Neural Texture Puppeteer: A Framework for Neural Geometry and Texture Rendering of Articulated Shapes, Enabling Re-Identification at Interactive Speed

In this paper, we present a neural rendering pipeline for textured articulated shapes that we call Neural Texture Puppeteer. Our method separates geometry and texture encoding. The geometry pipeline learns to capture spatial relationships on the surface of the articulated shape from ground truth data that provides this geometric information. A texture auto-encoder makes use of this information to encode textured images into a global latent code. This global texture embedding can be efficiently trained separately from the geometry, and used in a downstream task to identify individuals. The neural texture rendering and the identification of individuals run at interactive speeds. To the best of our knowledge, we are the first to offer a promising alternative to CNN- or transformer-based approaches for re-identification of articulated individuals based on neural rendering. Realistic looking novel view and pose synthesis for different synthetic cow textures further demonstrate the quality of our method. Restricted by the availability of ground truth data for the articulated shape's geometry, the quality for real-world data synthesis is reduced. We further demonstrate the flexibility of our model for real-world data by applying a synthetic to real-world texture domain shift where we reconstruct the texture from a real-world 2D RGB image. Thus, our method can be applied to endangered species where data is limited. Our novel synthetic texture dataset NePuMoo is publicly available to inspire further development in the field of neural rendering-based re-identification.

3D-MuPPET: 3D Multi-Pigeon Pose Estimation and Tracking

Markerless methods for animal posture tracking have been developing recently, but frameworks and benchmarks for tracking large animal groups in 3D are still lacking. To overcome this gap in the literature, we present 3D-MuPPET, a framework to estimate and track 3D poses of up to 10 pigeons at interactive speed using multiple-views. We train a pose estimator to infer 2D keypoints and bounding boxes of multiple pigeons, then triangulate the keypoints to 3D. For correspondence matching, we first dynamically match 2D detections to global identities in the first frame, then use a 2D tracker to maintain correspondences accross views in subsequent frames. We achieve comparable accuracy to a state of the art 3D pose estimator for Root Mean Square Error (RMSE) and Percentage of Correct Keypoints (PCK). We also showcase a novel use case where our model trained with data of single pigeons provides comparable results on data containing multiple pigeons. This can simplify the domain shift to new species because annotating single animal data is less labour intensive than multi-animal data. Additionally, we benchmark the inference speed of 3D-MuPPET, with up to 10 fps in 2D and 1.5 fps in 3D, and perform quantitative tracking evaluation, which yields encouraging results. Finally, we show that 3D-MuPPET also works in natural environments without model fine-tuning on additional annotations. To the best of our knowledge we are the first to present a framework for 2D/3D posture and trajectory tracking that works in both indoor and outdoor environments.