Twin-Surface-Extrapolation-TWISE-

Code for CVPR 2021 Submission of our paper 'Depth Completion with Twin Surface Extrapolation at Occlusion Boundaries' available at paper.

Overview

The following is a teaser result of our proposed algorithm: Fig.1: Overview of TWISE. The figure describes how our depth completion algorithm can input LiDAR data and image (a), and extrapolate the estimates of foreground depth $d_1$ (b) and background depth $d_2$ (c), along with a weight $\sigma$ (e). Fusing all three leads to the completed depth (d). The foreground-background depth difference (f) $d_2-d_1$ is small except at depth discontinuities.

Dependencies

We built our framework on Pytorch 1.3 and CUDA 10.1 in Ubuntu 18.1 and python 3.6. In terminal, the steps are:

1. conda create -n pytorch1.3_twise python=3.6
2. source activate pytorch1.3_twise
3. conda install pytorch==1.3.0 torchvision==0.4.1 cudatoolkit=10.1 -c pytorch

Training

We will release our training code soon. Stay tuned!

PreTrained Model

Our best pre-trained model on KITTI is obtained with Multi-Stack HourGlass Network. Our best pre-trained model can be obtained from here

Evaluation

We also provide an evaluation script to evaluate the model on 1000 validation images of KITTI. Download the selected images folder from [KITTI's website] (http://www.cvlibs.net/datasets/kitti/eval_depth.php?benchmark=depth_completion) and extract it in Data folder. The Data folder should look like this:

.
Data
  |__depth_selection

To evaluate the model, just extract the model provided in tar.gz format in the pretrained_models dir and in Codes directory, run:

python evaluate.py --data-folder datapath_dir

where datapath_dir is the folder where Data directory is. It evaluates the model based the metrics MAE, RMSE, TMAE, TRMSE etc.

Virtual KITTI

Modelling outliers with Semi-Dense GT

VKITTI Sparse Lidar	KITTI 64R Lidar Sparse
(a)	(b)
VKITTI SemiDense GT	KITTI SemiDense GT
(c)	(d)
Figure 2. Comparison of VKITTI Data vs KITTI Data

We subsample the dense GT depth in azimuth-elevation space to simulate LiDAR-like pattern as sparse inputs (See Figure 2 (a)). Further, we created semi-dense VKITTI to simulate outlier noise similar to that existing in real KITTI dataset (See Figure 2 (b)). We follow the similar procedure as followed by Uhrig et al when creating semi-dense GT. Refer to Fig.2 for a comparison between semi-dense VKITTI and semi-dense KITTI.

The VKITTI directory structure is in the following format:

.
VKITTI_2.0
  |__sampled_depth
     |__Scene01
        |__clone
           |__frames
              |__64R_sampled
                 |__Camera_0
                 |__Camera_1
              |__semi_dense
     |__Scene02        
     |__...
  |__vkitti_2.0.3_depth
  |__vkitti_2.0.3_rgb

The VKITTI sampled data can be found from this link.

Correction to our main CVPR paper

There is a correction of Equation 8 of our CVPR paper. The corrected equation is given below:

L(c1, c2, c3) = \sum_{i=1}^{N}(ALE_{\gamma}(c_{1i}) + RALE_{\gamma}{c_{2i}} + F(s(c_{3i}))) where c1 -> hat{d_1}, c2 -> hat{d_2}, and s(c3) is the sigmoid that -> \sigma respectively. We have made the correction in the arxiv version of the paper.

Citations

If you use our method and code in your work, please cite the following:

@inproceedings{ depth-completion-with-twin-surface-extrapolation-at-occlusion-boundaries, author = { Saif Imran and Xiaoming Liu and Daniel Morris }, title = { Depth Completion with Twin-Surface Extrapolation at Occlusion Boundaries }, booktitle = { In Proceeding of IEEE Computer Vision and Pattern Recognition }, address = { Nashville, TN }, month = { June }, year = { 2021 }, }