Jason M. Volack reports:
Doug Carner is obsessed with his job.
He is an "enhancement specialist" who spent the last 20 years poring over old and grainy video and audio to give it clarity for those who need it.
"I would do it for free if I could make a living on that," Carner said.
Carner's company, Forensic Protection, independently helped ABC News to clean and enhance Sanford, Fla., Police Department surveillance video revealing for the first time what appears to be a pair of vertical welts on the back of the head of George Zimmerman, the volunteer neighborhood watchman who fatally shot unarmed teen Trayvon Martin.
The clarified video complicates an already complex narrative of what really took place the night of the shooting.
Zimmerman told investigators that Martin jumped him from behind, punched him in the nose hard enough to break it and pounded his head into the sidewalk.
Although the welts seem to be consistent with Zimmerman's account of what happened the night of Feb. 26., the video enhancement also reveals no trace of blood and little sign of swelling on Zimmerman's nose.
To clarify the video, Carner said he utilized a two-step process.
The first step, called "focus correction," sharpened the image by refocusing the camera on the police badge of the officer standing next to Zimmerman.
Once the new focus was set, a mathematical formula was used to clarify the images around the badge, including Zimmerman's face.
The second step utilizes a process called "subpixal fusion," by which images are clarified by both increasing the detail of adjacent objects and looking at the frames that come before and after.
Carner also analyzed the audio 911 tapes the night of Feb. 26 and by identifying and boosting the human speech and suppressing all other audio such as wind, the screams become more audible. Although it's still unclear if the screams are those of Martin or Zimmerman.
Since Carner's enhanced video appeared on ABC's "Good Morning America" today, the forensics expert said he received more press calls in two hours than he had in his entire career.
Carner said he's not egotistical enough to believe he's the best in the business, but says his work speaks for itself.
He deals with a multitude of cases - ranging from grocery store slip-and-falls to audio recordings in a messy divorce.
"The greatest compliment is a case that is won or settled without seeing a courtroom," Carner said. "If I have to show up in a courtroom, I have not done my job well enough. The evidence speaks for itself."
Carner said the technology he uses is changing so rapidly that video enhancement - a process that takes more than 24 hours utilizing high power computers to clean up one minute of video - will soon be instantaneous.
Carner also said that he'll soon be able to "deblurr" images or reverse the path of motion without distorting the image.
Although he's been working in the field for more than 20 years, Carner still gets excited when someone asks "How did you do that?"
"It's gratifying when you bring the truth out," he said.