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# Ultralytics YOLO 🚀, GPL-3.0 license
import math
import random
from copy import deepcopy
import cv2
import numpy as np
import torch
import torchvision.transforms as T
from ..utils import LOGGER, colorstr
from ..utils.checks import check_version
from ..utils.instance import Instances
from ..utils.metrics import bbox_ioa
from ..utils.ops import segment2box
from .utils import IMAGENET_MEAN, IMAGENET_STD, polygons2masks, polygons2masks_overlap
# TODO: we might need a BaseTransform to make all these augments be compatible with both classification and semantic
class BaseTransform:
def __init__(self) -> None:
pass
def apply_image(self, labels):
pass
def apply_instances(self, labels):
pass
def apply_semantic(self, labels):
pass
def __call__(self, labels):
self.apply_image(labels)
self.apply_instances(labels)
self.apply_semantic(labels)
class Compose:
def __init__(self, transforms):
self.transforms = transforms
def __call__(self, data):
for t in self.transforms:
data = t(data)
return data
def append(self, transform):
self.transforms.append(transform)
def tolist(self):
return self.transforms
def __repr__(self):
format_string = f'{self.__class__.__name__}('
for t in self.transforms:
format_string += '\n'
format_string += f' {t}'
format_string += '\n)'
return format_string
class BaseMixTransform:
"""This implementation is from mmyolo"""
def __init__(self, dataset, pre_transform=None, p=0.0) -> None:
self.dataset = dataset
self.pre_transform = pre_transform
self.p = p
def __call__(self, labels):
if random.uniform(0, 1) > self.p:
return labels
# get index of one or three other images
indexes = self.get_indexes()
if isinstance(indexes, int):
indexes = [indexes]
# get images information will be used for Mosaic or MixUp
mix_labels = [self.dataset.get_label_info(i) for i in indexes]
if self.pre_transform is not None:
for i, data in enumerate(mix_labels):
mix_labels[i] = self.pre_transform(data)
labels['mix_labels'] = mix_labels
# Mosaic or MixUp
labels = self._mix_transform(labels)
labels.pop('mix_labels', None)
return labels
def _mix_transform(self, labels):
raise NotImplementedError
def get_indexes(self):
raise NotImplementedError
class Mosaic(BaseMixTransform):
"""Mosaic augmentation.
Args:
imgsz (Sequence[int]): Image size after mosaic pipeline of single
image. The shape order should be (height, width).
Default to (640, 640).
"""
def __init__(self, dataset, imgsz=640, p=1.0, border=(0, 0)):
assert 0 <= p <= 1.0, 'The probability should be in range [0, 1]. ' f'got {p}.'
super().__init__(dataset=dataset, p=p)
self.dataset = dataset
self.imgsz = imgsz
self.border = border
def get_indexes(self):
return [random.randint(0, len(self.dataset) - 1) for _ in range(3)]
def _mix_transform(self, labels):
mosaic_labels = []
assert labels.get('rect_shape', None) is None, 'rect and mosaic is exclusive.'
assert len(labels.get('mix_labels', [])) > 0, 'There are no other images for mosaic augment.'
s = self.imgsz
yc, xc = (int(random.uniform(-x, 2 * s + x)) for x in self.border) # mosaic center x, y
for i in range(4):
labels_patch = (labels if i == 0 else labels['mix_labels'][i - 1]).copy()
# Load image
img = labels_patch['img']
h, w = labels_patch.pop('resized_shape')
# place img in img4
if i == 0: # top left
img4 = np.full((s * 2, s * 2, img.shape[2]), 114, dtype=np.uint8) # base image with 4 tiles
x1a, y1a, x2a, y2a = max(xc - w, 0), max(yc - h, 0), xc, yc # xmin, ymin, xmax, ymax (large image)
x1b, y1b, x2b, y2b = w - (x2a - x1a), h - (y2a - y1a), w, h # xmin, ymin, xmax, ymax (small image)
elif i == 1: # top right
x1a, y1a, x2a, y2a = xc, max(yc - h, 0), min(xc + w, s * 2), yc
x1b, y1b, x2b, y2b = 0, h - (y2a - y1a), min(w, x2a - x1a), h
elif i == 2: # bottom left
x1a, y1a, x2a, y2a = max(xc - w, 0), yc, xc, min(s * 2, yc + h)
x1b, y1b, x2b, y2b = w - (x2a - x1a), 0, w, min(y2a - y1a, h)
elif i == 3: # bottom right
x1a, y1a, x2a, y2a = xc, yc, min(xc + w, s * 2), min(s * 2, yc + h)
x1b, y1b, x2b, y2b = 0, 0, min(w, x2a - x1a), min(y2a - y1a, h)
img4[y1a:y2a, x1a:x2a] = img[y1b:y2b, x1b:x2b] # img4[ymin:ymax, xmin:xmax]
padw = x1a - x1b
padh = y1a - y1b
labels_patch = self._update_labels(labels_patch, padw, padh)
mosaic_labels.append(labels_patch)
final_labels = self._cat_labels(mosaic_labels)
final_labels['img'] = img4
return final_labels
def _update_labels(self, labels, padw, padh):
"""Update labels"""
nh, nw = labels['img'].shape[:2]
labels['instances'].convert_bbox(format='xyxy')
labels['instances'].denormalize(nw, nh)
labels['instances'].add_padding(padw, padh)
return labels
def _cat_labels(self, mosaic_labels):
if len(mosaic_labels) == 0:
return {}
cls = []
instances = []
for labels in mosaic_labels:
cls.append(labels['cls'])
instances.append(labels['instances'])
final_labels = {
'im_file': mosaic_labels[0]['im_file'],
'ori_shape': mosaic_labels[0]['ori_shape'],
'resized_shape': (self.imgsz * 2, self.imgsz * 2),
'cls': np.concatenate(cls, 0),
'instances': Instances.concatenate(instances, axis=0),
'mosaic_border': self.border}
final_labels['instances'].clip(self.imgsz * 2, self.imgsz * 2)
return final_labels
class MixUp(BaseMixTransform):
def __init__(self, dataset, pre_transform=None, p=0.0) -> None:
super().__init__(dataset=dataset, pre_transform=pre_transform, p=p)
def get_indexes(self):
return random.randint(0, len(self.dataset) - 1)
def _mix_transform(self, labels):
# Applies MixUp augmentation https://arxiv.org/pdf/1710.09412.pdf
r = np.random.beta(32.0, 32.0) # mixup ratio, alpha=beta=32.0
labels2 = labels['mix_labels'][0]
labels['img'] = (labels['img'] * r + labels2['img'] * (1 - r)).astype(np.uint8)
labels['instances'] = Instances.concatenate([labels['instances'], labels2['instances']], axis=0)
labels['cls'] = np.concatenate([labels['cls'], labels2['cls']], 0)
return labels
class RandomPerspective:
def __init__(self,
degrees=0.0,
translate=0.1,
scale=0.5,
shear=0.0,
perspective=0.0,
border=(0, 0),
pre_transform=None):
self.degrees = degrees
self.translate = translate
self.scale = scale
self.shear = shear
self.perspective = perspective
# mosaic border
self.border = border
self.pre_transform = pre_transform
def affine_transform(self, img, border):
# Center
C = np.eye(3)
C[0, 2] = -img.shape[1] / 2 # x translation (pixels)
C[1, 2] = -img.shape[0] / 2 # y translation (pixels)
# Perspective
P = np.eye(3)
P[2, 0] = random.uniform(-self.perspective, self.perspective) # x perspective (about y)
P[2, 1] = random.uniform(-self.perspective, self.perspective) # y perspective (about x)
# Rotation and Scale
R = np.eye(3)
a = random.uniform(-self.degrees, self.degrees)
# a += random.choice([-180, -90, 0, 90]) # add 90deg rotations to small rotations
s = random.uniform(1 - self.scale, 1 + self.scale)
# s = 2 ** random.uniform(-scale, scale)
R[:2] = cv2.getRotationMatrix2D(angle=a, center=(0, 0), scale=s)
# Shear
S = np.eye(3)
S[0, 1] = math.tan(random.uniform(-self.shear, self.shear) * math.pi / 180) # x shear (deg)
S[1, 0] = math.tan(random.uniform(-self.shear, self.shear) * math.pi / 180) # y shear (deg)
# Translation
T = np.eye(3)
T[0, 2] = random.uniform(0.5 - self.translate, 0.5 + self.translate) * self.size[0] # x translation (pixels)
T[1, 2] = random.uniform(0.5 - self.translate, 0.5 + self.translate) * self.size[1] # y translation (pixels)
# Combined rotation matrix
M = T @ S @ R @ P @ C # order of operations (right to left) is IMPORTANT
# affine image
if (border[0] != 0) or (border[1] != 0) or (M != np.eye(3)).any(): # image changed
if self.perspective:
img = cv2.warpPerspective(img, M, dsize=self.size, borderValue=(114, 114, 114))
else: # affine
img = cv2.warpAffine(img, M[:2], dsize=self.size, borderValue=(114, 114, 114))
return img, M, s
def apply_bboxes(self, bboxes, M):
"""apply affine to bboxes only.
Args:
bboxes(ndarray): list of bboxes, xyxy format, with shape (num_bboxes, 4).
M(ndarray): affine matrix.
Returns:
new_bboxes(ndarray): bboxes after affine, [num_bboxes, 4].
"""
n = len(bboxes)
if n == 0:
return bboxes
xy = np.ones((n * 4, 3))
xy[:, :2] = bboxes[:, [0, 1, 2, 3, 0, 3, 2, 1]].reshape(n * 4, 2) # x1y1, x2y2, x1y2, x2y1
xy = xy @ M.T # transform
xy = (xy[:, :2] / xy[:, 2:3] if self.perspective else xy[:, :2]).reshape(n, 8) # perspective rescale or affine
# create new boxes
x = xy[:, [0, 2, 4, 6]]
y = xy[:, [1, 3, 5, 7]]
return np.concatenate((x.min(1), y.min(1), x.max(1), y.max(1))).reshape(4, n).T
def apply_segments(self, segments, M):
"""apply affine to segments and generate new bboxes from segments.
Args:
segments(ndarray): list of segments, [num_samples, 500, 2].
M(ndarray): affine matrix.
Returns:
new_segments(ndarray): list of segments after affine, [num_samples, 500, 2].
new_bboxes(ndarray): bboxes after affine, [N, 4].
"""
n, num = segments.shape[:2]
if n == 0:
return [], segments
xy = np.ones((n * num, 3))
segments = segments.reshape(-1, 2)
xy[:, :2] = segments
xy = xy @ M.T # transform
xy = xy[:, :2] / xy[:, 2:3]
segments = xy.reshape(n, -1, 2)
bboxes = np.stack([segment2box(xy, self.size[0], self.size[1]) for xy in segments], 0)
return bboxes, segments
def apply_keypoints(self, keypoints, M):
"""apply affine to keypoints.
Args:
keypoints(ndarray): keypoints, [N, 17, 2].
M(ndarray): affine matrix.
Return:
new_keypoints(ndarray): keypoints after affine, [N, 17, 2].
"""
n = len(keypoints)
if n == 0:
return keypoints
new_keypoints = np.ones((n * 17, 3))
new_keypoints[:, :2] = keypoints.reshape(n * 17, 2) # num_kpt is hardcoded to 17
new_keypoints = new_keypoints @ M.T # transform
new_keypoints = (new_keypoints[:, :2] / new_keypoints[:, 2:3]).reshape(n, 34) # perspective rescale or affine
new_keypoints[keypoints.reshape(-1, 34) == 0] = 0
x_kpts = new_keypoints[:, list(range(0, 34, 2))]
y_kpts = new_keypoints[:, list(range(1, 34, 2))]
x_kpts[np.logical_or.reduce((x_kpts < 0, x_kpts > self.size[0], y_kpts < 0, y_kpts > self.size[1]))] = 0
y_kpts[np.logical_or.reduce((x_kpts < 0, x_kpts > self.size[0], y_kpts < 0, y_kpts > self.size[1]))] = 0
new_keypoints[:, list(range(0, 34, 2))] = x_kpts
new_keypoints[:, list(range(1, 34, 2))] = y_kpts
return new_keypoints.reshape(n, 17, 2)
def __call__(self, labels):
"""
Affine images and targets.
Args:
labels(Dict): a dict of `bboxes`, `segments`, `keypoints`.
"""
if self.pre_transform and 'mosaic_border' not in labels:
labels = self.pre_transform(labels)
labels.pop('ratio_pad') # do not need ratio pad
img = labels['img']
cls = labels['cls']
instances = labels.pop('instances')
# make sure the coord formats are right
instances.convert_bbox(format='xyxy')
instances.denormalize(*img.shape[:2][::-1])
border = labels.pop('mosaic_border', self.border)
self.size = img.shape[1] + border[1] * 2, img.shape[0] + border[0] * 2 # w, h
# M is affine matrix
# scale for func:`box_candidates`
img, M, scale = self.affine_transform(img, border)
bboxes = self.apply_bboxes(instances.bboxes, M)
segments = instances.segments
keypoints = instances.keypoints
# update bboxes if there are segments.
if len(segments):
bboxes, segments = self.apply_segments(segments, M)
if keypoints is not None:
keypoints = self.apply_keypoints(keypoints, M)
new_instances = Instances(bboxes, segments, keypoints, bbox_format='xyxy', normalized=False)
# clip
new_instances.clip(*self.size)
# filter instances
instances.scale(scale_w=scale, scale_h=scale, bbox_only=True)
# make the bboxes have the same scale with new_bboxes
i = self.box_candidates(box1=instances.bboxes.T,
box2=new_instances.bboxes.T,
area_thr=0.01 if len(segments) else 0.10)
labels['instances'] = new_instances[i]
labels['cls'] = cls[i]
labels['img'] = img
labels['resized_shape'] = img.shape[:2]
return labels
def box_candidates(self, box1, box2, wh_thr=2, ar_thr=100, area_thr=0.1, eps=1e-16): # box1(4,n), box2(4,n)
# Compute box candidates: box1 before augment, box2 after augment, wh_thr (pixels), aspect_ratio_thr, area_ratio
w1, h1 = box1[2] - box1[0], box1[3] - box1[1]
w2, h2 = box2[2] - box2[0], box2[3] - box2[1]
ar = np.maximum(w2 / (h2 + eps), h2 / (w2 + eps)) # aspect ratio
return (w2 > wh_thr) & (h2 > wh_thr) & (w2 * h2 / (w1 * h1 + eps) > area_thr) & (ar < ar_thr) # candidates
class RandomHSV:
def __init__(self, hgain=0.5, sgain=0.5, vgain=0.5) -> None:
self.hgain = hgain
self.sgain = sgain
self.vgain = vgain
def __call__(self, labels):
img = labels['img']
if self.hgain or self.sgain or self.vgain:
r = np.random.uniform(-1, 1, 3) * [self.hgain, self.sgain, self.vgain] + 1 # random gains
hue, sat, val = cv2.split(cv2.cvtColor(img, cv2.COLOR_BGR2HSV))
dtype = img.dtype # uint8
x = np.arange(0, 256, dtype=r.dtype)
lut_hue = ((x * r[0]) % 180).astype(dtype)
lut_sat = np.clip(x * r[1], 0, 255).astype(dtype)
lut_val = np.clip(x * r[2], 0, 255).astype(dtype)
im_hsv = cv2.merge((cv2.LUT(hue, lut_hue), cv2.LUT(sat, lut_sat), cv2.LUT(val, lut_val)))
cv2.cvtColor(im_hsv, cv2.COLOR_HSV2BGR, dst=img) # no return needed
return labels
class RandomFlip:
def __init__(self, p=0.5, direction='horizontal') -> None:
assert direction in ['horizontal', 'vertical'], f'Support direction `horizontal` or `vertical`, got {direction}'
assert 0 <= p <= 1.0
self.p = p
self.direction = direction
def __call__(self, labels):
img = labels['img']
instances = labels.pop('instances')
instances.convert_bbox(format='xywh')
h, w = img.shape[:2]
h = 1 if instances.normalized else h
w = 1 if instances.normalized else w
# Flip up-down
if self.direction == 'vertical' and random.random() < self.p:
img = np.flipud(img)
instances.flipud(h)
if self.direction == 'horizontal' and random.random() < self.p:
img = np.fliplr(img)
instances.fliplr(w)
labels['img'] = np.ascontiguousarray(img)
labels['instances'] = instances
return labels
class LetterBox:
"""Resize image and padding for detection, instance segmentation, pose"""
def __init__(self, new_shape=(640, 640), auto=False, scaleFill=False, scaleup=True, stride=32):
self.new_shape = new_shape
self.auto = auto
self.scaleFill = scaleFill
self.scaleup = scaleup
self.stride = stride
def __call__(self, labels=None, image=None):
if labels is None:
labels = {}
img = labels.get('img') if image is None else image
shape = img.shape[:2] # current shape [height, width]
new_shape = labels.pop('rect_shape', self.new_shape)
if isinstance(new_shape, int):
new_shape = (new_shape, new_shape)
# Scale ratio (new / old)
r = min(new_shape[0] / shape[0], new_shape[1] / shape[1])
if not self.scaleup: # only scale down, do not scale up (for better val mAP)
r = min(r, 1.0)
# Compute padding
ratio = r, r # width, height ratios
new_unpad = int(round(shape[1] * r)), int(round(shape[0] * r))
dw, dh = new_shape[1] - new_unpad[0], new_shape[0] - new_unpad[1] # wh padding
if self.auto: # minimum rectangle
dw, dh = np.mod(dw, self.stride), np.mod(dh, self.stride) # wh padding
elif self.scaleFill: # stretch
dw, dh = 0.0, 0.0
new_unpad = (new_shape[1], new_shape[0])
ratio = new_shape[1] / shape[1], new_shape[0] / shape[0] # width, height ratios
dw /= 2 # divide padding into 2 sides
dh /= 2
if labels.get('ratio_pad'):
labels['ratio_pad'] = (labels['ratio_pad'], (dw, dh)) # for evaluation
if shape[::-1] != new_unpad: # resize
img = cv2.resize(img, new_unpad, interpolation=cv2.INTER_LINEAR)
top, bottom = int(round(dh - 0.1)), int(round(dh + 0.1))
left, right = int(round(dw - 0.1)), int(round(dw + 0.1))
img = cv2.copyMakeBorder(img, top, bottom, left, right, cv2.BORDER_CONSTANT,
value=(114, 114, 114)) # add border
if len(labels):
labels = self._update_labels(labels, ratio, dw, dh)
labels['img'] = img
labels['resized_shape'] = new_shape
return labels
else:
return img
def _update_labels(self, labels, ratio, padw, padh):
"""Update labels"""
labels['instances'].convert_bbox(format='xyxy')
labels['instances'].denormalize(*labels['img'].shape[:2][::-1])
labels['instances'].scale(*ratio)
labels['instances'].add_padding(padw, padh)
return labels
class CopyPaste:
def __init__(self, p=0.5) -> None:
self.p = p
def __call__(self, labels):
# Implement Copy-Paste augmentation https://arxiv.org/abs/2012.07177, labels as nx5 np.array(cls, xyxy)
im = labels['img']
cls = labels['cls']
h, w = im.shape[:2]
instances = labels.pop('instances')
instances.convert_bbox(format='xyxy')
instances.denormalize(w, h)
if self.p and len(instances.segments):
n = len(instances)
_, w, _ = im.shape # height, width, channels
im_new = np.zeros(im.shape, np.uint8)
# calculate ioa first then select indexes randomly
ins_flip = deepcopy(instances)
ins_flip.fliplr(w)
ioa = bbox_ioa(ins_flip.bboxes, instances.bboxes) # intersection over area, (N, M)
indexes = np.nonzero((ioa < 0.30).all(1))[0] # (N, )
n = len(indexes)
for j in random.sample(list(indexes), k=round(self.p * n)):
cls = np.concatenate((cls, cls[[j]]), axis=0)
instances = Instances.concatenate((instances, ins_flip[[j]]), axis=0)
cv2.drawContours(im_new, instances.segments[[j]].astype(np.int32), -1, (1, 1, 1), cv2.FILLED)
result = cv2.flip(im, 1) # augment segments (flip left-right)
i = cv2.flip(im_new, 1).astype(bool)
im[i] = result[i] # cv2.imwrite('debug.jpg', im) # debug
labels['img'] = im
labels['cls'] = cls
labels['instances'] = instances
return labels
class Albumentations:
# YOLOv8 Albumentations class (optional, only used if package is installed)
def __init__(self, p=1.0):
self.p = p
self.transform = None
prefix = colorstr('albumentations: ')
try:
import albumentations as A
check_version(A.__version__, '1.0.3', hard=True) # version requirement
T = [
A.Blur(p=0.01),
A.MedianBlur(p=0.01),
A.ToGray(p=0.01),
A.CLAHE(p=0.01),
A.RandomBrightnessContrast(p=0.0),
A.RandomGamma(p=0.0),
A.ImageCompression(quality_lower=75, p=0.0),] # transforms
self.transform = A.Compose(T, bbox_params=A.BboxParams(format='yolo', label_fields=['class_labels']))
LOGGER.info(prefix + ', '.join(f'{x}'.replace('always_apply=False, ', '') for x in T if x.p))
except ImportError: # package not installed, skip
pass
except Exception as e:
LOGGER.info(f'{prefix}{e}')
def __call__(self, labels):
im = labels['img']
cls = labels['cls']
if len(cls):
labels['instances'].convert_bbox('xywh')
labels['instances'].normalize(*im.shape[:2][::-1])
bboxes = labels['instances'].bboxes
# TODO: add supports of segments and keypoints
if self.transform and random.random() < self.p:
new = self.transform(image=im, bboxes=bboxes, class_labels=cls) # transformed
labels['img'] = new['image']
labels['cls'] = np.array(new['class_labels'])
bboxes = np.array(new['bboxes'])
labels['instances'].update(bboxes=bboxes)
return labels
# TODO: technically this is not an augmentation, maybe we should put this to another files
class Format:
def __init__(self,
bbox_format='xywh',
normalize=True,
return_mask=False,
return_keypoint=False,
mask_ratio=4,
mask_overlap=True,
batch_idx=True):
self.bbox_format = bbox_format
self.normalize = normalize
self.return_mask = return_mask # set False when training detection only
self.return_keypoint = return_keypoint
self.mask_ratio = mask_ratio
self.mask_overlap = mask_overlap
self.batch_idx = batch_idx # keep the batch indexes
def __call__(self, labels):
img = labels.pop('img')
h, w = img.shape[:2]
cls = labels.pop('cls')
instances = labels.pop('instances')
instances.convert_bbox(format=self.bbox_format)
instances.denormalize(w, h)
nl = len(instances)
if self.return_mask:
if nl:
masks, instances, cls = self._format_segments(instances, cls, w, h)
masks = torch.from_numpy(masks)
else:
masks = torch.zeros(1 if self.mask_overlap else nl, img.shape[0] // self.mask_ratio,
img.shape[1] // self.mask_ratio)
labels['masks'] = masks
if self.normalize:
instances.normalize(w, h)
labels['img'] = self._format_img(img)
labels['cls'] = torch.from_numpy(cls) if nl else torch.zeros(nl)
labels['bboxes'] = torch.from_numpy(instances.bboxes) if nl else torch.zeros((nl, 4))
if self.return_keypoint:
labels['keypoints'] = torch.from_numpy(instances.keypoints) if nl else torch.zeros((nl, 17, 2))
# then we can use collate_fn
if self.batch_idx:
labels['batch_idx'] = torch.zeros(nl)
return labels
def _format_img(self, img):
if len(img.shape) < 3:
img = np.expand_dims(img, -1)
img = np.ascontiguousarray(img.transpose(2, 0, 1)[::-1])
img = torch.from_numpy(img)
return img
def _format_segments(self, instances, cls, w, h):
"""convert polygon points to bitmap"""
segments = instances.segments
if self.mask_overlap:
masks, sorted_idx = polygons2masks_overlap((h, w), segments, downsample_ratio=self.mask_ratio)
masks = masks[None] # (640, 640) -> (1, 640, 640)
instances = instances[sorted_idx]
cls = cls[sorted_idx]
else:
masks = polygons2masks((h, w), segments, color=1, downsample_ratio=self.mask_ratio)
return masks, instances, cls
def v8_transforms(dataset, imgsz, hyp):
pre_transform = Compose([
Mosaic(dataset, imgsz=imgsz, p=hyp.mosaic, border=[-imgsz // 2, -imgsz // 2]),
CopyPaste(p=hyp.copy_paste),
RandomPerspective(
degrees=hyp.degrees,
translate=hyp.translate,
scale=hyp.scale,
shear=hyp.shear,
perspective=hyp.perspective,
pre_transform=LetterBox(new_shape=(imgsz, imgsz)),
),])
return Compose([
pre_transform,
MixUp(dataset, pre_transform=pre_transform, p=hyp.mixup),
Albumentations(p=1.0),
RandomHSV(hgain=hyp.hsv_h, sgain=hyp.hsv_s, vgain=hyp.hsv_v),
RandomFlip(direction='vertical', p=hyp.flipud),
RandomFlip(direction='horizontal', p=hyp.fliplr),]) # transforms
# Classification augmentations -----------------------------------------------------------------------------------------
def classify_transforms(size=224):
# Transforms to apply if albumentations not installed
if not isinstance(size, int):
raise TypeError(f'classify_transforms() size {size} must be integer, not (list, tuple)')
# T.Compose([T.ToTensor(), T.Resize(size), T.CenterCrop(size), T.Normalize(IMAGENET_MEAN, IMAGENET_STD)])
return T.Compose([CenterCrop(size), ToTensor(), T.Normalize(IMAGENET_MEAN, IMAGENET_STD)])
def classify_albumentations(
augment=True,
size=224,
scale=(0.08, 1.0),
hflip=0.5,
vflip=0.0,
jitter=0.4,
mean=IMAGENET_MEAN,
std=IMAGENET_STD,
auto_aug=False,
):
# YOLOv8 classification Albumentations (optional, only used if package is installed)
prefix = colorstr('albumentations: ')
try:
import albumentations as A
from albumentations.pytorch import ToTensorV2
check_version(A.__version__, '1.0.3', hard=True) # version requirement
if augment: # Resize and crop
T = [A.RandomResizedCrop(height=size, width=size, scale=scale)]
if auto_aug:
# TODO: implement AugMix, AutoAug & RandAug in albumentation
LOGGER.info(f'{prefix}auto augmentations are currently not supported')
else:
if hflip > 0:
T += [A.HorizontalFlip(p=hflip)]
if vflip > 0:
T += [A.VerticalFlip(p=vflip)]
if jitter > 0:
color_jitter = (float(jitter),) * 3 # repeat value for brightness, contrast, saturation, 0 hue
T += [A.ColorJitter(*color_jitter, 0)]
else: # Use fixed crop for eval set (reproducibility)
T = [A.SmallestMaxSize(max_size=size), A.CenterCrop(height=size, width=size)]
T += [A.Normalize(mean=mean, std=std), ToTensorV2()] # Normalize and convert to Tensor
LOGGER.info(prefix + ', '.join(f'{x}'.replace('always_apply=False, ', '') for x in T if x.p))
return A.Compose(T)
except ImportError: # package not installed, skip
pass
except Exception as e:
LOGGER.info(f'{prefix}{e}')
class ClassifyLetterBox:
# YOLOv8 LetterBox class for image preprocessing, i.e. T.Compose([LetterBox(size), ToTensor()])
def __init__(self, size=(640, 640), auto=False, stride=32):
super().__init__()
self.h, self.w = (size, size) if isinstance(size, int) else size
self.auto = auto # pass max size integer, automatically solve for short side using stride
self.stride = stride # used with auto
def __call__(self, im): # im = np.array HWC
imh, imw = im.shape[:2]
r = min(self.h / imh, self.w / imw) # ratio of new/old
h, w = round(imh * r), round(imw * r) # resized image
hs, ws = (math.ceil(x / self.stride) * self.stride for x in (h, w)) if self.auto else self.h, self.w
top, left = round((hs - h) / 2 - 0.1), round((ws - w) / 2 - 0.1)
im_out = np.full((self.h, self.w, 3), 114, dtype=im.dtype)
im_out[top:top + h, left:left + w] = cv2.resize(im, (w, h), interpolation=cv2.INTER_LINEAR)
return im_out
class CenterCrop:
# YOLOv8 CenterCrop class for image preprocessing, i.e. T.Compose([CenterCrop(size), ToTensor()])
def __init__(self, size=640):
super().__init__()
self.h, self.w = (size, size) if isinstance(size, int) else size
def __call__(self, im): # im = np.array HWC
imh, imw = im.shape[:2]
m = min(imh, imw) # min dimension
top, left = (imh - m) // 2, (imw - m) // 2
return cv2.resize(im[top:top + m, left:left + m], (self.w, self.h), interpolation=cv2.INTER_LINEAR)
class ToTensor:
# YOLOv8 ToTensor class for image preprocessing, i.e. T.Compose([LetterBox(size), ToTensor()])
def __init__(self, half=False):
super().__init__()
self.half = half
def __call__(self, im): # im = np.array HWC in BGR order
im = np.ascontiguousarray(im.transpose((2, 0, 1))[::-1]) # HWC to CHW -> BGR to RGB -> contiguous
im = torch.from_numpy(im) # to torch
im = im.half() if self.half else im.float() # uint8 to fp16/32
im /= 255.0 # 0-255 to 0.0-1.0
return im