  In applications such as optical see-through and projector augmented reality,
producing images amounts to solving non-negative image generation, where one
can only add light to an existing image. Most image generation methods,
however, are ill-suited to this problem setting, as they make the assumption
that one can assign arbitrary color to each pixel. In fact, naive application
of existing methods fails even in simple domains such as MNIST digits, since
one cannot create darker pixels by adding light. We know, however, that the
human visual system can be fooled by optical illusions involving certain
spatial configurations of brightness and contrast. Our key insight is that one
can leverage this behavior to produce high quality images with negligible
artifacts. For example, we can create the illusion of darker patches by
brightening surrounding pixels. We propose a novel optimization procedure to
produce images that satisfy both semantic and non-negativity constraints. Our
approach can incorporate existing state-of-the-art methods, and exhibits strong
performance in a variety of tasks including image-to-image translation and
style transfer.
