Method And A System For Determining The Location Of An Object

Abstract

A method for determining the location of a transmitter (respectively a receiver) in a space defined by one or more reflective surfaces, including the steps of ending a signal from the transmitter (respectively from a set of transmitters); receiving by a set of receivers (respectively by a receiver) the transmitted signal and echoes of the transmitted signal reflected by the reflective surfaces; finding by a first computing module the location of the virtual sources (respectively virtual receivers) of the echoes; mirroring by a second computing module the virtual sources (respectively virtual receivers) into the space and obtained mirrored virtual sources (respectively mirrored virtual receivers); combining by a third computing module the mirrored virtual sources (respectively mirrored virtual receivers) so as to obtain location of the transmitter (respectively the receiver). This method makes use of echoes for localizing the source (respectively receiver) when there is no line of sight between the transmitter(s) and the receiver(s).

1 . A method for determining the location of an object, comprising the steps of
 sending a signal with one transmitter;   receiving by one receiver said signal and echoes of the transmitted signal reflected by one or more reflective surfaces;   associating some of said echoes to the one or more reflective surfaces;   determining the location of said object on the basis of said association, said object being said transmitter or said receiver.   
     
     
         2 . The method of  claim 1 , said associating comprising:
 building with a computing module a Euclidean distance matrix,   adding to said Euclidean distance matrix a new row and a new column, the new row and the new column corresponding to a combination of some echoes, and obtaining a modified matrix,   computing the distance between the modified matrix from a true Euclidean distance matrix;   determining the location of the object based on the computed distance.   
     
     
         3 . The method of  claim 1 , the location and/or the orientation of said one or more reflective surfaces being known. 
     
     
         4 . The method of  claim 1 , said Euclidean distance matrix comprising the distances between said transmitter and first order image sources, said object being said receiver. 
     
     
         5 . The method of  claim 4 . the location of the transmitter being known. 
     
     
         6 . The method of  claim 1 , said Euclidean distance matrix comprising the distances between said receiver and first order image receivers, said object being said transmitter. 
     
     
         7 . The method of  claim 6 , the location of the receiver being known. 
     
     
         8 . The method of  claim 1 , wherein only first order echoes are considered. 
     
     
         9 . The method of  claim 1 , wherein only echoes received during a predetermined time window are considered for the association. 
     
     
         10 . The method of  claim 1 , comprising the step of labeling echoes. 
     
     
         11 . The method of  claim 1 , comprising determining which of the peaks of the impulse response received by said receiver correspond to which reflective surface. 
     
     
         12 . The method of  claim 1 , comprising the step of checking if the modified matrix still verify the rank property according which a Euclidian distance matrix in R n  has a rank at most n+2, n being an integer and positive number. 
     
     
         13 . The method of  claim 12 , comprising testing at least some echo combinations and selecting the combination for which the rank property is satisfied. 
     
     
         14 . The method of  claim 1 , comprising multi-dimensional scaling. 
     
     
         15 . The method of  claim 14 , comprising applying an s-stress criterion. 
     
     
         16 . The method of  claim 1 , said receiver being a microphone, said transmitter being a loudspeaker. 
     
     
         17 . The method of the previous  claim 16 , said reflective surface being a wall of a room. 
     
     
         18 . The method of  claim 17 , said room being a convex room. 
     
     
         19 . The method of the  claim 17 , said room being a non-convex room. 
     
     
         20 . The method of  claim 1 , said receiver being a light sensitive device as a photo diode or a camera, said transmitter being a light source. 
     
     
         21 . The method of  claim 20 , said reflective surface being a mirror. 
     
     
         22 . A system for determining the location of an object, comprising:
 one transmitter for sending a signal;   one receiver for receiving the transmitted signal and the echoes of the transmitted signals as reflected by one or more reflective surfaces;   a first computing module for associating some of said echoes to the one or more reflective surfaces;   a second computing module for determining the location of said object on the basis of said association, said object being said transmitter or said receiver.   
     
     
         23 . The system of  claim 22 , wherein said first computing module is configured for
 building a Euclidean distance matrix:   adding to said Euclidean distance matrix a new row and a new column, the new row and the new column corresponding to a combination of some echoes, and obtaining a modified matrix;   computing the distance between the modified matrix from a true Euclidean distance matrix.   
     
     
         24 . The system of  claim 23 , wherein said second computing module is configured for
 determining the location of the object based on the computed distance.   
     
     
         25 . The system of  claim 22 , the first and second computing modules being the same module. 
     
     
         26 . The system of  claim 22 , said receiver being a microphone, said transmitter being a loudspeaker. 
     
     
         27 . The system of  claim 26 , said reflective surface being a wall of a room. 
     
     
         28 . The system of  claim 27 , said room being a convex room. 
     
     
         29 . The system of the  claim 27 , said room being a non-convex room. 
     
     
         30 . The system of  claim 22 , said receiver being a light sensitive device as a photo diode or a camera, said transmitter being a light source. 
     
     
         31 . The system of  claim 30 , said reflective surface being a mirror. 
     
     
         32 . A computer program product, comprising:
 a tangible computer usable medium including computer usable program code for determining the location of an object, the computer usable program code being used for
 associating some of said echoes of a signal transmitted by a transmitter and received by a receiver, as reflected by one or more reflective surfaces, to these reflective surfaces; 
 determining the location of said object on the basis of said association, said object being said transmitter or said receiver.