Add LDM Super Resolution pipeline (#1116)

* Add ldm super resolution pipeline

* style

* fix copies

* style

* fix doc

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* add doc

* address comments

* address comments

* fix doc

* minor

* add tests

* add tests

* load text encoder from subfolder

* fix test

* fix test

* style

* style

* handle mps latents

* unfix typo

* unfix typo

* Update tests/pipelines/latent_diffusion/test_latent_diffusion_superresolution.py
Co-authored-by: Pedro Cuenca <pedro@huggingface.co>

* fix set_timesteps mps

* fix set_timesteps mps

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* Update src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py
Co-authored-by: Suraj Patil <surajp815@gmail.com>

* style

* test 64x64 instead of 256x256
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
Co-authored-by: Suraj Patil <surajp815@gmail.com>
Co-authored-by: Pedro Cuenca <pedro@huggingface.co>

docs/source/api/pipelines/latent_diffusion.mdx

@@ -33,6 +33,7 @@ The original codebase can be found [here](https://github.com/CompVis/latent-diff
 | Pipeline | Tasks | Colab
 |---|---|:---:|
 | [pipeline_latent_diffusion.py](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion.py) | *Text-to-Image Generation* | - |
+| [pipeline_latent_diffusion_superresolution.py](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py) | *Super Resolution* | - |
 
 ## Examples:
 
@@ -40,3 +41,7 @@ The original codebase can be found [here](https://github.com/CompVis/latent-diff
 ## LDMTextToImagePipeline
 [[autodoc]] pipelines.latent_diffusion.pipeline_latent_diffusion.LDMTextToImagePipeline
     - __call__
+
+## LDMSuperResolutionPipeline
+[[autodoc]] pipelines.latent_diffusion.pipeline_latent_diffusion_superresolution.LDMSuperResolutionPipeline
+    - __call__

src/diffusers/__init__.py

@@ -35,6 +35,7 @@ if is_torch_available():
         DDPMPipeline,
         KarrasVePipeline,
         LDMPipeline,
+        LDMSuperResolutionPipeline,
         PNDMPipeline,
         RePaintPipeline,
         ScoreSdeVePipeline,

src/diffusers/pipelines/__init__.py

@@ -5,6 +5,7 @@ if is_torch_available():
     from .dance_diffusion import DanceDiffusionPipeline
     from .ddim import DDIMPipeline
     from .ddpm import DDPMPipeline
+    from .latent_diffusion import LDMSuperResolutionPipeline
     from .latent_diffusion_uncond import LDMPipeline
     from .pndm import PNDMPipeline
     from .repaint import RePaintPipeline

src/diffusers/pipelines/latent_diffusion/__init__.py

 # flake8: noqa
 from ...utils import is_transformers_available
+from .pipeline_latent_diffusion_superresolution import LDMSuperResolutionPipeline
 
 
 if is_transformers_available():

src/diffusers/pipelines/latent_diffusion/pipeline_latent_diffusion_superresolution.py

+import inspect
+from typing import Optional, Tuple, Union
+
+import numpy as np
+import torch
+import torch.utils.checkpoint
+
+import PIL
+
+from ...models import UNet2DModel, VQModel
+from ...pipeline_utils import DiffusionPipeline, ImagePipelineOutput
+from ...schedulers import (
+    DDIMScheduler,
+    DPMSolverMultistepScheduler,
+    EulerAncestralDiscreteScheduler,
+    EulerDiscreteScheduler,
+    LMSDiscreteScheduler,
+    PNDMScheduler,
+)
+
+
+def preprocess(image):
+    w, h = image.size
+    w, h = map(lambda x: x - x % 32, (w, h))  # resize to integer multiple of 32
+    image = image.resize((w, h), resample=PIL.Image.LANCZOS)
+    image = np.array(image).astype(np.float32) / 255.0
+    image = image[None].transpose(0, 3, 1, 2)
+    image = torch.from_numpy(image)
+    return 2.0 * image - 1.0
+
+
+class LDMSuperResolutionPipeline(DiffusionPipeline):
+    r"""
+    A pipeline for image super-resolution using Latent
+
+    This class inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods the
+    library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)
+
+    Parameters:
+        vqvae ([`VQModel`]):
+            Vector-quantized (VQ) VAE Model to encode and decode images to and from latent representations.
+        unet ([`UNet2DModel`]): U-Net architecture to denoise the encoded image.
+        scheduler ([`SchedulerMixin`]):
+            A scheduler to be used in combination with `unet` to denoise the encoded image latens. Can be one of
+            [`DDIMScheduler`], [`LMSDiscreteScheduler`], [`EulerDiscreteScheduler`],
+            [`EulerAncestralDiscreteScheduler`], [`DPMSolverMultistepScheduler`], or [`PNDMScheduler`].
+    """
+
+    def __init__(
+        self,
+        vqvae: VQModel,
+        unet: UNet2DModel,
+        scheduler: Union[
+            DDIMScheduler,
+            PNDMScheduler,
+            LMSDiscreteScheduler,
+            EulerDiscreteScheduler,
+            EulerAncestralDiscreteScheduler,
+            DPMSolverMultistepScheduler,
+        ],
+    ):
+        super().__init__()
+        self.register_modules(vqvae=vqvae, unet=unet, scheduler=scheduler)
+
+    @torch.no_grad()
+    def __call__(
+        self,
+        init_image: Union[torch.Tensor, PIL.Image.Image],
+        batch_size: Optional[int] = 1,
+        num_inference_steps: Optional[int] = 100,
+        eta: Optional[float] = 0.0,
+        generator: Optional[torch.Generator] = None,
+        output_type: Optional[str] = "pil",
+        return_dict: bool = True,
+        **kwargs,
+    ) -> Union[Tuple, ImagePipelineOutput]:
+        r"""
+        Args:
+            init_image (`torch.Tensor` or `PIL.Image.Image`):
+                `Image`, or tensor representing an image batch, that will be used as the starting point for the
+                process.
+            batch_size (`int`, *optional*, defaults to 1):
+                Number of images to generate.
+            num_inference_steps (`int`, *optional*, defaults to 100):
+                The number of denoising steps. More denoising steps usually lead to a higher quality image at the
+                expense of slower inference.
+            eta (`float`, *optional*, defaults to 0.0):
+                Corresponds to parameter eta (η) in the DDIM paper: https://arxiv.org/abs/2010.02502. Only applies to
+                [`schedulers.DDIMScheduler`], will be ignored for others.
+            generator (`torch.Generator`, *optional*):
+                A [torch generator](https://pytorch.org/docs/stable/generated/torch.Generator.html) to make generation
+                deterministic.
+            output_type (`str`, *optional*, defaults to `"pil"`):
+                The output format of the generate image. Choose between
+                [PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`.
+            return_dict (`bool`, *optional*):
+                Whether or not to return a [`~pipeline_utils.ImagePipelineOutput`] instead of a plain tuple.
+
+        Returns:
+            [`~pipeline_utils.ImagePipelineOutput`] or `tuple`: [`~pipelines.utils.ImagePipelineOutput`] if
+            `return_dict` is True, otherwise a `tuple. When returning a tuple, the first element is a list with the
+            generated images.
+        """
+
+        if isinstance(init_image, PIL.Image.Image):
+            batch_size = 1
+        elif isinstance(init_image, torch.Tensor):
+            batch_size = init_image.shape[0]
+        else:
+            raise ValueError(
+                f"`init_image` has to be of type `PIL.Image.Image` or `torch.Tensor` but is {type(init_image)}"
+            )
+
+        if isinstance(init_image, PIL.Image.Image):
+            init_image = preprocess(init_image)
+
+        height, width = init_image.shape[-2:]
+
+        # in_channels should be 6: 3 for latents, 3 for low resolution image
+        latents_shape = (batch_size, self.unet.in_channels // 2, height, width)
+        latents_dtype = next(self.unet.parameters()).dtype
+
+        if self.device.type == "mps":
+            # randn does not work reproducibly on mps
+            latents = torch.randn(latents_shape, generator=generator, device="cpu", dtype=latents_dtype)
+            latents = latents.to(self.device)
+        else:
+            latents = torch.randn(latents_shape, generator=generator, device=self.device, dtype=latents_dtype)
+
+        init_image = init_image.to(device=self.device, dtype=latents_dtype)
+
+        # set timesteps and move to the correct device
+        self.scheduler.set_timesteps(num_inference_steps, device=self.device)
+        timesteps_tensor = self.scheduler.timesteps
+
+        # scale the initial noise by the standard deviation required by the scheduler
+        latents = latents * self.scheduler.init_noise_sigma
+
+        # prepare extra kwargs for the scheduler step, since not all schedulers have the same signature.
+        # eta (η) is only used with the DDIMScheduler, it will be ignored for other schedulers.
+        # eta corresponds to η in DDIM paper: https://arxiv.org/abs/2010.02502
+        # and should be between [0, 1]
+        accepts_eta = "eta" in set(inspect.signature(self.scheduler.step).parameters.keys())
+        extra_kwargs = {}
+        if accepts_eta:
+            extra_kwargs["eta"] = eta
+
+        for t in self.progress_bar(timesteps_tensor):
+            # concat latents and low resolution image in the channel dimension.
+            latents_input = torch.cat([latents, init_image], dim=1)
+            latents_input = self.scheduler.scale_model_input(latents_input, t)
+            # predict the noise residual
+            noise_pred = self.unet(latents_input, t).sample
+            # compute the previous noisy sample x_t -> x_t-1
+            latents = self.scheduler.step(noise_pred, t, latents, **extra_kwargs).prev_sample
+
+        # decode the image latents with the VQVAE
+        image = self.vqvae.decode(latents).sample
+        image = torch.clamp(image, -1.0, 1.0)
+        image = image / 2 + 0.5
+        image = image.cpu().permute(0, 2, 3, 1).numpy()
+
+        if output_type == "pil":
+            image = self.numpy_to_pil(image)
+
+        if not return_dict:
+            return (image,)
+
+        return ImagePipelineOutput(images=image)

src/diffusers/utils/dummy_pt_objects.py

@@ -227,6 +227,21 @@ class LDMPipeline(metaclass=DummyObject):
         requires_backends(cls, ["torch"])
 
 
+class LDMSuperResolutionPipeline(metaclass=DummyObject):
+    _backends = ["torch"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch"])
+
+
 class PNDMPipeline(metaclass=DummyObject):
     _backends = ["torch"]
 

tests/pipelines/latent_diffusion/test_latent_diffusion_superresolution.py

+# coding=utf-8
+# Copyright 2022 HuggingFace Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import random
+import unittest
+
+import numpy as np
+import torch
+
+import PIL
+from diffusers import DDIMScheduler, LDMSuperResolutionPipeline, UNet2DModel, VQModel
+from diffusers.utils import floats_tensor, load_image, slow, torch_device
+from diffusers.utils.testing_utils import require_torch
+
+from ...test_pipelines_common import PipelineTesterMixin
+
+
+torch.backends.cuda.matmul.allow_tf32 = False
+
+
+class LDMSuperResolutionPipelineFastTests(PipelineTesterMixin, unittest.TestCase):
+    @property
+    def dummy_image(self):
+        batch_size = 1
+        num_channels = 3
+        sizes = (32, 32)
+
+        image = floats_tensor((batch_size, num_channels) + sizes, rng=random.Random(0)).to(torch_device)
+        return image
+
+    @property
+    def dummy_uncond_unet(self):
+        torch.manual_seed(0)
+        model = UNet2DModel(
+            block_out_channels=(32, 64),
+            layers_per_block=2,
+            sample_size=32,
+            in_channels=6,
+            out_channels=3,
+            down_block_types=("DownBlock2D", "AttnDownBlock2D"),
+            up_block_types=("AttnUpBlock2D", "UpBlock2D"),
+        )
+        return model
+
+    @property
+    def dummy_vq_model(self):
+        torch.manual_seed(0)
+        model = VQModel(
+            block_out_channels=[32, 64],
+            in_channels=3,
+            out_channels=3,
+            down_block_types=["DownEncoderBlock2D", "DownEncoderBlock2D"],
+            up_block_types=["UpDecoderBlock2D", "UpDecoderBlock2D"],
+            latent_channels=3,
+        )
+        return model
+
+    def test_inference_superresolution(self):
+        unet = self.dummy_uncond_unet
+        scheduler = DDIMScheduler()
+        vqvae = self.dummy_vq_model
+
+        ldm = LDMSuperResolutionPipeline(unet=unet, vqvae=vqvae, scheduler=scheduler)
+        ldm.to(torch_device)
+        ldm.set_progress_bar_config(disable=None)
+
+        init_image = self.dummy_image.to(torch_device)
+
+        # Warmup pass when using mps (see #372)
+        if torch_device == "mps":
+            generator = torch.manual_seed(0)
+            _ = ldm(init_image, generator=generator, num_inference_steps=1, output_type="numpy").images
+
+        generator = torch.manual_seed(0)
+        image = ldm(init_image, generator=generator, num_inference_steps=2, output_type="numpy").images
+
+        image_slice = image[0, -3:, -3:, -1]
+
+        assert image.shape == (1, 64, 64, 3)
+        expected_slice = np.array([0.8634, 0.8186, 0.6416, 0.6846, 0.4427, 0.5676, 0.4679, 0.6247, 0.5176])
+        tolerance = 1e-2 if torch_device != "mps" else 3e-2
+        assert np.abs(image_slice.flatten() - expected_slice).max() < tolerance
+
+
+@slow
+@require_torch
+class LDMSuperResolutionPipelineIntegrationTests(unittest.TestCase):
+    def test_inference_superresolution(self):
+        init_image = load_image(
+            "https://huggingface.co/datasets/hf-internal-testing/diffusers-images/resolve/main"
+            "/vq_diffusion/teddy_bear_pool.png"
+        )
+        init_image = init_image.resize((64, 64), resample=PIL.Image.LANCZOS)
+
+        ldm = LDMSuperResolutionPipeline.from_pretrained("duongna/ldm-super-resolution", device_map="auto")
+        ldm.to(torch_device)
+        ldm.set_progress_bar_config(disable=None)
+
+        generator = torch.Generator(device=torch_device).manual_seed(0)
+        image = ldm(init_image, generator=generator, num_inference_steps=20, output_type="numpy").images
+
+        image_slice = image[0, -3:, -3:, -1]
+
+        assert image.shape == (1, 256, 256, 3)
+        expected_slice = np.array([0.7418, 0.7472, 0.7424, 0.7422, 0.7463, 0.726, 0.7382, 0.7248, 0.6828])
+        assert np.abs(image_slice.flatten() - expected_slice).max() < 1e-2