[gus_massa]

@OP: I tried but failed. In the main image the bottom left corner is darker. How did you took the photo? For slightly similar tasks I like natural light from a window in a cloudy day, so it's very diffuse. I take the photo far away from the paper to avoid shadows. It's better if you have a support for the phone/camera.

   O                     w
   |    ---camera        i
   |   /                 n
   me /                  d
   |        photo        o
   |   --------------    w
   |   |  table     |            
  / \  |            |