imaginAIry/imaginairy/vendored/k_diffusion/augmentation.py
Bryce b4a3b8c2b3 feature: k-diffusion samplers
- improved image logging functionality. can just stick log_latent wherever you want
- improved some variable naming
- moved all the samplers together
- vendored k-diffusion library
2022-09-14 00:40:25 -07:00

114 lines
3.6 KiB
Python

import math
import operator
from functools import reduce
import numpy as np
import torch
from skimage import transform
from torch import nn
def translate2d(tx, ty):
mat = [[1, 0, tx], [0, 1, ty], [0, 0, 1]]
return torch.tensor(mat, dtype=torch.float32)
def scale2d(sx, sy):
mat = [[sx, 0, 0], [0, sy, 0], [0, 0, 1]]
return torch.tensor(mat, dtype=torch.float32)
def rotate2d(theta):
mat = [
[torch.cos(theta), torch.sin(-theta), 0],
[torch.sin(theta), torch.cos(theta), 0],
[0, 0, 1],
]
return torch.tensor(mat, dtype=torch.float32)
class KarrasAugmentationPipeline:
def __init__(self, a_prob=0.12, a_scale=2**0.2, a_aniso=2**0.2, a_trans=1 / 8):
self.a_prob = a_prob
self.a_scale = a_scale
self.a_aniso = a_aniso
self.a_trans = a_trans
def __call__(self, image):
h, w = image.size
mats = [translate2d(h / 2 - 0.5, w / 2 - 0.5)]
# x-flip
a0 = torch.randint(2, []).float()
mats.append(scale2d(1 - 2 * a0, 1))
# y-flip
do = (torch.rand([]) < self.a_prob).float()
a1 = torch.randint(2, []).float() * do
mats.append(scale2d(1, 1 - 2 * a1))
# scaling
do = (torch.rand([]) < self.a_prob).float()
a2 = torch.randn([]) * do
mats.append(scale2d(self.a_scale**a2, self.a_scale**a2))
# rotation
do = (torch.rand([]) < self.a_prob).float()
a3 = (torch.rand([]) * 2 * math.pi - math.pi) * do
mats.append(rotate2d(-a3))
# anisotropy
do = (torch.rand([]) < self.a_prob).float()
a4 = (torch.rand([]) * 2 * math.pi - math.pi) * do
a5 = torch.randn([]) * do
mats.append(rotate2d(a4))
mats.append(scale2d(self.a_aniso**a5, self.a_aniso**-a5))
mats.append(rotate2d(-a4))
# translation
do = (torch.rand([]) < self.a_prob).float()
a6 = torch.randn([]) * do
a7 = torch.randn([]) * do
mats.append(translate2d(self.a_trans * w * a6, self.a_trans * h * a7))
# form the transformation matrix and conditioning vector
mats.append(translate2d(-h / 2 + 0.5, -w / 2 + 0.5))
mat = reduce(operator.matmul, mats)
cond = torch.stack(
[a0, a1, a2, a3.cos() - 1, a3.sin(), a5 * a4.cos(), a5 * a4.sin(), a6, a7]
)
# apply the transformation
image_orig = np.array(image, dtype=np.float32) / 255
if image_orig.ndim == 2:
image_orig = image_orig[..., None]
tf = transform.AffineTransform(mat.numpy())
image = transform.warp(
image_orig,
tf.inverse,
order=3,
mode="reflect",
cval=0.5,
clip=False,
preserve_range=True,
)
image_orig = torch.as_tensor(image_orig).movedim(2, 0) * 2 - 1
image = torch.as_tensor(image).movedim(2, 0) * 2 - 1
return image, image_orig, cond
class KarrasAugmentWrapper(nn.Module):
def __init__(self, model):
super().__init__()
self.inner_model = model
def forward(self, input, sigma, aug_cond=None, mapping_cond=None, **kwargs):
if aug_cond is None:
aug_cond = input.new_zeros([input.shape[0], 9])
if mapping_cond is None:
mapping_cond = aug_cond
else:
mapping_cond = torch.cat([aug_cond, mapping_cond], dim=1)
return self.inner_model(input, sigma, mapping_cond=mapping_cond, **kwargs)
def set_skip_stages(self, skip_stages):
return self.inner_model.set_skip_stages(skip_stages)
def set_patch_size(self, patch_size):
return self.inner_model.set_patch_size(patch_size)