Fisher 线性判别
Multiplying both sides of this result by wT and adding w0, and making use of y(x)=wTx+w0 and y(xΓ)=wTxΓ+w0=0, we have r=y(x)/||w||.
The idea proposed by Fisher is to maximize a function that will give a large separation between the projected class means while also giving a small variance within each class, thereby minimizing the class overlap.