Why Epipolar When we have Homography?

[AsDeadAsADodo]

Thanks for the work! I read several works about Epipolar Transofomer, e.g. MVSTER. Homography matrix is able to directly project point p to corresponding p'. Then why apply Epipolar Geometry to find point (p)'s corresponding epipolar line? I've read MVSTER code, they still construct a cost volume from Homography warping.

[TQTQliu]

Hi, constructing a cost volume through homography transformation is a part of the pipeline of cost volume-based MVS methods. Our method follows this pipeline as well, but focuses on its first phase, the feature encoding part. This paper aims to aggregate information of corresponding epipolar lines to enhance feature representation. Therefore, we extend the point-to-point homography transformation to the correspondence between the point and the epipolar line, and design the epipolar pair search algorithm. You can find these in the framework (Fig. 4) of the paper.

[AsDeadAsADodo]

Hi, constructing a cost volume through homography transformation is a part of the pipeline of cost volume-based MVS methods. Our method follows this pipeline as well, but focuses on its first phase, the feature encoding part. This paper aims to aggregate information of corresponding epipolar lines to enhance feature representation. Therefore, we extend the point-to-point homography transformation to the correspondence between the point and the epipolar line, and design the epipolar pair search algorithm. You can find these in the framework (Fig. 4) of the paper.

Thanks for your quick reply! So Epipolar is a way to enhance the feature maps, generate a new feature map for each one of them? After this phase, we still construct cost volume through homograhpy transformation?

[TQTQliu]

Yes, you're right.