I am little confuse in normalizing data. Suppose i am restoring the image by the formula
out =  (cnn_input_image - b) / cnn_output_image.
cnn_input_image and b = actually range are between 0 to 255 but normalize between -1 to 1
cnn_output_image             = actually range is between 0 to 1 not  between 0 to 255.
So numerator are in the range of 0 to 255 (which is normalized to -1 to 1) and denominator is in the range of 0 to 1.
The question is

how to restore the image using cnn_output_image and which activation function is
appropriate at last layer?
Is the normalization require of cnn_output_image?
Should it requires to take absolute value of denominator if it range -1 to 1