Peng Lu c46cc85cba
[Feature] Support VPD Depth Estimator (#3321)
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## Motivation


Support depth estimation algorithm [VPD](https://github.com/wl-zhao/VPD)

## Modification

1. add VPD backbone
2. add VPD decoder head for depth estimation
3. add a new segmentor `DepthEstimator` based on `EncoderDecoder` for
depth estimation
4. add an integrated metric that calculate common metrics in depth
estimation
5. add SiLog loss for depth estimation 
6. add config for VPD 

## BC-breaking (Optional)

Does the modification introduce changes that break the
backward-compatibility of the downstream repos?
If so, please describe how it breaks the compatibility and how the
downstream projects should modify their code to keep compatibility with
this PR.

## Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases
here, and update the documentation.

## Checklist

1. Pre-commit or other linting tools are used to fix the potential lint
issues.
7. The modification is covered by complete unit tests. If not, please
add more unit test to ensure the correctness.
8. If the modification has potential influence on downstream projects,
this PR should be tested with downstream projects, like MMDet or
MMDet3D.
9. The documentation has been modified accordingly, like docstring or
example tutorials.
2023-09-13 15:31:22 +08:00

384 lines
14 KiB
Python

# Copyright (c) OpenMMLab. All rights reserved.
# ------------------------------------------------------------------------------
# Adapted from https://github.com/wl-zhao/VPD/blob/main/vpd/models.py
# Original licence: MIT License
# ------------------------------------------------------------------------------
import math
from typing import List, Optional, Union
import torch
import torch.nn as nn
import torch.nn.functional as F
from ldm.modules.diffusionmodules.util import timestep_embedding
from ldm.util import instantiate_from_config
from mmengine.model import BaseModule
from mmengine.runner import CheckpointLoader, load_checkpoint
from mmseg.registry import MODELS
from mmseg.utils import ConfigType, OptConfigType
def register_attention_control(model, controller):
"""Registers a control function to manage attention within a model.
Args:
model: The model to which attention is to be registered.
controller: The control function responsible for managing attention.
"""
def ca_forward(self, place_in_unet):
"""Custom forward method for attention.
Args:
self: Reference to the current object.
place_in_unet: The location in UNet (down/mid/up).
Returns:
The modified forward method.
"""
def forward(x, context=None, mask=None):
h = self.heads
is_cross = context is not None
context = context or x # if context is None, use x
q, k, v = self.to_q(x), self.to_k(context), self.to_v(context)
q, k, v = (
tensor.view(tensor.shape[0] * h, tensor.shape[1],
tensor.shape[2] // h) for tensor in [q, k, v])
sim = torch.matmul(q, k.transpose(-2, -1)) * self.scale
if mask is not None:
mask = mask.flatten(1).unsqueeze(1).repeat(h, 1, 1)
max_neg_value = -torch.finfo(sim.dtype).max
sim.masked_fill_(~mask, max_neg_value)
attn = sim.softmax(dim=-1)
attn_mean = attn.view(h, attn.shape[0] // h,
*attn.shape[1:]).mean(0)
controller(attn_mean, is_cross, place_in_unet)
out = torch.matmul(attn, v)
out = out.view(out.shape[0] // h, out.shape[1], out.shape[2] * h)
return self.to_out(out)
return forward
def register_recr(net_, count, place_in_unet):
"""Recursive function to register the custom forward method to all
CrossAttention layers.
Args:
net_: The network layer currently being processed.
count: The current count of layers processed.
place_in_unet: The location in UNet (down/mid/up).
Returns:
The updated count of layers processed.
"""
if net_.__class__.__name__ == 'CrossAttention':
net_.forward = ca_forward(net_, place_in_unet)
return count + 1
if hasattr(net_, 'children'):
return sum(
register_recr(child, 0, place_in_unet)
for child in net_.children())
return count
cross_att_count = sum(
register_recr(net[1], 0, place) for net, place in [
(child, 'down') if 'input_blocks' in name else (
child, 'up') if 'output_blocks' in name else
(child,
'mid') if 'middle_block' in name else (None, None) # Default case
for name, child in model.diffusion_model.named_children()
] if net is not None)
controller.num_att_layers = cross_att_count
class AttentionStore:
"""A class for storing attention information in the UNet model.
Attributes:
base_size (int): Base size for storing attention information.
max_size (int): Maximum size for storing attention information.
"""
def __init__(self, base_size=64, max_size=None):
"""Initialize AttentionStore with default or custom sizes."""
self.reset()
self.base_size = base_size
self.max_size = max_size or (base_size // 2)
self.num_att_layers = -1
@staticmethod
def get_empty_store():
"""Returns an empty store for holding attention values."""
return {
key: []
for key in [
'down_cross', 'mid_cross', 'up_cross', 'down_self', 'mid_self',
'up_self'
]
}
def reset(self):
"""Resets the step and attention stores to their initial states."""
self.cur_step = 0
self.cur_att_layer = 0
self.step_store = self.get_empty_store()
self.attention_store = {}
def forward(self, attn, is_cross: bool, place_in_unet: str):
"""Processes a single forward step, storing the attention.
Args:
attn: The attention tensor.
is_cross (bool): Whether it's cross attention.
place_in_unet (str): The location in UNet (down/mid/up).
Returns:
The unmodified attention tensor.
"""
key = f"{place_in_unet}_{'cross' if is_cross else 'self'}"
if attn.shape[1] <= (self.max_size)**2:
self.step_store[key].append(attn)
return attn
def between_steps(self):
"""Processes and stores attention information between steps."""
if not self.attention_store:
self.attention_store = self.step_store
else:
for key in self.attention_store:
self.attention_store[key] = [
stored + step for stored, step in zip(
self.attention_store[key], self.step_store[key])
]
self.step_store = self.get_empty_store()
def get_average_attention(self):
"""Calculates and returns the average attention across all steps."""
return {
key: [item for item in self.step_store[key]]
for key in self.step_store
}
def __call__(self, attn, is_cross: bool, place_in_unet: str):
"""Allows the class instance to be callable."""
return self.forward(attn, is_cross, place_in_unet)
@property
def num_uncond_att_layers(self):
"""Returns the number of unconditional attention layers (default is
0)."""
return 0
def step_callback(self, x_t):
"""A placeholder for a step callback.
Returns the input unchanged.
"""
return x_t
class UNetWrapper(nn.Module):
"""A wrapper for UNet with optional attention mechanisms.
Args:
unet (nn.Module): The UNet model to wrap
use_attn (bool): Whether to use attention. Defaults to True
base_size (int): Base size for the attention store. Defaults to 512
max_attn_size (int, optional): Maximum size for the attention store.
Defaults to None
attn_selector (str): The types of attention to use.
Defaults to 'up_cross+down_cross'
"""
def __init__(self,
unet,
use_attn=True,
base_size=512,
max_attn_size=None,
attn_selector='up_cross+down_cross'):
super().__init__()
self.unet = unet
self.attention_store = AttentionStore(
base_size=base_size // 8, max_size=max_attn_size)
self.attn_selector = attn_selector.split('+')
self.use_attn = use_attn
self.init_sizes(base_size)
if self.use_attn:
register_attention_control(unet, self.attention_store)
def init_sizes(self, base_size):
"""Initialize sizes based on the base size."""
self.size16 = base_size // 32
self.size32 = base_size // 16
self.size64 = base_size // 8
def forward(self, x, timesteps=None, context=None, y=None, **kwargs):
"""Forward pass through the model."""
diffusion_model = self.unet.diffusion_model
if self.use_attn:
self.attention_store.reset()
hs, emb, out_list = self._unet_forward(x, timesteps, context, y,
diffusion_model)
if self.use_attn:
self._append_attn_to_output(out_list)
return out_list[::-1]
def _unet_forward(self, x, timesteps, context, y, diffusion_model):
hs = []
t_emb = timestep_embedding(
timesteps, diffusion_model.model_channels, repeat_only=False)
emb = diffusion_model.time_embed(t_emb)
h = x.type(diffusion_model.dtype)
for module in diffusion_model.input_blocks:
h = module(h, emb, context)
hs.append(h)
h = diffusion_model.middle_block(h, emb, context)
out_list = []
for i_out, module in enumerate(diffusion_model.output_blocks):
h = torch.cat([h, hs.pop()], dim=1)
h = module(h, emb, context)
if i_out in [1, 4, 7]:
out_list.append(h)
h = h.type(x.dtype)
out_list.append(h)
return hs, emb, out_list
def _append_attn_to_output(self, out_list):
avg_attn = self.attention_store.get_average_attention()
attns = {self.size16: [], self.size32: [], self.size64: []}
for k in self.attn_selector:
for up_attn in avg_attn[k]:
size = int(math.sqrt(up_attn.shape[1]))
up_attn = up_attn.transpose(-1, -2).reshape(
*up_attn.shape[:2], size, -1)
attns[size].append(up_attn)
attn16 = torch.stack(attns[self.size16]).mean(0)
attn32 = torch.stack(attns[self.size32]).mean(0)
attn64 = torch.stack(attns[self.size64]).mean(0) if len(
attns[self.size64]) > 0 else None
out_list[1] = torch.cat([out_list[1], attn16], dim=1)
out_list[2] = torch.cat([out_list[2], attn32], dim=1)
if attn64 is not None:
out_list[3] = torch.cat([out_list[3], attn64], dim=1)
class TextAdapter(nn.Module):
"""A PyTorch Module that serves as a text adapter.
This module takes text embeddings and adjusts them based on a scaling
factor gamma.
"""
def __init__(self, text_dim=768):
super().__init__()
self.fc = nn.Sequential(
nn.Linear(text_dim, text_dim), nn.GELU(),
nn.Linear(text_dim, text_dim))
def forward(self, texts, gamma):
texts_after = self.fc(texts)
texts = texts + gamma * texts_after
return texts
@MODELS.register_module()
class VPD(BaseModule):
"""VPD (Visual Perception Diffusion) model.
.. _`VPD`: https://arxiv.org/abs/2303.02153
Args:
diffusion_cfg (dict): Configuration for diffusion model.
class_embed_path (str): Path for class embeddings.
unet_cfg (dict, optional): Configuration for U-Net.
gamma (float, optional): Gamma for text adaptation. Defaults to 1e-4.
class_embed_select (bool, optional): If True, enables class embedding
selection. Defaults to False.
pad_shape (Optional[Union[int, List[int]]], optional): Padding shape.
Defaults to None.
pad_val (Union[int, List[int]], optional): Padding value.
Defaults to 0.
init_cfg (dict, optional): Configuration for network initialization.
"""
def __init__(self,
diffusion_cfg: ConfigType,
class_embed_path: str,
unet_cfg: OptConfigType = dict(),
gamma: float = 1e-4,
class_embed_select=False,
pad_shape: Optional[Union[int, List[int]]] = None,
pad_val: Union[int, List[int]] = 0,
init_cfg: OptConfigType = None):
super().__init__(init_cfg=init_cfg)
if pad_shape is not None:
if not isinstance(pad_shape, (list, tuple)):
pad_shape = (pad_shape, pad_shape)
self.pad_shape = pad_shape
self.pad_val = pad_val
# diffusion model
diffusion_checkpoint = diffusion_cfg.pop('checkpoint', None)
sd_model = instantiate_from_config(diffusion_cfg)
if diffusion_checkpoint is not None:
load_checkpoint(sd_model, diffusion_checkpoint, strict=False)
self.encoder_vq = sd_model.first_stage_model
self.unet = UNetWrapper(sd_model.model, **unet_cfg)
# class embeddings & text adapter
class_embeddings = CheckpointLoader.load_checkpoint(class_embed_path)
text_dim = class_embeddings.size(-1)
self.text_adapter = TextAdapter(text_dim=text_dim)
self.class_embed_select = class_embed_select
if class_embed_select:
class_embeddings = torch.cat(
(class_embeddings, class_embeddings.mean(dim=0,
keepdims=True)),
dim=0)
self.register_buffer('class_embeddings', class_embeddings)
self.gamma = nn.Parameter(torch.ones(text_dim) * gamma)
def forward(self, x):
"""Extract features from images."""
# calculate cross-attn map
if self.class_embed_select:
if isinstance(x, (tuple, list)):
x, class_ids = x[:2]
class_ids = class_ids.tolist()
else:
class_ids = [-1] * x.size(0)
class_embeddings = self.class_embeddings[class_ids]
c_crossattn = self.text_adapter(class_embeddings, self.gamma)
c_crossattn = c_crossattn.unsqueeze(1)
else:
class_embeddings = self.class_embeddings
c_crossattn = self.text_adapter(class_embeddings, self.gamma)
c_crossattn = c_crossattn.unsqueeze(0).repeat(x.size(0), 1, 1)
# pad to required input shape for pretrained diffusion model
if self.pad_shape is not None:
pad_width = max(0, self.pad_shape[1] - x.shape[-1])
pad_height = max(0, self.pad_shape[0] - x.shape[-2])
x = F.pad(x, (0, pad_width, 0, pad_height), value=self.pad_val)
# forward the denoising model
with torch.no_grad():
latents = self.encoder_vq.encode(x).mode().detach()
t = torch.ones((x.shape[0], ), device=x.device).long()
outs = self.unet(latents, t, context=c_crossattn)
return outs