To log some useful code snippets that I have learned and used.

Write an image from array

Need to convert to uint8 before writing to image to avoid color shift. And using cv2 will cause color shift (I didn’t try my best to find out why, there might be some other ways to use cv2 to write image without color shift).

Writing image using PIL and cv2. 
    from PIL import Image
    import torch 

    def save_images(images, save_path):
        assert(torch.is_tensor(images))
        assert(len(images.shape) == 4)
        assert(images.shape[1] == 3)
        assert(torch.min(images) == -1)
        assert(torch.max(images) == 1)

        for id, img_pixel in enumerate(images):
            save_path_id = save_path + str(id) + ".png"
            Image.fromarray(
                (img_pixel * 127.5 + 128).clamp(0, 255).to(torch.uint8).permute(1, 2, 0).cpu().numpy()
                ).save(save_path_id)

            # Using cv2 will cause color shift
            # cv2.imwrite(save_path_id, (img_pixel * 127.5 + 128).clamp(0, 255).to(torch.uint8).permute(1, 2, 0).cpu().numpy())
    
    if __name__ == "__main__":
        images = torch.load("https://raw.githubusercontent.com/tuananhbui89/tuananhbui89.github.io/master/files/images_tensor.pt")
        save_path = "./test/"
        save_images(images, save_path)

Github pages

Jupyter notebook

  • Clear Notebook Widgets State to show the notebook on Github pages: jq -M 'del(.metadata.widgets)' 001_vector_search.ipynb > 001_vector_search.fixed.ipynb source
  • Convert notebook to markdown to show on Github repos as README: jupyter nbconvert --to markdown notebook.ipynb

Cross-reference in markdown

Coding Convention for Python

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