You’re attending a baseball game and call Google’s 411 service for information about a nearby restaurant. The cheers of the crowd and the sounds of the announcer are picked up by your phone. Google’s system analyzes the background noise, takes into account your location, determines that you’re at a ballgame and delivers related ads or links to your phone with sports scores and news.

Or maybe you’re making the call from a concert hall, and the sound in the background is the instruments tuning up during intermission. Google figures out that you’re at a concert, and serves up musical news or ads about albums related to the performance.

Those are some of the actual examples described by Google in a patent just received by the company for “advertising based on environmental conditions.”

Sound a little creepy? The patent acknowledges that “it is important to respect the privacy of the users,” and explains that users would have the option of “enabling or disabling some or all of the sensors for the purpose of gathering information to support advertisements,” as governed by a privacy policy.

Google applied for the patent in January 2008 and received it today. Coincidentally, the patent approval comes at a time of heightened scrutiny over Google’s privacy practices. And the concept makes the automated ads in Gmail sound positively low-tech.

The patent doesn’t just reference background noise, but also input a from variety of sensors. For example, when the temperature sensed by a device dips below a certain threshhold, the system could serve up ads for winter coats, according to the patent.

The idea is to use a variety of conditions sensed by the phone to help serve up ads, not just on the phone itself but also on nearby digital billboards or similar advertising venues.

As with many of these things, there’s no indication that Google actually plans to implement the technology.

Photo by Ouij via Flickr