# Test-time Contrastive Concepts for Open-world Semantic Segmentation with Vision-Language Models Source: [Test-time Contrastive Concepts for Open-world Semantic Segmentation with Vision-Language Models]() Collection index: [llms.txt]() Data updated: 2025-10-26T04:58:48.249Z Authors: Monika Wysocza\\'nska, Antonin Vobecky, Amaia Cardiel, Tomasz Trzci\\'nski, Renaud Marlet, Andrei Bursuc, Oriane Sim\\'eoni Published: 2024-07-06T12:18:43.000Z ## Abstract Recent CLIP-like Vision-Language Models (VLMs), pre-trained on large amounts of image-text pairs to align both modalities with a simple contrastive objective, have paved the way to open-vocabulary semantic segmentation. Given an arbitrary set of textual queries, image pixels are assigned the closest query in feature space. However, this works well when a user exhaustively lists all possible visual concepts in an image that contrast against each other for the assignment. This corresponds to the current evaluation setup in the literature, which relies on having access to a list of in-domain relevant concepts, typically classes of a benchmark dataset. Here, we consider the more challenging (and realistic) scenario of segmenting a single concept, given a textual prompt and nothing else. To achieve good results, besides contrasting with the generic 'background' text, we propose two different approaches to automatically generate, at test time, query-specific textual contrastive concepts. We do so by leveraging the distribution of text in the VLM's training set or crafted LLM prompts. We also propose a metric designed to evaluate this scenario and show the relevance of our approach on commonly used datasets. ## Recorded benchmark results A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage. ## Original sources and implementation [Original paper]() [PDF]()