how to make the wavelet to positive and get it's inverse

here am taking baboon image

rgb_image_1=imread('baboon.tiff');
am applying lift wave 
LS = liftwave('cdf2.2','Int2Int');
[CA,CH,CV,CD] = lwt2(double(rgb_image_1),LS);

in CH,CV,CD am getting negative integer number i want to convert those negative to positive integers (i assume this as my encryption code )

similarly i have to get back to CH,CV,CD containing the negative (i assume this as my decryption process)

can any one help ?

i thought of taking abs so that i can get positive but the problem is exact inverse is not possible incase of abs

even mod will also not work