How do I get Wavelet features from region of interest?

Hi, I have decomposed an image using wavelet and got feature vectors from all subband.I have used wavelet coefficients as features. My feature vectors contain feature from region of interest and its background both. But the features of background is useless. In this situation how do I remove the background features from my feature vector or how do I select the features of my region of interest? or how do I separate wavelet coefficients of region of interest? Please help me.