiation and / or the detection radiation toward a common radiation direction and directs the interaction radiation toward the protection-level receiver and / or directs the reflected radiation toward the protection-level sensor. The determiner unit determines the coating characteristics based on the interaction radiation and the vibrations. Methods and computer programs that can be executed in the system are also provided.

Description

Technical Field

[0001] The present disclosure relates to a system for contactless determination of one or more characteristics of a coating having different layers. The present disclosure also relates to a method that can be performed in or by such a system and to a computer program suitable for performing said method.

[0002] This application claims the benefit of European patent application EP20382744 filed on August 12, 2020. Background Art

[0003] In the prior art, different methods and systems are known for contactless determination of characteristics of a coating having one or more layers. A typical coating characteristic extracted by the known methods and systems is the thickness of the coating or the thickness of individual layers of the coating.

[0004] Some of the known methods and systems are not suitable for environments with interfering elements, such as dust, water, paint particles or other external agents, which are typically present in, for example, production lines. The methods and systems are based on very sensitive components and may therefore produce distorted results due to interference caused by dust, water, paint particles or other interfering agents.

[0005] Some other known methods and systems for contactless determination of the characteristics of a coating do not produce good results due to vibrations. It is known that vibrations are real and unavoidable in production lines. Therefore, the other methods and systems are not suitable for environments with vibrations of the type described.

[0006] It is an object of the present disclosure to provide new methods, systems and computer programs aimed at solving at least some of the aforementioned problems. Summary of the invention

[0007] In one aspect, a system for contactlessly determining one or more characteristics of a coating having one or more layers is provided. The system comprises a plurality of units, the plurality of units having a determiner unit and a measuring unit. The measuring unit comprises a coating scanner, a vibration detector, and an optical arrangement. The coating scanner comprises an ingress-protected transmitter and an ingress-protected receiver, the ingress-protected transmitter being configured to transmit scanning radiation in use, the ingress-protected receiver being configured to sense interaction radiation formed by the interaction of the scanning radiation with the one or more layers of the coating in use. The vibration detector comprises an ingress-protected transmitter and an ingress-protected sensor, the ingress-protected transmitter being configured to transmit detection radiation in use, the ingress-protected sensor being configured to sense reflected radiation formed by reflection of the detection radiation on the coating in use, to detect vibrations of the coating based on the reflected radiation. The optical arrangement is configured to direct the scanning radiation and / or the detection radiation towards a common radiation direction in use, and / or to direct the interaction radiation towards the ingress-protected receiver and / or to direct the reflected radiation towards the ingress-protected sensor in use. The determiner unit is configured to determine the one or more characteristics of the coating based on the interacting radiation sensed by the coating scanner and the vibrations detected by the vibration detector.

[0008] The proposed system allows to obtain very effective results in environments with vibrations and interfering particles (for example, dust, water, paint particles, etc.). A typical environment of this type is, for example, a production line. Compared with the systems of the prior art, the proposed system allows the protection-grade coating scanner and the protection-grade vibration detector to coexist and cooperate in the same system in a more reliable way. The optical arrangement structure allows the corresponding radiation emitted by the coating scanner and the vibration detector to converge on the final path to impinge on substantially the same point or area of ​​the coating. Therefore, a dual effect is obtained at the same time with the proposed system: the protection-grade coating scanner and the protection-grade vibration detector coexist in the same system, and have reliable vibration compensation, because the radiation emitted by both the coating scanner and the vibration detector is guided to contact substantially the same point or area of ​​the coating. This coincidence of the impact point or area means that the vibration is detected at the same point where the coating is being inspected, so a more reliable vibration compensation can be applied.

[0009] The level of protection used in the system according to the present disclosure may meet corresponding standards, including classification and grades of the degree of protection provided by mechanical housings and electrical enclosures against intrusion, dust, accidental contact, and water. Examples of such standards are, for example, European standard EN 60529, IEC standard 60529, etc. The IEC standard 60529 is sometimes referred to as the International Protection Code and is published by the International Electrotechnical Commission (IEC).

[0010] According to some implementations, the optical arrangement may include: at least one reflector configured to reflect the scanning radiation and / or the detection radiation towards a common radiation direction in use, and at least one reflector configured to reflect the interaction radiation towards a protection-level receiver and / or the reflected radiation towards a protection-level sensor in use. Each of the reflectors may be movable so that the inclination of the reflector may be adjusted to optimize the reflection of the scanning radiation and / or the detection radiation on the corresponding reflector and the reflection of the interaction radiation and / or the reflected radiation on the corresponding reflector. In some configurations, the at least one reflector for reflecting the scanning radiation and / or the detection radiation and the at least one reflector for reflecting the interaction radiation and / or the reflected radiation may be the same at least one reflector. In some examples, only a single reflector is sufficient to cause all reflections.

[0011] In a configuration, the optical arrangement structure may include: at least one lens configured to direct the scanning radiation and / or the detection radiation towards a common radiation direction in use, and at least one lens configured to direct the interaction radiation towards a protection-level receiver and / or the reflected radiation towards a protection-level sensor in use. In some configurations, the at least one lens for directing the scanning radiation and / or the detection radiation and the at least one lens for directing the interaction radiation and / or the reflected radiation may be the same at least one lens. In some examples, only a single lens is sufficient to cause all desired directing. The directing of the corresponding radiation by one or more lenses may be achieved by suitable focusing features and / or appropriate collimation features and / or transparency features and / or any other convenient optical features of one or more lenses.

[0012] In some examples, the plurality of units may include a positioner unit configured to, in use, move the measurement unit towards a target position relative to the coating to be inspected. The target position may be such that, in use, the common radiation direction is substantially perpendicular to the coating. The target position may be such that, in use, the protection level transmitter of the coating scanner and / or the protection level transmitter of the vibration detector is at a target distance from the coating.

[0013] The locator unit may include a position detector configured to detect when the measuring unit reaches the target position. The position detector may be based on, for example, a set of triangulation sensors, which may or may not be assisted by a vibration detector. Such a triangulation system may use information from the vibration detector to detect when the measuring unit reaches the target position. In this way, the target position may be detected more reliably. The locator unit may include an actuator configured to move the measuring unit towards the target position. The actuator may, for example, include a robot arm or the like.

[0014] In some configurations, the coating scanner may be a Terahertz or THz scanner.

[0015] In another aspect, a method for contactlessly determining one or more characteristics of a coating having one or more layers is provided. The method comprises: operating a coating scanner (in a measuring unit), operating a vibration detector (in a measuring unit), and operating a determiner unit. The coating scanner is operated so that a protection-level transmitter of the coating scanner emits scanning radiation, and a protection-level receiver of the coating scanner senses interaction radiation formed by the interaction of the scanning radiation with the one or more layers of the coating. The vibration detector is operated so that a protection-level transmitter of the vibration detector emits detection radiation, and a protection-level sensor of the vibration detector senses reflected radiation formed by reflection of the detection radiation on the coating to detect vibrations of the coating based on the reflected radiation. An optical arrangement (in the measuring unit) directs the scanning radiation and / or the detection radiation toward a common radiation direction, and directs the interaction radiation toward the protection-level receiver and / or directs the reflected radiation toward the protection-level sensor. The determiner unit is operated so that the one or more characteristics of the coating are determined based on the interaction radiation sensed by the coating scanner and the vibration detected by the vibration detector.

[0016] In some examples, the step of operating the determiner unit may include: generating a simulated signal based on the physical model; and performing an optimization process to optimize one or more parameters of the physical model to modify the simulated signal until the simulated signal fits the interaction radiation sensed by the protection-level receiver of the coating scanner. The optimization process may be based on at least one of the following techniques: discrete differential evolution, terrain global optimization, basin-hopping, SHG, or dual annealing. The optimization process may be an adaptive and iterative optimization process with a stopping criterion based on an error function. The optimization process is performed in the time domain and / or the frequency domain.

[0017] When the deviation between the simulated signal and the sensed interaction radiation is within an acceptability threshold, the simulated signal may be determined to fit the sensed interaction radiation.

[0018] The one or more characteristics of the coating may be determined according to the optimized one or more parameters of the physical model, which parameters characterize the interaction of the scanning radiation with the one or more layers of the coating, since the optimized parameters have fitted the simulation signal to the sensed interaction radiation. In particular, the one or more characteristics of the coating may be determined according to the optimized one or more parameters of the physical model and according to vibration compensation based on vibrations detected by the vibration detector.

[0019] In some implementations, the method may further include the following steps: storing in a knowledge base knowledge acquired during the execution of the method, the knowledge may include one or more knowledge items, such as, for example, an optimized physical model, one or more optimized parameters of the physical model, the evolution of the one or more parameters during the optimization process, one or more determined characteristics of the coating, the correlation / relationship between the one or more determined characteristics and one or more other knowledge items, etc.

[0020] The optimization process may include retrieving an optimized physical model from a knowledge base, the optimized physical model to be used as the physical model for generating the simulation signal.

[0021] Operating the coating scanner to sense the interaction radiation may include applying one or more filtering techniques for noise reduction to the sensed interaction radiation. Filtering techniques for noise reduction may include, for example, recursive least squares filters, Wiener-Kolmogorov filters, minimum mean square error, Kalman filters, Bishrink filters, theoretical noise-free representations of the sensed interaction radiation, genetic algorithms combined with adaptive thresholding, matched filters and thresholding functions together with transform techniques such as Fourier, Wavelet, and Empirical Mode Decomposition (EMD), etc.

[0022] The one or more coating characteristics that can be determined by the method according to the present disclosure may include one or more of the following characteristics: number of layers, thickness of each layer, layer mixing level, refractive index of each layer, electrical parameters of each layer, magnetic parameters of each layer, electromagnetic parameters of each layer, Fresnel coefficient, propagation constant, propagation angle, roughness.

[0023] In yet another aspect, a computer program comprising program instructions for causing a computing system to perform a method for contactless determination of coating characteristics, such as those described in other parts of this disclosure, is provided. The computer program may be embodied on a storage medium and / or carried on a carrier signal.

[0024] On the other hand, a computing system for contactless determination of coating characteristics is provided, the computing system comprising a memory and a processor, so as to specifically implement instructions stored in the memory and executable by the processor, and the instructions include one or more functions for performing a method for contactless determination of coating characteristics, such as those described in other parts of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Non-limiting examples of the present disclosure will be described below with reference to the accompanying drawings, in which:

[0026] Figure 1 is a block diagram schematically illustrating a system for contactless determination of coating characteristics according to an example.

[0027] Figure 2 is a block diagram schematically illustrating a system for contactless determination of coating characteristics according to another example.

[0028] Figure 3a and Figure 3b is a block diagram schematically illustrating different examples of a system for contactless determination of coating characteristics according to the present disclosure.

[0029] Figure 4 is a flow chart schematically illustrating a method for contactless determination of coating characteristics according to an example. DETAILED DESCRIPTION

[0030] Figure 11 is a block diagram schematically illustrating a system for contactless determination of characteristics of a coating 100 according to an example. The coating 100 may include a layer 102 having an outermost layer 101 and an innermost layer 116. As generally illustrated in the figure, such a system for contactless determination of characteristics of a layered coating 100 may include a plurality of units or modules having a determiner unit or module (not shown) and a measuring unit or module 103 including a coating scanner module 104, a vibration detector module 105, and an optical arrangement module 106. The coating scanner 104 may include an ingress-protected transmitter 107 and an ingress-protected receiver 109, the ingress-protected transmitter 107 being configured in such a way that, in use, it transmits scanning radiation 108, and the ingress-protected receiver 109 being configured in such a way that, in use, it senses interaction radiation 110 formed by the interaction of the scanning radiation 108 with the layer 102 of the coating 100. The vibration detector 105 may include a protection-level transmitter 111 and a protection-level sensor 113, wherein the protection-level transmitter 111 is configured in such a manner that it sends or emits detection radiation 112 during use, and the protection-level sensor 113 is configured in such a manner that it receives reflected radiation 114 formed by reflection of the detection radiation 112 on the coating 100 during use to detect vibration of the coating 100 based on the reflected radiation 114.

[0031] according to Figure 1 , the scanning radiation 108 can be emitted substantially perpendicular to the coating 100, and the detection radiation 112 can be emitted with its longitudinal axis substantially perpendicular to the longitudinal axis of the scanning radiation 108. The interaction radiation 110 can follow the expected "reverse" path formed by the interaction of the scanning radiation 108 with the layer 102 of the coating 100 (from the coating 100 to the coating scanner 104). Similarly, the reflected radiation 114 can also follow the expected "reverse" path formed by the reflection of the detection radiation 112 on the coating 100 (from the coating 100 to the vibration detector 105). In an alternative arrangement, the arrangements of the coating scanner 104 and the vibration detector 105 can be interchanged with each other, and the overall arrangement can produce the same as the reference arrangement. Figure 1 The effects described are the same or similar effects.

[0032] The optical arrangement 106 may be configured in such a way that, in use, the scanning radiation 108 and / or the detection radiation 112 are directed towards a common radiation point / direction 115 and the interaction radiation 110 is directed towards a protection level receiver 109 and / or the reflected radiation 114 is directed towards a protection level sensor 113. In particular, Figure 1As shown generally, the optical arrangement 106 may include a reflector 106 c configured to reflect the detection radiation 112 (from the protection-grade transmitter 111) toward a common radiation point / direction 115 and to reflect the reflected radiation 114 (from the coating 100) toward the protection-grade sensor 113. In an alternative implementation, the detection radiation 112 may be emitted "directly" (i.e., without any redirection or reflection) perpendicularly toward the coating 100, while the corresponding reflector may reflect the scanning radiation 108 perpendicularly toward the coating 100 and reflect the interaction radiation 110 toward the protection-grade receiver 109.

[0033] according to Figure 1 In the specific example of FIG. 1 , in each case, the mirror 106 c can change the direction of the detection radiation 112 and the reflected radiation 114 by approximately 90°. This is consistent with the fact that in the specific example described, the scanning radiation 108 is emitted "directly", i.e., without any redirection / reflection, and substantially perpendicularly towards the coating 100, while the detection radiation 112 is emitted substantially perpendicularly to the scanning radiation 108. The same or similar principles can apply to the interaction radiation 110 and the reflected radiation 114, but in opposite directions relative to the scanning radiation 108 and the detection radiation 112, respectively.

[0034] The mirror 106 c may be movable to adjust the tilt of the mirror 106 c in order to optimize the reflection of the scanning radiation 108 and / or the detection radiation 112 and the reflection of the interaction radiation 110 and / or the reflected radiation 114 .

[0035] like Figure 1 As shown, the optical arrangement 106 may include a lens 106a having one side 118 facing the interior of a housing 117 of the measurement unit 103 and another side 119 facing the exterior of the housing 117. The lens 106a may have, for example, the function of collimating and / or focusing the scanning radiation 108 toward a common radiation point / direction 115, and a similar function for directing the interaction radiation 110 from the coating 100 toward a protection-grade receiver 109 in a "reverse" direction. The optical arrangement 106 may also include optical hardware or conditioning 106b for appropriately conditioning the scanning radiation 108 before it reaches the lens 106a. Thus, the optical hardware 106b and the lens 106a may optically cooperate to optimize the convergence of the scanning radiation 108 toward the common radiation point / direction 115. The optical hardware or conditioner 106 b may be movable and adjustable to properly optimize the conditioning of the scanning radiation 108 before it reaches the lens 106 a and to properly optimize the conditioning of the interaction radiation 110 before it reaches the protection grade receiver 109 .

[0036] Figure 1 The diagram includes an upper main schema and a lower schema, which corresponds to a more detailed view of a specific implementation and / or arrangement of the coating scanner 104. The lower schema shows the coating scanner 104 from a viewpoint 120 at a lateral side of the coating scanner 104, clearly showing the protection level receiver 109 and the protection level transmitter 107. The protection level receiver 109 can be arranged at a slope or angle 122 relative to the common radiation direction / point 115. The protection level transmitter 107 can be arranged at a slope or angle 121 relative to the common radiation direction / point 115.

[0037] The lower diagram also schematically illustrates the effect of the lens 106a (i.e., collimation and / or focusing properties or parameters) and the emission angle 121 on converging the scanned radiation 108 towards the common radiation point / direction 115. The lower diagram also schematically illustrates the effect of the lens 106a (i.e., collimation and / or focusing properties or parameters) and the reception angle 122 on the path of the interaction radiation 110 towards the protection-grade receiver 109. The described arrangement of the protection-grade transmitter 107 and the receiver 109, the effect of the lens 106a on the scanned radiation 108 and the interaction radiation 110, and the resulting tilts / angles 121, 122 allow any interference of the scanned radiation 108 and the interaction radiation 110 with the reflector 106c to be avoided. Each protection-grade transmitter 107 may be configured to cause a specific angle of incidence and / or a specific polarization of the scanned radiation 108, and its corresponding protection-grade receiver 109 may be arranged according to the specific angle of incidence and / or specific polarization. The arrangement, lens-related, and angle-based principles described with respect to the coating scanner 104 may be equally or similarly applied to the vibration detector 105 with the same or similar effects.

[0038] The determiner unit (not shown) may be configured to determine the one or more characteristics of the coating 100 based on the interaction radiation 110 sensed by the coating scanner 104 (e.g., signals and / or data characterizing the interaction radiation) and the vibrations detected by the vibration detector 105 (e.g., signals and / or data characterizing the vibrations). Thus, the determiner unit may be connected to the coating scanner 104 and the vibration detector 105, such that the determiner unit (not shown in this figure) may receive signals and / or data characterizing the interaction radiation 110 (from the coating scanner 104) and the vibrations of the coating 100 (from the vibration detector 105). The determiner unit (not shown) may be remotely arranged relative to the measurement unit 103.

[0039] The coating scanner 104 is a terahertz or THz scanner. The protection-grade receiver 109 and the protection-grade transmitter 107 may be antenna-based, such as, for example, one or more photoconductive LT-InGaAs antennas. The coating scanner 104 may include one or more light generators (not shown). The light generator may be a laser generator. The coating scanner 104 may include one or more delay lines (not shown), including: a movable delay line for the coating scanner 104 to operate with different scan windows, and / or a delay line adjustable by hardware for the coating scanner 104 to operate with a scan window that can be adjusted by displacement of the delay line.

[0040] Figure 2 2 is a block diagram schematically illustrating a system for contactless determination of characteristics of a coating 200 according to another example. The coating 200 may include several layers 202, including an outermost layer 201 and an innermost layer 216. Some components in the measurement unit 203 may be identical to or similar to Figure 1 For example, the coating scanner 204 having the protection level transmitter 207 and the protection level receiver 209 can be similar to Figure 1 The coating scanner 104 with a protection-grade transmitter 107 and a protection-grade receiver 109. The details regarding the scanning radiation 208 and the interaction radiation 210 can therefore be similar to those regarding Figure 1 The scanning radiation 108 and the interaction radiation 110 described above. The determiner unit or module (not shown) may also be similar to that described with respect to Figure 1 The described determiner unit.

[0041] Relative to Figure 1 The difference may be in the optical arrangement 206, in Figure 2 In the case of Figure 1 The optical arrangement 206 may include a reflector 106c similar to Figure 1 The lens 206a may be arranged relative to the housing 217 of the measuring unit 203, wherein one side 218 of the lens 206a faces the interior of the housing 217 and the other side 219 of the lens 206a faces the exterior of the housing 217. The lens 206a may be transparent to the scanning radiation 208 and the interaction radiation 210 as well as to the detection radiation 212 and the reflected radiation 214. The optical arrangement 206 may also include a lens similar to Figure 1 The optical hardware or adjuster 206b of the optical hardware or adjuster 106b is arranged at a position 220 between the coating scanner 204 and the vibration detector 205 and the lens 206a, as shown in FIG. Figure 1 The vibration detector 205 with the protection-level transmitter 211 and the protection-level sensor 213 can be similar to Figure 1 The vibration detector 105 having a protection-grade transmitter 111 and a protection-grade sensor 113, but with Figure 1 This different arrangement allows to avoid Figure 1 The mirror 106c is not necessary because there is no need to redirect / reflect the detection radiation 212 and the reflected radiation 214. Figure 2 As shown, the vibration detector 205 can be arranged between the protection level transmitter 207 and the protection level receiver 209 of the coating scanner 204. The scanning radiation 208 and the detection radiation 212 can be similar to the reference Figure 1 Convergence towards a common radiation point / direction 215 is explained, but reflections of the detection radiation 212 are not required. Figure 1 Similar considerations for the slopes or angles 121, 122 in FIG. 1 may apply to the slopes or angles 221, 222. In an alternative arrangement, the arrangements of the coating scanner 204 and the vibration detector 205 may be interchanged with one another, and the overall arrangement may produce the same arrangement as in the reference arrangement. Figure 2 The effects described are the same or similar effects.

[0042] Figure 3a is a block diagram schematically illustrating a system for contactless determination of coating characteristics according to yet another example. As generally shown in the figure, the system for contactless determination of coating characteristics can be used to inspect a paint coating 302 on a vehicle (such as a car 301) in or out of a corresponding production line. The system according to the present disclosure can be applicable to inspecting any layered coating on any product or object having a coating in or out of a production line.

[0043] The system for contactless determination of coating characteristics may include a positioner unit 300 configured to move a measurement unit 303a toward a target position relative to the coating 302. The measurement unit 303a may be identical to or similar to any of the measurement units 103, 203 described herein. Therefore, the positioner unit 300 may be reused in the following description of FIG. Figure 1 and Figure 2 The label of .

[0044] The target position of the measuring unit 303a may correspond to a position such that the common radiation point / direction 115, 215 is substantially perpendicular to the coating 302. Additionally or alternatively, the target position may correspond to a position of the protection-grade transmitter 107, 207 of the coating scanner 104, 204 and / or the protection-grade transmitter 111, 211 of the vibration detector 105, 205 at a target distance 310 from the coating 302. The coating scanner 104, 204 and its components (protection-grade transmitter 107, 207, protection-grade receiver 109, 209, etc.) and the vibration detector 105, 205 and its components (protection-grade transmitter 111, 211, protection-grade sensor 113, 213, etc.) and the optical arrangement 106, 206 may be adjustable to define different possible target distances 310.

[0045] The locator unit 300 may include a position detector (not shown) configured to detect when the measurement unit 303a reaches the target position. The position detector may be based on, for example, a set of triangulation sensors. The locator unit 300 may include an actuator configured to move the measurement unit 303a toward the target position. The actuator may, for example, include a robot arm 304, which may include different articulated joints 305, 306 with corresponding degrees of freedom. The locator unit 300 may include a collision detector configured to detect when the locator unit 300 and / or the measurement unit 303a become too close to an external component during use. The locator unit 300 may also include a collision protector configured to protect the locator unit 300 and / or the measurement unit 303a from damage caused by collision with a certain (some) external component during use.

[0046] like Figure 3a As generally illustrated, a system according to the present disclosure may include a controller unit 309 configured to control all or part of the other units in the system. The control unit 309 may be arranged inside a (e.g., appropriately protected) housing 308, which may also contain a determiner unit 311 or a complementary component 303b of the measurement unit 303a, such as, for example, a light generator, a delay line, etc. For example, the control unit 309 may be configured to send control signals to the robot arm 304, the measurement units 303a, 303b, etc., to appropriately control the respective ones of the units so that they cooperate synchronously and reliably extract features from the coating 302.

[0047] The measurement unit assembly 303a may include some components of the coating scanner 104, 204 and the vibration detector 105, 205, such as, for example, a protection-level transmitter 107, 207, a protection-level receiver 109, 209, a protection-level transmitter 111, 211, a protection-level sensor 113, 213, etc. The measurement unit assembly 303b may include some other components of the coating scanner 104, 204 and the vibration detector 105, 205, such as, for example, an optical generator, a delay line, etc. The measurement unit assemblies 303a and 303b are connected to each other by wired connections 307 of different lengths. Some of these connections may be electrical connections to transmit, for example, control signals, operating signals, data signals, power signals, etc., and some other connections may be used to transmit optical signals. The key characteristics of the optical signal may be preserved by techniques such as dispersion pre-compensation, cables with dispersion compensation, Bragg dispersion compensation, or any other known techniques that can appropriately compensate for distance effects, regardless of the distance cable 307.

[0048] Figure 3b is a block diagram schematically illustrating a system for contactless determination of coating characteristics according to yet another example. According to the figure, the system for contactless determination of coating characteristics may include, for example, Figure 3a 303a, which are connected to common hardware 303b, 309, 311 via connections 307, which common hardware can be contained in, for example, a housing 308. Thus, a single control unit 309, a single determiner unit 311, and a single measurement unit portion 303b can be shared by different systems 300, 303a according to a one-to-many approach (one common hardware 303b, 309, 311 combined with multiple systems 300, 303a). The functionality of this one-to-many configuration can be similar to the one-to-one setup described with respect to other figures, but with common hardware 303b, 309, 311 dedicated to several systems 300, 303a at the same time. In this way, the coating 302 can be analyzed simultaneously at different points or areas of the coated product / object 301, so that more reliable, effective, and complete results can be obtained.

[0049] Figure 4 4 is a flow chart schematically illustrating a method for contactless determination of coating characteristics according to an example. As generally shown in the figure, when a start condition is detected (for example, such as a request to start the method or calling the method from an operator interface, etc.), the contactless determination method can be started (e.g., at block 400). Figure 4 The contactless determination method can be performed by the system according to the previous figures, so that the following Figure 4 The description of Figure 1 , Figure 2 and the reference numerals of FIG. 3 .

[0050] The contactless determination method may also include (e.g., at block 401) operating 401 a coating scanner 104, 204 (in the measurement unit 103, 203) to cause a protection-level transmitter 107, 207 of the coating scanner 104, 204 to emit scanning radiation 108, 208, and to cause a protection-level receiver 109, 209 of the coating scanner 104, 204 to sense interaction radiation 110, 210 formed by the interaction of the scanning radiation 108, 208 with one or more layers 102, 202 of the coating 100, 200. This functionality implemented at block 401 may be implemented by, for example, a coating scanner module (such as previously described with reference to FIG. Figure 1 and Figure 2 The functional details and considerations explained with respect to the modules 104 and 204 can therefore be similarly attributed to the method block 401 .

[0051] The contactless determination method may also include (e.g., at block 402) operating the vibration detector 105, 205 (in the measuring unit 103, 203) to cause the protection-level transmitter 111, 211 of the vibration detector 105, 205 to emit detection radiation 112, 212, and to cause the protection-level sensor 113, 213 of the vibration detector 105, 205 to sense the reflected radiation 114, 214 formed by the reflection of the detection radiation 112, 212 on the coating 100, 200, so as to detect the vibration of the coating 100, 200 based on the reflected radiation 114, 214. The function implemented at block 402 may be implemented by, for example, a vibration detector module (such as previously described with reference to Figure 1 and Figure 2 The functional details and considerations explained with respect to the modules 105 and 205 can therefore be similarly attributed to the method block 402.

[0052] As a whole, refer to Figure 1 and Figure 2 As explained, the optical arrangement structure 106, 206 (in the measuring unit 103, 203) can guide the scanning radiation 108, 208 and / or the detection radiation 112, 212 towards a common radiation point / direction 115, 215, and can guide the interaction radiation 110, 210 towards the protection-level receiver 109, 209 and / or guide the reflected radiation 114, 214 towards the protection-level sensor 113, 213.

[0053] The contactless determination method may in turn include (e.g., at block 403) operating a determiner unit 311 so that one or more features of the coating 100, 200 are determined based on the interacting radiation 110, 210 sensed by the coating scanner 104, 204 and the vibrations detected by the vibration detector 105, 205. The functionality implemented at block 403 may be performed by, for example, a determiner unit or module 311 previously described with reference to other figures. The functional details and considerations explained with respect to the determiner module 311 may therefore be similarly attributed to the method block 403.

[0054] The contactless determination method may also include obtaining data from a knowledge base 405 containing knowledge learned in previous executions to enrich the feature determination performed, for example, at block 403. Similarly, output data or knowledge learned during the current execution may be stored in the knowledge base 405 to enrich the accumulated knowledge for future executions of the method. The knowledge stored or capable of being stored in the knowledge base may include, for example, optimization parameters, optimized models, acceptability thresholds, etc.

[0055] When an end condition is detected (eg, such as once one or more characteristics of the coating 100 , 200 have been determined), the contactless determination method may terminate (eg, at block 404 ).

[0056] The contactless determination method may further include generating a simulated signal based on the physical model, and performing an optimization process to optimize the parameters of the physical model, thereby modifying the simulated signal until the simulated signal fits the interaction radiation 110, 210 sensed by the protection-level receiver 109, 209 of the coating scanner 104, 204. In some configurations, the processing based on the simulated signal and the optimization process may be performed by the determiner unit 311. Therefore, there may be appropriate connections between the determiner unit 311 and the coating scanner 104, 204 and the vibration detector 105, 205 for the determiner unit 311 to receive corresponding data and / or signals from the coating scanner 104, 204 and the vibration detector 105, 205.

[0057] The optimization process can be based on at least one of the following: discrete differential evolution, terrain global optimization, watershed hopping, SHG or dual annealing, etc. Additionally or alternatively, the optimization process can be an adaptive and iterative optimization process with a stopping criterion based on an error function. Additionally or alternatively, the optimization process can be defined as being performed in the time domain and / or frequency domain. When the deviation between the simulated signal and the sensed interaction radiation 110, 210 is within an acceptability threshold, the simulated signal can be assumed to fit the sensed interaction radiation 110, 210. The acceptability threshold can have been defined based on previous experiments and / or based on knowledge accumulated during previous executions of the contactless determination method.

[0058] The characteristics of the coating 100, 200 may be determined according to the optimization parameters of the physical model, taking into account that the optimization parameters have fitted the simulation signal to the sensed interaction radiation 110, 210 and, therefore, characterize the interaction of the scanning radiation 108, 208 with one or more layers of the coating 100, 200. In particular, the characteristics of the coating 100, 200 may be determined according to the optimization parameters of the physical model and also according to the vibration compensation based on the vibrations detected by the vibration detector 105, 205.

[0059] The contactless determination method may also include storing knowledge from the execution of the method in a knowledge base. The knowledge may include knowledge items, such as, for example, an optimized physical model, and / or optimized parameters of the physical model, and / or the evolution of parameters during the optimization process, and / or determined features of the coating 100, 200, and / or correlations / relationships between the determined features and one or more other knowledge items, etc.

[0060] The optimization process may include retrieving an optimized physical model from a previous execution of the method from a knowledge base, and using the retrieved optimized physical model as a physical model for generating a simulation signal in a current execution of the method.

[0061] The coating scanner 104, 204 can be operated to sense the interaction radiation 110, 210 by applying one or more filtering techniques for noise reduction to the sensed interaction radiation 110, 210, and the filtering techniques for noise reduction are, for example, recursive least squares filters, and / or Wiener-Kolmogorov filters, and / or minimum mean square error, and / or Kalman filters, and / or Bishrink filters, and / or theoretical noise-free representations of the sensed interaction radiation 110, 210, and / or genetic algorithms combined with adaptive thresholding, and / or matched filters and thresholding functions together with transformation techniques such as Fourier, wavelet, and empirical mode decomposition (EMD), etc.

[0062] Characteristics of the coating 100, 200 that can be determined by the method according to the present disclosure may include, for example: the number of layers; and / or the thickness of each layer; and / or the layer mixing level; and / or the refractive index of each layer; and / or the electrical parameters of each layer; and / or the magnetic parameters of each layer; and / or the electromagnetic parameters of each layer; and / or the Fresnel coefficient; and / or the propagation constant; and / or the propagation angle; and / or the roughness, etc.

[0063] Therefore, the methods for contactless determination of coating characteristics according to the present disclosure can be considered as adaptive and / or self-learning methods in the sense that they continuously generate knowledge and learn from it. In particular, the proposed method can be adaptive to production, and each time a new coating feature is extracted or determined, the method can learn, for example, the physical model that has been used, and can store this knowledge (for example in a knowledge base) so that the stored knowledge can be used for future executions of the method. The method according to the present disclosure is also adaptive with respect to the model parameters of the physical model, which means that the physical parameters (for example, such as refractive index and absorption index) can be fixed, variable or pre-determined over the frequency bandwidth of the scanning radiation used to inspect the layer of the coating.

[0064] It may or may not be necessary to measure the innermost layer before determining one or more characteristics of the entire coating in the method and system according to the present disclosure. The innermost layer on which the coating can be deposited is also different, for example, ferrous and non-ferrous metals, fiber composite materials, polymer materials (e.g., thermoplastic materials), etc.

[0065] As used herein, the term "module" may be understood to refer to software, firmware, hardware, and / or various combinations thereof. It should be noted that modules are exemplary. Modules may be combined, integrated, separated, and / or replicated to support various applications. Moreover, the functions described herein as being performed by a specific module may be performed by one or more other modules and / or by one or more other devices, instead of performing the function by the described specific module or in addition to performing the function by the described feature module.

[0066] These modules can be implemented across multiple devices, which are associated or linked with the corresponding method for contactless determination of coating features proposed herein, and / or are associated or linked with other components that can be locally or away from each other. In addition, these modules can be moved from one device and added to another device, and / or can be included in two devices associated with the corresponding method for contactless determination of coating features proposed herein. Any software implementation can be tangibly embodied in one or more storage media, for example, such as a memory device, a floppy disk, a compact disc (CD), a digital versatile disc (DVD), or other devices that can store computer code.

[0067] The method for contactless determination of coating characteristics according to the present disclosure can be implemented by computational means, electronic means, or a combination thereof. The computational means can be a set of instructions (e.g., a computer program), and then the method for contactless determination of coating characteristics can include a memory and a processor, thereby specifically implementing the set of instructions stored in the memory and executable by the processor. These instructions can include one or more functions of executing a corresponding method for contactless determination of coating characteristics, for example, as described with reference to other figures.

[0068] In case the method of contactless determination of coating characteristics is implemented only electronically, the controller of the system can be, for example, a CPLD (Complex Programmable Logic Device), an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0069] In the case where the method for contactless determination of coating characteristics is a combination of electronic and computational means, the computational means can be a set of instructions (e.g., a computer program), and the electronic means can be any electronic circuit capable of implementing the corresponding steps of the method for contactless determination of coating characteristics presented herein, such as those described with reference to other figures.

[0070] The computer program may be embodied on a storage medium (eg, CD-ROM, DVD, USB drive, computer memory or read-only memory), or carried on a carrier signal (eg, an electrical or optical carrier signal).

[0071] The computer program may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in implementing the method for contactless determination of coating characteristics according to the present disclosure. The carrier may be any entity or device capable of carrying a computer program.

[0072] For example, the carrier may comprise a storage medium such as a ROM (e.g., a CD ROM or a semiconductor ROM) or a magnetic recording medium (e.g., a hard disk). Furthermore, the carrier may be a transmissible carrier such as an electrical or optical signal, which may be transmitted via an electrical or optical cable or by radio or by other means.

[0073] When the computer program is implemented using a signal that can be directly transmitted through a cable or other device or means, the carrier may be constituted by such a cable or other device or means. Alternatively, the carrier may be an integrated circuit in which the computer program is embedded, the integrated circuit being suitable for executing or being used in executing the method for contactless determination of coating characteristics proposed herein.

[0074] Although only a number of examples are disclosed herein, other alternatives, modifications, uses and / or their equivalents are possible. Moreover, all possible combinations of the examples are also covered. Therefore, the scope of the present disclosure should not be limited to specific examples, but should only be determined by correctly interpreting the attached claims.

Claims

1. A system for contactlessly determining one or more characteristics of a coating (100) having one or more layers (102), the system being characterized in that it comprises a plurality of units, the plurality of units having a determiner unit and a measuring unit (103, 303a), the measuring unit (103, 303a) comprising a coating scanner (104), a vibration detector (105) and an optical arrangement (106); wherein: The coating scanner (104) comprises a protection-grade transmitter (107) configured to transmit scanning radiation (108) in use and a protection-grade receiver (109) configured to sense interaction radiation (110) formed by interaction of the scanning radiation (108) with the one or more layers (102) of the coating (100) in use; wherein: The vibration detector (105) comprises a protection-grade transmitter and a protection-grade sensor (113), wherein the protection-grade transmitter is configured to transmit detection radiation (112) in use, and the protection-grade sensor (113) is configured to sense reflected radiation (114) formed by reflection of the detection radiation (112) on the coating (100) in use, so as to detect vibration of the coating (100) based on the sensed reflected radiation (114); wherein, The optical arrangement (106) is configured to direct the scanning radiation (108) and / or the detection radiation (112) towards a common radiation direction (115) in use, and to direct the interaction radiation (110) towards the protection-level receiver (109) and / or to direct the reflected radiation (114) towards the protection-level sensor (113) in use; and wherein: The determiner unit is configured to determine the one or more characteristics of the coating (100) based on the interaction radiation (110) sensed by the coating scanner (104) and the vibrations detected by the vibration detector (105).

2. The system according to claim 1, characterized in that The optical arrangement structure (106) comprises: at least one reflector (106c) configured to reflect the scanning radiation (108) and / or the detection radiation (112) towards the common radiation direction in use, and at least one reflector (106c) configured to reflect the interaction radiation (110) towards the protection-level receiver (109) and / or reflect the reflected radiation (114) towards the protection-level sensor (113) in use.

3. The system according to claim 2, characterized in that Each of the mirrors (106c) is movable to adjust the inclination of the mirror (106c) to optimize the reflection of the scanning radiation (108) and / or the detection radiation (112) and the reflection of the interaction radiation (110) and / or the reflected radiation (114).

4. The system according to claim 1, characterized in that The optical arrangement structure (106) comprises: at least one lens configured to direct the scanning radiation (108) and / or the detection radiation (112) towards the common radiation direction (115) during use, and at least one lens configured to direct the interaction radiation (110) towards the protection-level receiver (109) and / or the reflected radiation (114) towards the protection-level sensor (113) during use.

5. The system according to claim 1, characterized in that The plurality of units includes a positioner unit (300) configured to move the measurement unit (103, 303a) towards a target position relative to the coating (100).

6. The system according to claim 5, characterized in that The target position is such that, in use, the common radiation direction (115) is substantially perpendicular to the coating (100).

7. The system according to claim 5, characterized in that The target position is such that, in use, the protection level transmitter (107) of the coating scanner (104) and / or the protection level transmitter of the vibration detector (105) is at a target distance from the coating (100).

8. The system according to claim 5, characterized in that The locator unit (300) includes a position detector configured to detect when the measurement unit (103, 303a) reaches the target position.

9. The system according to claim 5, characterized in that The positioner unit (300) comprises an actuator configured to move the measurement unit (103, 303a) towards the target position.

10. The system according to claim 1, characterized in that The coating scanner (104) is a terahertz or THz scanner.

11. A method for contactlessly determining one or more characteristics of a coating (100) having one or more layers (102), the method comprising: operating a coating scanner (104) in a measurement unit (103, 303a) so that a protection-level transmitter (107) of the coating scanner (104) emits scanning radiation (108) and a protection-level receiver (109) of the coating scanner (104) senses interaction radiation (110) formed by interaction of the scanning radiation (108) with the one or more layers (102) of the coating (100); operating the vibration detector (105) in the measuring unit (103, 303a) so that a protection-grade transmitter of the vibration detector (105) emits detection radiation (112), and a protection-grade sensor (113) of the vibration detector (105) senses reflected radiation (114) formed by reflection of the detection radiation (112) on the coating (100), so as to detect vibration of the coating (100) based on the sensed reflected radiation (114); a determiner unit is operated so as to determine the one or more characteristics of the coating (100) based on the interaction radiation (110) sensed by the coating scanner (104) and the vibrations detected by the vibration detector (105); wherein, An optical arrangement (106) in the measuring unit (103, 303a) guides the scanning radiation (108) and / or the detection radiation (112) towards a common radiation direction (115), and guides the interaction radiation (110) towards the protection-level receiver (109) and / or guides the reflected radiation (114) towards the protection-level sensor (113).

12. The method according to claim 11, further comprising: Generate simulation signals based on physical models; An optimization process is performed to optimize one or more parameters of the physical model to modify the simulated signal until the simulated signal fits the interacting radiation (110) sensed by a protection-grade receiver (109) of the coating scanner (104).

13. The method according to claim 12, characterized in that The optimization process is an adaptive and iterative optimization process with a stopping criterion based on an error function with an acceptability threshold.

14. The method according to claim 12, characterized in that The optimization process is performed in the time domain and / or the frequency domain.

15. The method according to claim 12, characterized in that Determining the one or more characteristics of the coating (100) comprises: The one or more characteristics of the coating (100) are determined based on the optimized one or more parameters of the physical model, taking into account that the optimized parameters have fitted the simulated signal to the sensed interaction radiation (110) and therefore the optimized parameters characterize the interaction of the scanning radiation (108) with the one or more layers (102) of the coating (100).

16. The method according to claim 15, characterized in that Determining the one or more characteristics of the coating (100) includes determining the one or more characteristics of the coating (100) based on the optimized one or more parameters of the physical model and based on vibration compensation based on the vibration detected by the vibration detector (105).

17. The method according to claim 13, characterized in that The method also includes: storing knowledge obtained according to executing the method in a knowledge base, the knowledge including at least one of the following knowledge items: an optimized physical model, one or more optimized parameters of the physical model, the evolution of the one or more parameters during the optimization process, one or more determined characteristics of the coating (100), the correlation / relationship between the one or more determined characteristics and one or more other knowledge items, and the evolution of the acceptability threshold.

18. The method according to claim 17, characterized in that The optimization process includes retrieving an optimized physical model from the knowledge base, the optimized physical model to be used as the physical model for generating the simulation signal.

19. A computer program product, characterized in that it comprises program instructions for causing a computing system to execute the method for contactless determination of one or more characteristics of a coating (100) having one or more layers (102) according to claim 11.

20. A computing system for contactlessly determining one or more characteristics of a coating (100), the computing system being characterized in that it includes a memory and a processor, thereby implementing instructions stored in the memory and executable by the processor, the instructions including functions for executing the method for contactlessly determining one or more characteristics of a coating (100) having one or more layers (102) according to claim 11.

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