pix2gestalt: Amodal Segmentation by Synthesizing Wholes

1Columbia University 2Toyota Research Institute
Correspondence to: ege.ozguroglu@columbia.edu

pix2gestalt synthesizes whole objects from only partially visible ones, enabling amodal segmentation, recognition, and 3D reconstruction of occluded objects.

Abstract

We introduce pix2gestalt, a framework for zero-shot amodal segmentation, which learns to estimate the shape and appearance of whole objects that are only partially visible behind occlusions. By capitalizing on large-scale diffusion models and transferring their representations to this task, we learn a conditional diffusion model for reconstructing whole objects in challenging zero-shot cases, including examples that break natural and physical priors, such as art. As training data, we use a synthetically curated dataset containing occluded objects paired with their whole counterparts. Experiments show that our approach outperforms supervised baselines on established benchmarks. Our model can furthermore be used to significantly improve the performance of existing object recognition and 3D reconstruction methods in the presence of occlusions.

Zero-shot Amodal Perception

We demonstrate pix2gestalt's zero-shot amodal completion & segmentation capability on occlusions ranging from natural images to post-impressonist art. Please click on the videos to visualize our amodal reconstructions.

Natural Images (Amodal COCO)

We show qualitative results on Amodal COCO.

Natural Images (Amodal BSDS)

We show qualitative results on Amodal Berkeley Segmentation Dataset.

Visual Art

Occlusions in visual art often challenge priors on the natural image manifold. We showcase examples ranging from surrealist paintings to black & white photographs.

Negative Space Occlusions

While occluders are often elements of positive space, they can function as negative space too. Such cases challenge physical priors. We show negative space occlusions within sculptures, Magritte’s paintings, and one created by Harry Potter’s invisibility cloak.

Physical States within Occlusions

pix2gestalt can often uncover physical states of the world plausible within occlusions. In these examples, water accumulating on the tooth brush and the baby's weight marks on the sofa are captured.

Optical Illusions

While older methods can solve the checker-shadow illusion too, we sanity check whether our method can de-occlude its checkerboard with correct texture.

Practical Settings

Amodal perception is crucial for many downstream applications in vision, graphics, and robotics. We show practical examples from robotics and autonomous driving.

Limitations

We found that our approach has limitations in situations that require commonsense or physical reasoning. Notice the car going in the wrong direction, or the following samples that contradict physics.

How does it work?

We propose an amodal completion model using a latent diffusion architecture. Conditioned on an input occlusion image and a region of interest, the whole (amodal) form is synthesized, thereby allowing other visual tasks to be performed on it too.


More Qualitative Results

Please click on the videos to visualize our amodal reconstructions.



Concurrent Work

Related Work

BibTeX

@misc{ozguroglu2024pix2gestalt,
          title={pix2gestalt: Amodal Segmentation by Synthesizing Wholes}, 
          author={Ege Ozguroglu and Ruoshi Liu and Dídac Surís and Dian Chen and Achal Dave and Pavel Tokmakov and Carl Vondrick},
          year={2024},
          eprint={2401.14398},
          archivePrefix={arXiv},
          primaryClass={cs.CV}
    }