Difference between Organized and Unorganized Point cloud

source: http://stackoverflow.com/questions/18994680/can-anyone-explain-the-difference-between-organized-and-unorganized-point-cloud

Question: What is the difference between organized point cloud and an unorganized one?

Am I right in thinking that a point cloud is a column of [x,y,z] values? Than what is the difference in the structure of the point cloud if its organized or unorganized ?

How does it affect the later processing steps like filtering, normal estimation, registration etc ?

Answer:See the notes on this page on HEIGHT and WIDTH of a point cloud: Point Cloud File Format

An organised point cloud is organized as a 2D array of points with the same properties you'd expect if the points were obtained from a projective camera, like the Kinect, DepthSense or SwissRanger. In PCL the points array of a point cloud is actually a 2D array but one of those dimensions is only used for representing organised point clouds.

In both organised and unorganised point clouds, all of X Y and Z are provided for each point, but the memory layout of organised point clouds is that of a 2D array. The memory layout of the points then is closely related to the spatial layout as represented by these XYZ values.

Algorithms that work on unorganised point clouds will generally work on organised point clouds (since the 2D array of points is packed and can be interpreted as a 1D array) but specialised algorithms can be designed to work on organized point clouds. An example is the use of the organized property of a point cloud to speed up the process of calculating normals: Integral Images Normal Estimation Tutorial

Good Will Hunting, a must watch !!!

Yesterday night, I wanted to start my work after just seeing some movie scenes from Youtube. So i started to think of some movie names that come to my mind and it was Good Will Hunting. Having seen this movie before, i wanted to see some good scenes from this. The first link on the youtube was the scene in which , the Will Hunting(Matt Damon) will be asked by Robin Williams what he wanna do with his life ? He gives some bull shit answer by saying that he wants to become a shepherd. Robin William tells him that he doesnt even know and you have some stupid answer for every question.

This scene was so good that temped me to see the full movie. So I started to see the full movie.

I guess that this movie is based on a real life story. Matt Damon is a prodigy who is exceptionally good in math. But his childhood and many incidents from his life make him feel abandoned by the ones who should have loved him. Thus he hangs out with workers and not "intellectual"  people who work for a construction company. Robin says in the movie that he does that becoz he finds trust and loyalty in those people.

Matt Damon used to work as a janitor at MIT and a Prof. Gerald identifies this genius and wants him to go to great places and solve cutting edge problems. The problem with Matt is that he engages in lot of street fights but gets rid of them from the court arguing some previous incidents from history orcivilian rights from the constitution of United states of America. Prof. Gerald gets Matt from prison on two conditions that he ll do math and goes to a therapist.

Prof. Gerald finds Robin who is a psychologist by his profession and the whole movie is about how Robin helps Matt to make good choices in his life. 

Carpe-diem : Sieze the day

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