I assume that these photographs are found abstractions: Newly constructed signage that has yet to be adorned with typography and graphics. Captured in this incomplete stage, these photographs look equally surreal and futuristic, and our attention is turned away from the function of these objects to a heightened consideration of form and colour.
Update: As Maarten suggests in the comments, these photographs are more than likely digitally manipulated. Seen in this light, the work's title is literal. Sign Out refers to a removal of graphics in an attempt to reduce or minimalise what already exists to its most basic form.