Paul Browne <pbrowne@computing.dcu.ie> wrote:

 Prof. Alan Smeaton suggested it might benefit some
 Trec participants if we made available the shot keyframe
 images from the Trec 2002 Search test collection.
 ... 
 I found the representative shot keyframe by extracting
 a Jpeg closest to the average of all images within a
 shot. Attached is an Excel graph showing the distribution
 of the keyframes (the peak is the middle of the shot)