code: public int encodeK( DMatrix3x3 K , int which, int offset, double params[] ) {
  
  		if( fixedAspectRatio ) {
  			K.a11 = params[offset++];
  			K.a22 = aspect.data[which]*K.a11;
  		} else {
  			K.a11 = params[offset++];
  			K.a22 = params[offset++];
  		}
  
  		if( !zeroSkew ) {
  			K.a12 = params[offset++];
  		}
  
  		if( !zeroPrinciplePoint ) {
  			K.a13 = params[offset++];
  			K.a23 = params[offset++];
  		}
  		K.a33 = 1;
  		return  offset;
  	}
docs: Encode the calibration as a 3x3 matrix. K is assumed to zero initially or at
  least all non-zero elements will align with values that are written to.