333 lines
14 KiB
Python
333 lines
14 KiB
Python
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# YOLOv5 🚀 by Ultralytics, GPL-3.0 license
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"""
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Dataloaders
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"""
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import os
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import random
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import cv2
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import numpy as np
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import torch
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from torch.utils.data import DataLoader, distributed
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from ..augmentations import augment_hsv, copy_paste, letterbox
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from ..dataloaders import InfiniteDataLoader, LoadImagesAndLabels, seed_worker
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from ..general import LOGGER, xyn2xy, xywhn2xyxy, xyxy2xywhn
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from ..torch_utils import torch_distributed_zero_first
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from .augmentations import mixup, random_perspective
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RANK = int(os.getenv('RANK', -1))
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def create_dataloader(path,
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imgsz,
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batch_size,
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stride,
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single_cls=False,
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hyp=None,
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augment=False,
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cache=False,
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pad=0.0,
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rect=False,
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rank=-1,
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workers=8,
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image_weights=False,
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quad=False,
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prefix='',
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shuffle=False,
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mask_downsample_ratio=1,
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overlap_mask=False,
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seed=0):
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if rect and shuffle:
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LOGGER.warning('WARNING ⚠️ --rect is incompatible with DataLoader shuffle, setting shuffle=False')
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shuffle = False
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with torch_distributed_zero_first(rank): # init dataset *.cache only once if DDP
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dataset = LoadImagesAndLabelsAndMasks(
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path,
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imgsz,
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batch_size,
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augment=augment, # augmentation
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hyp=hyp, # hyperparameters
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rect=rect, # rectangular batches
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cache_images=cache,
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single_cls=single_cls,
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stride=int(stride),
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pad=pad,
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image_weights=image_weights,
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prefix=prefix,
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downsample_ratio=mask_downsample_ratio,
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overlap=overlap_mask)
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batch_size = min(batch_size, len(dataset))
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nd = torch.cuda.device_count() # number of CUDA devices
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nw = min([os.cpu_count() // max(nd, 1), batch_size if batch_size > 1 else 0, workers]) # number of workers
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sampler = None if rank == -1 else distributed.DistributedSampler(dataset, shuffle=shuffle)
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loader = DataLoader if image_weights else InfiniteDataLoader # only DataLoader allows for attribute updates
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generator = torch.Generator()
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generator.manual_seed(6148914691236517205 + seed + RANK)
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return loader(
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dataset,
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batch_size=batch_size,
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shuffle=shuffle and sampler is None,
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num_workers=nw,
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sampler=sampler,
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pin_memory=True,
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collate_fn=LoadImagesAndLabelsAndMasks.collate_fn4 if quad else LoadImagesAndLabelsAndMasks.collate_fn,
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worker_init_fn=seed_worker,
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generator=generator,
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), dataset
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class LoadImagesAndLabelsAndMasks(LoadImagesAndLabels): # for training/testing
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def __init__(
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self,
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path,
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img_size=640,
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batch_size=16,
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augment=False,
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hyp=None,
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rect=False,
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image_weights=False,
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cache_images=False,
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single_cls=False,
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stride=32,
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pad=0,
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min_items=0,
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prefix="",
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downsample_ratio=1,
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overlap=False,
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):
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super().__init__(path, img_size, batch_size, augment, hyp, rect, image_weights, cache_images, single_cls,
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stride, pad, min_items, prefix)
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self.downsample_ratio = downsample_ratio
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self.overlap = overlap
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def __getitem__(self, index):
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index = self.indices[index] # linear, shuffled, or image_weights
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hyp = self.hyp
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mosaic = self.mosaic and random.random() < hyp['mosaic']
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masks = []
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if mosaic:
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# Load mosaic
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img, labels, segments = self.load_mosaic(index)
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shapes = None
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# MixUp augmentation
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if random.random() < hyp["mixup"]:
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img, labels, segments = mixup(img, labels, segments, *self.load_mosaic(random.randint(0, self.n - 1)))
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else:
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# Load image
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img, (h0, w0), (h, w) = self.load_image(index)
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# Letterbox
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shape = self.batch_shapes[self.batch[index]] if self.rect else self.img_size # final letterboxed shape
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img, ratio, pad = letterbox(img, shape, auto=False, scaleup=self.augment)
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shapes = (h0, w0), ((h / h0, w / w0), pad) # for COCO mAP rescaling
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labels = self.labels[index].copy()
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# [array, array, ....], array.shape=(num_points, 2), xyxyxyxy
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segments = self.segments[index].copy()
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if len(segments):
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for i_s in range(len(segments)):
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segments[i_s] = xyn2xy(
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segments[i_s],
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ratio[0] * w,
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ratio[1] * h,
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padw=pad[0],
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padh=pad[1],
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)
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if labels.size: # normalized xywh to pixel xyxy format
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labels[:, 1:] = xywhn2xyxy(labels[:, 1:], ratio[0] * w, ratio[1] * h, padw=pad[0], padh=pad[1])
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if self.augment:
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img, labels, segments = random_perspective(img,
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labels,
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segments=segments,
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degrees=hyp["degrees"],
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translate=hyp["translate"],
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scale=hyp["scale"],
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shear=hyp["shear"],
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perspective=hyp["perspective"])
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nl = len(labels) # number of labels
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if nl:
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labels[:, 1:5] = xyxy2xywhn(labels[:, 1:5], w=img.shape[1], h=img.shape[0], clip=True, eps=1e-3)
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if self.overlap:
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masks, sorted_idx = polygons2masks_overlap(img.shape[:2],
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segments,
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downsample_ratio=self.downsample_ratio)
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masks = masks[None] # (640, 640) -> (1, 640, 640)
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labels = labels[sorted_idx]
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else:
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masks = polygons2masks(img.shape[:2], segments, color=1, downsample_ratio=self.downsample_ratio)
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masks = (torch.from_numpy(masks) if len(masks) else torch.zeros(1 if self.overlap else nl, img.shape[0] //
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self.downsample_ratio, img.shape[1] //
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self.downsample_ratio))
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# TODO: albumentations support
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if self.augment:
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# Albumentations
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# there are some augmentation that won't change boxes and masks,
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# so just be it for now.
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img, labels = self.albumentations(img, labels)
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nl = len(labels) # update after albumentations
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# HSV color-space
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augment_hsv(img, hgain=hyp["hsv_h"], sgain=hyp["hsv_s"], vgain=hyp["hsv_v"])
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# Flip up-down
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if random.random() < hyp["flipud"]:
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img = np.flipud(img)
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if nl:
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labels[:, 2] = 1 - labels[:, 2]
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masks = torch.flip(masks, dims=[1])
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# Flip left-right
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if random.random() < hyp["fliplr"]:
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img = np.fliplr(img)
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if nl:
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labels[:, 1] = 1 - labels[:, 1]
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masks = torch.flip(masks, dims=[2])
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# Cutouts # labels = cutout(img, labels, p=0.5)
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labels_out = torch.zeros((nl, 6))
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if nl:
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labels_out[:, 1:] = torch.from_numpy(labels)
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# Convert
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img = img.transpose((2, 0, 1))[::-1] # HWC to CHW, BGR to RGB
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img = np.ascontiguousarray(img)
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return (torch.from_numpy(img), labels_out, self.im_files[index], shapes, masks)
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def load_mosaic(self, index):
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# YOLOv5 4-mosaic loader. Loads 1 image + 3 random images into a 4-image mosaic
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labels4, segments4 = [], []
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s = self.img_size
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yc, xc = (int(random.uniform(-x, 2 * s + x)) for x in self.mosaic_border) # mosaic center x, y
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# 3 additional image indices
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indices = [index] + random.choices(self.indices, k=3) # 3 additional image indices
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for i, index in enumerate(indices):
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# Load image
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img, _, (h, w) = self.load_image(index)
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# place img in img4
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if i == 0: # top left
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img4 = np.full((s * 2, s * 2, img.shape[2]), 114, dtype=np.uint8) # base image with 4 tiles
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x1a, y1a, x2a, y2a = max(xc - w, 0), max(yc - h, 0), xc, yc # xmin, ymin, xmax, ymax (large image)
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x1b, y1b, x2b, y2b = w - (x2a - x1a), h - (y2a - y1a), w, h # xmin, ymin, xmax, ymax (small image)
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elif i == 1: # top right
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x1a, y1a, x2a, y2a = xc, max(yc - h, 0), min(xc + w, s * 2), yc
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x1b, y1b, x2b, y2b = 0, h - (y2a - y1a), min(w, x2a - x1a), h
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elif i == 2: # bottom left
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x1a, y1a, x2a, y2a = max(xc - w, 0), yc, xc, min(s * 2, yc + h)
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x1b, y1b, x2b, y2b = w - (x2a - x1a), 0, w, min(y2a - y1a, h)
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elif i == 3: # bottom right
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x1a, y1a, x2a, y2a = xc, yc, min(xc + w, s * 2), min(s * 2, yc + h)
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x1b, y1b, x2b, y2b = 0, 0, min(w, x2a - x1a), min(y2a - y1a, h)
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img4[y1a:y2a, x1a:x2a] = img[y1b:y2b, x1b:x2b] # img4[ymin:ymax, xmin:xmax]
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padw = x1a - x1b
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padh = y1a - y1b
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labels, segments = self.labels[index].copy(), self.segments[index].copy()
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if labels.size:
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labels[:, 1:] = xywhn2xyxy(labels[:, 1:], w, h, padw, padh) # normalized xywh to pixel xyxy format
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segments = [xyn2xy(x, w, h, padw, padh) for x in segments]
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labels4.append(labels)
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segments4.extend(segments)
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# Concat/clip labels
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labels4 = np.concatenate(labels4, 0)
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for x in (labels4[:, 1:], *segments4):
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np.clip(x, 0, 2 * s, out=x) # clip when using random_perspective()
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# img4, labels4 = replicate(img4, labels4) # replicate
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# Augment
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img4, labels4, segments4 = copy_paste(img4, labels4, segments4, p=self.hyp["copy_paste"])
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img4, labels4, segments4 = random_perspective(img4,
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labels4,
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segments4,
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degrees=self.hyp["degrees"],
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translate=self.hyp["translate"],
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scale=self.hyp["scale"],
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shear=self.hyp["shear"],
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perspective=self.hyp["perspective"],
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border=self.mosaic_border) # border to remove
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return img4, labels4, segments4
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@staticmethod
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def collate_fn(batch):
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img, label, path, shapes, masks = zip(*batch) # transposed
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batched_masks = torch.cat(masks, 0)
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for i, l in enumerate(label):
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l[:, 0] = i # add target image index for build_targets()
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return torch.stack(img, 0), torch.cat(label, 0), path, shapes, batched_masks
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def polygon2mask(img_size, polygons, color=1, downsample_ratio=1):
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"""
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Args:
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img_size (tuple): The image size.
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polygons (np.ndarray): [N, M], N is the number of polygons,
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M is the number of points(Be divided by 2).
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"""
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mask = np.zeros(img_size, dtype=np.uint8)
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polygons = np.asarray(polygons)
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polygons = polygons.astype(np.int32)
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shape = polygons.shape
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polygons = polygons.reshape(shape[0], -1, 2)
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cv2.fillPoly(mask, polygons, color=color)
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nh, nw = (img_size[0] // downsample_ratio, img_size[1] // downsample_ratio)
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# NOTE: fillPoly firstly then resize is trying the keep the same way
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# of loss calculation when mask-ratio=1.
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mask = cv2.resize(mask, (nw, nh))
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return mask
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def polygons2masks(img_size, polygons, color, downsample_ratio=1):
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"""
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Args:
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img_size (tuple): The image size.
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polygons (list[np.ndarray]): each polygon is [N, M],
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N is the number of polygons,
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M is the number of points(Be divided by 2).
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"""
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masks = []
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for si in range(len(polygons)):
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mask = polygon2mask(img_size, [polygons[si].reshape(-1)], color, downsample_ratio)
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masks.append(mask)
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return np.array(masks)
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def polygons2masks_overlap(img_size, segments, downsample_ratio=1):
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"""Return a (640, 640) overlap mask."""
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masks = np.zeros((img_size[0] // downsample_ratio, img_size[1] // downsample_ratio),
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dtype=np.int32 if len(segments) > 255 else np.uint8)
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areas = []
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ms = []
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for si in range(len(segments)):
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mask = polygon2mask(
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img_size,
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[segments[si].reshape(-1)],
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downsample_ratio=downsample_ratio,
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color=1,
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)
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ms.append(mask)
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areas.append(mask.sum())
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areas = np.asarray(areas)
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index = np.argsort(-areas)
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ms = np.array(ms)[index]
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for i in range(len(segments)):
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mask = ms[i] * (i + 1)
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masks = masks + mask
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masks = np.clip(masks, a_min=0, a_max=i + 1)
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return masks, index
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