ILLUMINATION SENSOR FOR DISTINGUISHING BETWEEN DIFFERENT CONTRIBUTIONS TO A SENSED LIGHT LEVEL

摘要

An apparatus comprises a first light sensor configured with a first field of view; and a second light sensor configured with a second, narrower field of view contained within the first field of view. The first and second light sensors may be arranged to detect light reflected from an illuminated surface, wherein the first and second field of view encompass light from an electric lighting device reflected from said surface and additional light reflected from said surface, e.g. natural light; but the second light sensor is concentrated on a region on said surface so as to exclude glare from objects outside said region, whereas the first field of view extends beyond said region. An illumination level of the environment in which the apparatus is installed may be adjusted to compensate for a change in the additional light based on information distinguishing between the two sensors.

主权项

1. An apparatus for sensing an illumination level in an environment, the apparatus comprising:
an input for receiving signals from at least two light sensors; and a signal level detector configured to receive a first signal indicative of light reflected from an illuminated surface into a first of said light sensors having a first field of view, and to receive a second signal indicative of light reflected from the illuminated surface into a second of said light sensors having a second, narrower field of view concentrated on a region on said surface, the first field of view extending beyond said region; wherein the signal level detector is configured to determine information distinguishing between the first and second signals, and thereby distinguishing between a change in the illumination level and an effect of glare from objects outside said region, wherein the first and second signals each comprise a contribution from an electric lighting device reflected from said surface and additional light reflected from said surface; and the signal level detector is configured to adjust the illumination level based on said information to compensate for a change in the additional light, on condition that, when a change in the first signal is identified, a corresponding change is identified in the second signal.