How does Ponga count "detected faces?"
In the Gallery, you'll see a count of the number of individual faces detected across all of the pictures you've uploaded.
As you upload images, Ponga examines each one to detect faces in the image. When you go through the Gallery to name people, Ponga will present you with a representative portrait of each of the faces it was able to detect in each image.
That count of faces appears along the left column in the gallery. Once you start going through the row of portraits in the gallery, you can add a name, skip, or ignore them. The total count of faces becomes the base in the calculation that shows you how far you've progressed in organizing your pictures.
If you add ten pictures of couples at prom, for example, Ponga would likely detect a total of 20 faces (assuming, of course, that each person came with just one date, and parents weren't lurking around in the background. That's two faces in each picture, 10 pictures, 20 faces.) Your progress percentage is calculated by dividing the number of faces named, plus those ignored, divided by the total number of faces.
For example, if while going through the gallery, you named 15 of the prom-goers, but skipped two and ignored three, then you've made 90% progress in getting through the gallery. The two that you skipped represent the last 10% you need to name to completely organize the pictures you've uploaded.
- (15 prom-goers named+3 ignored)/20 detected = 90% progress in organizing
Since the faces you ignore are counted toward your progress, the count of detected faces will not down as you ignore the blurry or stranger's faces in the gallery.
Note: If a pair of identical twins show up with separate dates, then it's possible Ponga would detect just 19 different people. You'll have two pictures with the same person appearing in both pictures. You can sort that out on the Face Details page where you can select "Change Person," then create a "New Person" for one of the two you've named. (It gets tricky, huh?)
(More about Using the Gallery here.)