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AmbientGAN: Generative models from lossy measurements

Motivation:

How can we train our generative models with partial, noisy observations”

Why do we care?

In many settings, it is expensive or even impossible to obtain fully-observed samples, but economical to obtain partial, noisy samples.

Proposes in this paper:

  • AmbientGAN: train the discriminator not on the raw day domain but on the measurement domain
  • Propose the way to train the generative model with a noisy, corrupted, or missing data without any clean images
  • Prove that it is theoretically possible to recover the original true data distribution even though the measurement process is not invertible

MODEL ARCHITECTURE

 

 

 

 

Generative Adversarial Networks

 

Limitation of GAN

  • Require Good (or fully observed ) training samples

Related work:

  • Compressed sensing attempts to address this problem by exploiting the models of the data structure, sparsity
  • Bora et al. ICML 2017 “Compressed Sensing using Generative Models”
  • Compressed sensing is a very promising study and can give amazing results (need to go deeper)

Chicken and Egg

  • they have proposed it is possible to solve the problem with a small number of measurements by using Generative models
  • what if it is even not possible to gather the good data in the first place?
  • How can we collect enough data to train a generative model to start with?

 

Measurements?

 

 

 

 

 

 

 

 

 

 

 

 

Results

 

Conclusion

  • it is possible to train the generator without fully-observed data
  • In theory, it is possible to find the true distribution by training the generator when the measurement process is invertible and differentiable
  • Empirically, it is possible to recover the good data distribution even though the measurement process is not clearly known.

Possible Applications?

  • OCR
  • Gayoung’s webtoon data
  • Adding Reconstructionloss and Cyclic loss
  • Learnable f(.) by FC
  • etc.

Qestions to consider:

  • Cycle-GAN v.s Ambient-GAN?

Source: https://www.slideshare.net/thinkingfactory/introduction-to-ambient-gan