A method for irradiating an image in an optical see-through (OST) head mounted display (HMD) for viewing through, the OST HMD by a user's eye, an object having at least one of known orientation and position and orientation (O/P&O), associated with a first reference frame, the method comprising: generating and irradiating said image for appearing to said user superimposed in an aligned manner to said object, according to predetermined information, eyeball feature position data, and said O/P&O; said predetermined information relates correction data with a plurality of different respective position data values of at least one eyeball feature position of said eye; said predetermined information further includes display corrections of said electro-optical display module with respect to said position data values of said at least one eyeball feature position, with respect to a second reference frame; and said O/P&O is between said second reference and said first reference frame.