| import numpy as np | |
| import math | |
| from PIL import Image | |
| import torch | |
| import copy | |
| import string | |
| import random | |
| def align_to(value, alignment): | |
| """align hight, width according to alignment | |
| Args: | |
| value (int): height or width | |
| alignment (int): target alignment factor | |
| Returns: | |
| int: the aligned value | |
| """ | |
| return int(math.ceil(value / alignment) * alignment) | |
| def black_image(width, height): | |
| """generate a black image | |
| Args: | |
| width (int): image width | |
| height (int): image height | |
| Returns: | |
| _type_: a black image | |
| """ | |
| black_image = Image.new("RGB", (width, height), (0, 0, 0)) | |
| return black_image | |
| def get_closest_ratio(height: float, width: float, ratios: list, buckets: list): | |
| """get the closest ratio in the buckets | |
| Args: | |
| height (float): video height | |
| width (float): video width | |
| ratios (list): video aspect ratio | |
| buckets (list): buckets generate by `generate_crop_size_list` | |
| Returns: | |
| the closest ratio in the buckets and the corresponding ratio | |
| """ | |
| aspect_ratio = float(height) / float(width) | |
| closest_ratio_id = np.abs(ratios - aspect_ratio).argmin() | |
| closest_ratio = min(ratios, key=lambda ratio: abs(float(ratio) - aspect_ratio)) | |
| return buckets[closest_ratio_id], float(closest_ratio) | |
| def generate_crop_size_list(base_size=256, patch_size=32, max_ratio=4.0): | |
| """generate crop size list | |
| Args: | |
| base_size (int, optional): the base size for generate bucket. Defaults to 256. | |
| patch_size (int, optional): the stride to generate bucket. Defaults to 32. | |
| max_ratio (float, optional): th max ratio for h or w based on base_size . Defaults to 4.0. | |
| Returns: | |
| list: generate crop size list | |
| """ | |
| num_patches = round((base_size / patch_size) ** 2) | |
| assert max_ratio >= 1.0 | |
| crop_size_list = [] | |
| wp, hp = num_patches, 1 | |
| while wp > 0: | |
| if max(wp, hp) / min(wp, hp) <= max_ratio: | |
| crop_size_list.append((wp * patch_size, hp * patch_size)) | |
| if (hp + 1) * wp <= num_patches: | |
| hp += 1 | |
| else: | |
| wp -= 1 | |
| return crop_size_list | |
| def align_floor_to(value, alignment): | |
| """align hight, width according to alignment | |
| Args: | |
| value (int): height or width | |
| alignment (int): target alignment factor | |
| Returns: | |
| int: the aligned value | |
| """ | |
| return int(math.floor(value / alignment) * alignment) | |