Abstract: A dual sensor scanner includes an optical sensor and a nuclear sensor such as a beta gauge for sensing the basis weight or other parameters of paper as it is being produced by a paper making machine. The nuclear sensor signal is filtered to pass a low frequency portion and the optical sensor is filtered to pass a high frequency portion. The two filtered signals are combined to provide a substantially full frequency signal indicative of the basis weight of the paper. The sensor signals may be manually calibrated or, preferably, the nuclear sensor signal may be used to provide continuous on-line calibration of the optical sensor signal.

Abstract: A paper weight sensor system is intended for use on a paper-making machine having a headbox with a slice-lip mounted thereon for forming a moving web of material. Plural slice-lip actuators are provided for setting the slice-lip gap to control the amount of material in the web and are mounted on the headbox. Plural stationary optical sensors are located at a first station and extend across the width of the web in a continuous array for detecting the transmissivity of the web in a one-to-one relationship with the slice-lip actuators at an aligned location downstream of each actuator. Each sensor includes plural light detectors therein which are operable to generate a first transmissivity signal representing the transmissivity of the web for discrete regions thereof adjacent each light detector corresponding to a given actuator.