Optical shape sensing with a plurality of optical fibers
An optical shape sensing system and method with at least two optical fibers (OSF 1 , OSF 2 ) both comprising optical shape sensing elements. A processor (P) is arranged to register a coordinate system indicative of a position of one of the optical fibers (OSF 1 ) in space, and to register a position (R 2 ) of the other optical fiber (OSF 2 ) in relation to this coordinate system. An optical console system (C, C 1 , C 2 ) serves to interrogate the optical shape sensing elements in both optical fibers (OSF 1 , OSF 2 ), and to accordingly determine a measure of a three-dimensional shape (I) of both optical fibers (OSF 1 , OSF 2 ), based on the registered position (R 2 ) of the second optical fiber (OSF 2 ) in relation to the coordinate system. This provide the possibility of providing 3D optical shape sensing of the length of both optical fibers (OSF 1 , OSF 2 ), thus allowing 3D shape reconstruction of e.g. long medical devices with lengths of several meters. More than two shape sensing optical fibers, e.g. incorporated in separate devices, can be registered in this manner in a hierarchical data structure, thus allowing shape sensing of very long instruments.
1. An optical shape sensing system comprising
a first optical fiber (OSF 1 ) comprising optical shape sensing elements,
a second optical fiber (OSF 2 ) comprising optical shape sensing elements,
a processor (P) arranged to register a first coordinate system indicative of a position of the first optical fiber (OSF 1 ) in space, and to register a position (R 2 ) of the second optical fiber (OSF 2 ) in relation to the first coordinate system, and
an optical console system (C, C 1 , C 2 ) arranged for interrogating the optical shape sensing elements in both of the first and second optical fibers (OSF 1 , OSF 2 ), and to accordingly determine a measure of a three-dimensional shape (I) of at least parts of both of the first and second optical fibers (OSF 1 , OSF 2 ), based on the registered position (R 2 ) of the second optical fiber (OSF 2 ) in relation to the first coordinate system,
characterized in that
the first optical fiber (OSF 1 ) and the second optical fiber (OSF 2 ) are mechanically concatenated so that the second optical fiber (OSF 2 ) serves to extend an effective length of the first optical fiber (OSF 1 ) or to improve accuracy of a three-dimensional shape reconstruction of the first optical fiber (OSF 1 ), and
the processor (P) is arranged to register a position in space (R 2 ) and an orientation of a proximal part of the second optical fiber (OSF 2 ) in relation to the first coordinate system.
2. Optical shape sensing system according to claim 1 , wherein the optical console system comprises a first optical console (C 1 ) arranged for interrogating the optical shape sensing elements in the first optical fiber (OSF 1 ), and a second optical console (C 2 ) arranged for interrogating the optical shape sensing elements in the second optical fiber (OSF 2 ).
3. Optical shape sensing system according to claim 1 , wherein an image detector (D) is arranged at or near a distal part of the first optical fiber (OSF 1 ), and wherein the image detector (D) is arranged to detect a measure of the position of the second optical fiber (OFS 2 ).
4. Optical shape sensing system according to claim 3 , wherein the image detector (D) comprises at least one of: a visible light camera, an ultrasound sensor, a radio frequency sensor, and an x-ray device.
5. Optical shape sensing system according to claim 1 , wherein a distal part of the first optical fiber (OSF 1 ) is mechanically arranged adjacent to the proximal part of the second optical fiber (OSF 2 ), so as to form an overlapping curve (OVC) between the first and second optical fibers (OSF 1 , OSF 2 ), and wherein the optical console system (C, C 1 , C 2 ) is arranged to generate a measure of three-dimensional shape of at least part of said overlapping curve (OVC) between the first and second optical fibers (OSF 1 , OSF 2 ).
6. Optical shape sensing system according to claim 5 , arranged to correct a three-dimensional shape reconstruction of the first optical fiber (OSF 1 ) in response to the measure of three-dimensional shape of said at least part of said overlapping curve (OVC) between the first and second optical fibers (OSF 1 , OSF 2 ).
7. Optical shape sensing system according to claim 1 , comprising an auxiliary object (D 3 , D 4 , D 5 ), and wherein the processor (P) is arranged to register a position of the auxiliary object in relation to the first coordinate system in a hierarchical data structure.
8. Optical shape sensing system according to claim 7 , comprising a plurality of auxiliary objects (D 3 , D 4 , D 5 ), wherein the processor (P) is arranged to register position of the plurality of auxiliary objects (D 3 , D 4 , D 5 ) in relation to the first coordinate system in a hierarchical data structure, wherein at least one of the plurality of objects (D 3 ) is linked to position data registered for at least two objects (D 2 , D 4 ) higher up in the hierarchical data structure.
9. Optical shape sensing system according to claim 7 , wherein at least one of the plurality of auxiliary object comprises a third optical fiber (D 3 ) with optical shape sensing elements, and wherein the optical shape sensing system is arranged to correct a three-dimensional shape reconstruction of the third optical fiber (D 3 ) in response to data registered higher up in the hierarchical data structure than where position data for the third optical fiber (D 3 ) is registered.
10. Optical shape sensing system according to claim 1 , wherein the optical shape sensing elements comprise at least one of: Rayleigh sensors, and fiber Bragg gratings.
11. Optical shape sensing system according to claim 1 , arranged to generate a three-dimensional image (I) of parts of both of the first and second optical fibers (OSF 1 , OSF 2 ) with one common three-dimensional coordinate system.
12. Method for increasing an effective length of an optical shape sensing system, the method comprising
providing (P_OSF 1 ) a first optical fiber comprising optical shape sensing elements,
providing (P_OSF 2 ) a second optical fiber comprising optical shape sensing elements,
registering (R_C 1 ) a first coordinate system indicative of a position of the first optical fiber in space,
registering (R_P 2 ) a position of the second optical fiber in relation to the first coordinate system,
interrogating (I_F 1 _ 2 ) the optical shape sensing elements in both of the first and second optical fibers, and
determining (D_S) a measure of a three-dimensional shape of at least parts of both of the first and second optical fibers, based on the registered position of the second optical fiber in relation to the first coordinate system,
characterized in that
the method comprises concatenating the first optical fiber (OSF 1 ) and the second optical fiber (OSF 2 ) to extend an effective length of the first optical fiber (OSF 1 ) and
registering a position in space (R 2 ) and an orientation of a proximal part of the second optical fiber (OSF 2 ) in relation to the first coordinate system.