docs: double computeAngle( int index1 ) {
  
  		int index0 = CircularIndex.addOffset(index1,-1, histogramMag.length);
  		int index2 = CircularIndex.addOffset(index1, 1, histogramMag.length);
  
  		// compute the peak location using a second order polygon
  		double v0 = histogramMag[index0];
  		double v1 = histogramMag[index1];
  		double v2 = histogramMag[index2];
  
  		double offset = FastHessianFeatureDetector.polyPeak(v0,v1,v2);
  
  		// interpolate using the index offset and angle of its neighbor
  		return interpolateAngle(index0, index1, index2, offset);
  	}