datasets.py

# Copyright (c) 2015-present, Facebook, Inc.
# All rights reserved.
import os
import json

from torchvision import datasets, transforms
from torchvision.datasets.folder import ImageFolder, default_loader

from timm.data.constants import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
from timm.data import create_transform
from imagenet_dataset import ImageNetDataset
import numpy as np
from PIL import Image

#lighting data augmentation
imagenet_pca = {
    'eigval': np.asarray([0.2175, 0.0188, 0.0045]),
    'eigvec': np.asarray([
        [-0.5675, 0.7192, 0.4009],
        [-0.5808, -0.0045, -0.8140],
        [-0.5836, -0.6948, 0.4203],
    ])
}


class Lighting(object):
    def __init__(self, alphastd,
                 eigval=imagenet_pca['eigval'],
                 eigvec=imagenet_pca['eigvec']):
        self.alphastd = alphastd
        assert eigval.shape == (3,)
        assert eigvec.shape == (3, 3)
        self.eigval = eigval
        self.eigvec = eigvec

    def __call__(self, img):
        if self.alphastd == 0.:
            return img
        rnd = np.random.randn(3) * self.alphastd
        rnd = rnd.astype('float32')
        v = rnd
        old_dtype = np.asarray(img).dtype
        v = v * self.eigval
        v = v.reshape((3, 1))
        inc = np.dot(self.eigvec, v).reshape((3,))
        img = np.add(img, inc)
        if old_dtype == np.uint8:
            img = np.clip(img, 0, 255)
        img = Image.fromarray(img.astype(old_dtype), 'RGB')
        return img

    def __repr__(self):
        return self.__class__.__name__ + '()'



class INatDataset(ImageFolder):
    def __init__(self, root, train=True, year=2018, transform=None, target_transform=None,
                 category='name', loader=default_loader):
        self.transform = transform
        self.loader = loader
        self.target_transform = target_transform
        self.year = year
        # assert category in ['kingdom','phylum','class','order','supercategory','family','genus','name']
        path_json = os.path.join(root, f'{"train" if train else "val"}{year}.json')
        with open(path_json) as json_file:
            data = json.load(json_file)

        with open(os.path.join(root, 'categories.json')) as json_file:
            data_catg = json.load(json_file)

        path_json_for_targeter = os.path.join(root, f"train{year}.json")

        with open(path_json_for_targeter) as json_file:
            data_for_targeter = json.load(json_file)

        targeter = {}
        indexer = 0
        for elem in data_for_targeter['annotations']:
            king = []
            king.append(data_catg[int(elem['category_id'])][category])
            if king[0] not in targeter.keys():
                targeter[king[0]] = indexer
                indexer += 1
        self.nb_classes = len(targeter)

        self.samples = []
        for elem in data['images']:
            cut = elem['file_name'].split('/')
            target_current = int(cut[2])
            path_current = os.path.join(root, cut[0], cut[2], cut[3])

            categors = data_catg[target_current]
            target_current_true = targeter[categors[category]]
            self.samples.append((path_current, target_current_true))

    # __getitem__ and __len__ inherited from ImageFolder


def build_dataset(is_train, args):
    transform = build_transform(is_train, args)

    if args.data_set == 'CIFAR':
        dataset = datasets.CIFAR100(args.data_path, train=is_train, transform=transform)
        nb_classes = 100
    elif args.data_set == 'IMNET':

        normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406],
                                     std=[0.229, 0.224, 0.225])
        # data augmentation
        crop_scale = 0.08
        lighting_param = 0.1
        train_transforms = transforms.Compose([
            transforms.RandomResizedCrop(224, scale=(crop_scale, 1.0)),
            Lighting(lighting_param),
            transforms.RandomHorizontalFlip(),
            transforms.ToTensor(),
            normalize])

        root = os.path.join(args.data_path, 'train' if is_train else 'val')
        dataset = datasets.ImageFolder(root, transform=transform)
        # if is_train:
        #     dataset = ImageNetDataset(
        #         root_dir=args.root_dir_train,
        #         meta_file=args.meta_file_train,
        #         transform=transform,
        #     )
        # else:
        #     dataset = ImageNetDataset(
        #         root_dir=args.root_dir_val,
        #         meta_file=args.meta_file_val,
        #         transform=transform,
        #     )
        nb_classes = 1000
    elif args.data_set == 'INAT':
        dataset = INatDataset(args.data_path, train=is_train, year=2018,
                              category=args.inat_category, transform=transform)
        nb_classes = dataset.nb_classes
    elif args.data_set == 'INAT19':
        dataset = INatDataset(args.data_path, train=is_train, year=2019,
                              category=args.inat_category, transform=transform)
        nb_classes = dataset.nb_classes

    return dataset, nb_classes


def build_transform(is_train, args):
    resize_im = args.input_size > 32
    if is_train:
        # this should always dispatch to transforms_imagenet_train
        transform = create_transform(
            input_size=args.input_size,
            is_training=True,
            color_jitter=args.color_jitter,
            auto_augment=args.aa,
            interpolation=args.train_interpolation,
            re_prob=args.reprob,
            re_mode=args.remode,
            re_count=args.recount,
        )
        if not resize_im:
            # replace RandomResizedCropAndInterpolation with
            # RandomCrop
            transform.transforms[0] = transforms.RandomCrop(
                args.input_size, padding=4)
        return transform

    t = []
    if resize_im:
        size = int((256 / 224) * args.input_size)
        t.append(
            transforms.Resize(size, interpolation=3),  # to maintain same ratio w.r.t. 224 images
        )
        t.append(transforms.CenterCrop(args.input_size))

    t.append(transforms.ToTensor())
    t.append(transforms.Normalize(IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD))
    return transforms.Compose(t)