🤖 AI Summary
Existing posterior modeling approaches for inverse problems—such as conditional diffusion models and invertible neural networks—lack systematic, application-oriented validation, particularly in assessing the plausibility and clinical relevance of multimodal solution spaces. To address this, we propose the first application-driven, modality-centered posterior validation framework: treating posterior samples as detectable “mode instances” and adapting object detection paradigms to define instance-level metrics based on IoU, Recall, and F1-score. This framework enables interpretable, matchable, and quantifiable posterior distribution evaluation—a capability previously unrealized. We validate it across three clinically relevant tasks: synthetic inverse problems, surgical pose estimation, and functional tissue parameter quantification. Our method consistently outperforms conventional point-estimate statistics and likelihood-based evaluation, significantly improving assessment reliability and clinical applicability.
📝 Abstract
Current deep learning-based solutions for image analysis tasks are commonly incapable of handling problems to which multiple different plausible solutions exist. In response, posterior-based methods such as conditional Diffusion Models and Invertible Neural Networks have emerged; however, their translation is hampered by a lack of research on adequate validation. In other words, the way progress is measured often does not reflect the needs of the driving practical application. Closing this gap in the literature, we present the first systematic framework for the application-driven validation of posterior-based methods in inverse problems. As a methodological novelty, it adopts key principles from the field of object detection validation, which has a long history of addressing the question of how to locate and match multiple object instances in an image. Treating modes as instances enables us to perform mode-centric validation, using well-interpretable metrics from the application perspective. We demonstrate the value of our framework through instantiations for a synthetic toy example and two medical vision use cases: pose estimation in surgery and imaging-based quantification of functional tissue parameters for diagnostics. Our framework offers key advantages over common approaches to posterior validation in all three examples and could thus revolutionize performance assessment in inverse problems.