Adaptive lighting system for even illumination

Abstract

An adaptive lighting system for even illumination is provided. In an embodiment, multiple lamps illuminate light in different areas or zones of the surroundings. These lamps modulate their light output in a known (but imperceptible) pattern. One or more light detectors detects light from the surroundings. Light sourced from each lamp is disambiguated and one or more light time-of-flight delays are calculated for each lamp-light detector pair. Based on these calculated delays, illumination levels of the lights are adjusted so as to produce even illumination.

I claim: 
     
         1 . A method comprising:
 providing a first rigid body,   providing a plurality of lamps attached to the first rigid body,   providing one or more light detectors attached to the first rigid body,   modulating the light output of each lamp in accordance with a flashing sequence,   detecting light reflected from the surroundings using the light detectors,   correlating the output of a light detector with the flashing sequence to generate at least one delay estimate, and   setting the illumination output of a lamp based on the delay estimate,   wherein the step of correlating the output of a light detector with a flashing sequence to generate at least one delay estimate comprises producing a cross correlation sequence from the flashing sequence and the output of the light detector.   
     
     
         2 . The method of  claim 1  wherein producing the cross correlation sequence from the flashing sequence and the output of the light detector comprises producing a present value of the k'th element of the cross correlation sequence by multiplying the current value of the output of the light detector with the k'th previous value of the flashing sequence and adding this to an estimate derived from the previous value of the k'th element of the cross correlation sequence. 
     
     
         3 . The method of  claim 2  wherein the estimate derived from the previous value of the k'th element of the cross correlation sequence is calculated as the previous value of the k'th element of the cross correlation sequence multiplied by a constant. 
     
     
         4 . The method of  claim 1  wherein the step of correlating the output of a light detector with the flashing sequence to generate at least one delay estimate further comprises detecting a peak in a cross correlation sequence, and calculating the delay estimate as the index of the peak in the cross correlation sequence 
     
     
         5 . The method of  claim 1  wherein setting the illumination output of a lamp based on the delay estimate comprises setting an illumination value that is higher for progressively higher delay estimates 
     
     
         6 . A system comprising:
 a first body,   a plurality of lamps attached to the first body,   one or more light detectors attached to the first body, and   a cross correlator,   wherein each lamp modulates its light output in accordance with a flashing sequence, the light detectors detect light reflected from the surroundings,   the cross correlator is configured to calculate a cross correlation sequence from the flashing sequence and the light detected by the light detector, and   the system is configured to change the illumination levels of the plurality of lamps based on the output of the cross correlator.   
     
     
         7 . The system of  claim 6  wherein the cross correlator uses the cross correlation sequence to produce a delay measurement 
     
     
         8 . The system of  claim 6  wherein the cross correlator comprises one or more delay registers arranged in a sequence such that the output of a delay register is the input of the next delay register, and the input of the first delay register is the flashing sequence. 
     
     
         9 . The system of  claim 8  wherein the cross correlator further comprises one or more multipliers, each multiplier multiplying the output of a delay register with the value of the light detected by the light detector. 
     
     
         10 . The system of  claim 9  wherein the cross correlator further comprises one or more adders, each adder adding the value produced by a multiplier with the previous output of the adder multiplied by a constant, to produce the cross correlation sequence. 
     
     
         11 . The system of  claim 10  wherein the cross correlator further comprises a peak detector that detects at least one peak in the cross correlation sequence, and each lamp in the plurality of lamps changes its illumination level based on the index of the peak calculated with respect to at least one cross correlation sequence corresponding to that lamp.