ISNet-general-use / image_processing_isnet.py
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from typing import Tuple
import torch
import torch.nn.functional as F
from PIL import Image
from PIL.Image import Image as PilImage
from torchvision import transforms
from torchvision.transforms.functional import normalize
from transformers.image_processing_utils import BaseImageProcessor, BatchFeature
from transformers.image_utils import ImageInput
def apply_transform(data):
transform = transforms.ToTensor()
return transform(data)
class ISNetImageProcessor(BaseImageProcessor):
def __init__(self, model_in_size: Tuple[int, int] = (1024, 1024), **kwargs) -> None:
super().__init__(**kwargs)
self.model_in_size = model_in_size
def preprocess(self, images: ImageInput, **kwargs) -> BatchFeature:
if not isinstance(images, PilImage):
raise ValueError(f"Expected PIL Image, got {type(images)}")
image_pil = images
image_tensor = apply_transform(image_pil)
# shape: (3, h, w) -> (1, 3, h, w)
image_tensor = image_tensor.unsqueeze(dim=0)
image_tensor = F.interpolate(
image_tensor, size=self.model_in_size, mode="bilinear", align_corners=False
)
image_tensor = normalize(
image_tensor, mean=[0.5, 0.5, 0.5], std=[1.0, 1.0, 1.0]
)
return BatchFeature(data={"pixel_values": image_tensor}, tensor_type="pt")
def postprocess(
self, prediction: torch.Tensor, width: int, height: int, **kwargs
) -> PilImage:
def _norm_prediction(d: torch.Tensor) -> torch.Tensor:
ma, mi = torch.max(d), torch.min(d)
# division while avoiding zero division
dn = (d - mi) / ((ma - mi) + torch.finfo(torch.float32).eps)
return dn
prediction = _norm_prediction(prediction)
prediction = prediction.squeeze()
prediction = prediction * 255 + 0.5
prediction = prediction.clamp(0, 255)
prediction_np = prediction.cpu().numpy()
image = Image.fromarray(prediction_np).convert("RGB")
image = image.resize((width, height), resample=Image.Resampling.BILINEAR)
return image