Face detection in Google Picasa 3.6

Facebook have had it for a long time: the option to tag people in pictures in your photo albums, that is a great part of a social network oriented site like Facebook. Now in the free photo album (and more) software from 3.6” the process of face dection can be done automatically!

How it works in the application

Starting up Picasa, it is very cool to see how it scans all your images for faces and groups them under the “People” folder. For a start Picasa will find (probertly) a lot of faces which it is up to you to identify. The faces is found using software inside Picasa – and I must say it works impressingly well.

Picasa has located me - Sten Hougaard and now has a group of images where I appear inThe face detection finds rectangles containing faces – here you see the face of the author of this post. To start with Picasa does not know who this face belongs, that part is your job. So you will have to prepare yourself to put some time into that part. Since it is a Google product I would however not doubt that they stored the information in a wise way (more on this later). I have put some hours into this task now, and “only”  meed to tag 466 unknown faces (!).

This have given me the option to view the 377 containing the face of my daughter as a slide show. I can also make a collage, a movie or perhaps uploade those containing the face of my daughter – nice.

What can this be used for?

I personally love this new feature, perhaps mainly because of the fact that it is a new feature – I love the option to view images from various “angles”: Where they were taken, the date, the people on the photo and other. I love the idea of EXIF data inside the images, so that in 20 years my daughter can see much information about the images – if or should I say when I have forgotten all such information related to images.

Another use… perhaps…
As soon as I saw this feature I got at quick thought:

  1. Google lets all its Picasa users identify all their freinds
  2. All the face to people relation information is uploaded to a central server
  3. Google can now do global people location based on the face to people relation done by the millions of Picasa users

- A bit scary! But ofcause Google is god (LOL) so something like that would never (LOL) happen! :-)

Sharing the added information

image The information about the faces on your images can actually be shared on online web albums you have. When you upload images you can see Picasa writing status information “Syncing face tags” and when images has been uploaded and is viewed in the web album you can see boxes around the faces. Both things you can see in the illustration to the right.

As far as I know however you can do nothing with the box that appears when hovering over a face of an image in a web album. In Facebook you get the option to view information about the person in focus, which can be a very strong feature. Ofcause we do not know what Google have in mind, which features it will release later, and you could argue that they are on the right path as they also couples the person data with the information of people in your contacts list.

I am not sure, but it might be so that when viewing photoes on you web album you actually get face detection of other people on photoes – people which you might or might not know.. But I am not sure if this is actually right!

The technical information

From an article “Google Responds to Picasa 3.5 Face Tagging Complaints” I got some information about how the actual data about the rectangles containing faces and the person inside the rectangle was stored. Here is the information:

Face tag data is stored in the Picasa database and also in the .picasa.ini file in the folder where your tagged photo sits. To see the location of the photo on your hard drive and the .ini file where the information is stored, right click the photo and select “Locate on Disk”.

I did that and discovered that it is not too difficult to read, though Google need to document just how to use it, and I look forward to a way to integrate Google contace (face) information with my Facebook albums and their people tagging information! Here are two parts of the “usefull” information inside “.picasa.ini” of one of my photo folders:


“And what is exactly that?!!” you might ask. Well, my guess:

  • rect64(…): This is coordinate information for an area containing a face
  • “5ca08dd0d7257594”, an identifier for a face
  • “5ca08dd0d7257594=netsi1964_lh,6b4f68cf8bba7447” information about the relation from between the face identifier and a contact inside my personal contact list

Given some more documentation it should be possibel to convert the “face found information” to other services like Facebook, but how about the “face pattern”, where is it stored?

It gets smart – intelligent!

When you start to establize the relation between the faces found by Picasa and your existing (or new) contacts/persons Picasa can figure out by its face detection software other occurences of this person – that is: You do not need to approve each and every instance of a face detected by the software. It intelligently figures out by it self, or at least guesses. You will see that Picasa gets better and better to find people you have recognized – and as you do, it will come up with suggestions, which you then can accept or cancel.

All in all I find this face detection feature very cool and love my Picasa even more! I am looking forward to seeing even more cool features added to Picasa..!

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