Tiger Woods, who can overtake Rory McIlroy for world No 1 by defending his title this week at Bay Hill, says he and ski star Lindsey Vonn went public as a couple to combat "stalker-azzi".

A day after Woods and Vonn told the world they were dating and shared photos on their Facebook pages, Woods explained why they made that decision at a news conference on the eve of the $6.2 million US PGA Arnold Palmer Invitational.

"We're very happy where we're at, but also we wanted to limit the 'stalker-azzi' and all those sleazy websites out there, paparazzi following us," Woods said.

Woods said photographers seeking a valuable picture of the couple could put at risk Woods' two children with ex-wife Elin Nordegren - 5-year-old daughter Sam Alexis and 4-year-old son Charlie.

"I've had situations where it has been very dangerous for my kids, the lengths paparazzi will go to," Woods said. "We basically devalued the first photos. Unfortunately that's just the way it is in our society right now. We felt it was the best thing to do and I'm very happy about it."

Woods, a 14-time major champion who will try to close the gap on the record 18 majors won by Jack Nicklaus when he plays at next month's Masters, has spent a record 623 weeks atop the world rankings, but none since October of 2010 after injuries and an infamous sex scandal saw him stumble from the top 50.

"I fell to 50-plus there for a while," Woods said. "To gradually work my way back is something I'm proud of. It's not easy to get there in the first place and to sustain it isn't easy at all.

"I'm very pleased where I've come from - 50-plus to where I'm at is no small task."

World No 2 Woods has won five titles in the past year, a run that began at Palmer's event last year when he won his first PGA title since the scandal. This year, Woods has already collected triumphs at Torrey Pines and Doral.

But doubters say he will not be fully back to the form of his glory days until he ends a major title drought that dates to the 2008 US Open.

"I feel like I'm headed in the right direction from where I have come from," Woods said. "I'd like to get to 19-plus myself."

Woods, whose return to success has coincided with his romance with Vonn, seeks his eighth career title at Bay Hill.

He would become the first man to win the same PGA event eight times, although he already has eight career victories on the same course from seven PGA titles and the US Open at Torrey Pines.

"It has been a long process," Woods said. "I was hurt for a long time. I had to make swing changes that were drastically different than what I was doing before. It has taken some time."