1. Unsupervised Learning
Supervised vs Unsupervised Learning:
2. Generative Models
概述:
Generative Models的作用:
Generative Models的分类:
3. PixelRNN and PixelCNN
基本原理:
PixelRNN:
PixelCNN:
Training is faster than PixelRNN (can parallelize convolutions since context region values known from training images)
Generation must still proceed sequentially=> still slow
Generation Samples:
PixelRNN and PixelCNN
4. Variational Autoencoders (VAE)
4.1 与PixelRNN/PixelCNN的比较:
4.2 Some background first: Autoencoders:
Tips:
如果将其用于特征提取,则在训练之后,将decoder部分丢弃!
Autoencoders can reconstruct data, and can learn features to initialize a supervised model!
4.3 Variational Autoencoders
利用高斯分布随机生成特征Z:
Variational Autoencoders: Intractability
$$pθ(z)$$ 跟据高斯分布随机获得, $$pθ(x|z)$$ 根据decoder net获得,而为每个z计算 $$pθ(x|z)$$ 并最终积分得到 $$pθ(x)$$ 是不可能的!
解决办法:
如何进行优化:
4.4 Generating Data
4.5 性能分析:
5. Generative Adversarial Networks (GAN)
回顾:
5.1 Training GANs: Two-player game
Generator network: try to fool the discriminator by generating real-looking images
Discriminator network: try to distinguish between real and fake images
网络优化:
优化存在的问题:
解决办法:
GAN training algorithm:
5.2 Generative Adversarial Nets
Generated samples:
Generative Adversarial Nets: Convolutional Architectures
Generator is an upsampling network with fractionally-strided convolutions
Discriminator is a convolutional network
Generator网络结构:
Samples from the model look amazing!
Generative Adversarial Nets: Interpretable Vector Math
GANs的优缺点: