| 摘要 |
The present invention relates to a method and a device for controlling a physical property of light emitted from a light source. In particular, the invention can be applied to a lighting system for atmosphere creation. The measurements needed for feedback control are made at a portable user device comprising a planar photodetector. More or less all industrially available photodetectors are of the planar type, but planarity is in fact a necessary feature to achieve faithful relative measurements. Since the user device is portable, variations in the orientation of the photodetector can introduce large and unpredictable measurement errors, making effective control of the light source impossible. According to one embodiment of the invention, the orientation-dependent errors are eliminated by measuring the actual orientation of the photodetector and processing the detection signal appropriately. According to a second embodiment, the photodetector is movably mounted in the user device in order to retain its preferred orientation irrespective of the orientation of the user device. In a third embodiment, the emitted light is monitored by a plurality of photodetectors; knowing the actual orientation of the user device, the control device can give priority to the measurements coming from the best oriented photodetector at every instant.
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