Tuesday, August 3, 2010

Facial Recognition - on trial - in the news

From SF Weekly: "... The trial of Charles Heard was, in other words, what criminal lawyers call an "identity case." The defendant's guilt or innocence rested on jurors' willingness to believe various statements about what the killer of Richard Barrett looked like.

It was into this setting that there walked a beguiling, self-described expert who claimed he could settle the question using a little-known branch of science.

From the get-go, Ben Bavarian made no secret of his eagerness to participate in a San Francisco criminal proceeding that, outside of its potential ripeness for his profession's techniques, had absolutely nothing to do with him ..."

"... Safire had enlisted Bavarian to analyze business surveillance videos of two young black men fleeing the site of Barrett's murder. The prosecution and defense agreed that one of these unidentified men was the shooter. They wore clothes matching those described by witnesses, and one can be seen in the footage holding an object that resembles a handgun.

Swart chose not to use the videos for identification purposes, asserting that they were too blurry. Yet they were a mainstay of Safire's case. Relying on Bavarian's techniques, the defense lawyer hoped to demonstrate that neither of the men captured on tape was Charles Heard.

The prosecution, for its part, argued forcefully against Bavarian being allowed any-where near a jury.

"At this point, it cannot be established that biometrics has been generally accepted in the relevant scientific community," Swart said in a motion. "Just as importantly, there are no prior published Court of Appeal opinions in California that establish the general scientific acceptance of this science."

Swart's characterization of facial-identification technology is accurate, according to Faigman: "My experience suggests that it's not generally accepted in the mainstream scientific community," he said. ..."

"... After some interrogation on the technical aspects of Bavarian's methods, Swart asked him whether his analysis of Heard's photo and that from the surveillance camera had been peer-reviewed by other scientists.

"Did anybody do a technical review of your work?"

"Yes," Bavarian replied.


"My colleagues and my friends."

Safire objected.

"Your Honor, I think this is misleading," he said somberly. "I really do."

If it seems odd that a relatively untested science, explained by a relatively unknown scientist, should be considered as evidence by a panel of men and women deciding whether to send a young man to prison for the rest of his life — well, it is.

State and federal courts ostensibly have rigorous tests for establishing the admissibility of scientific evidence. The goal, as a California appellate judge wrote in 1998, is to avoid bestowing "a misleading aura of certainty or a posture of mystic infallibility" on quackery ..."

"... Perhaps the most damning review of Bavarian's work came from the expert witness Swart put on the stand to debunk his analysis.

Richard Vorder Bruegge is a forensic scientist and photographic technologist employed by the FBI. He has a Ph.D. in geological sciences from Brown University, a full head of silver hair, and youthful good looks, presenting a stark contrast to Bavarian's vaguely reptilian allure.

The authoritativeness of Vorder Bruegge's résumé was almost comical. He worked with NASA on the Clementine mission, which carried out the first image mapping of the moon in 1994; he is the chairman of the Facial Identification Scientific Working Group — the same group Bavarian had claimed was "not relevant"; and he came to San Francisco for Heard's trial just two weeks after delivering the keynote address on facial identification at a biometrics conference in Australia.

On the stand, Vorder Bruegge argued that the technique used by Bavarian — measuring the distances between facial features, creating ratios, and then comparing them — was "not reliable," because it depended too much on such variables as a subject's pose and the angle of the camera. A more fundamental problem in Heard's case, he said, was that the image gleaned from the low-resolution surveillance video simply wasn't fit for scientific analysis ..."

Read the whole story by clicking here. Enjoy.

No comments: