Image Generation with Tiny-SD and OpenVINO™
===========================================

In recent times, the AI community has witnessed a remarkable surge in
the development of larger and more performant language models, such as
Falcon 40B, LLaMa-2 70B, Falcon 40B, MPT 30B, and in the imaging domain
with models like SD2.1 and SDXL. These advancements have undoubtedly
pushed the boundaries of what AI can achieve, enabling highly versatile
and state-of-the-art image generation and language understanding
capabilities. However, the breakthrough of large models comes with
substantial computational demands. To resolve this issue, recent
research on efficient Stable Diffusion has prioritized reducing the
number of sampling steps and utilizing network quantization.

Moving towards the goal of making image generative models faster,
smaller, and cheaper, Tiny-SD was proposed by Segmind. Tiny SD is a
compressed Stable Diffusion (SD) model that has been trained on
Knowledge-Distillation (KD) techniques and the work has been largely
based on this `paper <https://arxiv.org/pdf/2305.15798.pdf>`__. The
authors describe a Block-removal Knowledge-Distillation method where
some of the UNet layers are removed and the student model weights are
trained. Using the KD methods described in the paper, they were able to
train two compressed models using the 🧨 diffusers library; Small and
Tiny, that have 35% and 55% fewer parameters, respectively than the base
model while achieving comparable image fidelity as the base model. More
details about model can be found in `model
card <https://huggingface.co/segmind/tiny-sd>`__, `blog
post <https://huggingface.co/blog/sd_distillation>`__ and training
`repository <https://github.com/segmind/distill-sd>`__.

This notebook demonstrates how to convert and run the Tiny-SD model
using OpenVINO.

The notebook contains the following steps:

1. Convert PyTorch models to OpenVINO Intermediate Representation using
   OpenVINO Converter Tool (OVC).
2. Prepare Inference Pipeline.
3. Run Inference pipeline with OpenVINO.
4. Run Interactive demo for Tiny-SD model

**Table of contents:**


-  `Prerequisites <#prerequisites>`__
-  `Create PyTorch Models pipeline <#create-pytorch-models-pipeline>`__
-  `Convert models to OpenVINO Intermediate representation
   format <#convert-models-to-openvino-intermediate-representation-format>`__

   -  `Text Encoder <#text-encoder>`__
   -  `U-net <#u-net>`__
   -  `VAE <#vae>`__

-  `Prepare Inference Pipeline <#prepare-inference-pipeline>`__
-  `Configure Inference Pipeline <#configure-inference-pipeline>`__

   -  `Calibrate UNet for GPU
      inference <#calibrate-unet-for-gpu-inference>`__
   -  `Text-to-Image generation <#text-to-image-generation>`__
   -  `Image-to-Image generation <#image-to-image-generation>`__
   -  `Interactive Demo <#interactive-demo>`__

Installation Instructions
~~~~~~~~~~~~~~~~~~~~~~~~~

This is a self-contained example that relies solely on its own code.

We recommend running the notebook in a virtual environment. You only
need a Jupyter server to start. For details, please refer to
`Installation
Guide <https://github.com/openvinotoolkit/openvino_notebooks/blob/latest/README.md#-installation-guide>`__.

Prerequisites
-------------



Install required dependencies

.. code:: ipython3

    %pip install -q --extra-index-url https://download.pytorch.org/whl/cpu "torch>=2.1" torchvision "openvino>=2023.3.0" "opencv-python" "pillow" "diffusers>=0.18.0" "transformers>=4.30.2" "gradio>=4.19"

Create PyTorch Models pipeline
------------------------------



``StableDiffusionPipeline`` is an end-to-end inference pipeline that you
can use to generate images from text with just a few lines of code.

First, load the pre-trained weights of all components of the model.

.. code:: ipython3

    import gc
    from diffusers import StableDiffusionPipeline
    
    model_id = "segmind/tiny-sd"
    
    pipe = StableDiffusionPipeline.from_pretrained(model_id).to("cpu")
    text_encoder = pipe.text_encoder
    text_encoder.eval()
    unet = pipe.unet
    unet.eval()
    vae = pipe.vae
    vae.eval()
    
    del pipe
    gc.collect()

Convert models to OpenVINO Intermediate representation format
-------------------------------------------------------------



OpenVINO supports PyTorch through conversion to OpenVINO Intermediate
Representation (IR) format. To take the advantage of OpenVINO
optimization tools and features, the model should be converted using the
OpenVINO Converter tool (OVC). The ``openvino.convert_model`` function
provides Python API for OVC usage. The function returns the instance of
the OpenVINO Model class, which is ready for use in the Python
interface. However, it can also be saved on disk using
``openvino.save_model`` for future execution.

Starting from OpenVINO 2023.0.0 release OpenVINO supports direct
conversion PyTorch models. To perform conversion, we should provide
PyTorch model instance and example input into
``openvino.convert_model``. By default, model converted with dynamic
shapes preserving, in order to fixate input shape to generate image of
specific resolution, ``input`` parameter additionally can be specified.

The model consists of three important parts:

-  Text Encoder for creation condition to generate image from text
   prompt.
-  U-net for step by step denoising latent image representation.
-  Autoencoder (VAE) for encoding input image to latent space (if
   required) and decoding latent space to image back after generation.

Let us convert each part.

Text Encoder
~~~~~~~~~~~~



The text-encoder is responsible for transforming the input prompt, for
example, “a photo of an astronaut riding a horse” into an embedding
space that can be understood by the U-Net. It is usually a simple
transformer-based encoder that maps a sequence of input tokens to a
sequence of latent text embeddings.

Input of the text encoder is the tensor ``input_ids`` which contains
indexes of tokens from text processed by tokenizer and padded to maximum
length accepted by model. Model outputs are two tensors:
``last_hidden_state`` - hidden state from the last MultiHeadAttention
layer in the model and ``pooler_out`` - Pooled output for whole model
hidden states.

.. code:: ipython3

    from pathlib import Path
    import torch
    import openvino as ov
    
    TEXT_ENCODER_OV_PATH = Path("text_encoder.xml")
    
    
    def convert_encoder(text_encoder: torch.nn.Module, ir_path: Path):
        """
        Convert Text Encoder mode.
        Function accepts text encoder model, and prepares example inputs for conversion,
        Parameters:
            text_encoder (torch.nn.Module): text_encoder model from Stable Diffusion pipeline
            ir_path (Path): File for storing model
        Returns:
            None
        """
        input_ids = torch.ones((1, 77), dtype=torch.long)
        # switch model to inference mode
        text_encoder.eval()
    
        # disable gradients calculation for reducing memory consumption
        with torch.no_grad():
            # Export model to IR format
            ov_model = ov.convert_model(
                text_encoder,
                example_input=input_ids,
                input=[
                    (1, 77),
                ],
            )
        ov.save_model(ov_model, ir_path)
        del ov_model
        print(f"Text Encoder successfully converted to IR and saved to {ir_path}")
    
    
    if not TEXT_ENCODER_OV_PATH.exists():
        convert_encoder(text_encoder, TEXT_ENCODER_OV_PATH)
    else:
        print(f"Text encoder will be loaded from {TEXT_ENCODER_OV_PATH}")
    
    del text_encoder
    gc.collect();

U-net
~~~~~



U-net model has three inputs:

-  ``sample`` - latent image sample from previous step. Generation
   process has not been started yet, so you will use random noise.
-  ``timestep`` - current scheduler step.
-  ``encoder_hidden_state`` - hidden state of text encoder.

Model predicts the ``sample`` state for the next step.

.. code:: ipython3

    import numpy as np
    from openvino import PartialShape, Type
    
    UNET_OV_PATH = Path("unet.xml")
    
    dtype_mapping = {torch.float32: Type.f32, torch.float64: Type.f64}
    
    
    def convert_unet(unet: torch.nn.Module, ir_path: Path):
        """
        Convert U-net model to IR format.
        Function accepts unet model, prepares example inputs for conversion,
        Parameters:
            unet (StableDiffusionPipeline): unet from Stable Diffusion pipeline
            ir_path (Path): File for storing model
        Returns:
            None
        """
        # prepare inputs
        encoder_hidden_state = torch.ones((2, 77, 768))
        latents_shape = (2, 4, 512 // 8, 512 // 8)
        latents = torch.randn(latents_shape)
        t = torch.from_numpy(np.array(1, dtype=float))
        dummy_inputs = (latents, t, encoder_hidden_state)
        input_info = []
        for input_tensor in dummy_inputs:
            shape = PartialShape(tuple(input_tensor.shape))
            element_type = dtype_mapping[input_tensor.dtype]
            input_info.append((shape, element_type))
    
        unet.eval()
        with torch.no_grad():
            ov_model = ov.convert_model(unet, example_input=dummy_inputs, input=input_info)
        ov.save_model(ov_model, ir_path)
        del ov_model
        print(f"Unet successfully converted to IR and saved to {ir_path}")
    
    
    if not UNET_OV_PATH.exists():
        convert_unet(unet, UNET_OV_PATH)
        gc.collect()
    else:
        print(f"Unet will be loaded from {UNET_OV_PATH}")
    del unet
    gc.collect();

VAE
~~~



The VAE model has two parts, an encoder and a decoder. The encoder is
used to convert the image into a low dimensional latent representation,
which will serve as the input to the U-Net model. The decoder,
conversely, transforms the latent representation back into an image.

During latent diffusion training, the encoder is used to get the latent
representations (latents) of the images for the forward diffusion
process, which applies more and more noise at each step. During
inference, the denoised latents generated by the reverse diffusion
process are converted back into images using the VAE decoder. When you
run inference for text-to-image, there is no initial image as a starting
point. You can skip this step and directly generate initial random
noise.

As the encoder and the decoder are used independently in different parts
of the pipeline, it will be better to convert them to separate models.

.. code:: ipython3

    VAE_ENCODER_OV_PATH = Path("vae_encodr.xml")
    
    
    def convert_vae_encoder(vae: torch.nn.Module, ir_path: Path):
        """
        Convert VAE model for encoding to IR format.
        Function accepts vae model, creates wrapper class for export only necessary for inference part,
        prepares example inputs for conversion,
        Parameters:
            vae (torch.nn.Module): VAE model from StableDiffusio pipeline
            ir_path (Path): File for storing model
        Returns:
            None
        """
    
        class VAEEncoderWrapper(torch.nn.Module):
            def __init__(self, vae):
                super().__init__()
                self.vae = vae
    
            def forward(self, image):
                return self.vae.encode(x=image)["latent_dist"].sample()
    
        vae_encoder = VAEEncoderWrapper(vae)
        vae_encoder.eval()
        image = torch.zeros((1, 3, 512, 512))
        with torch.no_grad():
            ov_model = ov.convert_model(vae_encoder, example_input=image, input=[((1, 3, 512, 512),)])
        ov.save_model(ov_model, ir_path)
        del ov_model
        print(f"VAE encoder successfully converted to IR and saved to {ir_path}")
    
    
    if not VAE_ENCODER_OV_PATH.exists():
        convert_vae_encoder(vae, VAE_ENCODER_OV_PATH)
    else:
        print(f"VAE encoder will be loaded from {VAE_ENCODER_OV_PATH}")
    
    VAE_DECODER_OV_PATH = Path("vae_decoder.xml")
    
    
    def convert_vae_decoder(vae: torch.nn.Module, ir_path: Path):
        """
        Convert VAE model for decoding to IR format.
        Function accepts vae model, creates wrapper class for export only necessary for inference part,
        prepares example inputs for conversion,
        Parameters:
            vae (torch.nn.Module): VAE model frm StableDiffusion pipeline
            ir_path (Path): File for storing model
        Returns:
            None
        """
    
        class VAEDecoderWrapper(torch.nn.Module):
            def __init__(self, vae):
                super().__init__()
                self.vae = vae
    
            def forward(self, latents):
                return self.vae.decode(latents)
    
        vae_decoder = VAEDecoderWrapper(vae)
        latents = torch.zeros((1, 4, 64, 64))
    
        vae_decoder.eval()
        with torch.no_grad():
            ov_model = ov.convert_model(vae_decoder, example_input=latents, input=[((1, 4, 64, 64),)])
        ov.save_model(ov_model, ir_path)
        del ov_model
        print(f"VAE decoder successfully converted to IR and saved to {ir_path}")
    
    
    if not VAE_DECODER_OV_PATH.exists():
        convert_vae_decoder(vae, VAE_DECODER_OV_PATH)
    else:
        print(f"VAE decoder will be loaded from {VAE_DECODER_OV_PATH}")
    
    del vae
    gc.collect();

Prepare Inference Pipeline
--------------------------



Putting it all together, let us now take a closer look at how the model
works in inference by illustrating the logical flow.

.. figure:: https://user-images.githubusercontent.com/29454499/260981188-c112dd0a-5752-4515-adca-8b09bea5d14a.png
   :alt: sd-pipeline

   sd-pipeline

As you can see from the diagram, the only difference between
Text-to-Image and text-guided Image-to-Image generation in approach is
how initial latent state is generated. In case of Image-to-Image
generation, you additionally have an image encoded by VAE encoder mixed
with the noise produced by using latent seed, while in Text-to-Image you
use only noise as initial latent state. The stable diffusion model takes
both a latent image representation of size :math:`64 \times 64` and a
text prompt is transformed to text embeddings of size
:math:`77 \times 768` via CLIP’s text encoder as an input.

Next, the U-Net iteratively *denoises* the random latent image
representations while being conditioned on the text embeddings. The
output of the U-Net, being the noise residual, is used to compute a
denoised latent image representation via a scheduler algorithm. Many
different scheduler algorithms can be used for this computation, each
having its pros and cons. For Stable Diffusion, it is recommended to use
one of:

-  `PNDM
   scheduler <https://github.com/huggingface/diffusers/blob/main/src/diffusers/schedulers/scheduling_pndm.py>`__
-  `DDIM
   scheduler <https://github.com/huggingface/diffusers/blob/main/src/diffusers/schedulers/scheduling_ddim.py>`__
-  `K-LMS
   scheduler <https://github.com/huggingface/diffusers/blob/main/src/diffusers/schedulers/scheduling_lms_discrete.py>`__\ (you
   will use it in your pipeline)

Theory on how the scheduler algorithm function works is out of scope for
this notebook. Nonetheless, in short, you should remember that you
compute the predicted denoised image representation from the previous
noise representation and the predicted noise residual. For more
information, refer to the recommended `Elucidating the Design Space of
Diffusion-Based Generative Models <https://arxiv.org/abs/2206.00364>`__

The *denoising* process is repeated given number of times (by default
50) to step-by-step retrieve better latent image representations. When
complete, the latent image representation is decoded by the decoder part
of the variational auto encoder.

.. code:: ipython3

    import inspect
    from typing import List, Optional, Union, Dict
    
    import PIL
    import cv2
    
    from transformers import CLIPTokenizer
    from diffusers.pipelines.pipeline_utils import DiffusionPipeline
    from diffusers.schedulers import DDIMScheduler, LMSDiscreteScheduler, PNDMScheduler
    
    
    def scale_fit_to_window(dst_width: int, dst_height: int, image_width: int, image_height: int):
        """
        Preprocessing helper function for calculating image size for resize with peserving original aspect ratio
        and fitting image to specific window size
    
        Parameters:
          dst_width (int): destination window width
          dst_height (int): destination window height
          image_width (int): source image width
          image_height (int): source image height
        Returns:
          result_width (int): calculated width for resize
          result_height (int): calculated height for resize
        """
        im_scale = min(dst_height / image_height, dst_width / image_width)
        return int(im_scale * image_width), int(im_scale * image_height)
    
    
    def preprocess(image: PIL.Image.Image):
        """
        Image preprocessing function. Takes image in PIL.Image format, resizes it to keep aspect ration and fits to model input window 512x512,
        then converts it to np.ndarray and adds padding with zeros on right or bottom side of image (depends from aspect ratio), after that
        converts data to float32 data type and change range of values from [0, 255] to [-1, 1], finally, converts data layout from planar NHWC to NCHW.
        The function returns preprocessed input tensor and padding size, which can be used in postprocessing.
    
        Parameters:
          image (PIL.Image.Image): input image
        Returns:
           image (np.ndarray): preprocessed image tensor
           meta (Dict): dictionary with preprocessing metadata info
        """
        src_width, src_height = image.size
        dst_width, dst_height = scale_fit_to_window(512, 512, src_width, src_height)
        image = np.array(image.resize((dst_width, dst_height), resample=PIL.Image.Resampling.LANCZOS))[None, :]
        pad_width = 512 - dst_width
        pad_height = 512 - dst_height
        pad = ((0, 0), (0, pad_height), (0, pad_width), (0, 0))
        image = np.pad(image, pad, mode="constant")
        image = image.astype(np.float32) / 255.0
        image = 2.0 * image - 1.0
        image = image.transpose(0, 3, 1, 2)
        return image, {"padding": pad, "src_width": src_width, "src_height": src_height}
    
    
    class OVStableDiffusionPipeline(DiffusionPipeline):
        def __init__(
            self,
            vae_decoder: ov.Model,
            text_encoder: ov.Model,
            tokenizer: CLIPTokenizer,
            unet: ov.Model,
            scheduler: Union[DDIMScheduler, PNDMScheduler, LMSDiscreteScheduler],
            vae_encoder: ov.Model = None,
        ):
            """
            Pipeline for text-to-image generation using Stable Diffusion.
            Parameters:
                vae (Model):
                    Variational Auto-Encoder (VAE) Model to decode images to and from latent representations.
                text_encoder (Model):
                    Frozen text-encoder. Stable Diffusion uses the text portion of
                    [CLIP](https://huggingface.co/docs/transformers/model_doc/clip#transformers.CLIPTextModel), specifically
                    the clip-vit-large-patch14(https://huggingface.co/openai/clip-vit-large-patch14) variant.
                tokenizer (CLIPTokenizer):
                    Tokenizer of class CLIPTokenizer(https://huggingface.co/docs/transformers/v4.21.0/en/model_doc/clip#transformers.CLIPTokenizer).
                unet (Model): Conditional U-Net architecture to denoise the encoded image latents.
                scheduler (SchedulerMixin):
                    A scheduler to be used in combination with unet to denoise the encoded image latents. Can be one of
                    DDIMScheduler, LMSDiscreteScheduler, or PNDMScheduler.
            """
            super().__init__()
            self.scheduler = scheduler
            self.vae_decoder = vae_decoder
            self.vae_encoder = vae_encoder
            self.text_encoder = text_encoder
            self.unet = unet
            self._text_encoder_output = text_encoder.output(0)
            self._unet_output = unet.output(0)
            self._vae_d_output = vae_decoder.output(0)
            self._vae_e_output = vae_encoder.output(0) if vae_encoder is not None else None
            self.height = 512
            self.width = 512
            self.tokenizer = tokenizer
    
        def __call__(
            self,
            prompt: Union[str, List[str]],
            image: PIL.Image.Image = None,
            num_inference_steps: Optional[int] = 50,
            negative_prompt: Union[str, List[str]] = None,
            guidance_scale: Optional[float] = 7.5,
            eta: Optional[float] = 0.0,
            output_type: Optional[str] = "pil",
            seed: Optional[int] = None,
            strength: float = 1.0,
            gif: Optional[bool] = False,
            **kwargs,
        ):
            """
            Function invoked when calling the pipeline for generation.
            Parameters:
                prompt (str or List[str]):
                    The prompt or prompts to guide the image generation.
                image (PIL.Image.Image, *optional*, None):
                     Intinal image for generation.
                num_inference_steps (int, *optional*, defaults to 50):
                    The number of denoising steps. More denoising steps usually lead to a higher quality image at the
                    expense of slower inference.
                negative_prompt (str or List[str]):
                    The negative prompt or prompts to guide the image generation.
                guidance_scale (float, *optional*, defaults to 7.5):
                    Guidance scale as defined in Classifier-Free Diffusion Guidance(https://arxiv.org/abs/2207.12598).
                    guidance_scale is defined as `w` of equation 2.
                    Higher guidance scale encourages to generate images that are closely linked to the text prompt,
                    usually at the expense of lower image quality.
                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
                    [DDIMScheduler], will be ignored for others.
                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.
                seed (int, *optional*, None):
                    Seed for random generator state initialization.
                gif (bool, *optional*, False):
                    Flag for storing all steps results or not.
            Returns:
                Dictionary with keys:
                    sample - the last generated image PIL.Image.Image or np.array
                    iterations - *optional* (if gif=True) images for all diffusion steps, List of PIL.Image.Image or np.array.
            """
            if seed is not None:
                np.random.seed(seed)
    
            img_buffer = []
            do_classifier_free_guidance = guidance_scale > 1.0
            # get prompt text embeddings
            text_embeddings = self._encode_prompt(
                prompt,
                do_classifier_free_guidance=do_classifier_free_guidance,
                negative_prompt=negative_prompt,
            )
    
            # set timesteps
            accepts_offset = "offset" in set(inspect.signature(self.scheduler.set_timesteps).parameters.keys())
            extra_set_kwargs = {}
            if accepts_offset:
                extra_set_kwargs["offset"] = 1
    
            self.scheduler.set_timesteps(num_inference_steps, **extra_set_kwargs)
            timesteps, num_inference_steps = self.get_timesteps(num_inference_steps, strength)
            latent_timestep = timesteps[:1]
    
            # get the initial random noise unless the user supplied it
            latents, meta = self.prepare_latents(image, latent_timestep)
    
            # 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_step_kwargs = {}
            if accepts_eta:
                extra_step_kwargs["eta"] = eta
    
            for i, t in enumerate(self.progress_bar(timesteps)):
                # expand the latents if you are doing classifier free guidance
                latent_model_input = np.concatenate([latents] * 2) if do_classifier_free_guidance else latents
                latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
    
                # predict the noise residual
                noise_pred = self.unet([latent_model_input, t, text_embeddings])[self._unet_output]
                # perform guidance
                if do_classifier_free_guidance:
                    noise_pred_uncond, noise_pred_text = noise_pred[0], noise_pred[1]
                    noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
    
                # compute the previous noisy sample x_t -> x_t-1
                latents = self.scheduler.step(
                    torch.from_numpy(noise_pred),
                    t,
                    torch.from_numpy(latents),
                    **extra_step_kwargs,
                )["prev_sample"].numpy()
                if gif:
                    image = self.vae_decoder(latents * (1 / 0.18215))[self._vae_d_output]
                    image = self.postprocess_image(image, meta, output_type)
                    img_buffer.extend(image)
    
            # scale and decode the image latents with vae
            image = self.vae_decoder(latents * (1 / 0.18215))[self._vae_d_output]
    
            image = self.postprocess_image(image, meta, output_type)
            return {"sample": image, "iterations": img_buffer}
    
        def _encode_prompt(
            self,
            prompt: Union[str, List[str]],
            num_images_per_prompt: int = 1,
            do_classifier_free_guidance: bool = True,
            negative_prompt: Union[str, List[str]] = None,
        ):
            """
            Encodes the prompt into text encoder hidden states.
    
            Parameters:
                prompt (str or list(str)): prompt to be encoded
                num_images_per_prompt (int): number of images that should be generated per prompt
                do_classifier_free_guidance (bool): whether to use classifier free guidance or not
                negative_prompt (str or list(str)): negative prompt to be encoded
            Returns:
                text_embeddings (np.ndarray): text encoder hidden states
            """
            batch_size = len(prompt) if isinstance(prompt, list) else 1
    
            # tokenize input prompts
            text_inputs = self.tokenizer(
                prompt,
                padding="max_length",
                max_length=self.tokenizer.model_max_length,
                truncation=True,
                return_tensors="np",
            )
            text_input_ids = text_inputs.input_ids
    
            text_embeddings = self.text_encoder(text_input_ids)[self._text_encoder_output]
    
            # duplicate text embeddings for each generation per prompt
            if num_images_per_prompt != 1:
                bs_embed, seq_len, _ = text_embeddings.shape
                text_embeddings = np.tile(text_embeddings, (1, num_images_per_prompt, 1))
                text_embeddings = np.reshape(text_embeddings, (bs_embed * num_images_per_prompt, seq_len, -1))
    
            # get unconditional embeddings for classifier free guidance
            if do_classifier_free_guidance:
                uncond_tokens: List[str]
                max_length = text_input_ids.shape[-1]
                if negative_prompt is None:
                    uncond_tokens = [""] * batch_size
                elif isinstance(negative_prompt, str):
                    uncond_tokens = [negative_prompt]
                else:
                    uncond_tokens = negative_prompt
                uncond_input = self.tokenizer(
                    uncond_tokens,
                    padding="max_length",
                    max_length=max_length,
                    truncation=True,
                    return_tensors="np",
                )
    
                uncond_embeddings = self.text_encoder(uncond_input.input_ids)[self._text_encoder_output]
    
                # duplicate unconditional embeddings for each generation per prompt, using mps friendly method
                seq_len = uncond_embeddings.shape[1]
                uncond_embeddings = np.tile(uncond_embeddings, (1, num_images_per_prompt, 1))
                uncond_embeddings = np.reshape(uncond_embeddings, (batch_size * num_images_per_prompt, seq_len, -1))
    
                # For classifier free guidance, we need to do two forward passes.
                # Here we concatenate the unconditional and text embeddings into a single batch
                # to avoid doing two forward passes
                text_embeddings = np.concatenate([uncond_embeddings, text_embeddings])
    
            return text_embeddings
    
        def prepare_latents(self, image: PIL.Image.Image = None, latent_timestep: torch.Tensor = None):
            """
            Function for getting initial latents for starting generation
    
            Parameters:
                image (PIL.Image.Image, *optional*, None):
                    Input image for generation, if not provided randon noise will be used as starting point
                latent_timestep (torch.Tensor, *optional*, None):
                    Predicted by scheduler initial step for image generation, required for latent image mixing with nosie
            Returns:
                latents (np.ndarray):
                    Image encoded in latent space
            """
            latents_shape = (1, 4, self.height // 8, self.width // 8)
            noise = np.random.randn(*latents_shape).astype(np.float32)
            if image is None:
                # if you use LMSDiscreteScheduler, let's make sure latents are multiplied by sigmas
                if isinstance(self.scheduler, LMSDiscreteScheduler):
                    noise = noise * self.scheduler.sigmas[0].numpy()
                    return noise, {}
            input_image, meta = preprocess(image)
            latents = self.vae_encoder(input_image)[self._vae_e_output] * 0.18215
            latents = self.scheduler.add_noise(torch.from_numpy(latents), torch.from_numpy(noise), latent_timestep).numpy()
            return latents, meta
    
        def postprocess_image(self, image: np.ndarray, meta: Dict, output_type: str = "pil"):
            """
            Postprocessing for decoded image. Takes generated image decoded by VAE decoder, unpad it to initila image size (if required),
            normalize and convert to [0, 255] pixels range. Optionally, convertes it from np.ndarray to PIL.Image format
    
            Parameters:
                image (np.ndarray):
                    Generated image
                meta (Dict):
                    Metadata obtained on latents preparing step, can be empty
                output_type (str, *optional*, pil):
                    Output format for result, can be pil or numpy
            Returns:
                image (List of np.ndarray or PIL.Image.Image):
                    Postprocessed images
            """
            if "padding" in meta:
                pad = meta["padding"]
                (_, end_h), (_, end_w) = pad[1:3]
                h, w = image.shape[2:]
                unpad_h = h - end_h
                unpad_w = w - end_w
                image = image[:, :, :unpad_h, :unpad_w]
            image = np.clip(image / 2 + 0.5, 0, 1)
            image = np.transpose(image, (0, 2, 3, 1))
            # 9. Convert to PIL
            if output_type == "pil":
                image = self.numpy_to_pil(image)
                if "src_height" in meta:
                    orig_height, orig_width = meta["src_height"], meta["src_width"]
                    image = [img.resize((orig_width, orig_height), PIL.Image.Resampling.LANCZOS) for img in image]
            else:
                if "src_height" in meta:
                    orig_height, orig_width = meta["src_height"], meta["src_width"]
                    image = [cv2.resize(img, (orig_width, orig_width)) for img in image]
            return image
    
        def get_timesteps(self, num_inference_steps: int, strength: float):
            """
            Helper function for getting scheduler timesteps for generation
            In case of image-to-image generation, it updates number of steps according to strength
    
            Parameters:
               num_inference_steps (int):
                  number of inference steps for generation
               strength (float):
                   value between 0.0 and 1.0, that controls the amount of noise that is added to the input image.
                   Values that approach 1.0 enable lots of variations but will also produce images that are not semantically consistent with the input.
            """
            # get the original timestep using init_timestep
            init_timestep = min(int(num_inference_steps * strength), num_inference_steps)
    
            t_start = max(num_inference_steps - init_timestep, 0)
            timesteps = self.scheduler.timesteps[t_start:]
    
            return timesteps, num_inference_steps - t_start

Configure Inference Pipeline
----------------------------



First, you should create instances of OpenVINO Model.

.. code:: ipython3

    core = ov.Core()

Select device from dropdown list for running inference using OpenVINO.

.. code:: ipython3

    import ipywidgets as widgets
    
    device = widgets.Dropdown(
        options=core.available_devices + ["AUTO"],
        value="AUTO",
        description="Device:",
        disabled=False,
    )
    
    device




.. parsed-literal::

    Dropdown(description='Device:', index=2, options=('CPU', 'GPU', 'AUTO'), value='AUTO')



.. code:: ipython3

    text_enc = core.compile_model(TEXT_ENCODER_OV_PATH, device.value)

Calibrate UNet for GPU inference
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



On a GPU device a model is executed in FP16 precision. For Tiny-SD UNet
model there known to be accuracy issues caused by this. Therefore, a
special calibration procedure is used to selectively mark some
operations to be executed in full precision.

.. code:: ipython3

    import pickle
    import requests
    import os
    
    # Fetch `model_upcast_utils` which helps to restore accuracy when inferred on GPU
    r = requests.get("https://raw.githubusercontent.com/openvinotoolkit/openvino_notebooks/latest/utils/model_upcast_utils.py")
    with open("model_upcast_utils.py", "w") as f:
        f.write(r.text)
    
    # Fetch an example input for UNet model needed for upcasting calibration process
    r = requests.get("https://storage.openvinotoolkit.org/repositories/openvino_notebooks/data/data/pkl/unet_calibration_example_input.pkl")
    with open("unet_calibration_example_input.pkl", "wb") as f:
        f.write(r.content)
    
    from model_upcast_utils import (
        is_model_partially_upcasted,
        partially_upcast_nodes_to_fp32,
    )
    
    unet_model = core.read_model(UNET_OV_PATH)
    if "GPU" in core.available_devices and not is_model_partially_upcasted(unet_model):
        with open("unet_calibration_example_input.pkl", "rb") as f:
            example_input = pickle.load(f)
        unet_model = partially_upcast_nodes_to_fp32(unet_model, example_input, upcast_ratio=0.7, operation_types=["Convolution"])
    
        ov.save_model(unet_model, UNET_OV_PATH.with_suffix("._tmp.xml"))
        del unet_model
        os.remove(UNET_OV_PATH)
        os.remove(str(UNET_OV_PATH).replace(".xml", ".bin"))
        UNET_OV_PATH.with_suffix("._tmp.xml").rename(UNET_OV_PATH)
        UNET_OV_PATH.with_suffix("._tmp.bin").rename(UNET_OV_PATH.with_suffix(".bin"))

.. code:: ipython3

    unet_model = core.compile_model(UNET_OV_PATH, device.value)

.. code:: ipython3

    ov_config = {"INFERENCE_PRECISION_HINT": "f32"} if device.value != "CPU" else {}
    
    vae_decoder = core.compile_model(VAE_DECODER_OV_PATH, device.value, ov_config)
    vae_encoder = core.compile_model(VAE_ENCODER_OV_PATH, device.value, ov_config)

Model tokenizer and scheduler are also important parts of the pipeline.
Let us define them and put all components together

.. code:: ipython3

    from transformers import CLIPTokenizer
    from diffusers.schedulers import LMSDiscreteScheduler
    
    lms = LMSDiscreteScheduler(beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear")
    tokenizer = CLIPTokenizer.from_pretrained("openai/clip-vit-large-patch14")
    
    ov_pipe = OVStableDiffusionPipeline(
        tokenizer=tokenizer,
        text_encoder=text_enc,
        unet=unet_model,
        vae_encoder=vae_encoder,
        vae_decoder=vae_decoder,
        scheduler=lms,
    )

Text-to-Image generation
~~~~~~~~~~~~~~~~~~~~~~~~



Now, let’s see model in action

.. code:: ipython3

    text_prompt = "RAW studio photo of An intricate forest minitown landscape trapped in a bottle, atmospheric oliva lighting, on the table, intricate details, dark shot, soothing tones, muted colors "
    seed = 431
    num_steps = 20

.. code:: ipython3

    print("Pipeline settings")
    print(f"Input text: {text_prompt}")
    print(f"Seed: {seed}")
    print(f"Number of steps: {num_steps}")


.. parsed-literal::

    Pipeline settings
    Input text: RAW studio photo of An intricate forest minitown landscape trapped in a bottle, atmospheric oliva lighting, on the table, intricate details, dark shot, soothing tones, muted colors 
    Seed: 431
    Number of steps: 20


.. code:: ipython3

    result = ov_pipe(text_prompt, num_inference_steps=num_steps, seed=seed)



.. parsed-literal::

      0%|          | 0/20 [00:00<?, ?it/s]


Finally, let us save generation results. The pipeline returns several
results: ``sample`` contains final generated image, ``iterations``
contains list of intermediate results for each step.

.. code:: ipython3

    final_image = result["sample"][0]
    final_image.save("result.png")

Now is show time!

.. code:: ipython3

    text = "\n\t".join(text_prompt.split("."))
    print("Input text:")
    print("\t" + text)
    display(final_image)


.. parsed-literal::

    Input text:
    	RAW studio photo of An intricate forest minitown landscape trapped in a bottle, atmospheric oliva lighting, on the table, intricate details, dark shot, soothing tones, muted colors 



.. image:: tiny-sd-image-generation-with-output_files/tiny-sd-image-generation-with-output_35_1.png


Nice. As you can see, the picture has quite a high definition 🔥.

Image-to-Image generation
~~~~~~~~~~~~~~~~~~~~~~~~~



One of the most amazing features of Stable Diffusion model is the
ability to condition image generation from an existing image or sketch.
Given a (potentially crude) image and the right text prompt, latent
diffusion models can be used to “enhance” an image.

Image-to-Image generation, in additionally to the text prompt, requires
providing the initial image. Optionally, you can also change
``strength`` parameter, which is a value between 0.0 and 1.0, that
controls the amount of noise that is added to the input image. Values
that approach 1.0 enable lots of variations but will also produce images
that are not semantically consistent with the input. One of the
interesting use cases for Image-to-Image generation is depainting -
turning sketches or paintings into realistic photographs.

Additionally, to improve image generation quality, model supports
negative prompting. Technically, positive prompt steers the diffusion
toward the images associated with it, while negative prompt steers the
diffusion away from it.In other words, negative prompt declares
undesired concepts for generation image, e.g. if we want to have
colorful and bright image, gray scale image will be result which we want
to avoid, in this case gray scale can be treated as negative prompt. The
positive and negative prompt are in equal footing. You can always use
one with or without the other. More explanation of how it works can be
found in this
`article <https://stable-diffusion-art.com/how-negative-prompt-work/>`__.

.. code:: ipython3

    text_prompt_i2i = "professional photo portrait of woman, highly detailed, hyper realistic, cinematic effects, soft lighting"
    negative_prompt_i2i = (
        "blurry, poor quality, low res, worst quality, cropped, ugly, poorly drawn face, without eyes, mutation, unreal, animate, poorly drawn eyes"
    )
    num_steps_i2i = 40
    seed_i2i = 82698152
    strength = 0.68

.. code:: ipython3

    from diffusers.utils import load_image
    
    default_image_url = "https://user-images.githubusercontent.com/29454499/260418860-69cc443a-9ee6-493c-a393-3a97af080be7.jpg"
    # read uploaded image
    image = load_image(default_image_url)
    print("Pipeline settings")
    print(f"Input positive prompt: \n\t{text_prompt_i2i}")
    print(f"Input negative prompt: \n\t{negative_prompt_i2i}")
    print(f"Seed: {seed_i2i}")
    print(f"Number of steps: {num_steps_i2i}")
    print(f"Strength: {strength}")
    print("Input image:")
    display(image)
    processed_image = ov_pipe(
        text_prompt_i2i,
        image,
        negative_prompt=negative_prompt_i2i,
        num_inference_steps=num_steps_i2i,
        seed=seed_i2i,
        strength=strength,
    )


.. parsed-literal::

    Pipeline settings
    Input positive prompt: 
    	professional photo portrait of woman, highly detailed, hyper realistic, cinematic effects, soft lighting
    Input negative prompt: 
    	blurry, poor quality, low res, worst quality, cropped, ugly, poorly drawn face, without eyes, mutation, unreal, animate, poorly drawn eyes
    Seed: 82698152
    Number of steps: 40
    Strength: 0.68
    Input image:



.. image:: tiny-sd-image-generation-with-output_files/tiny-sd-image-generation-with-output_39_1.png



.. parsed-literal::

      0%|          | 0/27 [00:00<?, ?it/s]


.. code:: ipython3

    final_image_i2i = processed_image["sample"][0]
    final_image_i2i.save("result_i2i.png")

.. code:: ipython3

    text_i2i = "\n\t".join(text_prompt_i2i.split("."))
    print("Input text:")
    print("\t" + text_i2i)
    display(final_image_i2i)


.. parsed-literal::

    Input text:
    	professional photo portrait of woman, highly detailed, hyper realistic, cinematic effects, soft lighting



.. image:: tiny-sd-image-generation-with-output_files/tiny-sd-image-generation-with-output_41_1.png


Interactive Demo
~~~~~~~~~~~~~~~~



.. code:: ipython3

    import gradio as gr
    
    sample_img_url = "https://storage.openvinotoolkit.org/repositories/openvino_notebooks/data/data/image/tower.jpg"
    
    img = load_image(sample_img_url).save("tower.jpg")
    
    
    def generate_from_text(text, negative_text, seed, num_steps, _=gr.Progress(track_tqdm=True)):
        result = ov_pipe(text, negative_prompt=negative_text, num_inference_steps=num_steps, seed=seed)
        return result["sample"][0]
    
    
    def generate_from_image(img, text, negative_text, seed, num_steps, strength, _=gr.Progress(track_tqdm=True)):
        result = ov_pipe(
            text,
            img,
            negative_prompt=negative_text,
            num_inference_steps=num_steps,
            seed=seed,
            strength=strength,
        )
        return result["sample"][0]
    
    
    with gr.Blocks() as demo:
        with gr.Tab("Text-to-Image generation"):
            with gr.Row():
                with gr.Column():
                    text_input = gr.Textbox(lines=3, label="Positive prompt")
                    negative_text_input = gr.Textbox(lines=3, label="Negative prompt")
                    seed_input = gr.Slider(0, 10000000, value=751, label="Seed")
                    steps_input = gr.Slider(1, 50, value=20, step=1, label="Steps")
                out = gr.Image(label="Result", type="pil")
            sample_text = (
                "futuristic synthwave city, retro sunset, crystals, spires, volumetric lighting, studio Ghibli style, rendered in unreal engine with clean details"
            )
            sample_text2 = "RAW studio photo of tiny cute happy  cat in a yellow raincoat in the woods, rain, a character portrait, soft lighting, high resolution, photo realistic, extremely detailed"
            negative_sample_text = ""
            negative_sample_text2 = "bad anatomy, blurry, noisy, jpeg artifacts, low quality, geometry, mutation, disgusting. ugly"
            btn = gr.Button()
            btn.click(
                generate_from_text,
                [text_input, negative_text_input, seed_input, steps_input],
                out,
            )
            gr.Examples(
                [
                    [sample_text, negative_sample_text, 42, 20],
                    [sample_text2, negative_sample_text2, 1561, 25],
                ],
                [text_input, negative_text_input, seed_input, steps_input],
            )
        with gr.Tab("Image-to-Image generation"):
            with gr.Row():
                with gr.Column():
                    i2i_input = gr.Image(label="Image", type="pil")
                    i2i_text_input = gr.Textbox(lines=3, label="Text")
                    i2i_negative_text_input = gr.Textbox(lines=3, label="Negative prompt")
                    i2i_seed_input = gr.Slider(0, 10000000, value=42, label="Seed")
                    i2i_steps_input = gr.Slider(1, 50, value=10, step=1, label="Steps")
                    strength_input = gr.Slider(0, 1, value=0.5, label="Strength")
                i2i_out = gr.Image(label="Result", type="pil")
            i2i_btn = gr.Button()
            sample_i2i_text = "amazing watercolor painting"
            i2i_btn.click(
                generate_from_image,
                [
                    i2i_input,
                    i2i_text_input,
                    i2i_negative_text_input,
                    i2i_seed_input,
                    i2i_steps_input,
                    strength_input,
                ],
                i2i_out,
            )
            gr.Examples(
                [["tower.jpg", sample_i2i_text, "", 6400023, 40, 0.3]],
                [
                    i2i_input,
                    i2i_text_input,
                    i2i_negative_text_input,
                    i2i_seed_input,
                    i2i_steps_input,
                    strength_input,
                ],
            )
    
    try:
        demo.queue().launch(debug=False)
    except Exception:
        demo.queue().launch(share=True, debug=False)
    # if you are launching remotely, specify server_name and server_port
    # demo.launch(server_name='your server name', server_port='server port in int')
    # Read more in the docs: https://gradio.app/docs/
