TECHNICAL FIELD

[0001] The present subject matter relates, in general, to detecting synthetic gemstones, and in particular, to detecting synthetic gemstones using image processing.

BACKGROUND

[0002] There are many kinds of gemstones available commercially, and their values differ from each other based on different properties associated with the gemstones. Typically, the commercial value of a gemstone depends upon factors, such as weight of a gemstone, cut of a gemstone, clarity of a gemstone, and color of a gemstone, which are also indicative of the grade of quality of the gemstone. Therefore, to assess a value or grade for the gemstones, the gemstones are evaluated based on these factors. For example, diamonds are generally graded into four basic types, namely type la, lb, lla, and lib, based on amount and type of impurities that may be measured at an atomic level within a crystal lattice of carbon atoms of the diamonds, and each grade is accordingly associated with a different range of commercial value.

[0003] Further, the enormous value of real or natural diamonds has resulted in various activities aimed at imitating the natural diamonds and producing synthetic or man-made gemstones. The synthetic gemstones may -appear like a real gemstone but are generally of much lower value.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference l ike features and components. [0005] Fig. 1 illustrates a schematic view of a gemstone evaluation apparatus, in accordance with an embodiment of the present subject matter.

[0006] Fig. 2 illustrates a pattern generated on a screen of the gemstone evaluation apparatus, in accordance with an embodiment of the present subject matter.

[0007] Fig. 3 illustrates a method for detecting synthetic gemstones using image processing, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION

[0008] Apparatus and method for detecting synthetic gemstones using image processing are described herein. A gemstone may be understood as a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. As gemstones are considered precious and are available at high costs, their authenticity is usually checked every time before being traded. A number of different systems and processes are known for registering and verifying the gemstones, such as diamonds, based on unique features of the gemstones, for later comparison to determine whether a gemstone purporting to be the original is indeed the original.

[0009] Conventional techniques for registering and verifying the gemstones typically include illuminating a gemstone, such as a polished diamond, and capturing a pattern generated by the gemstone. As each gemstone, due to its inherent properties produces a pattern upon being illuminated; the pattern is considered as a basis to verify authenticity of the gemstone. This pattern may then be stored in a database as a unique pattern for that gemstone and may be referred later.

[0010] In some cases, a printer is deployed to print a certificate with the unique pattern and a gemstone identifier (ID) thereupon. This certificate may be used for comparing the unique pattern of the gemstone with the pattern stored in the database corresponding to the gemstone ID. As may be understood, the conventional techniques of verifying gemstones rely on the fact that no two gemstones, such as diamonds, may have a similar pattern. However, with the increase in demand of gemstones, synthetic gemstones are increasingly being produced, which appear to be similar to natural gemstones, but are man-made and are typically of lower value. In such scenarios, the conventional gemstone registration and verification techniques may not be helpful in distinguishing between synthetic and natural gemstones as the conventional techniques compare the unique pattern printed on the certificate with the pattern that may be pre-stored in the database. Hence, while the gemstone tested may be found to be authentic, i.e., having the same pattern as that stored in database, it may still be synthetic and not natural.

[0011] The present subject matter discloses aspects related to detecting synthetic gemstones using image processing techniques. The present subject matter describes an apparatus and a method for examining gemstones, such as a cut, multi- faceted diamond, for detecting synthetic gemstones, such as synthetic diamonds. For example, as the diamonds have a table (i.e., the uppermost, largest facet at the top of the diamond) and a culet (i.e., the pointed or blunted bottom of the diamond), the diamonds may be examined for one or more optical properties. In an embodiment, the apparatus may include an illumination means, such as a laser source for illuminating the gemstone with a laser beam. In an implementation, the illumination means may be deployed at a right angle from the gemstone. The apparatus may further include a gemstone holder for holding the gemstone in a pre-determined substantially upright position such that the table of the gemstone is uncovered and can be directly exposed to the laser beam. [0012] In an implementation, the laser beam may be passed through a prism before it strikes the gemstone. In an example, the laser beam is passed through the prism to turn the laser beam by 90 degrees and to increase distance at which the gemstone can be placed from the illumination means. This facilitates the impacting laser beam to cover a larger area thereby covering the entire table of gemstone.

[0013] Further, the apparatus may include a screen on which a reflection/refraction pattern produced by the gemstone when exposed to the laser beam can be projected. An image of the pattern is captured by an image capturing device mounted opposite to the screen. In an implementation, the image capturing device may be coupled to a computing device for processing the captured image of the reflection/refraction pattern. The computing device may employ at least one image processing technique on the image received by the image capturing device to determine the authenticity of the gemstone. In an example, an image processing technique may facilitate in converting the image to a black and white image so that all white spots can be detected from the black and white image. Further, by applying the image processing techniques, the computing system may determine co-ordinates of the white spots. Thereafter, co-ordinates of these white spots are subtracted from a pre-defined calibrated image centre point. The pre-defined calibrated image centre- point may be understood as a rotation centre point of gemstone pattern obtained on the screen. As each machine has its own centre point, the machine is aligned in such a way that distance between each spot and centre point is not changed when the gemstone is rotated. [0014] In operation, the gemstone is illuminated by the laser beam after the laser beam passes through the prism. The laser beam upon striking the gemstone may get reflected and may create a pattern on the screen. As may be appreciated by a person skilled in the art, the pattern may be unique for each gemstone. In an example, the pattern may be formed as a plurality of spots on the screen. This pattern may be captured by the image capturing device in the form of an image and provided to the computing device for further processing. The computing device may apply one or more image processing techniques on the captured image to determine co-ordinates of these white spots, as described above. Based on these co-ordinates a final pattern of the image is obtained. The final pattern may be understood as the co-ordinates of the white spots obtained upon application of image processing techniques.

[0015] In an implementation, if symmetrical gaps are found in about 50% outer area of the pattern and if minimum degree of rotation of these gaps is between 12 to 24, then the gemstone being analyzed may be considered as a synthetic or man made gemstone. The percentage of presence of symmetrical gaps and the minimum degree of rotation of gaps for ascertaining the authenticity of the polished diamonds has been derived on the basis of analysis of more than 50,000 synthetic and natural gemstones. The symmetrical gaps may be understood as the gaps that are located at equal rotation degree from each other. In an implementation, in case either of the two conditions, i.e., presence of symmetrical gaps in 50% outer area of the pattern or minimum degree of rotation of these gaps being between 12 to 24, is not satisfied, the gemstones may be considered as real gemstones.

[0016] Accordingly, the present subject matter provides a quick and inexpensive technique for detecting synthetic gemstones using image processing. This may provide an accurate examination of a gemstone for true price valuation of the gemstone. Further, the present subject matter facilitates in reducing theft of gemstones and providing actual value of the money to end-users.

[0017] It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art. Moreover, all statements herein reciting principles, aspects, and embodiments of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[0018] While aspects of described methods for detecting synthetic gemstones can be implemented in any number of different production environments, and configurations, the embodiments are described in the context of the following environment(s). It will be evident to a person skilled in the art that although the subject matter is explained in context of diamonds, the principles explained herein can be extended to detecting other gemstones as well.

[0019] Fig. 1 illustrates a schematic view of a gemstone evaluation apparatus 100 (hereinafter referred as apparatus 100), in accordance with an embodiment of the present subject matter. The apparatus 100 may be configured to use image processing techniques for detecting synthetic gemstones. The apparatus 100 may include a gemstone holder (not shown) for holding a gemstone, such as a diamond 102. The gemstone holder may be configured to hold and automatically position the diamond 102 in a pre-determined upright position in which the table of the diamond 102 is uncovered and directly exposed to each light ray. In other words, the gemstone holder may be configured to orient the diamond 102 in such a way that the table of the diamond 102 becomes perpendicular to a radiation beam. Further, the apparatus 100 may include an illumination means 104, such as a laser source. In an implementation, the illumination means 104 may be mounted in a holder (not shown). The illumination means 104 may be disposed at a right angle from the diamond 102. The illumination means 104 may be configured to illuminate the diamond 102 with a laser beam 106. The laser beam 106 may pass through a prism 108, before striking the diamond 102. In an example, the prism 108 may be mounted in a prism holder (not shown).

[0020] In an implementation, the apparatus 1 00 may include a screen 1 10 to project a pattern of scattered laser beam 106 due to reflection of the laser beam 106 from the diamond 102. In an example, the screen 1 10 may be located between the diamond 102 and the prism 108. Further, the apparatus 100 may include an image capturing device 1 12 placed opposite to the diamond 102. In an example, the image capturing device 1 12 may be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device. Accordingly, the prism 108 may be positioned such that the diamond 102 and the screen 1 10 are at one side of the prism 108 and the image capturing device 1 12 is at the other side of the prism 108, Further, the image capturing device 1 12 may be adjusted to cover reflection and/or refraction pattern of the laser beam 106 on the screen 1 10. [0021] Further, an output of the image capturing device 1 12 may be fed to a computing device 1 14 for further analysis. It will be evident that the computing device 1 14 may include a memory, an interface, a keyboard, and a processor. The processor can be a single processing unit or a number of units, all of which could also include multiple computing units. The processor may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor is configured to fetch and execute computer-readable instructions and data stored in the memory. [0022] The computing device 1 14 may further include modules. The module(s) include routines, programs, objects, components, data structures, etc., which perform particular tasks or implement particular abstract data types. In one implementation, the module(s) includes a pattern identification module and an evaluation module. The computing device 1 14 may simplify the image to a monochromatic display by applying various corrections to the image. In an implementation, the computing device 1 14 may apply various image processing techniques on the image of the pattern obtained as the output from the image capturing device 1 12. In an implementation, the pattern identification module may receive an image of a pattern of the gemstone 102. The pattern may be created on the screen 1 10 on reflection of the laser beam 106. In an example, the pattern includes a plurality of spots. The pattern identification module may convert the image to a black and white image. Thereafter, the pattern identification module may detect white spots in the black and white image. The pattern identification module may apply at least one image processing technique to identify co-ordinates of the plurality of spots in the image.

[0023] In an implementation, the pattern identification module may subtract the co-ordinates of these white spots from a pre-defined calibrated image centre point. The pre-defined calibrated image centre-point may be understood as a rotation centre point of gemstone patterns plotted on a screen. As each machine has its own centre point, the machine is aligned in such a way that distance between each spot and centre point is not changed when the gemstone is rotated. After the subtraction, a final pattern of the diamond 102 is obtained. [0024] Based on the final pattern, the evaluation module of the computing device 1 14 may identify if there are any symmetrical gaps in an outer area of the final pattern. In an example, the outer area may be understood as a circumference of the pattern created on the screen. The term 'symmetrical gaps' may indicate that each gap is located on equal rotation degree from each other. In an implementation, if symmetrical gaps are found in about 50% outer area of the pattern of the gemstone 102 and minimum degree of rotation of the symmetrical gaps is between 12 to 24, the gemstone 102 may be considered as a synthetic gemstone. In other words, if the symmetrical gaps are found at the circumference of the pattern such that the symmetrical gaps are present at major portion of the circumference and the minimum degree of rotation of the symmetrical gaps is between 12 to 24, the gemstone 102 may be considered as a synthetic gemstone. In an example, the symmetrical gaps may cover about 40%-60% of the circumference of the final pattern. In case either of the two conditions, i.e., presence of symmetrical gaps in 50% outer area of the pattern or minimum degree of rotation of these gaps between 12 to 24 is satisfied, the gemstone 102 may be considered as real or natural gemstone.

[0025] Referring to Fig. 2, a pattern 200 generated on the screen 1 10 of the gemstone detection apparatus 100 is depicted, in accordance with an embodiment of the present subject matter. The pattern 200 includes a plurality of black spots 202 as a result of the refraction or reflection of the laser beam 106 by the diamond 102. As mentioned above, the image capturing device 1 12 may capture an image of the pattern 200 and provide that image as an input to the computing device 1 14. The computing device 1 14 may employ at least one image processing technique to convert the image to a black and white image. In an implementation, the black and white image may include a plurality of white spots (hereinafter referred to as gaps 204-1 , 204-2...204-N, collectively referred to as gaps 204 and individually referred to as gap 204.

[0026] Further, the computing device 1 14 may compute coordinates of the gaps 204. In an example, the co-ordinates of the gaps 204 may be determined on the basis of the co-ordinates of the white spots or the final pattern. Thereafter, the coordinates of the gaps 204 are subtracted from a pre-defined calibrated image centre point to get a final pattern of the gemstone. In an implementation, if symmetrical gaps, such as gap 204- 1 and gap 204-2, are found at about 50% of the circumference of the pattern and if minimum degree of rotation of these gaps 204 are between 12 to 24, then the diamond 102 being analyzed may be considered as a man-made or synthetic diamond. In an implementation, in case either of the two conditions, i.e., presence of symmetrical gaps in about 50% outer area of the pattern or minimum degree of these gaps between 12 to 24 is satisfied, the gemstones 102 may be considered as real gemstones. The symmetrical gaps may be understood as the gaps that are located on equal rotation degree from each other. [0027] Referring to Fig. 3, a flowchart showing a method 300 for detecting synthetic gemstones using the image processing technique is illustrated, in accordance with an embodiment of the present subject matter. The order in which the method(s) is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method 300, or an alternative method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the method 300 can be implemented in any suitable hardware, software, firmware, or combination thereof. [0028] In an implementation, one or more of the method(s) described herein may be implemented at least in part as instructions embodied in a non-transitory computer-readable medium and executable by one or more computing devices. In general, a processor (for example a microprocessor) receives instructions, from a non-transitory computer-readable medium, for example, a memory, and executes those instructions, thereby performing one or more method(s), including one or more of the method(s) described herein. Such instructions may be stored or transmitted using any of a variety of known computer-readable media.

[0029] Referring to Fig. 3, at block 302, a gemstone, such as diamond 102, may be illuminated by a laser beam, such as the laser beam 106. In an implementation, the diamond 102 is received in a gemstone holder of the apparatus 100. It will be understood that the diamond 102 may be provided by a user. In an implementation, the apparatus 100 may include an automatic feeding mechanism (not shown) for placing the diamond 102 in the gemstone holder. The gemstones may be illuminated by the light source as described above. In an implementation, structural light triangulation method may be used for illuminating the gemstones with a predefined pattern of light/laser. When such pattern of the light/laser strikes the gemstones, the beam of light may get interrupted. [0030] As shown in block 304, the method 300 may include capturing a pattern, such as pattern 200, displayed on a screen, such as the screen 1 10 of the apparatus 100, as a result of the reflection of the laser beam 106 from the diamond 102. In an implementation, the image capturing device 1 12, such as a Charge Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS) device, may capture the pattern 200 of the diamond 102.

[0031] Further, at block 306, the method 300 may include providing the captured pattern to the computing device 1 14 for image processing. In an implementation, an output of the image capturing device 1 12 may be fed to the computing device 1 14. The computing device 1 14 may apply one or more image processing techniques on the captured pattern 200. For example, the computing device 1 14 may convert the image of the pattern 200 into a black and white image. Thereafter, the computing device 1 14 may detect white spots in the black and white image. The computing device 1 14 may identify co-ordinates of the white spots which are then subtracted from a pre-defined calibrated image centre point. Thereafter, a final pattern of the gemstone 102 may be obtained.

[0032] At block 308, the method 300 may include identifying whether there are any symmetrical gaps in an outer area of the pattern. In an implementation, the computing device 1 14 may analyze the final pattern to identify whether symmetrical gaps are present in more than 50% of the outer area. The symmetrical gaps 204 may mean that each gap in the final pattern is located on equal rotation degree from each other. If it is identified that the there are no symmetrical gaps in the outer area of the final pattern, the diamond 102 may be considered as a natural or real diamond, as shown in block 310. On the other hand, if there are symmetrical gaps in outer area of the pattern, the method 300 may move to block 3 12.

[0033] As shown in block 3 12, the method 300 may include determining if a minimum degree of rotation of the symmetrical gaps is between 1 2 to 24. The computing device 1 14 may determine the degree of rotation of the symmetrical gaps. If the minimum degree of rotation of the symmetrical gaps is not between 12 to 24, the method 300 may move to block 310 to indicate that the diamond 102 is natural.

[0034] At block 314, if the symmetrical gaps are present in the outer area of the pattern and the minimum degree of rotation of the symmetrical gaps is between 12 to 24, the gemstone is considered to be synthetic.

[0035] Although embodiments for detecting synthetic gemstones using image processing have been described in language specific to structural features and/or methods, it is to be understood that the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as exemplary implementations for detecting synthetic gemstones using image processing.