added extract_multilabel_pics.py

from pycocotools.coco import COCO

import numpy as np

import skimage.io as io

import matplotlib.pyplot as plt

import pylab

import shutil

import os

coco = COCO(

    '/softpro/ss18/caption/cocoapi/annotations/train/instances_train2017.json')

cats = coco.loadCats(coco.getCatIds())

nms = [cat['name'] for cat in cats]

for category in nms:

    print(category)

    catIds = coco.getCatIds(catNms=[category])

    imgIds = coco.getImgIds(catIds=catIds)

    for pic in imgIds:

        name = coco.loadImgs(pic)[0]['file_name']

        shutil.copy2('images/train/' + name, 'multilabel_images/' + name)