image enhancement using dwt

iam doing image enhancement using dwt. the code below is dwt for decompose n reconstruction. how do i do the enhancement? should i put thresholding function after decomposition?

[cA,cH,cV,cD] = dwt2(Green_Input_Image,'db4');

sX = size(Green_Input_Image);

A0 = idwt2(cA,cH,cV,cD,'db4',sX);

please help me, iam really stuck to do image enhancement using dwt