Friday, 1 August 2014

KAIRA Pan-Lapse Film

In late June, we visited the KAIRA site in Kilpisjärvi on a maintenance trip. One of many tasks was to repair an HBA cell, which got damaged in a severe storm in spring. Another task was to take lots of high-quality photos of KAIRA and its surroundings for various documentation and illustration purposes.

Right on the first evening, we put a tripod bridging the gap between tiles H57 and H47 on which we mounted a wide-angle GoPro camera, which was glued onto a very cheap and simple egg timer. The egg timer rotates 360° in one hour, and the camera was set to take a photo every 10 seconds, thus taking 360 images, one per degree of rotation.

The full 360° panorama can be assembled by sticking together twelve images, which are five minutes apart. The only problem is to find out how many pixel the image rotates in five minutes, which is 30° of rotation.

The photo above shows such a montage (click to enlarge), featuring the famous mountain of Saana in the sixth pane from the left. Since we have a full rotation, one photo per degree, we can assemble such a panoramic view in 360 different directions, each one showing the a full 360° panorama. Then, we combined them into a short film, giving the impression of full-panorama rotation.

The above explains how we did it, but one can understand what's going on also this way. We generate a time-lapse film from all the images, showing a slow rotation. Then we cut out the centre vertical section equivalent of 30° rotation from this film. Thereafter we glue twelve copies of the very same film side-by-side, but advance the film for each step just the right amount, so that it fits to the previous copy of the film.

We hope you enjoy the result.

We got the idea for these pan-lapse films from Ken Murphy of Murphlab, please visit his site for this and other exciting time-lapse projects.

Photos & pan-lapse: Thomas Ulich.

PS1: You might wonder why we didn't choose a nicer day with more blue sky for this experiment. In fact we did, but due to the GoPro's automatic exposure settings, the large contrasts between looking into the Sun and away from the Sun, paired with shadows of clouds moving across the sky, make the different panes/frames look very different and the result is much less pleasing. So grey skies are good for something!

PS2: Another somewhat more explicit blog post about this went out today on the MiVyoo blog.

No comments:

Post a Comment