A new electronic scoring system at the London Games is a significant step forward, Campbell said.
"It's a huge leap forward as not only can they now record and score multiple points, any unconscious bias towards a higher-ranked athlete is also removed," he said.
Electronic scoring now means there is a new winner every tournament. We've got a good chance of bringing home a medal."
Campbell took a break from the sport after Beijing, but now sits eighth in rankings.
"I've grown up mentally and physically. I know I'm better than last time. I'm a better fighter. I'm fitter, faster and smarter," he said.
The New Zealand team for London now stands at 43, including sailors, rowers, canoe slalom exponents, and a dressage contestant. Selections will continue until July.