Abstract: A light output control system for implementing a method for sensing the tri-stimulus values for controlling a light output illuminated from an LED based luminary is disclosed. The system comprises one or more filter/photo diode sensors for sensing a first set of tri-stimulus values of the light output and providing signals indicative thereof. The signals are utilized in a transformation matrix whereby a second set of tri-stimulus values is obtained. The system controls the light output as a function of the second set of tri-stimulus values.

Abstract: In a method of correcting defects in image data comprising an array of pixels, the intensity of pixels of the image data in each side of the defect is sampled (5), differences between the samples intensities are calculated (6) to generate intensity difference signals (D1-D4) indicative of intensity differences across and on respective sides of the defect, and the defect is corrected (7-11) in dependence on the intensity difference signals (D1-D4). Preferably, depending on the intensity difference signals (D1-D4) either an average correction technique or no defect pixel correction is used, the average correction technique being used if the intensity difference signals do not exceed a predetermined level value (L1, L2).