Code for the paper Efficient Action Localization with Approximately Normalized Fisher Vectors.

Dependencies

• The fisher_vectors module. The data stored at stats_path (see the function load_sample_data from load_data.py) are not exactly Fisher vectors, but an intermediate representation, sufficient statistics. To get the sufficient statistics from low-level descriptors, use the descs_to_sstats function from fv_model.py; to get the Fisher vectors from sufficient statistics use sstats_to_features from fv_model.py. TODO Instead of using the entire module, just isolate those functions.

• You need to define a Dataset factory that produces an object instance dataset. The dataset behaves like a container of the data information (like paths and other similar information). TODO Add example of Dataset. Among others the dataset should know how to responds to following attributes and methods:

• D int attribute representing the dimension of the low-level descriptor,
• VOC_SIZE int attribute representing the number of GMM components (the vocabulary size),
• GMM str attribute indicating the path to the GMM object.
• SSTATS_DIR str attribute indicating the path to the sufficient statistics.
• get_data a method that takes a string representing the data split (it can be either train or test) and returns the video names and their corresponding labels.

Code to reproduce the results

Action recognition experiments

Experiments for the exact normalizations:

for s in none exact; do
    for l in none exact; do
        python cvpr14camera_ready.py -d hollywood2.delta_5 --e_std_1 --sqrt $s --l2_norm $l -vv
    done
done

Experiments for the approximate square rooting:

python cvpr14camera_ready.py -d hollywood2.delta_5 --e_std_1 --sqrt approx --e_std_2 --l2_norm exact -vv

Experiments for approximating the both square rooting and the L2 normalization:

for i in 1 2 4 8 16 32; do
   python cvpr14camera_ready.py -d hollywood2.delta_5 --e_std_1 --sqrt approx --e_std_2 --l2_norm approx -n $i -vv
done

The evaluate.py script is a simpler version that does evaluation for action recognition, but it doesn't support more complicated data, i.e, spatial pyramids and spatial Fisher vectors.

Temporal action localization experiments

Experiments for the temporal action localization case.

for d in cc.no_stab duch.no_stab; do 
  for c in 1 2; do
    for a in "e_std_1.fast" "exact_L2+e_std_1" "exact_sqrt+e_std_1" "exact+e_std_1" "approx+e_std_1"; do
      python -u ~/experiments/normalizations_approximation/detection.py \
          -d $d \
          -a $a \
          --stride 5 \
          --begin 20 \
          -D 5 \
          --end 180 \
          --class_idx $c \
          --rescore \
          -w
    done
  done
done