  Light field (LF) depth estimation is a crucial task with numerous practical
applications. However, mainstream methods based on the multi-view stereo (MVS)
are resource-intensive and time-consuming as they need to construct a finer
cost volume. To address this issue and achieve a better trade-off between
accuracy and efficiency, we propose an occlusion-aware cascade cost volume for
LF depth (disparity) estimation. Our cascaded strategy reduces the sampling
number while keeping the sampling interval constant during the construction of
a finer cost volume. We also introduce occlusion maps to enhance accuracy in
constructing the occlusion-aware cost volume. Specifically, we first obtain the
coarse disparity map through the coarse disparity estimation network. Then, the
sub-aperture images (SAIs) of side views are warped to the center view based on
the initial disparity map. Next, we propose photo-consistency constraints
between the warped SAIs and the center SAI to generate occlusion maps for each
SAI. Finally, we introduce the coarse disparity map and occlusion maps to
construct an occlusion-aware refined cost volume, enabling the refined
disparity estimation network to yield a more precise disparity map. Extensive
experiments demonstrate the effectiveness of our method. Compared with
state-of-the-art methods, our method achieves a superior balance between
accuracy and efficiency and ranks first in terms of MSE and Q25 metrics among
published methods on the HCI 4D benchmark. The code and model of the proposed
method are available at https://github.com/chaowentao/OccCasNet.
