"Mean.npy" and "Std.npy"

[sherlhw]

Hi! What are the "Mean.npy" and "Std.npy" files? If I want to make my own dataset, how do I get the "Mean.npy" and "Std.npy" files?

[roykapon]

The Mean.npy and Std.npy save the mean and standard deviation of each joint across all frames in the dataset (Its dimension is 2×(number of joints) since we treat the x and y dimensions separately). It is obtained by concatenating all motion sequences and apply np.mean or np.std across the time dimension. This is the code we used for our datasets.

import os
from tqdm import tqdm
import numpy as np
from os.path import join as pjoin

data_dir = 'your/motions/directory'
save_dir = pjoin(data_dir, '..')

source_list = os.listdir(data_dir)

data = []
for source_file in tqdm(source_list):
    source_data = np.load(pjoin(data_dir, source_file))
    data += [*source_data]

mean = np.mean(data, axis=0)
mean = mean[...,:2]
std = np.std(data, axis=0)
std = std[...,:2]
print(f'mean: {mean}')
print(f'std: {std}')

print(f'saving mean and std to {save_dir}')
np.save(pjoin(save_dir, 'Mean'), mean)
np.save(pjoin(save_dir, 'Std'), std)

The mean = mean[...,:2] row is meant to delete the confidence of the joint (mostly relevant when the joints were predicted by some detector) if it exists.

[GithubAccountTo]

How do I get.npy files for my own dataset

[roykapon]

This issue is discussed in #3 so closing it for now.