Object identification system and method

Abstract

A system and method for authenticating an object includes directing a laser beam onto a surface of the object to induce a thermoelastic excitation in a bulk material of the object without altering the surface of the object, wherein the laser beam is pulsed. Surface ultrasound waves at the surface of the object caused by the thermoelastic excitation are detected using a detector. A detection signal is generated using the detected surface ultrasound waves. Digital data is generated using the detection signal. An authenticity of the object is determined by comparing the digital data to reference data stored in a database.

Description

[0001] Related applications

[0002] This application claims the benefits of U.S. Provisional Application No. 62 / 947,230, filed December 12, 2019, and U.S. Patent Application No. 17 / 116,434, filed December 9, 2020. Technical Field

[0003] This invention relates to the authentication, counterfeiting detection, and imitation detection of physical objects. More particularly, it relates to such authentication and detection based on a non-destructive assessment of the unique microstructure of each object. Background Technology

[0004] Providing authentication, detecting counterfeits, identifying imitations, and / or ensuring the definitive identification of an object all rely on proving that the object is identical to the original creation. This challenge applies across disciplines including collectibles, art, medicine, manufactured goods, handicrafts, jewelry, and many others. In many of these fields, the preferred testing methods are non-destructive, ensuring that the original object is not damaged, altered, or destroyed during the examination process.

[0005] Existing methods for providing authentication, detecting counterfeiting, detecting imitation, and / or ensuring the affirmative identification of objects lack the ability to provide a non-destructive method that, with virtual certainty, ensures that the characteristics of an object match or do not match those stored in a database. This invention provides a solution to overcome these challenges. Summary of the Invention

[0006] The aforementioned problems and requirements are addressed by an authentication method comprising guiding a laser beam onto the surface of an object to induce thermoelastic excitation in the object's bulk material without altering the object's surface, wherein the laser beam is pulsed; detecting surface ultrasonic waves at the object's surface induced by the thermoelastic excitation; generating a detection signal using the detected surface ultrasonic waves; generating digital data using the detection signal; and determining the object's authenticity by comparing the digital data with reference data stored in a database.

[0007] An apparatus for analyzing an object having a bulk material and a surface includes a laser configured to generate a laser beam for inducing thermoelastic excitation in the bulk material upon impact with the surface of the object without altering the surface of the object, wherein the laser beam is pulsed; a detector configured to detect surface ultrasonic waves at the object surface induced by thermoelastic excitation and to generate a detection signal using the detected surface ultrasonic waves; a processor configured to generate digital data using the detection signal; and a database configured to determine the authenticity of the object by comparing the digital data with reference data stored in the database.

[0008] Other objects and features of the invention will become apparent upon examination of the specification, claims and drawings. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the identification system of the present invention.

[0010] Figure 2 This is a schematic diagram illustrating the generation of reference data and subsequent query data.

[0011] Figure 3 This is a schematic diagram of an alternative embodiment of the identification system of the present invention.

[0012] Figure 4 This is a schematic diagram of another alternative embodiment of the identification system of the present invention.

[0013] Figure 5 This is a schematic diagram of another alternative embodiment of the identification system of the present invention. Detailed Implementation

[0014] This invention utilizes the uniqueness of the microstructure of the material forming the object. For most microstructures, except those with very few grains, there is no known method to clone, replicate, recreate, or reproduce them. Although the microstructure and elemental composition of the object's surface may change due to environmental influences, wear, oxidation, and other effects, the internal structure remains stable. This combination of stability and non-reproducibility provides an ideal basis for identification used to determine the authenticity of an object (i.e., determining that the object is genuine, making it identical to the previously inquired object, or determining that the object is not genuine, making it a different object or even a forgery).

[0015] For objects of at least a certain size, ultrasound is ideal for inquiring about the microstructure beneath the object's surface with sufficient detail. This makes ultrasound the preferred inquiry method. However, conventional sonographing techniques are not ideal because the physical contact between the probe and the surface can be limited by the examination and carries the risk of damaging the object. Furthermore, conventional sonographing techniques make it difficult to excite precise locations on surfaces, especially complex ones. Certain surface geometries are unfavorable to conventional sonographing techniques. Additionally, conventional sonographing techniques have limitations in their ability to create synchronous broadband excitations across the spectrum.

[0016] Laser-stimulated ultrasound (LSU) has been found to offer reliable performance exceeding that of conventional identification techniques. LSU uses laser pulses to generate rapid, localized heating of the object, creating a thermoelastic shock wave that propagates along the object's surface and through its bulk material. This thermoelastic bulk wave generates an ultrasonic response that is altered by the microstructure of the material beneath the object's surface. The shock wave is broadband, generating excitations across a range of frequencies, enabling broad interrogation of the object across a spectrum ranging from deep-penetrating low-frequency excitations to high-frequency excitations that inquire about smaller feature sizes. The laser beam's power, wavelength, spot size, and pulse duration are configured to generate thermoelastic excitations without ablating the material (i.e., without altering the object's surface), providing non-destructive interrogation. Furthermore, the non-contact nature of laser excitation and detection ensures no damage is caused by physical contact between the probe and the object's surface. Moreover, a wide range of surface geometries can be interrogated without necessarily requiring contact with the probe.

[0017] Figure 1 The diagram illustrates the components of an identification system 1 for analyzing an object. A laser source 10 (e.g., a nanosecond pulsed fiber laser, a picosecond pulsed fiber laser, or a femtosecond pulsed fiber laser) generates a pulsed laser (excitation) beam 12. The pulsed laser beam 12 is directed at the surface 14 of the object 16, whereby the pulsed laser beam 12 strikes and interacts with the object 16 to create thermoelastic waves 18, which penetrate and interact with the microstructure 16a of the object's material. These interactions generate ultrasonic reflected waves 20, which return to the surface 14 of the object 16. Although Figure 1 A single ultrasonic reflected wave 20 from a single microstructural boundary 16a is shown, but it should be understood that many such reflections are created from different depths and locations within the material of the object and return to the surface of the object. This means that the amplitude of the overall ultrasonic shape at any point on the surface 14 of the object (referred to herein as surface ultrasonic wave 22) is the combination (sum) of all ultrasonic reflected waves 20 reaching that point on the surface 14 of the object from within the object.

[0018] The amplitude of the surface ultrasonic wave 22 is measured by a detector 24 at one or more discrete locations. The detector 24 is preferably an interferometer using the Sagnac effect and illuminated by a superluminescent diode. A detection laser beam 26 from the interferometer is directed toward the surface 14 of the object 16, and the vibration amplitude and frequency of the surface ultrasonic wave 22 are extracted from the interference of the frequency of the light 28 of the detection laser beam 26, which bounces due to the surface motion (i.e., by reflection and / or scattering). Specifically, an interference pattern can be created using a ring interferometer, which compares the relative phase of the light traveling in each direction around the ring. A laser Doppler vibrometer (LDV), a well-known scientific instrument for non-contact vibration measurement of surfaces, can also be used as the detector 24. The detection laser beam 26 from the LDV is directed toward the surface 14 of the object 16, and the vibration amplitude and frequency are extracted from the Doppler shift of the frequency of the light 28 of the detection laser beam 26, which bounces due to the surface motion (i.e., by reflection and / or scattering). Specifically, the vibrometer is typically a dual-beam laser interferometer that measures the frequency (or phase) difference between an internal reference beam and the light 28 reflected from the surface 14 of the object. The most common laser type used in LDV is a helium-neon laser, although laser diodes, fiber lasers, and Nd:YAG lasers are also used. The detection laser beam 26 is directed at the object surface 14, and the reflected light 28 from the object surface 14 is collected by a detector 24 and interferes with the reference beam on a photodetector (typically a photodiode). The output of the photodetector is a standard frequency modulated (FM) signal, where the Bragg unit frequency is used as the carrier frequency and the Doppler shift as the modulation frequency. This signal can be demodulated to derive the velocity versus time relationship of the vibrating target. The detector output is a detection signal 30, which is typically a continuous analog voltage signal proportional to the velocity component of the surface ultrasonic wave 22 along the direction of the detection laser beam 26. Although Figure 1 A single laser source 10 and a single detector 24 are shown, but one or more laser sources 10 can be used simultaneously with one or more detectors 24. The position of one or more laser sources 10 relative to the surface 14 can be stationary or moving, combined with the position of one or more detectors 24 relative to the surface 14 being stationary or moving, wherein the measurement is performed at one or more discrete locations on the surface 14.

[0019] The detection signal 30 is provided to the signal processor 32, which digitizes and / or otherwise processes the detection signal 30 into digital data suitable for digital processing and storage. This digital data is then preferably stored in the database 34 as interrogation data 36 (for subsequent interrogation of the object 16 to determine its authenticity) or as reference data 38 (for the initial interrogation of the object 16). Authentication or forgery detection is then enabled because identical objects will have the same internal microstructure away from the surface 14, and therefore, interrogation using ultrasound as described above will produce a substantially similar response in terms of the detection signal. This response is seen in the spatial variation of the surface ultrasound waves 22, as reflected in the detection signal 30. Other non-microstructural properties, such as mesoscale cracks, voids, porosity, compositional variations, and inclusions, can also contribute to the uniqueness of the detection signal 30 for any given object 16. The ultrasonic response of thermoelastic waves to grain structure and boundaries is particularly important for determining whether the object 16 is the same as the object from which the reference data 38 was initially generated.

[0020] Reference data 38 in database 34 can be generated from any query executed at a time earlier than subsequent queries. This earlier time can be a previous query, or, when more than two queries have been executed, any earlier query or combination of earlier queries can be used. Figure 2 The diagram conceptually illustrates the initialization interrogation on the left, where reference data 38 is created and stored, and the subsequent authentication interrogation on the right, where interrogation data 36 is created and compared with reference data 38 to determine authentication. As shown, the identification system 1 used to create the reference data does not need to have any interrogation data 36 already stored. The authentication system 1 used to create the reference data 38 may be physically the same as or physically different from the authentication system 1 used to create the interrogation data 36. If they are physically different systems, then the reference data 38 of one database 34 can be transferred to the database 34 of another system performing the subsequent interrogation. Alternatively, a single database 34 may be physically separate from the different laser sources 10, detectors 24, and processors 32 used to collect the reference and interrogation data 38 / 36.

[0021] Then, if the difference(s) between query data 36 and reference data 38 is below one or more thresholds, then authentication is determined. Thus, database 34 is configured to provide a determination of authentication when the difference(s) is below the threshold(s), and a determination of non-authentication when the difference(s) is above the threshold(s). Specifically, the determination of the similarity of objects 16 can use thresholds, variable thresholds depending on scan parameters, deep learning or machine learning interpretations, human interpretations, statistical correlation methods, or any combination of these methods and other similar analytical techniques. Query and reference data 36 / 38 can be graphically displayed and compared. Examples of analytical and / or comparative methods include principal component analysis, multiple regression, binning histograms, scale-invariant feature transformations, accelerated robust feature techniques, robust independent fundamental features, rotationally robust independent fundamental features, shape histograms based on local energy, gradient location and orientation histograms, structural similarity indices, oriented gradient histograms, Haar-like features, eigenvalue analysis, wavelet-based analysis, spectral decomposition, and / or mean squared error. These examples are presented as illustrative purposes and do not represent a comprehensive set of techniques that can be used individually or in combination.

[0022] Grain boundaries and their corresponding locations are used directly or indirectly through their interaction with the thermoelastic waves 18 that generate ultrasonic reflected waves 20. The sum of the ultrasonic reflected waves 20 is detected as surface ultrasonic waves 22, which are used to generate interrogation and reference data 36 / 38. Therefore, while the exact location of grain boundaries, their orientation, shape, the orientation of the grain lattice, the location of the grain structure, and any combination of these properties may not be precisely determined, they do provide a reproducible effect, as reflected in the interrogation and reference data 36 / 38, which serve as unique markers for object 16. Data regarding the grain structure does not need to be complete to provide sufficient information for authentication or counterfeit detection.

[0023] The influence of grain boundaries and grain structure on ultrasound can be determined using a pitch-catch configuration of the laser ultrasonic laser beam 12 and detector beam 26 (or transducer 46 described below). By analyzing the data to select only frequencies corresponding to the size of grain boundary features, portions of the detection signal 30 or interrogation / reference data 36 / 38 associated only with internal grain boundaries can be extracted from the surface wave 22. The range for reliable detection of grain boundaries is approximately 20 MHz and higher. Spectral decomposition and spectral bracketing can be used to extract portions of the detection signal 30 or interrogation / reference data 36 / 38 associated with the desired spectral range. Filters (e.g., high-pass filters) can be applied to retain portions of the detection signal 30 or interrogation / reference data 36 / 38 associated with values ​​above a specified threshold (e.g., 20 MHz). Collecting multiple records and deconvolving these records as the detector 24 moves relative to a fixed excitation source improves the resolution and / or repeatability of grain boundary information. As detector 24 changes its angle relative to surface 14, multiple records are collected (i.e., light 28 reflected from the surface at two or more discrete angles relative to surface 14 is collected), and deconvolution of these multi-angle records also improves the resolution and / or repeatability of grain boundary information. Grain boundaries are indicated by rapid changes in the material's wave velocity. Edge detection, clustering, and many other techniques can be applied to identify these rapid velocity changes.

[0024] Laser-based ultrasonic interrogation can be performed using single pulses, multiple pulses, or pulses applied continuously at a set or variable frequency. Any arrangement of these pulse modes can be used. The laser source 10 can be Q-switched, mode-locked, pulse-pumped, or use other means to create pulse output. The laser beam 12 can be single-wavelength, broadband, or have a selected wavelength range or set of ranges. These pulses can be focused on specific points, scanned along a line, scanned over a region, or scanned over multiple points, lines, or regions, where these locations are discrete from each other. Any arrangement of these locations can be used. For authentication and counterfeit detection, recording and storing the scanned locations on the object in a database (e.g., as part of reference / interrogation data 38 / 36) provides useful information for achieving accurate integration of the same areas of the object. The selection of points can be completely random, partially random, or deterministic.

[0025] The relationship between sound velocity and material elasticity and density can be used to understand material properties from ultrasonic reflection. Furthermore, the relationship between sound attenuation and sound scattering and absorption can be used to understand material properties from ultrasonic reflection. The location and timing of surface ultrasonic waveform characteristics can be used to determine location and material depth characteristics along the surface. These waveforms can be combined along planes parallel or perpendicular to the object's surface, sometimes referred to as B-scans and C-scans. A combination of one or more of the following properties—excitation location, detection location, detection angle, sound velocity, sound attenuation, material properties, and sound travel time—can be used to interpret inquiries about microstructure, material properties, and / or inquiry characteristics.

[0026] One embodiment of the invention uses a challenge-response protocol for authentication determination. A set of points, lines, or regions is queried, and their responses are recorded as reference data 38. Subsets of these points, lines, or regions are then used in subsequent queries to determine the similarity of the ultrasound responses. The queried subsets may include only some or the entire set of points, lines, or regions. The selection of points can be completely random, partially random, or deterministic. Furthermore, a subset of each region investigated can be used as a challenge. The digital data obtained from the queries provides a response in the challenge-response authentication protocol. This response should be within one or more similarity thresholds to determine whether the object subjected to subsequent queries is genuine.

[0027] The surface of an object is frequently subjected to environmental aging, abrasive wear, dust and dirt collection, chemical damage, and many other factors that alter the material structure, composition, or location of the object's surface. According to the invention, interrogation below the surface allows access to areas unaffected by surface alteration factors. Excluding some or all of the contribution from the actual surface 14 from the initial interrogation or analysis from the detection signal 30 provides an improved ability to compare interrogations of the same area at different time points. The depth of surface effects varies based on material, environmental, and object properties, but often ranges from a few atoms to 1000 micrometers.

[0028] Interrogation using non-ablative laser-induced ultrasound can be combined with any other method to provide enhanced resolution, additional information, or contextual information. One or more other methods can be used simultaneously or at different times. These methods can interrogate the same points, lines, or regions as non-ablative laser-induced ultrasound, or different points, lines, or regions, or combinations thereof. These additional methods can be destructive or non-destructive in nature, or combinations thereof. These methods include combinations with probe-based ultrasound, including the potential use of one or more phased array transducers. Ablative laser ultrasound can be combined with non-ablative laser ultrasound, with ablative laser ultrasound used in a destructive manner, or with an ablated sacrificial layer. Additional methods that can be combined with non-ablative laser-induced ultrasound include computed tomography, X-ray diffraction computed tomography, X-ray radiography, X-ray diffraction radiography, terahertz radiography, harmonic testing, echo attenuation, eddy current inspection, surface resonance acoustic spectroscopy, white light interferometry, stereoscopic ranging, and laser detection and ranging. Destructive methods can also be used, such as the integration of physically unclonable functions containing elements, including optical, electrical, and electromagnetic physically unclonable functions.

[0029] Encryption can be employed at numerous steps in the authentication process, including data transfer from database 34 to any device, data transfer within the device, data transfer to database 34, data processing steps in processor 32 and / or in any other processor used for comparing data from database 34, and any arrangement of the above steps. The encrypted information can be directly compared or decrypted to enable the comparison.

[0030] Reference data and query data can be converted into a digital signature of a unique element of the captured object 16. This digital signature can be encrypted and can include additional information, such as the time and location of the queried object. The digital signature can be used for comparison to detect counterfeit or fake objects.

[0031] The data in database 34 can be linked to blockchain blocks. It can also be recorded in a distributed ledger. This enables object data to be linked to digital verification methods. To ensure that query data 36 can be used for authentication or forgery detection, it can be recorded in database 34 in such a way that it is assigned to object 16, so that the data can be used later for authentication queries.

[0032] The wavelength of laser source 10 can be selected to target only certain materials within the object. One example is selecting a wavelength primarily absorbed by metals rather than polymers. In another example, a wavelength highly absorbed by pigments can be selected. Yet another example is selecting a wavelength minimally absorbed by pigments. Measurements can be collected at more than one wavelength to supplement the robustness of reference / interrogation data 38 / 36.

[0033] Recording the signal-to-noise ratio of the ultrasonic response during interrogation can yield additional benefits. This can be used to determine the quality of the interrogation or to help determine thresholds for authentication. Various methods can be used to improve the resolution, speed, or non-destructive nature of the invention for focusing, amplifying, or filtering acoustic signals. Acoustic lenses can be used to focus ultrasonic emissions. Mechanical, electrical, and / or computational filters, such as bandpass filters, resonators, Wheatstone bridges, and fast Fourier transform modules, can be implemented to modify the acoustic signal and / or the resulting waveform. Static and / or dynamic reflectors can be used to guide, modify, and / or amplify acoustic emissions.

[0034] Various methods can be used to improve the quality of the detected signal for creating the desired ultrasonic propagation. A profiled laser beam 12 can be used to create excitation and / or wavefronts in a desired pattern, such as points, loops, lines, or regions with a desired amplitude profile. Spatial and / or temporal phase shifts of the laser beam 12 can be used to provide excitation and / or wavefronts with the desired form. The focus of the laser beam 12 can be varied spatially and / or temporally to provide excitation and / or wavefronts with the desired form. Feedback regarding diffraction, microstructure, light diffusion, acoustic reflection, acoustic attenuation, or any other process or material property can be used as factors in determining the excitation beamforming and propagation.

[0035] This invention is ideal for authenticating artworks (such as sculptures, paintings and drawings), jewelry, and any object containing metal, clay, ceramics, epoxy resin, polymer, wood, pigment, binder, and / or combinations thereof.

[0036] Figure 3 An alternative embodiment of detector 24 is illustrated, which uses one or more transducers 46 preferably close to or even in contact with surface 14 to convert surface ultrasonic waves 22 into one or more electrical signals. If multiple transducers 46 are used, the transducers 46 can be configured at various angles relative to surface 14 to detect ultrasonic reflections from different directions. The transducers (one or more) 46 can be a planar array, a hemispherical array, a parabolic array, a hyperbolic array, a line, a circle, or any other desired shape.

[0037] Figure 4 Another alternative embodiment of detector 24 is illustrated, which uses both optical detection (e.g., LDV-based scattered light collection) and one or more transducers 46 to measure different aspects of surface ultrasonic waves 22 and generate appropriate detection signals 30 from them.

[0038] As described above, one option is to use the data for authentication to exclude contributions from surface 14 of object 16. Waves originating from the surface, which may be called Rayleigh waves, are surface waves, not volume waves originating from deeper within the object. Excluding these surface wave contributions reduces the file size of the reference / interrogation data 38 / 36 and can enhance comparisons between interrogations. Optical or physical contact transducer arrays can be used to distinguish between surface waves and volume waves, thereby enabling the filtering of surface wave contributions from the detection signal. The wave frequency can also be used to filter surface waves using mechanical, electrical, and / or computational filters. The excitation with a selected frequency and / or power used to primarily excite the surface waves can also be used to distinguish between surface waves and volume waves.

[0039] Figure 5 Another alternative embodiment is illustrated, in which database 50, physically located away from detector 24, is performing a comparison between query data 36 and reference data 38 to determine authentication. Specifically, database 34 may be connected to database 50 via network 52 (e.g., the Internet, cellular network, etc.). Database 50 stores query data 36 and reference data 38, as received from database 34. Database 50 performs a comparison between query data 36 and reference data 38 to determine authentication. The authentication result can then be transmitted back to database 34 via network 50. Although Figure 5 The query data 36 and reference data 38 stored in both database 34 and database 50 are shown, but the query system 1 may instead be configured to send the query data 36 and reference data 38 to database 50 instead of storing them in database 34.

[0040] It should be understood that the invention is not limited to the embodiments described above and illustrated herein, but covers any and all variations falling within the scope of any claim. For example, references to the invention herein are not intended to limit the scope of any claim or claim terminology, but rather refer only to one or more features that may be covered by one or more of the claims. The examples of materials, processes, and numerical values ​​described above are merely exemplary and should not be construed as limiting the claims. For example, a single detection signal 30 is shown, but it could be many separate signals used collectively to generate / store interrogation or reference data 36 / 38. Furthermore, during subsequent interrogations, the digital data generated from the detection signals does not need to be stored in database 34, but can be directly compared as interrogation data with reference data, which is never stored in database 34. Finally, the preamble to any apparatus claim is intended to provide a prior basis and is not intended to be limiting in any other way.

Claims

1. A method comprising: A laser beam is directed onto the surface of an object to induce thermoelastic excitation in the bulk material of the object without altering the surface of the object, wherein the laser beam is pulsed; Detecting surface ultrasonic waves at the surface of an object caused by thermoelastic excitation; The detected surface ultrasonic waves are used to generate a detection signal; Digital data is generated using the detection signal; Storing digital data in a database as reference data; The second laser beam is directed onto the surface of the object to induce a second thermoelastic excitation in the bulk material of the object, wherein the second laser beam is pulsed; Detecting second-surface ultrasonic waves at the surface of an object caused by second thermoelastic excitation; A second detection signal is generated using the detected ultrasonic waves from the second surface. The second detection signal is used to generate the second digital data; as well as The authenticity of an object is determined by comparing second digital data with the reference data, wherein determining the authenticity of an object includes determining that the object is authentic by determining that the difference between the second digital data and the reference data is less than one or more thresholds.

2. The method according to claim 1, further comprising: Store the second digital data in the database.

3. The method according to claim 1, further comprising: Spectral decomposition is performed on the second detection signal or second digital data to identify one or more portions of the second detection signal or second digital data associated with a predetermined frequency range, wherein the authenticity of an object is determined based on the one or more portions.

4. The method according to claim 3, wherein the predetermined frequency range is higher than 20 MHz.

5. The method of claim 1, wherein guiding the second laser beam comprises pointing the second laser beam at a plurality of different locations on the surface of the object.

6. The method of claim 1, wherein detecting the second surface ultrasonic wave comprises detecting the second surface ultrasonic wave at multiple different locations on the surface of the object.

7. The method according to claim 1, wherein: The detection of surface ultrasonic waves further includes detecting surface ultrasonic waves at multiple discrete locations on the surface of the object; and The detection of the second surface ultrasonic waves further includes detecting the second surface ultrasonic waves at some, but not all, of a plurality of discrete locations on the surface of the object.

8. The method of claim 1, wherein the ultrasonic detection of the second surface further comprises: Generate a detection laser beam to impact the surface of the object; as well as Detecting the light of a detection laser beam reflected from the surface of an object; The detection of ultrasonic waves on the second surface uses light detected by a detection laser beam that bounces off the surface of the object.

9. The method of claim 8, wherein detecting the light of the detection laser beam reflected from the surface of the object further comprises detecting the light of the detection laser beam reflected from the surface of the object at two or more discrete angles relative to the surface of the object.

10. The method of claim 9, further comprising: Deconvolve a portion of the second detection signal or second digital data associated with the two or more discrete angles.

11. The method according to claim 8, wherein: Generating the detection laser beam further includes pointing the detection laser beam to multiple discrete locations on the surface of the object; Detecting light from the detection laser beam further includes detecting light from the detection laser beam bounced off the plurality of discrete locations on the surface of the object.

12. The method of claim 11, further comprising: Deconvolve a portion of the second detection signal or second digital data associated with the plurality of discrete locations.

13. The method of claim 11, further comprising: The velocity of the second surface ultrasonic wave at each of the plurality of discrete locations is determined using light from a detection laser beam that bounces off the plurality of discrete locations on the surface of the object.

14. The method of claim 8, wherein detecting the light of the detection laser beam reflected from the surface of the object comprises using a Sagnac interferometer.

15. The method of claim 8, wherein the ultrasonic detection of the second surface further comprises: The second surface ultrasonic wave is detected using a transducer, wherein the generation of the second detection signal is performed using the transducer and the detected light from the detection laser beam bounced off the surface of the object.

16. The method of claim 1, wherein the detection of the second surface ultrasonic wave further comprises: Use a transducer to detect ultrasonic waves on the second surface.

17. The method of claim 16, wherein the transducer is a phased array transducer.

18. An apparatus for analyzing an object having bulk material and a surface, comprising: A laser configured to generate a laser beam for inducing thermoelastic excitation in a bulk material upon impact with the surface of an object without altering the surface of the object, wherein the laser beam is pulsed; A detector is configured to detect surface ultrasonic waves at the surface of an object caused by thermoelastic excitation, and to generate a detection signal using the detected surface ultrasonic waves; A processor configured to generate digital data using a detection signal; as well as A database configured to determine the authenticity of an object by comparing numerical data with reference data stored in the database; The reference data is generated in the following ways: The second laser beam is directed onto the surface of the object to induce a second thermoelastic excitation in the bulk material of the object, wherein the second laser beam is pulsed; Detecting second-surface ultrasonic waves at the surface of an object caused by second thermoelastic excitation; A second detection signal is generated using the detected ultrasonic waves from the second surface. The second detection signal is used to generate the second digital data; as well as The second digital data is stored in the database as reference data; The determination of the authenticity of an object includes determining that the object is authentic by finding that the difference between the numerical data and the reference data is less than one or more thresholds.

19. The apparatus of claim 18, wherein the database is further configured to store digital data.

20. The apparatus of claim 18, wherein the detector is further configured to: Generate a detection laser beam to impact the surface of the object; and Detecting the light of a detection laser beam reflected from the surface of an object; The detector uses the detected light from the detection laser beam that bounces off the surface of the object to detect surface ultrasound.

21. The apparatus of claim 20, wherein the detector further comprises: A transducer configured to detect surface ultrasonic waves, wherein the detector is further configured to generate a detection signal using the transducer and the detected light from a detection laser beam bounced off the surface of the object.

22. The apparatus of claim 18, wherein the detector further comprises: A transducer configured to detect ultrasonic waves on a surface.

23. The apparatus of claim 22, wherein the transducer is a phased array transducer.

24. The apparatus of claim 18, wherein the detector comprises a Sagnac interferometer.

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