GAN

Challenges

Mode Collapse / Mode Diversity

generator collapses, produces limited varieties of sample to fake discrimator cuased by: dimension deficient solutions: generalized dataset, Orthonormal constraint (正交約束), diversity loss (e.g. multi-scale structural similarity (MS-SSIM))

Non-convergence, Convergence difficulty

the model parameters oscillate, destabilize

Vanishing gradient because of too good discriminator

the discriminator gets too successful that the generator gradient vanishes and learns nothing solution: WGAN - Wasserstein distance

Image quality

  • resolution
  • noise
  • high frequencey