Method and system for visual inspection of wind turbine generators

A method of visually inspecting a wind turbine generator and parts thereof during operation, the method including the following steps performed with a visual inspection system:

• pointing the visual inspection system with a field of view about a line of sight in a plane of a rotor blade of the wind turbine generator;
• triggering, based on the field of view, the visual inspection system;
• capturing multiple images of the field of view using the visual inspection system;
• selecting at least one reference image amongst the captured multiple images;
• comparing at least one other image of the captured multiple images with the selected at least one reference image;
• inspecting structural aspects of the wind turbine generator as a function of the result of comparing;
• and
• wherein the step of inspecting includes determining relative blade pitch misalignment between at least two rotor blades of the wind turbine generator, and applying a set of pitch angle metrics to the at least one reference image and the at least one other captured image, wherein the pitch angle metrics include a nacelle line defined by two reference regions of interest on the nacelle and a blade line defined by two regions of interest on the rotor blade;
• and
• wherein the step of comparing is performed on the pitch angle metrics of the at least one reference image and those of the at least one other captured image,
• wherein the step of triggering is according to a trigger which triggering setting is performed using a graphical user interface of the visual inspection system configured to present at least one captured image and with at least one means for an operator to adjust a trigger parameter, and
• wherein the trigger parameter is a brightness value of a region of interest.