While I can't quite identify her from that pic alone, I'd say she has a similar build to either Harumi Nemoto, Hanai Miri, mehbeh Megumi :3, I don't think it's Rio Natusme (the breasts seem a little to small to be hers). But I do indeed have a feeling its a Japanese gravure Idol :3
From 0 to KICKASS in .stupid seconds.