Don't skip the skips: autoencoder skip connections improve latent representation discrepancy for anomaly detection

Reconstruction-based anomaly detection typically relies on the reconstruction of a defect-free output from an input image. Such reconstruction can be obtained by training an autoencoder to reconstruct clean images from inputs corrupted with a synthetic defect. Previous works have shown that adopting an autoencoder with skip connections improves reconstruction sharpness. However, it remains unclear how skip connections aect the latent representations learned during training. Here, we compare internal representations of autoencoders with and without skip connections. Experiments over the MVTec AD dataset reveal that skip connections enable the autoencoder latent representations to intrinsically discriminate between clean and defective images.