Abstract: A retro-reflective marker comprising a bare retro-reflective layer; a protective layer with a near-infrared (NIR) wavelength specific anti-reflective coating; and a border with an NIR absorbent coating.

Abstract: A retro-reflective marker comprising a bare retro-reflective layer; a protective layer with a near-infrared (NIR) wavelength specific anti-reflective coating; and a border with an NIR absorbent coating.

Abstract: An apparatus comprising a retro-reflective marker and a device configured to receive the retro-reflective marker in a socket located on the top surface of the device. The retro-reflective marker comprises a retro-reflective layer having a first retro-reflectance capability. The retro-reflective layer comprises a textured surface, a portion of the textured surface having a surface topology such that surface normal vectors positioned across the portion extend from the portion of the textured surface in different directions, and a plurality of retro-reflective micro elements distributed across the textured surface. The retro-reflective marker further comprises a border defining a retro-reflective area of the retro-reflective layer, where a portion of the border provides a second retro-reflectance capability lower than the first retro-reflectance capability.

Abstract: An apparatus including a retro-reflective section. The retro-reflective section includes an outer surface, an inner surface, and a plurality of retro-reflective microelement. One or more of the plurality of retro-reflective microelements include a plurality of reflective surfaces. Each of the plurality of retro-reflective microelements extends from the inner surface at a location different from locations of the other retro-reflective microelements, and each of the plurality of retro-reflective microelements comprises a central axis extending along a direction that corresponds to a surface normal of the outer surface.

Abstract: An apparatus comprising a retro-reflective marker and a device configured to receive the retro-reflective marker in a socket located on the top surface of the device. The retro-reflective marker comprises a retro-reflective layer having a first retro-reflectance capability. The retro-reflective layer comprises a textured surface, a portion of the textured surface having a surface topology such that surface normal vectors positioned across the portion extend from the portion of the textured surface in different directions, and a plurality of retro-reflective micro elements distributed across the textured surface. The retro-reflective marker further comprises a border defining a retro-reflective area of the retro-reflective layer, where a portion of the border provides a second retro-reflectance capability lower than the first retro-reflectance capability.

Abstract: An apparatus including a retro-reflective section. The retro-reflective section includes an outer surface, an inner surface, and a plurality of retro-reflective microelement. One or more of the plurality of retro-reflective microelements include a plurality of reflective surfaces. Each of the plurality of retro-reflective microelements extends from the inner surface at a location different from locations of the other retro-reflective microelements, and each of the plurality of retro-reflective microelements comprises a central axis extending along a direction that corresponds to a surface normal of the outer surface.

Abstract: An apparatus including a retro-reflective section. The retro-reflective section includes an outer surface, an inner surface, and a plurality of retro-reflective microelement. One or more of the plurality of retro-reflective microelements include a plurality of reflective surfaces. Each of the plurality of retro-reflective microelements extends from the inner surface at a location different from locations of the other retro-reflective microelements, and each of the plurality of retro-reflective microelements comprises a central axis extending along a direction that corresponds to a surface normal of the outer surface.

Abstract: A marker comprising: a retro-reflective layer having a first retro-reflectance capability and a border defining a retro-reflective area of the retro-reflective layer. The retro-reflective layer includes a textured surface, a portion of the textured surface having a surface topology such that surface normal vectors positioned across the portion extend from the portion of the textured surface in different directions. A plurality of retro-reflective micro elements are distributed across the textured surface. A portion of the border provides a second retro-reflectance capability lower than the first retro-reflectance capability.

Abstract: A marker comprising: a retro-reflective layer having a first retro-reflectance capability and a border defining a retro-reflective area of the retro-reflective layer. The retro-reflective layer includes a textured surface, a portion of the textured surface having a surface topology such that surface normal vectors positioned across the portion extend from the portion of the textured surface in different directions. A plurality of retro-reflective micro elements are distributed across the textured surface. A portion of the border provides a second retro-reflectance capability lower than the first retro-reflectance capability.

Abstract: Tracking system for tracking one or more reflective markers includes at least two optical sensors configured to obtain image data of an environment that includes at least one marker. The tracking system obtains the image data from the at least two optical sensors. The tracking system is configured for extracting, from the image data, optical signatures representing reflections of the optical signal from at least one marker, determining optical centroids of the optical signatures of the at least one marker, estimating an initial pose for at least one marker, determining offset error vectors from the optical centroids of the at least one marker based on the initial pose, determining corrected optical centroids based on the offset error vectors and the optical centroids, and determining a corrected three dimensional position of the marker in the environment based on the corrected optical centroids of the marker.

Abstract: A retro-reflective marker comprising a bare retro-reflective layer; a protective layer with a near-infrared (NIR) wavelength specific anti-reflective coating; and a border with an NIR absorbent coating.

Abstract: Tracking system for tracking one or more reflective markers includes at least two optical sensors configured to obtain image data of an environment that includes at least one marker. The tracking system obtains the image data from the at least two optical sensors. The tracking system is configured for extracting, from the image data, optical signatures representing reflections of the optical signal from at least one marker, determining optical centroids of the optical signatures of the at least one marker, estimating an initial pose for at least one marker, determining offset error vectors from the optical centroids of the at least one marker based on the initial pose, determining corrected optical centroids based on the offset error vectors and the optical centroids, and determining a corrected three dimensional position of the marker in the environment based on the corrected optical centroids of the marker.

Abstract: A marker for an optical tracking system includes an object having a curved surface and a plurality of beads adhered to the curved surface with an adhesive. The beads of the plurality of beads are configured for being retroreflectors. A bead of the plurality of beads can include a first portion having a reflective surface and a second portion that is substantially transparent. The first portion of the bead is oriented toward the curved surface of the object. The second portion of the bead is oriented away from the curved surface of the object. The beads are applied to the marker. A bead of the plurality of beads can be transparent and embedded in a reflective medium on the marker surface.

Abstract: An injector for injecting particulate material into a metallurgical furnace has a first tubular barrel and a housing defining a chamber having an inlet for particulate material, a first gas inlet and a particulate material/gas outlet connected to the rear end of the first barrel. The first air inlet has a first nozzle operable to inject gas into the chamber at a supersonic velocity when gas at suitable pressure is passed through the nozzle. A second tubular barrel surrounds the first barrel in spaced relationship therewith. The second barrel has a second gas inlet adjacent its rear end and a second nozzle adjacent its front end. Gas under pressure supplied to the second gas inlet passes between the barrels and is discharged at supersonic velocity from the front end thereof adjacent gas and entrained particulate material discharged from the first barrel so as to shroud the particulate material.

Abstract: An injector for injecting particulate material into a metallurgical furnace has a first tubular barrel and a housing defining a chamber having an inlet for particulate material, a first gas inlet and a particulate material/gas outlet connected to the rear end of the first barrel. The first air inlet has a first nozzle operable to inject gas into the chamber at a supersonic velocity when gas at suitable pressure is passed through the nozzle. A second tubular barrel surrounds the first barrel in spaced relationship therewith. The second barrel has a second gas inlet adjacent its rear end and a second nozzle adjacent its front end. Gas under pressure supplied to the second gas inlet passes between the barrels and is discharged at supersonic velocity from the front end thereof adjacent gas and entrained particulate material discharged from the first barrel so as to shroud the particulate material.