PyTorch-YOLOv3/utils/datasets.py

155 lines
5.1 KiB
Python

import glob
import random
import os
import sys
import numpy as np
from PIL import Image
import torch
import torch.nn.functional as F
from utils.augmentations import horisontal_flip
from torch.utils.data import Dataset
import torchvision.transforms as transforms
def pad_to_square(img, pad_value):
c, h, w = img.shape
dim_diff = np.abs(h - w)
# (upper / left) padding and (lower / right) padding
pad1, pad2 = dim_diff // 2, dim_diff - dim_diff // 2
# Determine padding
pad = (0, 0, pad1, pad2) if h <= w else (pad1, pad2, 0, 0)
# Add padding
img = F.pad(img, pad, "constant", value=pad_value)
return img, pad
def resize(image, size):
image = F.interpolate(image.unsqueeze(0), size=size, mode="nearest").squeeze(0)
return image
def random_resize(images, min_size=288, max_size=448):
new_size = random.sample(list(range(min_size, max_size + 1, 32)), 1)[0]
images = F.interpolate(images, size=new_size, mode="nearest")
return images
class ImageFolder(Dataset):
def __init__(self, folder_path, img_size=416):
self.files = sorted(glob.glob("%s/*.*" % folder_path))
self.img_size = img_size
def __getitem__(self, index):
img_path = self.files[index % len(self.files)]
# Extract image as PyTorch tensor
img = transforms.ToTensor()(Image.open(img_path))
# Pad to square resolution
img, _ = pad_to_square(img, 0)
# Resize
img = resize(img, self.img_size)
return img_path, img
def __len__(self):
return len(self.files)
class ListDataset(Dataset):
def __init__(self, list_path, img_size=416, augment=True, multiscale=True, normalized_labels=True):
with open(list_path, "r") as file:
self.img_files = file.readlines()
self.label_files = [
path.replace("images", "labels").replace(".png", ".txt").replace(".jpg", ".txt")
for path in self.img_files
]
self.img_size = img_size
self.max_objects = 100
self.augment = augment
self.multiscale = multiscale
self.normalized_labels = normalized_labels
self.min_size = self.img_size - 3 * 32
self.max_size = self.img_size + 3 * 32
self.batch_count = 0
def __getitem__(self, index):
# ---------
# Image
# ---------
img_path = self.img_files[index % len(self.img_files)].rstrip()
img_path = 'E:\\eclipse-workspace\\PyTorch\\PyTorch-YOLOv3\\data\\coco' + img_path
#print (img_path)
# Extract image as PyTorch tensor
img = transforms.ToTensor()(Image.open(img_path).convert('RGB'))
# Handle images with less than three channels
if len(img.shape) != 3:
img = img.unsqueeze(0)
img = img.expand((3, img.shape[1:]))
_, h, w = img.shape
h_factor, w_factor = (h, w) if self.normalized_labels else (1, 1)
# Pad to square resolution
img, pad = pad_to_square(img, 0)
_, padded_h, padded_w = img.shape
# ---------
# Label
# ---------
label_path = self.label_files[index % len(self.img_files)].rstrip()
label_path = 'E:\\eclipse-workspace\\PyTorch\\PyTorch-YOLOv3\\data\\coco\\labels' + label_path
#print (label_path)
targets = None
if os.path.exists(label_path):
boxes = torch.from_numpy(np.loadtxt(label_path).reshape(-1, 5))
# Extract coordinates for unpadded + unscaled image
x1 = w_factor * (boxes[:, 1] - boxes[:, 3] / 2)
y1 = h_factor * (boxes[:, 2] - boxes[:, 4] / 2)
x2 = w_factor * (boxes[:, 1] + boxes[:, 3] / 2)
y2 = h_factor * (boxes[:, 2] + boxes[:, 4] / 2)
# Adjust for added padding
x1 += pad[0]
y1 += pad[2]
x2 += pad[1]
y2 += pad[3]
# Returns (x, y, w, h)
boxes[:, 1] = ((x1 + x2) / 2) / padded_w
boxes[:, 2] = ((y1 + y2) / 2) / padded_h
boxes[:, 3] *= w_factor / padded_w
boxes[:, 4] *= h_factor / padded_h
targets = torch.zeros((len(boxes), 6))
targets[:, 1:] = boxes
# Apply augmentations
if self.augment:
if np.random.random() < 0.5:
img, targets = horisontal_flip(img, targets)
return img_path, img, targets
def collate_fn(self, batch):
paths, imgs, targets = list(zip(*batch))
# Remove empty placeholder targets
targets = [boxes for boxes in targets if boxes is not None]
# Add sample index to targets
for i, boxes in enumerate(targets):
boxes[:, 0] = i
targets = torch.cat(targets, 0)
# Selects new image size every tenth batch
if self.multiscale and self.batch_count % 10 == 0:
self.img_size = random.choice(range(self.min_size, self.max_size + 1, 32))
# Resize images to input shape
imgs = torch.stack([resize(img, self.img_size) for img in imgs])
self.batch_count += 1
return paths, imgs, targets
def __len__(self):
return len(self.img_files)