{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T16:53:09Z","timestamp":1777654389696,"version":"3.51.4"},"reference-count":54,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T00:00:00Z","timestamp":1657497600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"German Academic Exchange Service (DAAD)","award":["91803781"],"award-info":[{"award-number":["91803781"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Contrast maximization (CMax) is a framework that provides state-of-the-art results on several event-based computer vision tasks, such as ego-motion or optical flow estimation. However, it may suffer from a problem called event collapse, which is an undesired solution where events are warped into too few pixels. As prior works have largely ignored the issue or proposed workarounds, it is imperative to analyze this phenomenon in detail. Our work demonstrates event collapse in its simplest form and proposes collapse metrics by using first principles of space\u2013time deformation based on differential geometry and physics. We experimentally show on publicly available datasets that the proposed metrics mitigate event collapse and do not harm well-posed warps. To the best of our knowledge, regularizers based on the proposed metrics are the only effective solution against event collapse in the experimental settings considered, compared with other methods. We hope that this work inspires further research to tackle more complex warp models.<\/jats:p>","DOI":"10.3390\/s22145190","type":"journal-article","created":{"date-parts":[[2022,7,12]],"date-time":"2022-07-12T03:50:36Z","timestamp":1657597836000},"page":"5190","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":37,"title":["Event Collapse in Contrast Maximization Frameworks"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6053-2285","authenticated-orcid":false,"given":"Shintaro","family":"Shiba","sequence":"first","affiliation":[{"name":"Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1, Kohoku-ku, Yokohama 223-8522, Kanagawa, Japan"},{"name":"Department of Electrical Engineering and Computer Science, Technische Universit\u00e4t Berlin, 10587 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshimitsu","family":"Aoki","sequence":"additional","affiliation":[{"name":"Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1, Kohoku-ku, Yokohama 223-8522, Kanagawa, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2672-9241","authenticated-orcid":false,"given":"Guillermo","family":"Gallego","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Computer Science, Technische Universit\u00e4t Berlin, 10587 Berlin, Germany"},{"name":"Einstein Center Digital Future and Science of Intelligence Excellence Cluster, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,11]]},"reference":[{"key":"ref_1","unstructured":"Delbruck, T. 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