The infrared camera captures three dimensional data - two spatial plus time. With the geometry studied here, the data is essentially two dimensional, where the two spatial dimensions have been collapsed into the single measurement of angular position around the ring.
The figure below shows how the space-time plots on these pages are constructed. On the left, four images are shown with all but the platinum masked off. Each image is then "unwrapped" to form a horizontal slice through the space-time plot on the right.