app.py

import argparse
import requests
import gradio as gr
import numpy as np
import cv2
import torch
import torch.nn as nn
from PIL import Image
from pathlib import Path
from torchvision import transforms
from timm.data.constants import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
from timm.data import create_transform
from config import get_config
from model import build_model

# Download human-readable labels for ImageNet.
response = requests.get("https://git.io/JJkYN")
labels = response.text.split("\n")

def parse_option():
    parser = argparse.ArgumentParser('UniCL demo script', add_help=False)
    parser.add_argument('--cfg', type=str, default="configs/unicl_swin_base.yaml", metavar="FILE", help='path to config file', )
    args, unparsed = parser.parse_known_args()

    config = get_config(args)

    return args, config

def build_transforms(img_size, center_crop=True):
    t = [transforms.ToPILImage()]
    if center_crop:
        size = int((256 / 224) * img_size)
        t.append(
            transforms.Resize(size)
        )
        t.append(
            transforms.CenterCrop(img_size)    
        )
    else:
        t.append(
            transforms.Resize(img_size)
        )        
    t.append(transforms.ToTensor())
    t.append(transforms.Normalize(IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD))
    return transforms.Compose(t)

def build_transforms4display(img_size, center_crop=True):
    t = [transforms.ToPILImage()]
    if center_crop:
        size = int((256 / 224) * img_size)
        t.append(
            transforms.Resize(size)
        )
        t.append(
            transforms.CenterCrop(img_size)    
        )
    else:
        t.append(
            transforms.Resize(img_size)
        )  
    t.append(transforms.ToTensor())
    return transforms.Compose(t)

args, config = parse_option()

'''
build model
'''
model = build_model(config)

url = './in21k_yfcc14m_gcc15m_swin_base.pth'
checkpoint = torch.load(url, map_location="cpu")
model.load_state_dict(checkpoint["model"])
model.eval()

'''
build data transform
'''
eval_transforms = build_transforms(224, center_crop=True)
display_transforms = build_transforms4display(224, center_crop=True)

'''
build upsampler
'''
# upsampler = nn.Upsample(scale_factor=16, mode='bilinear')

'''
borrow code from here: https://github.com/jacobgil/pytorch-grad-cam/blob/master/pytorch_grad_cam/utils/image.py
'''
def show_cam_on_image(img: np.ndarray,
                      mask: np.ndarray,
                      use_rgb: bool = False,
                      colormap: int = cv2.COLORMAP_JET) -> np.ndarray:
    """ This function overlays the cam mask on the image as an heatmap.
    By default the heatmap is in BGR format.
    :param img: The base image in RGB or BGR format.
    :param mask: The cam mask.
    :param use_rgb: Whether to use an RGB or BGR heatmap, this should be set to True if 'img' is in RGB format.
    :param colormap: The OpenCV colormap to be used.
    :returns: The default image with the cam overlay.
    """
    heatmap = cv2.applyColorMap(np.uint8(255 * mask), colormap)
    if use_rgb:
        heatmap = cv2.cvtColor(heatmap, cv2.COLOR_BGR2RGB)
    heatmap = np.float32(heatmap) / 255

    if np.max(img) > 1:
        raise Exception(
            "The input image should np.float32 in the range [0, 1]")

    cam = 0.7*heatmap + 0.3*img
    # cam = cam / np.max(cam)
    return np.uint8(255 * cam)

def recognize_image(image, texts):
    img_t = eval_transforms(image) 
    img_d = display_transforms(image).permute(1, 2, 0).numpy()

    text_embeddings = model.get_text_embeddings(texts.split(';'))

    # compute output
    feat_img, feat_map, H, W = model.encode_image(img_t.unsqueeze(0), output_map=True)
    output = model.logit_scale.exp() * feat_img @ text_embeddings.t()
    prediction = output.softmax(-1).flatten()

    # generate feat map given the top matched texts
    output_map = (feat_map * text_embeddings[prediction.argmax()].unsqueeze(-1)).sum(1).softmax(-1)
    output_map = output_map.view(1, 1, H, W)

    output_map = nn.Upsample(size=img_t.shape[1:], mode='bilinear')(output_map)
    output_map = output_map.squeeze(1).detach().permute(1, 2, 0).numpy()
    output_map = (output_map - output_map.min()) / (output_map.max() - output_map.min())
    heatmap = show_cam_on_image(img_d, output_map, use_rgb=True)
    
    show_img = np.concatenate((np.uint8(255 * img_d), heatmap), 1)
    return {texts.split(';')[i]: float(prediction[i]) for i in range(len(texts.split(';')))}, Image.fromarray(show_img)


image = gr.inputs.Image()
label = gr.outputs.Label(num_top_classes=100)

description = "UniCL for Zero-shot Image Recognition. Given an image, our model maps it to an arbitary text in a candidate pool."
gr.Interface(
    description=description,
    fn=recognize_image,
    inputs=["image", "text"],
    outputs=[                          
        label, 
        gr.outputs.Image(
        type="pil",
        label="crop input/heat map"),                
    ],
    examples=[
    ["./elephants.png", "an elephant; an elephant walking in the river; four elephants walking in the river"], 
    ["./apple_with_ipod.jpg", "an ipod; an apple with a write note 'ipod'; an apple"], 
    ["./crowd2.jpg", "a street; a street with a woman walking in the middle; a street with a man walking in the  middle"],
    ],
    article=Path("docs/intro.md").read_text()    
).launch()