112 lines
3.8 KiB
Python
112 lines
3.8 KiB
Python
# Copyright (c) Meta Platforms, Inc. and affiliates.
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# All rights reserved.
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# This source code is licensed under the license found in the
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# LICENSE file in the root directory of this source tree.
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import torch
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from torch import nn
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from torch.nn import functional as F
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from typing import Any, Dict, List, Tuple
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from .image_encoder import ImageEncoderViT
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from .mask_decoder import MaskDecoder
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from .prompt_encoder import PromptEncoder
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class Sam(nn.Module):
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mask_threshold: float = 0.0
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image_format: str = "RGB"
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def __init__(
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self,
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image_encoder: ImageEncoderViT,
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prompt_encoder: PromptEncoder,
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mask_decoder: MaskDecoder,
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pixel_mean: List[float] = [123.675, 116.28, 103.53],
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pixel_std: List[float] = [58.395, 57.12, 57.375],
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) -> None:
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super().__init__()
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self.image_encoder = image_encoder
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self.prompt_encoder = prompt_encoder
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self.mask_decoder = mask_decoder
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self.register_buffer("pixel_mean", torch.Tensor(pixel_mean).view(-1, 1, 1), False)
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self.register_buffer("pixel_std", torch.Tensor(pixel_std).view(-1, 1, 1), False)
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@property
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def device(self) -> Any:
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return self.pixel_mean.device
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@torch.no_grad()
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def forward(
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self,
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batched_input: List[Dict[str, Any]],
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multimask_output: bool,
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) -> List[Dict[str, torch.Tensor]]:
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input_images = torch.stack([self.preprocess(x["image"]) for x in batched_input], dim=0)
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image_embeddings = self.image_encoder(input_images)
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outputs = []
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for image_record, curr_embedding in zip(batched_input, image_embeddings):
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if "point_coords" in image_record:
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points = (image_record["point_coords"], image_record["point_labels"])
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else:
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points = None
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sparse_embeddings, dense_embeddings = self.prompt_encoder(
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points=points,
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boxes=image_record.get("boxes", None),
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masks=image_record.get("mask_inputs", None),
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)
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low_res_masks, iou_predictions = self.mask_decoder(
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image_embeddings=curr_embedding.unsqueeze(0),
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image_pe=self.prompt_encoder.get_dense_pe(),
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sparse_prompt_embeddings=sparse_embeddings,
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dense_prompt_embeddings=dense_embeddings,
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multimask_output=multimask_output,
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)
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masks = self.postprocess_masks(
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low_res_masks,
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input_size=image_record["image"].shape[-2:],
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original_size=image_record["original_size"],
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)
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masks = masks > self.mask_threshold
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outputs.append(
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{
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"masks": masks,
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"iou_predictions": iou_predictions,
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"low_res_logits": low_res_masks,
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}
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)
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return outputs
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def postprocess_masks(
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self,
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masks: torch.Tensor,
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input_size: Tuple[int, ...],
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original_size: Tuple[int, ...],
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) -> torch.Tensor:
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masks = F.interpolate(
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masks,
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(self.image_encoder.img_size, self.image_encoder.img_size),
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mode="bilinear",
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align_corners=False,
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)
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masks = masks[..., : input_size[0], : input_size[1]]
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masks = F.interpolate(masks, original_size, mode="bilinear", align_corners=False)
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return masks
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def preprocess(self, x: torch.Tensor) -> torch.Tensor:
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"""Normalize pixel values and pad to a square input."""
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# Normalize colors
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x = (x - self.pixel_mean) / self.pixel_std
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# Pad
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h, w = x.shape[-2:]
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padh = self.image_encoder.img_size - h
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padw = self.image_encoder.img_size - w
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x = F.pad(x, (0, padw, 0, padh))
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return x
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