Surface analysis of gemstones
Systems and methods here may be used for capturing and analyzing reflectance images of facets on a gemstone under particular lighting and camera setups to automatically generate a clarity grade and/or surface polish grade for the gemstone.
1. A system for analyzing a gemstone using reflectance analysis, the system comprising:
a computer with a processor and memory in communication with a camera, a plurality of motors, and a light source,
the computer configured to cause the light source to illuminate a gemstone mounted on a rotatable stage;
the computer further configured to command the plurality of motors to adjust the camera such that a long focal axis of the camera is aligned with a normal of a target facet of the gemstone;
the camera configured to capture an image of the gemstone target facet using the camera and send the captured image to the computer;
the computer further configured to cause storage of the captured image and a correlated data set of information from the plurality of motors indicating an azimuth of the stage, slope angle of the camera to a horizontal, and distance of the camera to the gemstone;
the computer further configured to receive a first image of the target facet of the gemstone from the camera, detect a feature in the captured image of the target facet of the gemstone, map the feature in the captured image of the target facet of the gemstone, identify the feature in the captured image of the facet of the gemstone, and
determine a clarity grade or surface polish grade of the gemstone using all mapped and identified features on all facets of the gemstone.
2. The system of claim 1 wherein the determination of the azimuth of the stage, a slope angle of the camera to a horizontal, and a distance of the camera to the gemstone includes using wireframe information from the plurality of motors sent to the computer.
3. The system of claim 1 wherein one of the plurality of motors is a motor configured to turn the stage on which the gemstone sits.
4. The system of claim 1 wherein one of the plurality of motors is a motor configured to tilt the camera relative to the stage on which the gemstone sits.
5. The system of claim 1 wherein the light source and the camera are mounted to aim their respective focuses on the stage at an angle of between 10 and 30 degrees.
6. The system of claim 1 wherein one of the plurality of motors is a motor configured to increase and decrease the distance between the camera and the stage on which the gemstone sits to focus the camera.
7. The system of claim 1 wherein the computer is further configured to determine a surface polish grade of the gemstone using all mapped and identified features on all facets of the gemstone.
8. The system of claim 3 wherein the computer is configured to command the camera to focus and capture an image of the target facet, determine a position of a second facet, command the stage to rotate to bring the second facet into a field of view of the camera to capture a new image of the second facet.
9. The system of claim 1 wherein the feature to be identified and used in the clarity grade include at least one of a blemish, an inclusion, and a polish line.
10. A method for analyzing a gemstone using reflectance analysis, the method comprising:
by a computer with a processor and memory, in communication with a camera, a plurality of motors, and a light source,
causing the light source to illuminate a gemstone mounted on a rotatable stage;
commanding, by the computer, the plurality of motors to adjust the camera such that a long focal axis of the camera is aligned with a normal of a target facet of the gemstone;
capturing an image of the gemstone target facet using the camera;
causing storage, by the computer, of the captured image and a correlated data set of information from the plurality of motors indicating an azimuth of the stage, slope angle of the camera to a horizontal, and distance of the camera to the gemstone;
receiving, by the computer, a first image of the target facet of the gemstone from the camera;
detecting, by the computer, a feature in the captured image of the target facet of the gemstone;
mapping, by the computer, the feature in the captured image of the target facet of the gemstone;
identifying, by the computer, the feature in the captured image of the target facet of the gemstone; and
determining a clarity grade or surface polish grade of the gemstone using the mapped and identified feature on the target facet of the gemstone.
11. The method of claim 10 further comprising, generating a wireframe model of the gemstone by capturing a plurality of silhouette images of the gemstone by a silhouette camera and a back light source, wherein each of the plurality of silhouetted images is captured at a different rotation angle then the next, using the rotatable stage; and
using the wireframe model for mapping the feature in the captured image of the facet of the gemstone.
12. The method of claim 11 wherein the determining the azimuth of the stage, slope angle of the camera to a horizontal, and distance of the camera to the gemstone includes using the wireframe model.
13. The method of claim 10 wherein the determining the azimuth of the stage, slope angle of the camera to a horizontal, and distance of the camera to the gemstone includes using sensor data from the plurality of motors sent to the computer.
14. The method of claim 10 further comprising, receiving, by the computer, a second image of a second target facet of the gemstone from the camera;
detecting, by the computer, a second feature in the captured image of the second target facet of the gemstone;
mapping, by the computer, the second feature in the captured image of the second target facet of the gemstone;
identifying, by the computer, the second feature in the captured image of the second target facet of the gemstone; and
determining a clarity grade of the gemstone using the mapped and identified second feature on the second target facet of the gemstone.
15. The method of claim 10 wherein the identifying, by the computer, the feature is identifying at least one of a blemish, inclusion, oil fillings of surface reaching fractures, epoxy, chemicals and polishing line.
16. The method of claim 15 wherein the identifying, by the computer, the feature is identifying a surface inclusion.
17. The method of claim 15 wherein determining the clarity grade is conducted using machine learning analysis of the captured image.
18. A non-transitory computer readable media to command a computer process for executing a method for analyzing a gemstone using reflectance analysis, the method comprising:
by a computer with a processor and memory, in communication with a camera mounted with at least one motor, a stage with at least one rotatable motor, and a light source,
causing the light source to illuminate a gemstone mounted on the rotatable stage;
commanding, by the computer, the camera motor to adjust the camera such that a long focal axis of the camera is aligned with a normal of a target facet of the gemstone on the rotatable stage;
capturing an image of the gemstone target facet using the camera;
causing storage, by the computer, of the captured image;
receiving, by the computer, an image of the target facet of the gemstone from the camera;
detecting, by the computer, a feature in the captured image of the target facet of the gemstone;
mapping, by the computer, the feature in the captured image of the target facet of the gemstone;
identifying, by the computer, the feature in the captured image of the target facet of the gemstone; and
determining a clarity grade or surface polish grade of the gemstone using the mapped and identified feature on the target facet of the gemstone.
19. The non-transitory computer readable media of claim 18 wherein the causing storage, by the computer, of the captured image includes storage of correlated data of information from the camera and stage motors indicating an azimuth of the stage, slope angle of the camera to a horizontal, and distance of the camera to the gemstone.
20. The non-transitory computer readable media of claim 18 , the method further comprising, generating a wireframe model of the gemstone by capturing a plurality of silhouette images of the gemstone by a silhouette camera and a back light source, wherein each of the plurality of silhouetted images is captured at a different rotation angle then the next, using the rotatable stage; and
using the wireframe model for mapping the feature in the captured image of the facet of the gemstone.