  Recent studies on face forgery detection have shown satisfactory performance
for methods involved in training datasets, but are not ideal enough for unknown
domains. This motivates many works to improve the generalization, but
forgery-irrelevant information, such as image background and identity, still
exists in different domain features and causes unexpected clustering, limiting
the generalization. In this paper, we propose a controllable guide-space (GS)
method to enhance the discrimination of different forgery domains, so as to
increase the forgery relevance of features and thereby improve the
generalization. The well-designed guide-space can simultaneously achieve both
the proper separation of forgery domains and the large distance between
real-forgery domains in an explicit and controllable manner. Moreover, for
better discrimination, we use a decoupling module to weaken the interference of
forgery-irrelevant correlations between domains. Furthermore, we make
adjustments to the decision boundary manifold according to the clustering
degree of the same domain features within the neighborhood. Extensive
experiments in multiple in-domain and cross-domain settings confirm that our
method can achieve state-of-the-art generalization.
