[Digikam-devel] Status of face detection

[Marcel Wiesweg]

Hi,

in my impression, the face detection, both in backend and UI, has matured 
enough now that it deserves some wider testing.
(be sure to have libface from yesterday, and also OpenCV 2.1.0)

I have scanned about 3000 real-life holiday images in the last days.
The scanning is on the "fast and safe" side: You will have false positives, 
but the real faces form the majority. You will easily find faces which are not 
recognized - strong shadows, rotated head, closed eyes are typical.
But my overall impression is quite good (at least I have this evidence with a 
certain female face I happen to take photos of quite often)

Since some weeks, only one cascade in libface is used for initial scanning, 
which makes is considerably faster. I need less than an hour for 1000 images. 
(That means of course a face will not be found if this cascade does not find 
it)

There are some known issues with the UI:
- in the icon view, when a face from the "Unconfirmed" folder is confirmed or 
rejected, there is a slight delay before the view is refreshed. Ideally, the 
face should disappear immediately, but that's not easy to do properly
- the overlays only act on the single, hovered image. I plan to make them act 
on all selected images, with a tooltip-like indicator for this fact
- in the icon view, it's a line edit, in the preview view, a combo box. We'll 
see which solution is better
- the popups in the preview view are clipped to within the view. There's a Qt 
bug involved, it's not easy to solve.
- there are two different popups from the combo box: a tree view for 
selection, and a list view for completion when typing. Though, the problems to 
solve by these popups are different as well
- the counter on the tree view of the People side bar does not work - it still 
counts tag assignments, 0 for unconfirmed, not faces.
- when scrolling with the mouse wheel, scrolling gets stuck when over one of 
the confirm/reject tool buttons 

Issues with the face scanner and dialog:
- selecting the albums / tags to scan, child albums are not scanned
- missing to set a lower thread priority for the worker threads.

Recognition:
Dont test recognition. It is currently reworked by Alex. We must add an option 
to retrain all confirmed images later.

Marcel