| CPC G06F 21/32 (2013.01) [G02B 27/017 (2013.01); G06V 10/145 (2022.01); G06V 10/147 (2022.01); G06V 40/166 (2022.01); G06V 40/167 (2022.01); G06V 40/176 (2022.01); G06V 40/20 (2022.01); G06V 40/70 (2022.01); G10L 13/02 (2013.01); G10L 15/183 (2013.01); G10L 15/22 (2013.01); G02B 2027/0178 (2013.01); G10L 2015/223 (2013.01)] | 20 Claims | 

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               1. A system for detecting facial muscle activity comprising: 
            wearable apparatus comprising; 
                an optical flow sensor located so as to, in use when the apparatus is worn, image an area of skin associated with one or more facial muscles, the optical flow sensor being configured to capture time-varying data describing movement of the respective area of skin substantially in the plane of the imaged area of skin; and 
                  an EMG sensor and/or a proximity sensor arranged to detect the activity of a first muscle along with the optical flow sensor; and 
                a processor configured to process the time-varying data in dependence on a predetermined dataset relating facial muscle activity to movement of the areas of skin so as to determine activity of the set of facial muscles, the processor being configured to combine, with the time-varying data captured by the optical flow sensor, time-varying data describing movement of the respective area of skin which is captured by the EMG sensor and/or the proximity sensor. 
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