- Goal:
$x=(I_x,S_x), y=(I_y,S_y), G(x,y)=(I_x,S_y)$
identity: can be seen as a set-level characteristic shape: can be seen as an instance-level characteristic
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Loss
- Identity loss $$ \begin{array}l L_I(G,D)=\mathbb E_{x,\hat x\sim p_{data}(x)}[\log D(x,\hat x)]+ \mathbb E_{x\sim p_{data}(x),y\sim p_{data}(y)}[\log( 1-D(x,G(x,y)))] \ L_I(G,D)=\mathbb E_{x,\hat x\sim p_{data}(x)}[||1-D(x,\hat x)||_ 2]+ \mathbb E_{x\sim p_{data}(x),y\sim p_{data}(y)}[||D(x,G(x,y))||_ 2] \end{array} $$
$x, y$ 是两个输入,$\hat x$是和$x$同identity的另一个图像。实际上用下面的loss- Shape Loss $$ \begin{array}l L_{S_1}(G)=\mathbb E_{x\sim p_{data}(x),y\sim p_{data}(y)}[||y-G(x,y)||_ 1] \ L_{S_{2a}}=\mathbb E_{x\sim p_{data}(x),y\sim p_{data}}(||y-G(y,G(x,y))||_ 1) \ L_{S_{2b}}=\mathbb E_{x\sim p_{data}(x),y\sim p_{data}}(||G(x,y)-G(G(x,y),y)||_ 1) \end{array} $$
$s_1: I_x=I_y$ $s_{2a}: (I_x,S_x)\to (I_x,S_y)\to (I_y,S_y)$ $s_{2b}: (I_x,S_x)\to (I_x,S_y)\to (I_x,S_y)$ -
Min-Patch Training patch-GAN 的最后一层再加层Minimum pooling,找到最困难的区域
- condition GAN,这里有两个condition