US 11,906,658 B2
Systems and methods for shapelet decomposition based gesture recognition using radar
Arijit Chowdhury, Kolkata (IN); Smriti Rani, Kolkata (IN); Tapas Chakravarty, Kolkata (IN); and Arpan Pal, Kolkata (IN)
Assigned to TATA CONSULTANCY SERVICES LIMITED, Mumbai (IN)
Filed by Tata Consultancy Services Limited, Mumbai (IN)
Filed on Sep. 29, 2020, as Appl. No. 17/037,335.
Claims priority of application No. 201921052641 (IN), filed on Dec. 18, 2019.
Prior Publication US 2021/0199761 A1, Jul. 1, 2021
Int. Cl. G01S 7/41 (2006.01); G06N 20/00 (2019.01); G06F 3/01 (2006.01); G06N 5/04 (2023.01)
CPC G01S 7/415 (2013.01) [G06F 3/017 (2013.01); G06N 5/04 (2013.01); G06N 20/00 (2019.01)] 12 Claims
OG exemplary drawing
 
1. A processor implemented method, comprising:
obtaining, using a radar system, a plurality of time domain signals reflected by a subject performing one or more activities, wherein the subject refers to a living being including a human or an animal or a bird;
identifying one or more gesture windows in the plurality of obtained time domain signals, by applying one or more signal properties on the plurality of obtained time domain signals to detect a no motion region and a motion region in the plurality of obtained time domain signals, wherein width of each gesture window is indicative of a time duration in which a gesture is performed, wherein applying the one or more signal properties comprises determining an average energy for the plurality of obtained time domain signals to identify a region where the average energy is minimum as the no motion region;
obtaining, using a spectrogram, one or more shapelets of one or more gestures captured from the one or more gesture windows;
creating a dictionary of basic shapelets of one or more motion patterns of a plurality of gestures comprised in the one or more activities performed by the subject;
decomposing, using the created dictionary of basic shapelets, the one or more shapelets to obtain a plurality of sub-shapelets of the one or more gestures captured from the one or more gesture windows, wherein each sub-shapelet is representative of a specific motion pattern of each of the one or more gestures captured from the one or more gesture windows;
applying, at least one of (i) a positive or (ii) negative time delay to each of the plurality of sub-shapelets of the one or more gestures to obtain a plurality of composite shapelets for the one or more gestures, wherein the plurality of composite shapelets for the one or more gestures are obtained by superimposing the positive and the negative time delays of each of the plurality of sub-shapelets, and wherein the positive and the negative time delay is provided to each of the plurality of sub-shapelets based on a displacement and a time pattern of the one or more gestures; and
performing, a mapping of each of the plurality of composite shapelets with a plurality of trained shapelets stored in a system database to recognize the plurality of gestures comprised in the one or more activities being performed by the subject, wherein each of the plurality of composite shapelet is converted into a 2-dimensional or 3-dimensional vector and mapping is performed to recognize a new gesture performed by the subject.