facepainter / facegrab

Batch extract known face from video/image sequence (CNN GPU with CUDA / HoG)

FaceGrab

Batch extract aligned images of a known face from a video or image sequence.

Uses a combination of a (precomputed) deep learning CNN model to quickly batch detect faces in video frames then HoG face recognition with single or multiple encodings computed from known references. Then a (precomputed) set of average face landmarks to transpose and extract any recognised faces to a normalised pose.

Using the GPU with CUDA in this way means batch processing face detection in up to 128 frames at at time can be achieved (VRAM dependant). This combined with other speed/optimisation techniques (such as downsampling the process frames, early frame skipping, etc) means that very high quality, normalised, low false positive, faces can be extracted from video or image sequences file many times faster than using seperate frame splitting/extraction/detection applications, or by methods that are CPU bound and only operate on individual images.

One important caveat in this process is that the input frames/images must be exactly the same dimensions. As this is primarily geared towards extraction from video this should not be an issue. However it is worth bearing in mind should you get errors processing image sequences :)

Usage

Script based

Example

python facegrab.py -r ./pics/russell-crowe -i "./movies/Gladiator (2000).avi" -o ./output 

If you like you can also watch the process in action with display_output :)

python facegrab.py -r ./pics/russell-crowe -i "./movies/Gladiator (2000).avi" -o ./output --display_output

You can save encoding sets used...

python facegrab.py -r ./pics/A -i ./video/A.mp4 -o ./extract/A --save_references A.npz

And load from the saved file (so that you don't need to save reference images or reprocess for the same person)

python facegrab.py -r A.npz -i ./video/A2.mp4 -o ./extract/A

You can get help by passing -h or --help ... you should always ask for help or rtfm :)

Class based

FG = FaceGrab('./images/nick-cage-reference')
FG.process('./movies/The Wicker Man.mp4', './extracted/nick-cage-wicker-man')

Or use the Process/Recognition settings to tweak :) you can set/miss any or else leave them out entirely

RS = RecognitionSettings(jitter=1)
PS = ProcessSettings(batch_size=64, extract_size=512, scale=.5)
personA = FaceGrab("someone", RS, PS)
personA.process('a1.mp4', 'a')
personA.process('a2.mp4', 'a')

Or like...

personB = FaceGrab("someone-else", process=ProcessSettings(scale=.125))
personB.process('b.mp4', 'b')
personC = FaceGrab("another-person", recognition=RecognitionSettings(tolerance=.4))
personC.process('c.mp4', 'c')

Also If you want to ensure you have recognition encodings before you begin...

FG = FaceGrab('./images/nick-cage-reference')
if FG.reference_count:
    FG.process('./movies/The Wicker Man.mp4', './extracted/nick-cage-wicker-man')

Output details

tl;dr - Sort the output images by name

Any faces detected and recognised in the input will be saved in the specified output directory. The naming convention is simple and should allow you to quickly sort for any false positives in the results.

For example, imagine you have the following images in your output folder

• 9-345.jpg - 345 matched 9 references
• 4-343.jpg - 343 matched 4 references
• 1-276.jpg - 276 matched 1 reference

Each extracted face has been given a two number name (separated by a hyphen) in the format X-Y.jpg Where X represents the number of reference matches for that image - i.e. a number between 1 and the total number references - and Y is a unique extract number for each image.

This way you can quickly sort the extracted frames to check for false positives in the results - as frames with a low reference match count will have corresponding lower starting numbers.

Help!

Stuff that might happen that isn't what you wanted or expected...oh cruel world!

OOM :( - Memory issues

Very roughly speaking process.batch_size * [input frame dimensions] * process.scale = VRAM As long as you have 2GB+ VRAM and you play with the settings you should be golden :)

The two key things being

1. Reduce the process.batch_size - note the whole thing will take longer!
2. Decrease the process.scale e.g. 0.125 (1/8) - you may well get fewer face detections

You could also try re-encoding the video to a lower resolution, but that is cheating and punishable by...nothing.

Too many blurry results (extracted images are out of focus, etc)

1. Increase the process.blur_threshold so that the test for variance in extracted face edges is stricter.
2. Also decrease the process.skip_frames so that more of the input is processed (so that you have a higher chance of good input frames)

Too many false positives (extracted images of the wrong face/not faces)

1. Use a more varied, higher quality, more representative, range of reference images (ideally ones that look like the person in the input)
2. Increase the recognition.jitter so that each encoding/check is done using a higher number of resamples - note this will increase the processing time.
3. Decrease the recognition.tolerance so that each recognition is stricter e.g. 0.55

Too few matches (missing lots of good images from input)

1. Use a more varied, higher quality, more representative, range of reference images (ideally ones that look like the person in the input)
2. Increase the recognition.tolerance so that each recognition is less strict e.g. 0.65
3. Decrease the recognition.jitter so that each recognition is done fewer resamples (less accurate)
4. Decrease the process.skip_frames so that more of the input is processed (this might result in very similar extracted images)
5. Increase the process.scale e.g. 0.5 (1/2) - bearing in mind you may need to reduce the batch_size accordingly

Built using

• CUDA 8.0 - https://developer.nvidia.com/cuda-80-ga2-download-archive
• cudnn 6 for cuda 8 - https://developer.nvidia.com/compute/machine-learning/cudnn/secure/v6/prod/8.0_20170427/cudnn-8.0-windows10-x64-v6.0-zip (login required)
• dlib - https://github.com/davisking/dlib.git compiled with CUDA (and preferably AVX) see notes.
• Visual C++ 2015 Build Tools - http://landinghub.visualstudio.com/visual-cpp-build-tools

YMMV - pretty sure it would work just as well with CUDA 9 / cuDNN 7 / etc - but personally I could not get dlib to build with CUDA support against v9/9.1 on WindBlows...In linux not a problem - in short - go for the latest verions you can build against :)