code: public double computeFeatureDiversity(Se3_F32 keyToCurrent ) {
  
  		diversity.reset();
  		for (int i = 0; i < keypixels.size(); i++) {
  			Pixel p = keypixels.data[i];
  
  			if( !p.valid )
  				continue;
  
  			SePointOps_F32.transform(keyToCurrent, p.p3, S);
  			diversity.addPoint(S.x, S.y, S.z);
  		}
  
  		diversity.process();
  		return diversity.getSpread();
  	}
docs: Computes the diversity of valid pixels in keyframe to the location in the current frame.
  @return Angular spread along the smallest axis in radians