After all the data was captured, the processing work started. The first thing we did was send the raw Lidar data to 510 Systems, an engineering company in Berkeley, California that has a lot of experience processing this type of data. The company assigned the project to its in-house Lidar data guru, Pierre-Yves Droz. He's an expert at turning raw Lidar data into usable formats.
Pierre did two things for us after receiving the data, which we mailed to him on DVDs. First, for the landscape scenes, he isolated a single laser out of the 64 and created a data set of just that laser's points. Second, he converted all of the raw Lidar data, including the dynamic party scene data, into individual data points consisting of
x, y, z, and
To convert the raw data, Pierre needed to know the precise position and orientation of each of the Lidar's laser emitter and detector pairs. This calibration information is provided by Velodyne, and the parameters are unique to each Lidar unit. Pierre also used the speed of the van to help calculate how far the Lidar moved in the real world as it rotated.
All told, we gave 510 approximately 4 gigabytes of raw data, which turned into almost 50 gigabytes of processed data in text .obj format.