{"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/unidb-a-unified-diffusion-bridge-framework","title":"UniDB: A Unified Diffusion Bridge Framework via Stochastic Optimal Control","arxiv_id":"2502.05749","date":"2025-02-09","proceeding":null,"authors":["Kaizhen Zhu","Mokai Pan","Yuexin Ma","Yanwei Fu","Jingyi Yu","Jingya Wang","Ye Shi"],"abstract":"Recent advances in diffusion bridge models leverage Doob's $h$-transform to establish fixed endpoints between distributions, demonstrating promising results in image translation and restoration tasks. However, these approaches frequently produce blurred or excessively smoothed image details and lack a comprehensive theoretical foundation to explain these shortcomings. To address these limitations, we propose UniDB, a unified framework for diffusion bridges based on Stochastic Optimal Control (SOC). UniDB formulates the problem through an SOC-based optimization and derives a closed-form solution for the optimal controller, thereby unifying and generalizing existing diffusion bridge models. We demonstrate that existing diffusion bridges employing Doob's $h$-transform constitute a special case of our framework, emerging when the terminal penalty coefficient in the SOC cost function tends to infinity. By incorporating a tunable terminal penalty coefficient, UniDB achieves an optimal balance between control costs and terminal penalties, substantially improving detail preservation and output quality. Notably, UniDB seamlessly integrates with existing diffusion bridge models, requiring only minimal code modifications. Extensive experiments across diverse image restoration tasks validate the superiority and adaptability of the proposed framework. Our code is available at https://github.com/UniDB-SOC/UniDB/.","url_abs":"https://arxiv.org/abs/2502.05749v5","url_pdf":"https://arxiv.org/pdf/2502.05749v5.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":"unidb-a-unified-diffusion-bridge-framework","repo_url":"https://github.com/unidb-soc/unidb","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"pytorch","reach":{"status":"ok","spdx":"MIT"}}],"tasks":[{"task_slug":"image-restoration","task_name":"Image Restoration"}],"methods":[{"method_slug":"diffusion","method_name":"Diffusion"}],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":"https://app.syntology.ai/?focus=2502.05749","mcp":{"get_harvested_code_for_paper":{"arxiv_id":"2502.05749"}},"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":"external:paperswithcode_snapshot_2025-07-28","url":"https://github.com/unidb-soc/unidb","reach":{"status":"ok","spdx":"MIT"}}],"summary":{"ran":4,"ran_violates":2,"unverified":3},"by_repo_kind":{"official":{"samples":9,"ran":6,"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":"5b4b368d735cbee9","entry":"NonLinearity","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/models/modules/module_util.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/models/modules/module_util.py","link_basis":"harvester_set","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"5b4b368d735cbee9"}},{"code_sha256_prefix":"85bf2da666cd3d07","entry":"add_noise","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/deg_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/deg_utils.py","link_basis":"harvester_set","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":true,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"85bf2da666cd3d07"}},{"code_sha256_prefix":"d1ef6b8cb9a28a53","entry":"default","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/models/modules/module_util.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/models/modules/module_util.py","link_basis":"harvester_set","language":"python","status":"ran_violates","verification_level":1,"contract_check":"VIOLATES","metamorphic_tier":"deterministic","behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"d1ef6b8cb9a28a53"}},{"code_sha256_prefix":"608e364a9d2376a3","entry":"exists","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/models/modules/module_util.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/models/modules/module_util.py","link_basis":"harvester_set","language":"python","status":"ran_violates","verification_level":1,"contract_check":"VIOLATES","metamorphic_tier":"deterministic","behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"608e364a9d2376a3"}},{"code_sha256_prefix":"0a0f56e2ac5b29cf","entry":"mask_to","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/deg_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/deg_utils.py","link_basis":"harvester_set","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"0a0f56e2ac5b29cf"}},{"code_sha256_prefix":"b3ccfc519d222aca","entry":"upscale","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/deg_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/deg_utils.py","link_basis":"harvester_set","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"MIT","inline_ok":true,"mcp_get_code":{"code_sha256":"b3ccfc519d222aca"}},{"code_sha256_prefix":"1b40b4f3f0ea0b6e","entry":"tensor2img","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/img_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/img_utils.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":"1b40b4f3f0ea0b6e"}},{"code_sha256_prefix":"d7114767266ade00","entry":"to_pil_image","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/img_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/img_utils.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":"d7114767266ade00"}},{"code_sha256_prefix":"ed7d86a762c62a9e","entry":"to_tensor","repo":"unidb-soc/unidb","repo_kind":"official","path":"UniDB-GOU/utils/img_utils.py","file_url":"https://github.com/unidb-soc/unidb/blob/HEAD/UniDB-GOU/utils/img_utils.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":"ed7d86a762c62a9e"}}]},"arxiv_metadata":null,"syntology_extracted_results":null}