Method of preparing histograms of a sensor signal from an array of sensors, in particular proximity sensors, and corresponding device

Abstract

A method includes preparing a first histogram from the emission of initial optical radiation and including at least one processing iteration performed at a rate of a clock signal having an internal period equal to a sub-multiple of the optical period a sensor signal and a reference signal. Successive iterations of histogram preparation are performed so that in each iteration a time shift of the initial optical radiation is provided by a first fraction of the internal period until at least one portion of the internal period is covered to obtain an additional histogram at the conclusion of each iteration. A numerical combination of the first histogram and additional histograms is performed to obtain a final histogram having a finer time granularity than that of the first histogram.

1 - 15 . (canceled) 
     
     
         16 . A histogram generation method using a sensor array providing a sensor signal based upon optical radiation from an emitter reflected off of an object, the emitter emitting the optical radiation based upon an optical period, the method comprising:
 (a) generating a first histogram by processing the sensor signal and a reference signal based upon a clock signal having an internal period equal to a submultiple of the optical period;   (b) iteratively performing step (a) with each iteration having the optical signal time-shifted by a first fraction of the internal period for at least one portion of the internal period to obtain at least one second histogram; and   (c) combining the first histogram and the at least one second histogram to obtain a final histogram having a finer time granularity than the first histogram.   
     
     
         17 . The method of  claim 16  wherein step (a) further comprises successively processing the sensor signal over the entire optical period using successive time shifts with respect to an initial optical emission. 
     
     
         18 . The method of  claim 17  wherein step (a) further comprises a step (a1) comprising:
 generating a first portion of the first histogram from the initial optical emission over an acquisition cycle comprising multiple optical periods; 
 wherein the initial optical emission begins at a first instant within each optical period of the acquisition cycle; 
 wherein generating the first portion comprises processing, based upon the clock signal, the sensor signal and the reference signal at a second instant within each optical period of the acquisition cycle. 
 
     
     
         19 . The method of  claim 18  wherein step (a) further comprises a step (a2) comprising repeating step (a1) while time-shifting the reference signal by an initial fraction of the optical period corresponding to a whole number of internal periods to obtain another portion of the first histogram. 
     
     
         20 . The method of  claim 19  wherein step (a) further comprises a step (a3) comprising repeating step (a2) for the entire optical period until the first histogram is completed. 
     
     
         21 . The method of  claim 19  wherein the initial fraction of the optical period corresponds to two internal periods. 
     
     
         22 . The method of  claim 16  wherein step (c) further comprises subtracting consecutive histograms to generate the final histogram. 
     
     
         23 . The method of  claim 16  wherein the optical period is equal to n times the internal period, and the first fraction is equal to the internal period divided by n. 
     
     
         24 . The method of  claim 16  wherein the sensor array comprises a proximity sensor array. 
     
     
         25 . An electronic device comprising:
 an emitter to emit optical radiation based upon an optical period;   a sensor array providing a sensor signal based upon optical radiation from the emitter reflected off of an object;   a processor to generate a first histogram by processing the sensor signal and a reference signal based upon a clock signal having an internal period equal to a submultiple of the optical period;   a controller to control the processor to iteratively perform histogram generation with each iteration having the optical signal time-shifted by a first fraction of the internal period for at least one portion of the internal period to obtain at least one second histogram; and   a calculator to combine the first histogram and the at least one second histogram to obtain a final histogram having a finer time granularity than the first histogram.   
     
     
         26 . The electronic device of  claim 25  wherein said processor successively processes the sensor signal over the entire optical period using successive time shifts with respect to an initial optical emission. 
     
     
         27 . The electronic device of  claim 26  wherein said processor generates a first portion of the first histogram from the initial optical emission over an acquisition cycle comprising multiple optical periods;
 wherein the initial optical emission begins at a first instant within each optical period of the acquisition cycle; 
 wherein said processor generates the first portion by processing, based upon the clock signal, the sensor signal and the reference signal at a second instant within each optical period of the acquisition cycle. 
 
     
     
         28 . The electronic device of  claim 27  wherein said controller reactivates said processor to repeat generating the first portion while time-shifting the reference signal by an initial fraction of the optical period corresponding to a whole number of internal periods to obtain another portion of the first histogram over the entire optical period until the first histogram is complete. 
     
     
         29 . The electronic device of  claim 28  wherein the initial fraction of the optical period corresponds to two internal periods. 
     
     
         30 . The electronic device of  claim 28  wherein said calculator subtracts consecutive histograms to generate the final histogram. 
     
     
         31 . The electronic device of  claim 28  wherein the optical period is equal to n times the internal period, and the first fraction is equal to the internal period divided by n. 
     
     
         32 . The electronic device of  claim 28  wherein said sensor array comprises a proximity sensor array. 
     
     
         33 . A mobile electronic device comprising:
 a housing; and   an electronic device carried by said housing and comprising
 an emitter to emit optical radiation based upon an optical period, 
 a sensor array providing a sensor signal based upon optical radiation from the emitter reflected off of an object, 
 a processor to generate a first histogram by processing the sensor signal and a reference signal based upon a clock signal having an internal period equal to a submultiple of the optical period, 
 a controller to control the processor to iteratively perform histogram generation with each iteration having the optical signal time-shifted by a first fraction of the internal period for at least one portion of the internal period to obtain at least one second histogram, and 
 a calculator to combine the first histogram and the at least one second histogram to obtain a final histogram having a finer time granularity than the first histogram. 
   
     
     
         34 . The mobile electronic device of  claim 33  wherein said processor successively processes the sensor signal over the entire optical period using successive time shifts with respect to an initial optical emission. 
     
     
         35 . The mobile electronic device of  claim 34  wherein said processor generates a first portion of the first histogram from the initial optical emission over an acquisition cycle comprising multiple optical periods;
 wherein the initial optical emission begins at a first instant within each optical period of the acquisition cycle; 
 wherein said processor generates the first portion by processing, based upon the clock signal, the sensor signal and the reference signal at a second instant within each optical period of the acquisition cycle. 
 
     
     
         36 . The mobile electronic device of  claim 35  wherein said controller reactivates said processor to repeat generating the first portion while time-shifting the reference signal by an initial fraction of the optical period corresponding to a whole number of internal periods to obtain another portion of the first histogram over the entire optical period until the first histogram is complete. 
     
     
         37 . The mobile electronic device of  claim 33  wherein said sensor array comprises a proximity sensor array.