I can’t really say much about Tuyuan yet since it’s in Chinese and there isn’t much information (translated page here), but it certainly looks like they’re trying to tackle the facial recognition problem that has destroyed many a startup.

We’ve seen Riya (now focused on ecommerce via Like.com), Ookles (never launched), and Polar Rose (in private beta for nearly a year), among others. Most recently Tagcow came on the scene, but it turns out it uses humans to tag photos, which tends to produce bad data.

Will Tuyuan be any different? We have no idea yet. But we’re contacting them to find out. More soon. Thanks for the tip, Orli.

Most people have thousands of digital photos sitting on their hard drive. And the vast majority of those photos aren’t tagged or searchable. Want to find the 300 pictures of your youngest son amongst 10,000 others? It’s not going to happen. Unless you’ve been diligently tagging and categorizing those photos over the years, and who does that?

The problem is obvious. The solution, not so much. A trail of failed startups have tried to tackle the problem with a fairly serious application of technology, including: Riya (now focused on ecommerce via Like.com), Ookles (never launched), and Polar Rose (in private beta for nearly a year), among others.

And now suddenly TagCow appears, which allows users to upload photos and have them tagged within a few minutes. The technology appears to be “magic,” meaning there’s no explanation of it.

If there’s a mountain in the photo, it’s tagged. A dog? yep. A yellow cup? Absolutely. It does people, too. Upload an image of a person and say who it is, and all other images you upload will be tagged with that person, too. The service also integrates with Flickr and will auto tag the photos you have on the service.

Thomas Hawk, the CEO of photo site Zooomr, tried the service and declared it “really, really cool,” although he wonders how it works.

The answer is, humans do it. I note that the TagCow site is careful not to say anything about the tagging process, and never use the word “automated” or anything else that would suggests computers are doing the work. Munjal Shah, the founder of Riya/Like, agreed, noting that it recognized a witch in Thomas’ photo – he says this just isn’t something a computer can do today.

I haven’t confirmed this yet. I’ve emailed the company for a description of how the service works but have yet to hear back. Until we do, I’m betting that humans are the taggers. Note that Google has effectively thrown in the towel and uses humans for this kind of work, too.

TagCow appears to be offering the service for free, so the cost side of the business may be a problem for them down the road. And the business is definitely a little sketchy. Worried about the privacy of your data? Just don’t click on their Privacy Policy or Terms of Use: “Privacy policy is TBD.” and “Legal stuff TBD.” Not exactly a way to build confidence.

Polar Rose, a European startup that has a unique approach to recognizing faces in photos (remember Riya?), is having a bit of a pre-launch coming out party at the Gnomedex conference in Seattle today.

We first wrote about the company last December, way before they were ready to take beta testers. But even then it was clear that they were on to something. They use a browser plugin to allow users to tag people in photos anywhere on the web. They use those photos to construct a 3D image of the person, and then make educated guesses as to who is in untagged photos. See the post linked at the top of this paragraph for more details.

The company has been testing the service with a very limited number of beta users. The beta will expand significantly today, however. Every attendee of the Gnomedex conference will be able to register, and will be encouraged to tag photos of the event. A special page at Polar Rose was set up to show the tagged photos (none yet, the conference hasn’t started).

250 Polar Rose Beta Accounts Available

Polar Rose has also given us 250 beta accounts to give out immediately. Just send an email to techcrunch@polarrose.com. If you aren’t one of the first 250, you’ll be placed on the waiting list for the beta – more invites are coming every week.

Malmö, Sweden based Polar Rose is having its coming out party today and pre-announcing a product release slated for early next year. CEO Nikolaj Nyholm gave me demo of what’s coming last weekend.

Polar Rose is trying to solve the increasingly important problem of making sense out of photos. Without semantic data, a photo isn’t much use to a computer trying to convert a keyword query into image results. Google created a game to get users to tag photos for them. Flickr and some of its competitors are doing a pretty good job at getting users to tag photos. And of course newcomer Ookles will soon release their own product. But the vast majority of images on the net have little or no semantic data associated with them, and for all practical purposes they are therefore invisible.

Polar Rose wants to change that. They won’t be a destination site for photos. Instead, they’ve planned a two pronged approach to winning market share – distribution of a browser plugin for users and freely available APIs for photo sites. Users of the plugin will be able to add data about any photo on the internet, and search those photos later. Companies integrating the API will get a copy of the data created by users for free.

The technology behind Polar Rose creates a virtual 3D image of a person, factoring out lighting and other conditions that can affect recognition. That 3D image is then used to try to guess when a person appears in a photo. The plugin, for example, will provide a link to try to find other images on the Internet of the person being tagged. At first, this data will be very thin. But if and when users adopt the Polar Rose plugin, the search feature could become a useful tool for finding additional pictures of people.

Polar Rose announced $5.1 million in Series A funding from Nordic Venture Partners last month.