Abstract: A method for minimizing cross-machine direction variations in temperature and moisture content of a web running through a corrugator single facer. The method includes running the web through a web preheater station of the single facer and capturing an image representing an actual temperature of the web downstream of the preheater station in the cross-machine direction with a thermal imaging device. The method includes sending the image to a programmed process controller that applies thermal pattern recognition to the image and determining with the controller if the actual temperature of the web deviates from a desired temperature range. The method also includes determining with the controller a corrective action that will bring the actual temperature of the web within the desired temperature range and generating and sending a control signal with the controller to vary an operating condition of the preheater station so as to bring about the corrective action.