Five years ago, Olympus Corp. was caught up in the oddest of corporate scandals. Its then-CEO, Michael Woodford, uncovered an accounting scandal at the company that went undetected for years, besmirching the name of a once-proud Japanese maker of digital cameras and medical equipment.

The challenge of getting the company out of the penalty box, restoring investors' trust and expanding again has fallen to Hiroyuki Sasa, who took over as CEO in 2012. "It's an endless effort," Sasa said in an interview at the company's Tokyo headquarters.

Though the company's stock is priced about eight times higher than the lows of 2011, Sasa has his work cut out for him. Governments are curbing health-care expenditure and competition is rising. Meanwhile, some of the company's medical devices have drawn scrutiny from U.S. regulators regarding an issue of bacterial contamination, and it faces lawsuits from patients.