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"""This module implements an abstract base class (ABC) 'BaseDataset' for datasets.
It also includes common transformation functions (e.g., get_transform, __scale_width), which can be later used in subclasses.
"""
import random
import numpy as np
import torch.utils.data as data
from PIL import Image
import torchvision.transforms as transforms
from abc import ABC, abstractmethod
class BaseDataset(data.Dataset, ABC):
"""This class is an abstract base class (ABC) for datasets.
To create a subclass, you need to implement the following four functions:
-- <__init__>: initialize the class, first call BaseDataset.__init__(self, opt).
-- <__len__>: return the size of dataset.
-- <__getitem__>: get a data point.
-- <modify_commandline_options>: (optionally) add dataset-specific options and set default options.
"""
def __init__(self, opt):
"""Initialize the class; save the options in the class
Parameters:
opt (Option class)-- stores all the experiment flags; needs to be a subclass of BaseOptions
"""
self.opt = opt
# self.root = opt.dataroot
self.current_epoch = 0
@staticmethod
def modify_commandline_options(parser, is_train):
"""Add new dataset-specific options, and rewrite default values for existing options.
Parameters:
parser -- original option parser
is_train (bool) -- whether training phase or test phase. You can use this flag to add training-specific or test-specific options.
Returns:
the modified parser.
"""
return parser
@abstractmethod
def __len__(self):
"""Return the total number of images in the dataset."""
return 0
@abstractmethod
def __getitem__(self, index):
"""Return a data point and its metadata information.
Parameters:
index - - a random integer for data indexing
Returns:
a dictionary of data with their names. It ususally contains the data itself and its metadata information.
"""
pass
def get_transform(grayscale=False):
transform_list = []
if grayscale:
transform_list.append(transforms.Grayscale(1))
transform_list += [transforms.ToTensor()]
return transforms.Compose(transform_list)
def get_affine_mat(opt, size):
shift_x, shift_y, scale, rot_angle, flip = 0., 0., 1., 0., False
w, h = size
if 'shift' in opt.preprocess:
shift_pixs = int(opt.shift_pixs)
shift_x = random.randint(-shift_pixs, shift_pixs)
shift_y = random.randint(-shift_pixs, shift_pixs)
if 'scale' in opt.preprocess:
scale = 1 + opt.scale_delta * (2 * random.random() - 1)
if 'rot' in opt.preprocess:
rot_angle = opt.rot_angle * (2 * random.random() - 1)
rot_rad = -rot_angle * np.pi/180
if 'flip' in opt.preprocess:
flip = random.random() > 0.5
shift_to_origin = np.array([1, 0, -w//2, 0, 1, -h//2, 0, 0, 1]).reshape([3, 3])
flip_mat = np.array([-1 if flip else 1, 0, 0, 0, 1, 0, 0, 0, 1]).reshape([3, 3])
shift_mat = np.array([1, 0, shift_x, 0, 1, shift_y, 0, 0, 1]).reshape([3, 3])
rot_mat = np.array([np.cos(rot_rad), np.sin(rot_rad), 0, -np.sin(rot_rad), np.cos(rot_rad), 0, 0, 0, 1]).reshape([3, 3])
scale_mat = np.array([scale, 0, 0, 0, scale, 0, 0, 0, 1]).reshape([3, 3])
shift_to_center = np.array([1, 0, w//2, 0, 1, h//2, 0, 0, 1]).reshape([3, 3])
affine = shift_to_center @ scale_mat @ rot_mat @ shift_mat @ flip_mat @ shift_to_origin
affine_inv = np.linalg.inv(affine)
return affine, affine_inv, flip
def apply_img_affine(img, affine_inv, method=Image.BICUBIC):
return img.transform(img.size, Image.AFFINE, data=affine_inv.flatten()[:6], resample=Image.BICUBIC)
def apply_lm_affine(landmark, affine, flip, size):
_, h = size
lm = landmark.copy()
lm[:, 1] = h - 1 - lm[:, 1]
lm = np.concatenate((lm, np.ones([lm.shape[0], 1])), -1)
lm = lm @ np.transpose(affine)
lm[:, :2] = lm[:, :2] / lm[:, 2:]
lm = lm[:, :2]
lm[:, 1] = h - 1 - lm[:, 1]
if flip:
lm_ = lm.copy()
lm_[:17] = lm[16::-1]
lm_[17:22] = lm[26:21:-1]
lm_[22:27] = lm[21:16:-1]
lm_[31:36] = lm[35:30:-1]
lm_[36:40] = lm[45:41:-1]
lm_[40:42] = lm[47:45:-1]
lm_[42:46] = lm[39:35:-1]
lm_[46:48] = lm[41:39:-1]
lm_[48:55] = lm[54:47:-1]
lm_[55:60] = lm[59:54:-1]
lm_[60:65] = lm[64:59:-1]
lm_[65:68] = lm[67:64:-1]
lm = lm_
return lm
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