US Pat. No. 9,250,193

GEMSTONE SPARKLE ANALYSIS

De Beers UK Ltd., London...

1. A system for obtaining images of a gemstone, and performing quantitative analysis on the images to obtain measures of properties
of the gemstone, comprising:
a support structure for supporting the gemstone at an observation position;
an illumination system arranged to illuminate the gemstone, the illumination system comprising a plurality of directional
light sources directed towards the observation position, the support structure and illumination system being rotatable relative
to one another around a rotation axis so that the gemstone can be illuminated by one or more of the directional light sources
at each of a plurality of rotational positions, the directional light sources being disposed at a series of discrete inclination
angles relative to the axis of rotation, and at polar angles chosen around the axis of rotation such that the imaging system
does not possess rotational symmetry;

an imaging device directed towards the gemstone for obtaining images of the gemstone at each of the rotational positions,
the imaging device having an imaging axis parallel to or coincident with the axis of rotation; and

an image processor for identifying sparkle regions in the images corresponding to reflections from individual light sources
by the gemstone and providing a quantitative measure of the gemstone on the basis of properties of the sparkle regions.

US Pat. No. 9,188,542

GEMSTONE VIEWER

De Beers UK Ltd., London...

1. Apparatus for viewing images of a gemstone, comprising:
a support structure for supporting the gemstone at an observation position;
an illumination structure arranged to illuminate the gemstone, the illumination structure comprising a plurality of directional
light sources having finite widths directed towards the observation position, the support structure and illumination structure
being rotatable relative to one another about a rotation axis; and

an imaging device for obtaining images of the gemstone at the observation position at a variety of relative rotational positions
between the illumination structure and support structure, the imaging device having an imaging axis passing through the observation
position;

wherein the support structure is arranged so that the gemstone can be placed at the observation position in such a way that
the normal to a selected facet of the gemstone is within a range of tilt angles from the rotation axis, the tilt angle remaining
constant as the illumination structure and support structure are rotated relative to each other; and

the arrangement of directional light sources is such that loci of a reversed ray reflected in the selected facet from the
imaging device for a 360° rotation of the support structure at a series of discrete tilt angles within the range of tilt angles
can be visualised on the illumination structure as a set of nested rings separated by at most the finite widths of the directional
light sources, and at least one of the directional light sources is located on each ring so that, for any tilt angle within
the range, at least one of the directional light sources will be specularly reflected from the selected facet into the imaging
device for at least one rotational position of the support structure.

US Pat. No. 9,322,785

INCLUSION DETECTION IN POLISHED GEMSTONES

De Beers UK Ltd., London...

12. A method of obtaining a 3D model of the surface of a gemstone, comprising:
analysing a set of silhouette images of the gemstone illuminated by collimated light obtained at a series of incremental rotational
positions of the gemstone;

identifying each silhouette image in which a plane of a facet of the gemstone is generally parallel to the axis of the camera
so that said facet appears as a facet line in the silhouette image, and labelling such images as key frames; and

in each key frame, calculating a normal to the facet line, the normal to the facet line in the plane of the image corresponding
to a normal to the facet in the 3D model.

US Pat. No. 9,796,536

AUTOMATIC GEMSTONE ORIENTATION

DE BEERS UK LTD., London...

1. An apparatus for orientating gemstones, said apparatus comprising:
a movable surface configured to support said gemstones thereon and provide a travelling path for said gemstones such that
the direction of travel of the gemstones is the same as the direction of travel of the movable surface;

a pair of opposed walls extending generally along the direction of the path; and
an oscillator arranged to generate relative oscillatory movement between said pair of walls and said movable surface, in a
direction generally transverse to the direction of the path, so that, in use, said pair of walls imparts lateral force to
the gemstones to thereby urge them into their most stable orientation as they progress along the path while supported on the
movable surface;

wherein each gemstone has at least two flat surfaces and the pair of walls imparts sufficient lateral force to urge the gemstones
into their most stable orientation on one of the flat surfaces.

US Pat. No. 9,625,393

GEMSTONE VIEWER

De Beers UK Ltd., London...

1. Apparatus for viewing images of a gemstone, comprising:
a support structure for supporting the gemstone at an observation position;
an illumination structure arranged to illuminate the gemstone, the illumination structure comprising a plurality of directional
light sources directed towards the observation position, the illumination structure being effectively rotatable relative to
the support structure about a rotation axis by sequential operation of the directional light sources; and

an imaging device for obtaining images of the gemstone at the observation position at a variety of effective rotational positions
of the illumination structure, the imaging device having an imaging axis passing through the observation position;

wherein the support structure is arranged so that the gemstone can be placed at the observation position in such a way that
the normal to a selected facet of the gemstone is within a predetermined range of tilt angles from the rotation axis; and

the arrangement of directional light sources is such that, for any tilt angle within the range, light from at least one of
the directional light sources will be specularly reflected from the selected facet into the imaging device for at least one
effective rotational position of the illumination structure.

US Pat. No. 10,215,706

GEMSTONE SPARKLE ANALYSIS

De Beers UK Ltd., London...

1. An apparatus for viewing a mark on a facet of a gemstone, comprising:an array of independently operable directional light sources for directing collimated light towards the facet of the gemstone;
viewing means for viewing the gemstone along an imaging axis; and
control means for controlling the operation of the light sources so that the light sources are activated one at a time in sequence, and configured to stop sequential activation of the light sources in response to observation at the viewing means of a specular reflection, from the facet, of light emitted by one of the light sources, the sequential activation being stopped with the one of the light sources that caused observation of the specular reflection remaining activated so the mark can be viewed.

US Pat. No. 9,958,398

MEASURING PARAMETERS OF A CUT GEMSTONE

De Beers UK Ltd., London...

1. An apparatus for measuring a plurality of parameters of a cut gemstone while it is positioned at a single measurement location, the apparatus comprising:a plurality of light sources each configured to emit light at a different one of a plurality of emission wavelengths or ranges of wavelengths such that the emitted light illuminates at least part of the measurement location;
a sensor assembly configured to sense light at a plurality of sensing wavelengths or ranges of wavelengths for measuring the plurality of parameters, the sensed light being received at the sensor assembly from the measurement location as a result of illumination of a cut gemstone located at the measurement location, wherein the sensor assembly comprises a plurality of sensors, each configured to sense light at a different one or more of the plurality of sensing wavelengths or ranges of wavelengths; and
a multi-furcated optical fibre assembly configured to direct light from the light source assembly to the measurement location and to direct light from the measurement location to the sensor assembly, the multi-furcated optical fibre assembly comprising a plurality of optical fibre filaments, each configured to direct light from one of the plurality of light sources to one of the plurality of sensors;
wherein the plurality of light sources includes a broadband light source configured to emit light for measuring the absorption of a cut gemstone, and a laser light source configured to emit light at a wavelength suitable for stimulating Raman emission at a detectable wavelength from a cut gemstone;
and wherein the plurality of sensors includes a first spectrometer configured to sense light at a range of wavelengths for measuring the absorption of a cut gemstone, and a second spectrometer configured to sense light at a range of wavelengths for measuring the Raman emission spectrum of a cut gemstone.

US Pat. No. 9,618,443

GEMSTONE INSPECTION

De Beers UK Ltd., London...

1. Apparatus for inspecting gemstones, comprising:
a vacuum nozzle for picking up a gemstone from a supply of gemstones;
a transport mechanism for transporting the nozzle and associated gemstone to one or more measurement locations;
a measurement system comprising a plurality of measuring devices proximate to the one or more measurement locations, the measuring
devices configured to measure one or more properties of the gemstone,

wherein at least one of the plurality of measuring devices is located proximate to at least one of the one or more measurement
locations in such a way as to measure at least one of the one or more properties of the gemstone while the gemstone is held
on the nozzle,

and wherein the transport mechanism is configured such that the gemstone is conveyed to the plurality of measuring devices
in sequence, each receiving the gemstone at controlled times and locations;

a control system operatively coupled to the vacuum nozzle and measurement system and configured so that the gemstone arrives
at the or each measurement location at a time known by the measurement system; and

a positive pressure application system for releasing the gemstone from the nozzle at an ejection location.

US Pat. No. 10,082,469

LUMINESCENCE MEASUREMENTS IN DIAMOND

DE BEERS UK LTD, London ...

1. A method of providing an indicator for a diamond as to whether it is natural by testing for the presence or absence of one or more specific markers in the luminescence properties of the diamond, said markers characterised by luminescence decay time and luminescence wavelength, the method comprising:irradiating the diamond with at least one excitation pulse of electromagnetic radiation;
during and/or following the excitation pulse, detecting light emitted by the diamond in at least one time window having a predetermined time relationship relative to the excitation pulse so as to obtain luminescence data, the or each time window being chosen to include luminescence having a decay time characteristic of one or more of the markers; and
analysing the luminescence data in order to establish the presence or absence of the one or more markers.