The Importance of Estimating 3D Human Pose and Shape
Estimating 3D Human Pose and Shape (HPS) from photos and videos is essential for understanding human actions in real-world scenarios. However, this task comes with challenges such as depth ambiguities, occlusion, unusual clothing, and motion blur, which can lead to errors in the inference process. To ensure the accuracy of HPS results, it is necessary to have a mechanism to assess the uncertainty or confidence level of the estimation.
Addressing Uncertainty in 3D Human Pose and Shape Estimation
One approach to handling uncertainty is to output multiple bodies, but this still lacks a clear measure of uncertainty. Some methods estimate a distribution over body parameters, but they are slow and trade off accuracy for speed. They require multiple forward network passes to generate samples, and the accuracy improves with more samples but at the cost of increased computational demands.
Recently, a new approach called POCO (POse and shape estimation with COnfidence) has been developed to address these challenges. POCO extends existing HPS methods to estimate uncertainty by directly inferring both body parameters and regression uncertainty in a single feed-forward pass. This uncertainty value is highly correlated with the quality of the reconstruction. The key innovation in POCO is the Dual Conditioning Strategy (DCS), which enhances the base density function and scale network. This approach improves both pose reconstruction and uncertainty estimation.
The Benefits of POCO in 3D Human Pose and Shape Estimation
Unlike previous approaches, POCO uses a conditional vector (Cond-bDF) to model the base density function of the inferred pose error. Instead of a simplistic one-hot encoding, POCO utilizes image features for conditioning, allowing for more scalable training on diverse and complex image datasets. Additionally, POCO improves uncertainty estimation by using image features and conditioning the network on the SMPL pose. This integration into existing HPS models improves accuracy without any downsides.
In comparative evaluations, POCO outperforms state-of-the-art methods in correlating uncertainty with pose errors. This means that POCO provides more accurate and reliable uncertainty estimation, making it a valuable framework for 3D human pose and shape estimation.