#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = "heider"
__doc__ = r"""
Created on 5/5/22
"""
import math
import random
import warnings
from PIL import Image
from torchvision.transforms.functional import resized_crop
_pil_interpolation_to_str = {
Image.NEAREST: "PIL.Image.NEAREST",
Image.BILINEAR: "PIL.Image.BILINEAR",
Image.BICUBIC: "PIL.Image.BICUBIC",
Image.LANCZOS: "PIL.Image.LANCZOS",
Image.HAMMING: "PIL.Image.HAMMING",
Image.BOX: "PIL.Image.BOX",
}
def _pil_interp(method):
if method == "bicubic":
return Image.BICUBIC
elif method == "lanczos":
return Image.LANCZOS
elif method == "hamming":
return Image.HAMMING
else:
# default bilinear, do we want to allow nearest?
return Image.BILINEAR
_RANDOM_INTERPOLATION = (Image.BILINEAR, Image.BICUBIC)
[docs]class RandomResizedCropAndInterpolationWithTwoPic:
"""Crop the given PIL Image to random size and aspect ratio with random interpolation.
A crop of random size (default: of 0.08 to 1.0) of the original size and a random
aspect ratio (default: of 3/4 to 4/3) of the original aspect ratio is made. This crop
is finally resized to given size.
This is popularly used to train the Inception networks.
Args:
size: expected output size of each edge
scale: range of size of the origin size cropped
ratio: range of aspect ratio of the origin aspect ratio cropped
interpolation: Default: PIL.Image.BILINEAR
"""
[docs] def __init__(
self,
size,
second_size=None,
scale=(0.08, 1.0),
ratio=(3.0 / 4.0, 4.0 / 3.0),
interpolation="bilinear",
second_interpolation="lanczos",
):
if isinstance(size, tuple):
self.size = size
else:
self.size = (size, size)
if second_size is not None:
if isinstance(second_size, tuple):
self.second_size = second_size
else:
self.second_size = (second_size, second_size)
else:
self.second_size = None
if (scale[0] > scale[1]) or (ratio[0] > ratio[1]):
warnings.warn("range should be of kind (min, max)")
if interpolation == "random":
self.interpolation = _RANDOM_INTERPOLATION
else:
self.interpolation = _pil_interp(interpolation)
self.second_interpolation = _pil_interp(second_interpolation)
self.scale = scale
self.ratio = ratio
[docs] @staticmethod
def get_params(img, scale, ratio):
"""Get parameters for ``crop`` for a random sized crop.
Args:
img (PIL Image): Image to be cropped.
scale (tuple): range of size of the origin size cropped
ratio (tuple): range of aspect ratio of the origin aspect ratio cropped
Returns:
tuple: params (i, j, h, w) to be passed to ``crop`` for a random
sized crop.
"""
area = img.size[0] * img.size[1]
for attempt in range(10):
target_area = random.uniform(*scale) * area
log_ratio = (math.log(ratio[0]), math.log(ratio[1]))
aspect_ratio = math.exp(random.uniform(*log_ratio))
w = int(round(math.sqrt(target_area * aspect_ratio)))
h = int(round(math.sqrt(target_area / aspect_ratio)))
if w <= img.size[0] and h <= img.size[1]:
i = random.randint(0, img.size[1] - h)
j = random.randint(0, img.size[0] - w)
return i, j, h, w
# Fallback to central crop
in_ratio = img.size[0] / img.size[1]
if in_ratio < min(ratio):
w = img.size[0]
h = int(round(w / min(ratio)))
elif in_ratio > max(ratio):
h = img.size[1]
w = int(round(h * max(ratio)))
else: # whole image
w = img.size[0]
h = img.size[1]
i = (img.size[1] - h) // 2
j = (img.size[0] - w) // 2
return i, j, h, w
def __call__(self, img):
"""
Args:
img (PIL Image): Image to be cropped and resized.
Returns:
PIL Image: Randomly cropped and resized image.
"""
i, j, h, w = self.get_params(img, self.scale, self.ratio)
if isinstance(self.interpolation, (tuple, list)):
interpolation = random.choice(self.interpolation)
else:
interpolation = self.interpolation
if self.second_size is None:
return resized_crop(img, i, j, h, w, self.size, interpolation)
else:
return resized_crop(
img, i, j, h, w, self.size, interpolation
), resized_crop(
img, i, j, h, w, self.second_size, self.second_interpolation
)
def __repr__(self):
if isinstance(self.interpolation, (tuple, list)):
interpolate_str = " ".join(
[_pil_interpolation_to_str[x] for x in self.interpolation]
)
else:
interpolate_str = _pil_interpolation_to_str[self.interpolation]
format_string = self.__class__.__name__ + "(size={0}".format(self.size)
format_string += ", scale={0}".format(tuple(round(s, 4) for s in self.scale))
format_string += ", ratio={0}".format(tuple(round(r, 4) for r in self.ratio))
format_string += ", interpolation={0}".format(interpolate_str)
if self.second_size is not None:
format_string += ", second_size={0}".format(self.second_size)
format_string += ", second_interpolation={0}".format(
_pil_interpolation_to_str[self.second_interpolation]
)
format_string += ")"
return format_string
