Walid Bousselham1, Angie Boggust2, Sofian Chaybouti1, Hendrik Strobelt3,4 and Hilde Kuehne1,3
1 University of Bonn & Goethe University Frankfurt, 2 MIT CSAIL, 3 MIT-IBM Watson AI Lab, 4 IBM Research.
Vision-Language foundation models have shown remarkable performance in various zero-shot settings such as image retrieval, classification, or captioning. we propose LeGrad, an explainability method specifically designed for ViTs. We LeGrad we explore how the decision-making process of such models by leveraging their feature formation process. A by-product of understanding VL models decision-making is the ability to produce localised heatmap for any text prompt.
The following is the code for a wrapper around the OpenCLIP library to equip VL models with LeGrad.
legrad
library can be simply installed via pip:
$ pip install legrad_torch
- Try out our web demo on HuggingFace Spaces
- Run the demo on Google Colab:
- Run
playground.py
for a usage example.
To run the gradio app locally, first install gradio and then run app.py
:
$ pip install gradio
$ python app.py
To see which pretrained models is available use the following code snippet:
import legrad
legrad.list_pretrained()
To process an image and a text prompt use the following code snippet:
Note: the wrapper does not affect the original model, hence all the functionalities of OpenCLIP models can be used seamlessly.
import requests
from PIL import Image
import open_clip
import torch
from legrad import LeWrapper, LePreprocess
from utils import visualize
# ------- model's paramters -------
model_name = 'ViT-B-16'
pretrained = 'laion2b_s34b_b88k'
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
# ------- init model -------
model, _, preprocess = open_clip.create_model_and_transforms(
model_name=model_name, pretrained=pretrained, device=device)
tokenizer = open_clip.get_tokenizer(model_name=model_name)
model.eval()
# ------- Equip the model with LeGrad -------
model = LeWrapper(model)
# ___ (Optional): Wrapper for Higher-Res input image ___
preprocess = LePreprocess(preprocess=preprocess, image_size=448)
# ------- init inputs: image + text -------
url = "http://images.cocodataset.org/val2017/000000039769.jpg"
image = preprocess(Image.open(requests.get(url, stream=True).raw)).unsqueeze(0).to(device)
text = tokenizer(['a photo of a cat']).to(device)
# -------
text_embedding = model.encode_text(text, normalize=True)
print(image.shape)
explainability_map = model.compute_legrad_clip(image=image, text_embedding=text_embedding)
# ___ (Optional): Visualize overlay of the image + heatmap ___
visualize(heatmaps=explainability_map, image=image)
This code is build as wrapper around OpenCLIP library from LAION, visit their repo for more vision-language models. This project also takes inspiration from Transformer-MM-Explainability and the timm library, please visit their repository.
If you find this repository useful, please consider citing our work 📝 and giving a star 🌟 :
@article{bousselham2024legrad,
author = {Bousselham, Walid and Boggust, Angie and Chaybouti, Sofian and Strobelt, Hendrik and Kuehne, Hilde}
title = {LeGrad: An Explainability Method for Vision Transformers via Feature Formation Sensitivity},
journal = {arXiv preprint arXiv:2404.03214},
year = {2024},
}