1. A method for detecting and diagnosing faults of an object, comprising the steps of: obtaining an emissivity map of said object, while said object is substantially in thermal equilibrium with its ambient environment, by capturing a basis thermal image, illuminating said object, capturing an illumination image while said object is illuminated, calculating a difference image between said basis thermal image and said illumination image, and using said difference image to determine an emissivity map at various points on said object; heating said object; obtaining a thermal image of said object during said heating step; correcting said thermal image, using said emissivity map to compensate for varying emissivities on said object, such that an emissivity-corrected thermal image is obtained; inputting data representing said emissivity-corrected thermal image to an artificial neural network, wherein said neural network has been previously trained to provide a certain output when said data is associated with a known fault; and using said neural network to indicate whether a fault exists on said object.