Abstract: A surgical system includes at least one light emitter and an array of light sensors disposed at the working end of the surgical instrument, individual light sensors in the array of light sensors adapted to generate a signal comprising a non-pulsatile component. The system also includes a controller coupled to the array of light sensors, the controller including an analyzer configured to determine a curve of the non-pulsatile components of the signals of each of the individual light sensors in the array of light sensors, to identify a plurality of regions of interest along the curve, to determine one or more regions of interest of the plurality of regions of interest to consider further based on one or more measures of closeness between the plurality of regions of interest, and to determine if one or more of the one or more regions of interest are more likely to be associated with a vessel or a tissue based on one or more parameters.