function?[?JG?]?=?pingjia（?YpYopan?）
%UNtitleD3?Summary?of?this?function?goes?here
%???Detailed?explanation?goes?here
Yo=Yo（:::）;
Yp=Yp（:::）;
for?k=1:4
????yo=Yo（::k）;
????yp=Yp（::k）;
????[MN]=size（yo）;
diffX=yo（:2:N）-yo（:1:N-1）;
diffY=yo（2:M:）-yo（1:M-1:）;
diffX=diffX.^2;
diffY=diffY.^2;
diffX=diffX（:）;
diffY=diffY（:）;
AVEGRAD=sum（diffX+diffY）;
AVEGRAD=sqrt（AVEGRAD/2）;
PJTD_o（k）=AVEGRAD*10000/（（M-1）*（N-1））;

[MN]=size（yp）;
diffX=yp（:2:N）-yp（:1:N-1）;
diffY=yp（2:M:）-yp（1:M-1:）;
diffX=diffX.^2;
diffY=diffY.^2;
diffX=diffX（:）;