cs.CVOct 16, 2026

Look, Reason, Draw a Region: Recursive Refinement for Spatial Context Prediction

Authors: Wajeeha Tahir, Anna Tegon, Lionnus Kesting, Gamze İslamoğlu, Kristóf Karacs, Luca Benini, Thorir Mar Ingolfsson

Organizations: Integrated Systems Laboratory, ETH Zürich, Switzerland · Pázmány Péter Catholic University, Hungary

Abstract

Spatial context prediction requires visual grounding and spatial reasoning to identify vacant regions relative to objects in a scene. Spatial relationships and physical constraints remain challenging for large vision-language models (VLMs). Recursive reasoning has demonstrated strong performance on discrete and abstract reasoning tasks, motivating its use for improving spatial context prediction in natural images. Weight sharing enables higher accuracy with a small trainable parameter count. We introduce Spatial-TRM, a compact recursive model with frozen vision-language features, a convex region decoder, and just 11.2M trainable parameters. This weight-tied reasoner supports six spatial relationships, three reference frames, and open-vocabulary anchor objects. On the RoboSpatial-Home benchmark, Spatial-TRM achieves 29.51% context accuracy, a gain of 9.02 percentage points (44.0% relative) over a separately trained single-step model with the same parameter count. Including the frozen encoders, the model has 877.8M total parameters, approximately 15×15\times fewer than the reported 13B size of RoboPoint. These results show that repeated refinement improves spatial context prediction from pretrained vision-language features at a fixed trainable parameter count on this benchmark.

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