Unsupervised learning trains models without human-provided labels by exploiting structure in the input data. Self-supervision creates implicit labels from the input, allowing familiar regression or classification losses to drive learning. section 7.0
Common self-supervised tasks include:
- Inpainting: reconstruct an obscured portion of an image. section 7.0
- Image sorting: restore the correct order of shuffled image pieces. section 7.0
- Autoencoding: reconstruct the original input from the input itself. section 7.0
Autoencoding digits
A larger PyTorch autoencoder expands the encoded representation, reconstructs 28×28 digit images, and trains with mean squared error. Better visual reconstruction does not necessarily prove that the representation is useful. section 7.3
Figure 7.1 Three different types of self-supervised problems: inpainting, image sorting, and autoencoding. In each case, we do not need to know what the image is of because the network will try to predict the original image no matter what. In the first case (red), we randomly block out a portion of the image and ask the network to fill in the missing piece. In the second case, we break the image into pieces, shuffle them, and ask the network to put them back in the correct order. In the last case, we simply ask the network to predict the original image from the original image.
Compare inpainting, image sorting, and autoencoding as three ways to generate targets directly from images. section 7.0



















