By Peter Berton

SAN FRANCISCO – An iPhone app that uses selfies to determine a woman’s bra size has scored $5.6 million from eager investors.

ThirdLove will use the investment, spearheaded by venture capital heavyweights New Enterprise Associates and Andreessen Horowitz, to launch the app and a new lingerie brand the company claims will fit each woman perfectly based on images she captures using the app.

“The number one reason people return products that they buy online is due to fit,” ThirdLove cofounder Heidi Zak told VentureBeat.“We have created an app using computer vision technology that consumers can use to fit themselves. We use computer algorithms to calculate her actual measurements and place her in the correct size.”

The key to ThirdLove’s better-fitting bras is a unique, guided self-shot imaging system that helps users snap photos of their bust from the front and the side, even while clothed. One the app determines the appropriate bust measurement, it whisks the user into ThirdLove’s online store, where she can pick styles, colors and customized features. Matching panties are available, as well.

A recent review of the ThirdLove app by Fast Company’s Sarah Kessler provides a firsthand account of how the app works.

The app offers “a tutorial in the voice of a polite but firm woman who sounds a bit like my grade school principal,” Kessler wrote. “As instructed, I stand in front of my mirror with my phone at my belly button. ‘Slightly raise right end of the phone,’ she says. Then ‘slightly raise left end of the phone.’ Then, ‘slightly raise right end of the phone.’ After about 50 more rounds of this, there’s a gratifying ‘Good job’ and a countdown to the photo.”

If all goes according to plan, ThirdLove’s bra-fitting app will be available this fall, Zak indicated.