# Template-free 3D Reconstruction of Poorly-textured Nonrigid Surfaces
Supplementary Material

Paper ID 1507

In this supplementary material, we firstly show the video sequences of our results. Then we compare this initialization with our final results and evaluate potential failure cases of our approach.

## Video Sequences of Our Results

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The following videos compare the results of our approach with those of the baselines described in the main paper for the three synthetic and three real sequences discussed in Section 4. Note that our approach, that jointly performs 2D registration and 3D reconstruction, yields much more accurate results than the baselines. The videos are encoded in MOV format and were tested with the QuickTime player and with the VLC player.

### Synthetic data with Ground-Truth (Section 4.1)

- synthetic-cardboard.mov

- synthetic-cardboard-minimal.mov

- synthetic-cloth.mov

### Real Images without Ground-Truth (Section 4.2)

- real-cardboard.mov

- real-napkin.mov

- real-cap.mov

### Starting from a non-planar surface

In addition to the cap sequence above, we further illustrate that our approach can handle the case where the shape in the first frame is not planar using the same real cardboard sequence as above, but starting from the middle of the sequence. The results of our approach are shown in the following video. Note that our reconstructions remain accurate.

- non-planar.mov

## Evaluation Initialization

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In Table 1, we compare the 2D and 3D errors of our initialization with our results. It shows that our approach improves both 2D and 3D errors.

Table 1. Comparison of our initialization with our results. We show the 2D registration and 3D reconstruction errors (initialization/final) on three synthetic datasets.

| Cardboard | Minimal texture | Cloth
Mean error (2D) | 4.8063/2.1778 | 8.1102/6.5911 | 5.9234/4.1810
Max error (2D) | 15.558/10.127 | 37.869/32.252 | 38.404/28.667
Mean error (3D) | 0.1204/0.0359 | 0.3221/0.1239 | 0.1476/0.0176
Max error (3D) | 0.1638/0.0623 | 0.3693/0.2734 | 0.1594/0.0274

## Failure Cases

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To evaluate potential failure cases, we used images without surface boundary. To this end, we employed the synthetic cardboard data and used the same color for the background and the main surface area. As shown in Fig. 1, the results of our method remain better than the baselines on the same data. It shows that not observing boundary together with having only minimal texture constitutes a real challenge which will be a topic for future research.

Fig. 1. Reconstructing surfaces without boundary. We plot the ground-truth mesh (red) and our result (green) for the frame with the largest deformation. The bar plots compare the mean and max 3D errors of our approach with the baselines. While the errors increased, note that our method still yields more accurate reconstructions than the baselines.