[1 − cos(v − vi)] · [1 + ⟨ϕ(Iv), ϕ(Ivi)⟩] ,

(10)
where we randomly select n additional views {vi}n
i=1 and
measure the similarity between Iv and each Ivi in feature
space. The feature extractor ϕ is the image encoder of
CLIP [42], and ⟨·,·⟩ represents the cosine similarity. The
rationale for this design is that a higher similarity between
different views indicates more severe multi-head effect, and
conversely, a lower similarity value among different views
suggests a less significant Janus problem. Besides, we
weight the contribution of different view angles in Equa-
tion 10 with 1 − cos(v − vi). This weighting mechanism
takes into account that high similarity between views that
are farther apart indicates a more severe multi-head effect.

n(cid:88)

i=1

C =

1
4n
Instant3D