3D Flash LIDAR point cloud video registered with hand-held color camera

[ucesrlc]

What are the two clusters of grey point clusters that appear to be in mid-air? At first i thought they were trees, based on their fragmented structure and general shape, but they don't appear to have the colour of trees, and appear to be transparent (when the person walks through their 'shadow' his or her 'image' is not obscured, only displaced).

[DonaldNatale]

@ucesrlc

Hello. Your intuition is correct, these were trees. The reason they are gray is because this was kind of an impromptu experiment where a guy literally made a cell phone video holding his camera in the area in a position which wasn't near the camera. The video was stabilized and warped to fit the field of view as best we could, but the trees were not in the original video. If you were going to do this for real you would obviously want to attach the color camera to the range camera.

[DonaldNatale]

@DonaldNatale

as for the lack of shadowing, from the trees, I think that that is more of a trick of the artificial perspectives shown by the rotating around visualization. Two things, first, when the video starts up with the front on view, right as it rotates you see the shadow on the ground near the edge of the image for a few frames. You can also see the shadow on the ground later in the clip. When this was done we were about 60 ft. in the air and had full view of the guy the whole time.