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import glob
import math
import os
from multiprocessing.pool import ThreadPool
from pathlib import Path
from typing import Optional
import cv2
import numpy as np
from torch.utils.data import Dataset
from tqdm import tqdm
from ..utils import NUM_THREADS, TQDM_BAR_FORMAT
from .utils import HELP_URL, IMG_FORMATS, LOCAL_RANK
class BaseDataset(Dataset):
"""Base Dataset.
Args:
img_path (str): image path.
pipeline (dict): a dict of image transforms.
label_path (str): label path, this can also be an ann_file or other custom label path.
"""
def __init__(
self,
img_path,
imgsz=640,
label_path=None,
cache=False,
augment=True,
hyp=None,
prefix="",
rect=False,
batch_size=None,
stride=32,
pad=0.5,
single_cls=False,
):
super().__init__()
self.img_path = img_path
self.imgsz = imgsz
self.label_path = label_path
self.augment = augment
self.single_cls = single_cls
self.prefix = prefix
self.im_files = self.get_img_files(self.img_path)
self.labels = self.get_labels()
if self.single_cls:
self.update_labels(include_class=[])
self.ni = len(self.im_files)
# rect stuff
self.rect = rect
self.batch_size = batch_size
self.stride = stride
self.pad = pad
if self.rect:
assert self.batch_size is not None
self.set_rectangle()
# cache stuff
self.ims = [None] * self.ni
self.npy_files = [Path(f).with_suffix(".npy") for f in self.im_files]
if cache:
self.cache_images(cache)
# transforms
self.transforms = self.build_transforms(hyp=hyp)
def get_img_files(self, img_path):
"""Read image files."""
try:
f = [] # image files
for p in img_path if isinstance(img_path, list) else [img_path]:
p = Path(p) # os-agnostic
if p.is_dir(): # dir
f += glob.glob(str(p / "**" / "*.*"), recursive=True)
# f = list(p.rglob('*.*')) # pathlib
elif p.is_file(): # file
with open(p) as t:
t = t.read().strip().splitlines()
parent = str(p.parent) + os.sep
f += [x.replace("./", parent) if x.startswith("./") else x for x in t] # local to global path
# f += [p.parent / x.lstrip(os.sep) for x in t] # local to global path (pathlib)
else:
raise FileNotFoundError(f"{self.prefix}{p} does not exist")
im_files = sorted(x.replace("/", os.sep) for x in f if x.split(".")[-1].lower() in IMG_FORMATS)
# self.img_files = sorted([x for x in f if x.suffix[1:].lower() in IMG_FORMATS]) # pathlib
assert im_files, f"{self.prefix}No images found"
except Exception as e:
raise Exception(f"{self.prefix}Error loading data from {img_path}: {e}\n{HELP_URL}")
return im_files
def update_labels(self, include_class: Optional[list]):
"""include_class, filter labels to include only these classes (optional)"""
include_class_array = np.array(include_class).reshape(1, -1)
for i in range(len(self.labels)):
if include_class:
cls = self.labels[i]["cls"]
bboxes = self.labels[i]["bboxes"]
segments = self.labels[i]["segments"]
j = (cls == include_class_array).any(1)
self.labels[i]["cls"] = cls[j]
self.labels[i]["bboxes"] = bboxes[j]
if segments:
self.labels[i]["segments"] = segments[j]
if self.single_cls:
self.labels[i]["cls"] = 0
def load_image(self, i):
# Loads 1 image from dataset index 'i', returns (im, resized hw)
im, f, fn = self.ims[i], self.im_files[i], self.npy_files[i]
if im is None: # not cached in RAM
if fn.exists(): # load npy
im = np.load(fn)
else: # read image
im = cv2.imread(f) # BGR
assert im is not None, f"Image Not Found {f}"
h0, w0 = im.shape[:2] # orig hw
r = self.imgsz / max(h0, w0) # ratio
if r != 1: # if sizes are not equal
interp = cv2.INTER_LINEAR if (self.augment or r > 1) else cv2.INTER_AREA
im = cv2.resize(im, (math.ceil(w0 * r), math.ceil(h0 * r)), interpolation=interp)
return im, (h0, w0), im.shape[:2] # im, hw_original, hw_resized
return self.ims[i], self.im_hw0[i], self.im_hw[i] # im, hw_original, hw_resized
def cache_images(self, cache):
# cache images to memory or disk
gb = 0 # Gigabytes of cached images
self.im_hw0, self.im_hw = [None] * self.ni, [None] * self.ni
fcn = self.cache_images_to_disk if cache == "disk" else self.load_image
results = ThreadPool(NUM_THREADS).imap(fcn, range(self.ni))
pbar = tqdm(enumerate(results), total=self.ni, bar_format=TQDM_BAR_FORMAT, disable=LOCAL_RANK > 0)
for i, x in pbar:
if cache == "disk":
gb += self.npy_files[i].stat().st_size
else: # 'ram'
self.ims[i], self.im_hw0[i], self.im_hw[i] = x # im, hw_orig, hw_resized = load_image(self, i)
gb += self.ims[i].nbytes
pbar.desc = f"{self.prefix}Caching images ({gb / 1E9:.1f}GB {cache})"
pbar.close()
def cache_images_to_disk(self, i):
# Saves an image as an *.npy file for faster loading
f = self.npy_files[i]
if not f.exists():
np.save(f.as_posix(), cv2.imread(self.im_files[i]))
def set_rectangle(self):
bi = np.floor(np.arange(self.ni) / self.batch_size).astype(int) # batch index
nb = bi[-1] + 1 # number of batches
s = np.array([x.pop("shape") for x in self.labels]) # hw
ar = s[:, 0] / s[:, 1] # aspect ratio
irect = ar.argsort()
self.im_files = [self.im_files[i] for i in irect]
self.labels = [self.labels[i] for i in irect]
ar = ar[irect]
# Set training image shapes
shapes = [[1, 1]] * nb
for i in range(nb):
ari = ar[bi == i]
mini, maxi = ari.min(), ari.max()
if maxi < 1:
shapes[i] = [maxi, 1]
elif mini > 1:
shapes[i] = [1, 1 / mini]
self.batch_shapes = np.ceil(np.array(shapes) * self.imgsz / self.stride + self.pad).astype(int) * self.stride
self.batch = bi # batch index of image
def __getitem__(self, index):
return self.transforms(self.get_label_info(index))
def get_label_info(self, index):
label = self.labels[index].copy()
label["img"], label["ori_shape"], label["resized_shape"] = self.load_image(index)
if self.rect:
label["rect_shape"] = self.batch_shapes[self.batch[index]]
label = self.update_labels_info(label)
return label
def __len__(self):
return len(self.im_files)
def update_labels_info(self, label):
"""custom your label format here"""
return label
def build_transforms(self, hyp=None):
"""Users can custom augmentations here
like:
if self.augment:
# training transforms
return Compose([])
else:
# val transforms
return Compose([])
"""
raise NotImplementedError
def get_labels(self):
"""Users can custom their own format here.
Make sure your output is a list with each element like below:
dict(
im_file=im_file,
shape=shape, # format: (height, width)
cls=cls,
bboxes=bboxes, # xywh
segments=segments, # xy
keypoints=keypoints, # xy
normalized=True, # or False
bbox_format="xyxy", # or xywh, ltwh
)
"""
raise NotImplementedError