When Dr. Gretchen Berland gave video cameras to three Los Angeles residents in wheelchairs and asked them to film their daily lives, she wasn’t sure what they would capture. In the end — after nearly two years and 212 hours of tape — Galen Buckwalter, Ernie Wallengren and Vicki Elman did far more than accomplish Berland’s goal of providing care givers, policy makers and health care professionals insight into life on wheels for 1.6 million Americans.