Method of imaging a wind turbine rotor blade
A wind turbine rotor blade imaging arrangement is provided, including a multi-axis gimbal mounted to the exterior of the wind turbine and configured to adjust its orientation in response to one or more received settings; a camera mounted on the multi-axis gimbal and arranged to capture images of a rotor blade; an image analysis unit configured to analyze the captured images; and a camera orientation controller configured to compute updated gimbal settings on the basis of the image analysis output.
1. A wind turbine rotor blade imaging arrangement, comprising:
a multi-axis gimbal mounted to the exterior of the wind turbine and configured to adjust its orientation in response to one or more received gimbal settings wherein the gimbal settings comprise any of a pitch angle, a roll angle, a yaw angle;
a camera mounted on the multi-axis gimbal and arranged to capture images of a rotor blade;
an image analysis unit configured to analyze the captured images and generating image analysis output out; and
a camera orientation controller configured to compute updated gimbal settings on the basis of the image analysis output.
2. The wind turbine rotor blade imaging arrangement according to claim 1 , wherein the wind turbine rotor blade imaging arrangement, the image analysis unit and/or the camera orientation controller, is/are configured for repeating capturing an image of the rotor blade or of a rotor blade region, analyzing the captured image, and adjusting the gimbal settings on the basis of the image analysis output until the image of the rotor blade or of the rotor blade region is deemed satisfactory.
3. The wind turbine rotor blade imaging arrangement according to claim 1 , wherein the multi-axis gimbal is configured to rotate about a first axis, to rotate about a second axis, which second axis is orthogonal to the first axis, and wherein the multi-axis gimbal is configured to rotate about a third axis, which third axis is orthogonal to the first axis and the second axis.
4. The wind turbine rotor blade imaging arrangement according to as claim 1 , comprising a rangefinder configured to measure a distance between the camera and an imaged region of the rotor blade, further comprising a camera controller configured to adjust the focal length of the camera on the basis of the measured distance and/or on the basis of the image analysis output.
5. The wind turbine rotor blade imaging arrangement according to claim 1 , wherein the multi-axis gimbal is mounted to the exterior of the wind turbine tower.
6. A method of imaging a wind turbine rotor blade, which method comprises:
providing the multi-axis gimbal of the wind turbine rotor blade imaging arrangement according to claim 1 to an exterior of the wind turbine; and
operating the camera of the wind turbine rotor blade imaging arrangement to capture images of the rotor blade, whereby a step of capturing an image is preceded by a step of adjusting one or more gimbal settings of the multi-axis gimbal at least on the basis of the image analysis output.
7. The method according to claim 6 , comprising a step of analyzing the images and computing the gimbal settings to direct the optical axis of the camera at a target region on the rotor blade.
8. The method according to claim 6 , wherein the steps of capturing an image of a rotor blade region, analyzing the captured image, and adjusting the gimbal settings on the basis of the image analysis output are repeated until the image of that rotor blade region is deemed satisfactory.
9. The method according to claim 6 , wherein the method comprises a step of determining the imaged fraction of the rotor blade.
10. The method according to claim 6 , wherein a completion of the imaging procedure is detected by the image analysis unit.
11. The method according to claim 6 , wherein an imaging procedure comprises:
bringing the rotor blade into a first angular position prior to imaging one side of the rotor blade; and
bringing the rotor blade into a second angular position prior to imaging the other side of the rotor blade.
12. The method according to claim 6 , comprising a step of pitching the rotor blade about its longitudinal axis during the imaging procedure.
13. The method according to claim 6 , comprising a step of analyzing the captured images to identify a finding on the rotor blade and to determine the coordinates of the finding in a reference frame of the rotor blade.
14. The method according to claim 1 , wherein an initial calibration procedure comprises,
defining a fixed reference frame;
directing the optical axis of the camera towards the origin of the reference, frame and capturing an initial image; and
recording a distance measurement for the initial image.
15. A computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code executable by a processor of a computer system to implement a method for carrying out the steps of the method according to claim 6 when the computer program product is loaded into a memory of a programmable device configured to control one or more components of the wind turbine rotor blade imaging arrangement.