{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/lposs-label-propagation-over-patches-and","title":"LPOSS: Label Propagation Over Patches and Pixels for Open-vocabulary Semantic Segmentation","arxiv_id":"2503.19777","date":"2025-03-25","proceeding":"CVPR 2025 1","authors":["Vladan Stojnić","Yannis Kalantidis","Jiří Matas","Giorgos Tolias"],"abstract":"We propose a training-free method for open-vocabulary semantic segmentation using Vision-and-Language Models (VLMs). Our approach enhances the initial per-patch predictions of VLMs through label propagation, which jointly optimizes predictions by incorporating patch-to-patch relationships. Since VLMs are primarily optimized for cross-modal alignment and not for intra-modal similarity, we use a Vision Model (VM) that is observed to better capture these relationships. We address resolution limitations inherent to patch-based encoders by applying label propagation at the pixel level as a refinement step, significantly improving segmentation accuracy near class boundaries. Our method, called LPOSS+, performs inference over the entire image, avoiding window-based processing and thereby capturing contextual interactions across the full image. LPOSS+ achieves state-of-the-art performance among training-free methods, across a diverse set of datasets. Code: https://github.com/vladan-stojnic/LPOSS","url_abs":"https://arxiv.org/abs/2503.19777v1","url_pdf":"https://arxiv.org/pdf/2503.19777v1.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"abstracts"},"code_links":[{"paper_slug":"lposs-label-propagation-over-patches-and","repo_url":"https://github.com/vladan-stojnic/lposs","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"pytorch","reach":{"status":"ok","spdx":"MIT"}}],"tasks":[{"task_slug":"open-vocabulary-semantic-segmentation","task_name":"Open Vocabulary Semantic Segmentation"},{"task_slug":"open-vocabulary-semantic-segmentation-1","task_name":"Open-Vocabulary Semantic Segmentation"},{"task_slug":"semantic-segmentation","task_name":"Semantic Segmentation"},{"task_slug":"cross-modal-alignment","task_name":"cross-modal alignment"}],"methods":[{"method_slug":"set","method_name":"SET"}],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":"https://app.syntology.ai/?focus=2503.19777","mcp":{"get_harvested_code_for_paper":{"arxiv_id":"2503.19777"}},"developers":"https://syntology.ai/developers","read_at":"2026-09-24T18:15:14+00:00","read_at_is":"when the build read Syntology's graph, not when any sample ran","claim":"Per-sample execution status on synthesized fixtures; not a correctness claim about the paper. Samples come from repositories linked to the paper, official or community; repo_kind says which.","repos":[{"provenance":"deterministic:regex_extraction","url":"https://github.com/vladan-stojnic/LPOSS","reach":{"status":"ok","spdx":"MIT"}}],"summary":{"unverified":5},"by_repo_kind":{"official":{"samples":5,"ran":0,"repositories":1}},"repo_kind_vocabulary":{"official":"The archive marks this repository official for the paper","named_in_paper":"The archive records that the paper mentions this repository; it is not marked official","listed":"In the archive's code links for this paper, not marked official and not recorded as mentioned in the paper","found_in_text":"Syntology found this repository in the paper's own text; whether it is the authors' implementation is not asserted","community":"Not in the archive's code links for this paper; a community repository Syntology harvested"},"n_pointer_only_for_licence":0,"samples":[{"code_sha256_prefix":"7888a0f3e835a7bc","entry":"boundary_iou","repo":"vladan-stojnic/LPOSS","repo_kind":"official","path":"metrics/boundary_iou.py","file_url":"https://github.com/vladan-stojnic/LPOSS/blob/HEAD/metrics/boundary_iou.py","link_basis":"harvester_set","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"7888a0f3e835a7bc"}},{"code_sha256_prefix":"be404cf84d0db914","entry":"boundary_iou_per_mask","repo":"vladan-stojnic/LPOSS","repo_kind":"official","path":"metrics/boundary_iou.py","file_url":"https://github.com/vladan-stojnic/LPOSS/blob/HEAD/metrics/boundary_iou.py","link_basis":"harvester_set","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"be404cf84d0db914"}},{"code_sha256_prefix":"d02ceb35d0c18e97","entry":"mask_to_boundary","repo":"vladan-stojnic/LPOSS","repo_kind":"official","path":"metrics/boundary_iou.py","file_url":"https://github.com/vladan-stojnic/LPOSS/blob/HEAD/metrics/boundary_iou.py","link_basis":"harvester_set","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"d02ceb35d0c18e97"}},{"code_sha256_prefix":"b8af38e8e300b135","entry":"reshape_features","repo":"vladan-stojnic/LPOSS","repo_kind":"official","path":"models/lposs/lposs.py","file_url":"https://github.com/vladan-stojnic/LPOSS/blob/HEAD/models/lposs/lposs.py","link_basis":"harvester_set","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"b8af38e8e300b135"}},{"code_sha256_prefix":"65435ed786c7ca91","entry":"reshape_windows","repo":"vladan-stojnic/LPOSS","repo_kind":"official","path":"segmentation/evaluation/lposs_eval.py","file_url":"https://github.com/vladan-stojnic/LPOSS/blob/HEAD/segmentation/evaluation/lposs_eval.py","link_basis":"harvester_set","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"65435ed786c7ca91"}}]},"arxiv_metadata":null,"syntology_extracted_results":null}