app.py

import os
import cv2
import numpy as np
import torch
import gradio as gr
import spaces

from PIL import Image
from transformers import AutoModelForImageSegmentation
from torchvision import transforms

torch.set_float32_matmul_precision('high')
torch.jit.script = lambda f: f

device = "cuda" if torch.cuda.is_available() else "cpu"

def refine_foreground(image, mask, r=90):
    if mask.size != image.size:
        mask = mask.resize(image.size)
    image = np.array(image) / 255.0
    mask = np.array(mask) / 255.0
    estimated_foreground = FB_blur_fusion_foreground_estimator_2(image, mask, r=r)
    image_masked = Image.fromarray((estimated_foreground * 255.0).astype(np.uint8))
    return image_masked

def FB_blur_fusion_foreground_estimator_2(image, alpha, r=90):
    alpha = alpha[:, :, None]
    F, blur_B = FB_blur_fusion_foreground_estimator(
        image, image, image, alpha, r)
    return FB_blur_fusion_foreground_estimator(image, F, blur_B, alpha, r=6)[0]

def FB_blur_fusion_foreground_estimator(image, F, B, alpha, r=90):
    if isinstance(image, Image.Image):
        image = np.array(image) / 255.0
    blurred_alpha = cv2.blur(alpha, (r, r))[:, :, None]

    blurred_FA = cv2.blur(F * alpha, (r, r))
    blurred_F = blurred_FA / (blurred_alpha + 1e-5)

    blurred_B1A = cv2.blur(B * (1 - alpha), (r, r))
    blurred_B = blurred_B1A / ((1 - blurred_alpha) + 1e-5)
    F = blurred_F + alpha * \
        (image - alpha * blurred_F - (1 - alpha) * blurred_B)
    F = np.clip(F, 0, 1)
    return F, blurred_B

class ImagePreprocessor():
    def __init__(self, resolution=(1024, 1024)) -> None:
        self.transform_image = transforms.Compose([
            transforms.Resize(resolution),
            transforms.ToTensor(),
            transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]),
        ])

    def proc(self, image: Image.Image) -> torch.Tensor:
        image = self.transform_image(image)
        return image

birefnet = AutoModelForImageSegmentation.from_pretrained('zhengpeng7/BiRefNet-matting', trust_remote_code=True)
birefnet.to(device)
birefnet.eval()

@spaces.GPU
def remove_background(image):
    if image is None:
        raise gr.Error("Please upload an image.")

    image_ori = Image.fromarray(image).convert('RGB')
    
    # Preprocess the image
    image_preprocessor = ImagePreprocessor(resolution=(1024, 1024))
    image_proc = image_preprocessor.proc(image_ori)
    image_proc = image_proc.unsqueeze(0)

    # Prediction
    with torch.no_grad():
        preds = birefnet(image_proc.to(device))[-1].sigmoid().cpu()
    pred = preds[0].squeeze()

    # Show Results
    pred_pil = transforms.ToPILImage()(pred)
    image_masked = refine_foreground(image_ori, pred_pil)
    image_masked.putalpha(pred_pil.resize(image_ori.size))

    torch.cuda.empty_cache()

    # Save mask as PNG
    mask_path = "mask.png"
    pred_pil.save(mask_path)

    # Save output as PNG
    output_path = "output.png"
    image_masked.save(output_path)

    return mask_path, output_path

css = """
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}
.gradio-container {
    background: linear-gradient(
        135deg,
        #e0f7fa, #e8f5e9, #fff9c4, #ffebee,
        #f3e5f5, #e1f5fe, #fff3e0, #e8eaf6
    );
    background-size: 400% 400%;
    animation: gradient-animation 15s ease infinite;
}
@keyframes gradient-animation {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}
.gradio-button {
    font-family: inherit;
    font-size: 16px;
    font-weight: bold;
    color: #000000;
    background: white;
    border: 2px solid black;
    border-radius: 10px;
}
.gradio-button:hover {
    background: #f0f0f0;
}
"""

iface = gr.Interface(
    fn=remove_background,
    inputs=gr.Image(type="numpy"),
    outputs=[
        gr.Image(type="filepath", label="Mask"),
        gr.Image(type="filepath", label="Output")
    ],
    title="<div style='font-size: 36px; font-weight: bold;'>{.Remove Background}</div>",
    description="Upload an image to remove its background using BiRefNet.",
    allow_flagging="never",
    css=css
)

if __name__ == "__main__":
    iface.launch(debug=True)