  The image-to-image translation (I2IT) model takes a target label or a
reference image as the input, and changes a source into the specified target
domain. The two types of synthesis, either label- or reference-based, have
substantial differences. Particularly, the label-based synthesis reflects the
common characteristics of the target domain, and the reference-based shows the
specific style similar to the reference. This paper intends to bridge the gap
between them in the task of multi-attribute I2IT. We design the label- and
reference-based encoding modules (LEM and REM) to compare the domain
differences. They first transfer the source image and target label (or
reference) into a common embedding space, by providing the opposite directions
through the attribute difference vector. Then the two embeddings are simply
fused together to form the latent code S_rand (or S_ref), reflecting the domain
style differences, which is injected into each layer of the generator by SPADE.
To link LEM and REM, so that two types of results benefit each other, we
encourage the two latent codes to be close, and set up the cycle consistency
between the forward and backward translations on them. Moreover, the
interpolation between the S_rand and S_ref is also used to synthesize an extra
image. Experiments show that label- and reference-based synthesis are indeed
mutually promoted, so that we can have the diverse results from LEM, and high
quality results with the similar style of the reference.
