System and method used to detect or differentiate tissue or an artifact

A surgical system including a surgical instrument, the surgical system comprising:

• at least one light emitter disposed at a working end of the surgical instrument;
• 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;
• and
• a controller coupled to the array of light sensors, the controller comprising 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,
• smooth the curve to generate a smoothed curve;
• calculate a derivative of the smoothed curve;
• invert the smoothed curve to generate an inverted smoothed curve;
• calculate a derivative of the inverted smoothed curve;
• take a difference between the derivative of the inverted smoothed curve and the derivative of the smoothed curve to generate a resultant curve;
• smooth the resultant curve to generate a smoothed, resultant curve;
• estimate zero crossings of the smoothed, resultant curve;
• apply a signum function to points adjacent each zero crossing, if any, to generate a result;
• and
• identify a region of interest, if any, based on the result for points adjacent each zero crossing, if any.