A method for measuring a spatial displacement between reference coordinates and corresponding measured image coordinates relating to at least a part of an irradiating nuclear fuel assembly, the method comprising: - receiving a first image data frame, captured using an imaging system (110, 700), said first image data frame comprising information representing a first view of an observed real world scene comprising at least a part of an irradiating nuclear fuel assembly, wherein said first image data frame is captured from a first direction; - generating a set of reference coordinates, corresponding to image coordinates relating to image positions in which said part of the fuel assembly is identified in said first image data frame; - generating a reference line by performing a linear approximation based on two or more of the reference coordinates of said set of reference coordinates; and - for each image data frame in a set of image data frames, extracting measurement data indicative of a spatial displacement between coordinates along said reference line and corresponding measured image coordinates relating to said part of the fuel assembly, based on information from said image data frame and information from said reference line, wherein said extraction of measurement data comprises: - identifying said part of the fuel assembly in said image data frame; - determining a set of measured image coordinates, wherein each of the measured image coordinates of said set of measured image coordinates is associated with a coordinate along said reference line, wherein measured image coordinates in said set of measured image coordinates relate to image positions in which said part of the fuel assembly is identified in said image; and - extracting measurement data indicative of a spatial displacement, by determining the displacement between each of said coordinates of said reference line and the corresponding image coordinate of said set of measured image coordinates. - receiving a first image data frame, captured using an imaging system (110, 700), said first image data frame comprising information representing a first view of an observed real world scene comprising at least a part of an irradiating nuclear fuel assembly, wherein said first image data frame is captured from a first direction; - generating a set of reference coordinates, corresponding to image coordinates relating to image positions in which said part of the fuel assembly is identified in said first image data frame; - generating a reference line by performing a linear approximation based on two or more of the reference coordinates of said set of reference coordinates; and - for each image data frame in a set of image data frames, extracting measurement data indicative of a spatial displacement between coordinates along said reference line and corresponding measured image coordinates relating to said part of the fuel assembly, based on information from said image data frame and information from said reference line, - identifying said part of the fuel assembly in said image data frame; - determining a set of measured image coordinates, wherein each of the measured image coordinates of said set of measured image coordinates is associated with a coordinate along said reference line, wherein measured image coordinates in said set of measured image coordinates relate to image positions in which said part of the fuel assembly is identified in said image; and - extracting measurement data indicative of a spatial displacement, by determining the displacement between each of said coordinates of said reference line and the corresponding image coordinate of said set of measured image coordinates.