Alignment/Transformation Matrix

[ziarehmann]

Hello,

Maybe the question had been discussed before but i am unable to find some concrete post regardig that. I am new to the CC. I would like know how one can analyze that the alignement of 2 objects is very good. Are there any paramters in CC which give an idea whether the aligned object is fitted with maximun precesion.

Secondly what does a transformation matrix tells. And what values does a good aligned object represents? Can one see explicitly which points were aligned together?

Hope to have an answer soon.

Regards!

[daniel]

Are you referring to the ICP registration tool or the point pair-based alignment tool?

In both cases you have the resulting 'RMS' but it has not the same meaning for each algorithm. For the first one it is computed on a random part of the cloud (50.000 by default I believe) so it's pretty reliable. In the other case it's only computed on the selected pairs (so it doesn't give an information on the whole cloud).

Anyway, you can always compute the distance between the two entities afterwards (with the Distances computation tools: http://www.cloudcompare.org/doc/wiki/in ... omputation).

The transformation matrix is only a rotation (3 first columns - forget the last row) and a translation vector (4th column - forget the last value which is always 1 in our case).