Christian Schellewald

About

I received my Ph.D. degree from the Department of Mathematics and Computer Science, University of Mannheim, Germany. Then I was a Marie Curie Postdoctoral Researcher in the School of Computing, Dublin City University (DCU), Dublin, Ireland. In 2009, I became a Postdoctoral Researcher at Norwegian University of Science and Technology (NTNU), Norway, and was supported by an Alain Bensoussan fellowship from the European Research Consortium for Informatics and Mathematics (ERCIM). Between 2012 and 2016 I was employed as Associate Professor at NTNU doing research and teaching. Currently I am working at SINTEF Ocean. My research interests include mathematical and applied problems that arise in the field of computer vision with particular focus in mathematical optimization and convex programming, statistical object and pattern recognition, symmetry detection, segmentation, classification, and 3-D reconstruction methods.

Publications

2025

Høgstedt, Espen Uri; Schellewald, Christian; Stahl, Annette; Mester, Rudolf. (2025) A Multi-Purpose Tracking Framework for Salmon Welfare Monitoring in Challenging Environments.
Academic chapter
Fjorden, Thomas; Høgstedt, Espen B.; Schellewald, Christian; Mester, Rudolf; Remen, Mette; Nytrø, Ane Vigdisdatter; Stahl, Annette. (2025) Image-based quantification of scale loss in fish using machine learning and computer vision. Proceedings of SPIE, the International Society for Optical Engineering
Academic article

2024

Skaldebø, Martin Breivik; Schellewald, Christian; Evjemo, Linn Danielsen; Amundsen, Herman Biørn; Xanthidis, Marios; Kelasidi, Eleni. (2024) Approaches Enabling Underwater Autonomy and Sensing in Sea-Based Aquaculture Settings.
Academic chapter
Høgstedt, Espen Berntzen; Schellewald, Christian; Mester, Rudolf; Stahl, Annette. (2024) Automated computer vision based individual salmon (Salmo salar) breathing rate estimation (SaBRE) for improved state observability. Aquaculture
Academic article
Fjorden, Thomas; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) AI-driven Analysis: Image based qualification of Scale Loss in Fish using Machine Learning and Computer Vision. Norges teknisk-naturvitenskapelige universitet
Master thesis
Wiik, Magnus; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) Assessing Re-Identification Capabilities of Salmon Body Parts Using AI-Based Computer Vision Methods. Norges teknisk-naturvitenskapelige universitet
Master thesis
Larsen, Sindre; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) Objective Analysis of Melanin Spots as Welfare Signals in Atlantic Salmon Using AI-Based Computer Vision. Norges teknisk-naturvitenskapelige universitet
Master thesis
Yip, Mau Hing; Stahl, Annette; Schellewald, Christian. (2024) Robust Hole-Detection in Triangular Meshes Irrespective of the Presence of Singular Vertices. Computer-Aided Design
Academic article
Yip, Mau Hing; Schellewald, Christian; Gambin, Timmy; Stahl, Annette. (2024) Active Pose - Autonomous Hole-Filling Techniques for 3D Surface Reconstruction in Underwater Exploration. IFAC-PapersOnLine
Academic article
Schellewald, Christian; Saad, Aya; Stahl, Annette. (2024) Mouth Opening Frequency of Salmon from Underwater Video Exploiting Computer Vision. IFAC-PapersOnLine
Academic article

2023

Høgstedt, Espen Berntzen; Stahl, Annette; Schellewald, Christian. (2023) Developing a deep learning pipeline for automated salmon welfare analysis by respiration frequency. Norges teknisk-naturvitenskapelige universitet
Master thesis

2022

Madshaven, Arild; Schellewald, Christian; Stahl, Annette. (2022) Hole Detection in Aquaculture Net Cages from Video Footage. Proceedings of SPIE, the International Society for Optical Engineering
Academic article
Schellewald, Christian; Stahl, Annette. (2022) Irregularity Detection in Net Pens Exploiting Computer Vision. IFAC-PapersOnLine
Academic article
Nygård, Trym Anthonsen; Jahren, Jan Henrik; Schellewald, Christian; Stahl, Annette. (2022) Motion Trajectory Estimation of Salmon Using Stereo Vision. IFAC-PapersOnLine
Academic article
Eilertsen, Espen; Asderis, Michalis; Papandroulakis, Nikos; Caharija, Walter; Frank, Kevin; kapelonis, Zacharias; Schellewald, Christian. (2022) Quantification of acoustic target shadowing for biomass estimation in aquaculture net-pens. OCEANS
Academic article

2021

Jónsdóttir, Kristbjörg Edda; Mathiassen, John Reidar Bartle; Schellewald, Christian; Volent, Zsolt; Rosten, Carolyn; Sunde, Leif Magne; Schrøder, Merete Bjørgan. (2021) Akustiske og visuelle verktøy kan bidra til dokumentasjon av fiskevelferd ved håndteringsoperasjoner. Norsk Fiskeoppdrett
Popular science article
Schellewald, Christian; Stahl, Annette; Kelasidi, Eleni. (2021) Vision-based pose estimation for autonomous operations in aquacultural fish farms. IFAC-PapersOnLine
Academic article
Svendsen, Eirik; Volent, Zsolt; Schellewald, Christian; Tsarau, Andrei; Bjorgan, Asgeir; Venås, Birger; Bloecher, Nina; Bondø, Morten Steen; Føre, Martin; Jónsdóttir, Kristbjörg Edda. (2021) Identification of spectral signature for in situ real-time monitoring of smoltification. Applied Optics
Academic article

2020

Kelasidi, Eleni; Schellewald, Christian; Yip, Mauhing; Remmen, Bjørnar Moe. (2020) Data capture and real-time data quality analysis - OC2020 A-033. SINTEF Ocean AS
Research report
Kelasidi, Eleni; Su, Biao; Thorbjørnsen, Eirik Storås; Moen, Endre; Schellewald, Christian; Yip, Mau Hing; Remmen, Bjørnar Moe; Mulelid, Mats. (2020) CAGEREPORTER - Development of technology for autonomous, bio-interactive and high-quality data acquisition from aquaculture net cages. SINTEF Ocean AS
Research report

2019

Lien, Andreas Myskja; Schellewald, Christian; Stahl, Annette; Frank, Kevin; Skøien, Kristoffer Rist; Tjølsen, Jan Inge. (2019) Determining spatial feed distribution in sea cage aquaculture using an aerial camera platform. Aquacultural Engineering
Academic literature review

2017

Føre, Martin; Svendsen, Eirik; Frank, Kevin; Schellewald, Christian; Sunde, Leif Magne; Stahl, Annette; Alfredsen, Jo Arve. (2017) LAKSIT:Telemetri og maskinsyn for overvåkning og dokumentasjon av fiskevelferd i avlusningsprosesser. Norsk Fiskeoppdrett
Popular science article
Føre, Martin; Frank, Kevin; Svendsen, Eirik; Schellewald, Christian; Sunde, Leif Magne; Alfredsen, Jo Arve; Stahl, Annette. (2017) Telemetri og maskinsyn for overvåking av trender i tilstander hos laks før, under og etter avlusning Prosjektrapport for prosjektet "Teknologi for nye datatyper og informasjon som beskriver situasjon og tilstand hos laksefisk i kommersielle merder (LAKSIT)" FHF Pnr. 901184. SINTEF Ocean AS
Research report
Føre, Martin; Frank, Kevin; Norton, Tomas; Svendsen, Eirik; Alfredsen, Jo Arve; Dempster, Timothy David; Eguiraun, Harkaitz; Watson, Win; Stahl, Annette; Sunde, Leif Magne. (2017) Precision fish farming: A new framework to improve production in aquaculture. Biosystems Engineering
Academic article

2016

Stahl, Annette; Kvamsdal, Trond; Schellewald, Christian. (2016) Post-processing and visualization techniques for isogeometric analysis results. Computer Methods in Applied Mechanics and Engineering
Academic article

2014

Schellewald, Christian; Kazakauskas, Vilius. (2014) 3D Surface Matching Optimization Techniques and Registration of Large Data Sets. Tapir Akademisk Forlag
Master thesis

2013

Schellewald, Christian; Theoharis, Theoharis; Gebremariam, Kidane Fanta; Kvittingen, Lise. (2013) FP7-ICT D3.1 State-of-the-art Report on Deterioration Simulation; Deliverable Workpackage 3. presious
Research report

2012

Stahl, Annette; Schellewald, Christian; Stavdahl, Øyvind; Aamo, Ole Morten; Adde, Lars; Kirkerød, Harald. (2012) An Optical Flow-Based Method to Predict Infantile Cerebral Palsy. IEEE transactions on neural systems and rehabilitation engineering
Academic article
Schellewald, Christian. (2012) A Convex Relaxation Bound for Subgraph Isomorphism. International Journal of Combinatorics
Academic article

2007

Schellewald, Christian. (2007) A Bound for Non-subgraph Isomorphism. Springer
Anthology
Schellewald, Christian; Roth, Stefan; Schnoerr, Christoph. (2007) Evaluation of a convex relaxation approach to the quadratic assignment of relational object views. Image and Vision Computing
Academic article

2005

Schellewald, Christian; Schnoerr, Christoph. (2005) Probabilistic Subgraph Matching Based on Convex Relaxation. Springer
Anthology
Schellewald, Christian. (2005) Convex Mathematical Programs for Relational Matching of Object Views. University of Mannheim
Doctoral thesis

2003

Schellewald, Christian; Schnoerr, Christoph. (2003) Subgraph Matching with Semidefinite Programming. Electronic Notes in Discrete Mathematics
Academic article
Keuchel, Jens; Schnoerr, Christoph; Schellewald, Christian; Cremers, Daniel. (2003) Binary Partitioning, Perceptual Grouping, and Restoration with Semidefinite Programming. IEEE Transactions on Pattern Analysis and Machine Intelligence
Academic article
Schellewald, Christian; Winkler, Florian. (2003) Optimization techniques for the estimation of disparity in stereo images. CVGPR--group, University of Mannheim, Germany
Master thesis

2002

Schellewald, Christian; Roth, Stefan. (2002) Performance evaluation of a convex relaxation ap- proach to the quadratic assignment of relational object views. University of Mannheim
Research report
Schellewald, Christian. (2002) Unsupervised Image Partitioning with Semidefinite Programming. Springer
Anthology
Schellewald, Christian; Schnoerr, Christoph. (2002) Subgraph matching with semidefinite programming. University of Mannheim
Research report
Keuchel, Jens; Schnoerr, Christoph; Schellewald, Christian; Cremers, Daniel. (2002) Binary partitioning, perceptual grouping, and restoration with semidefinite programming. University of Mannheim
Research report

2001

Schellewald, Christian; Roth, Stefan; Schnoerr, Christoph. (2001) Evaluation of Convex Optimization Techniques for the Weighted Graph-Matching Problem in Computer Vision. Lecture Notes in Computer Science (LNCS)
Academic article
Keuchel, Jens; Schellewald, Christian; Cremers, Daniel; Schnoerr, Christoph. (2001) Convex Relaxations for Binary Image Partitioning and Perceptual Grouping. Lecture Notes in Computer Science (LNCS)
Academic article
Schellewald, Christian; Keuchel, Jens; Schnoerr, Christoph. (2001) Image Labeling and Grouping by Minimizing Linear Functionals over Cones. Lecture Notes in Computer Science (LNCS)
Academic article
Schellewald, Christian; Roth, Stefan. (2001) Analysis of a Deterministic Annealing Method for Graph Matching and Quadratic Assignment Problems in Computer Vision. CVGPR--group, University of Mannheim
Master thesis

2000

Cremers, Daniel; Schnoerr, Christoph; Weickert, J.; Schellewald, Christian. (2000) Learning Translation Invariant Shape Knowledge for Steering Diffusion-Snakes. The journal of artificial intelligence research
Academic article
Cremers, Daniel; Schnoerr, Christoph; Weickert, J.; Schellewald, Christian. (2000) Diffusion-snakes using statistical shape knowledge. Lecture Notes in Computer Science (LNCS)
Academic article

1996

Schellewald, Christian. (1996) Kriterien für quantenmechanische integrabilität. Institut of Physics, University of Dortmund
Master thesis

Journal publications

Fjorden, Thomas; Høgstedt, Espen B.; Schellewald, Christian; Mester, Rudolf; Remen, Mette; Nytrø, Ane Vigdisdatter; Stahl, Annette. (2025) Image-based quantification of scale loss in fish using machine learning and computer vision. Proceedings of SPIE, the International Society for Optical Engineering
Academic article
Schellewald, Christian; Roth, Stefan; Schnoerr, Christoph. (2001) Evaluation of Convex Optimization Techniques for the Weighted Graph-Matching Problem in Computer Vision. Lecture Notes in Computer Science (LNCS)
Academic article
Schellewald, Christian; Schnoerr, Christoph. (2003) Subgraph Matching with Semidefinite Programming. Electronic Notes in Discrete Mathematics
Academic article
Stahl, Annette; Schellewald, Christian; Stavdahl, Øyvind; Aamo, Ole Morten; Adde, Lars; Kirkerød, Harald. (2012) An Optical Flow-Based Method to Predict Infantile Cerebral Palsy. IEEE transactions on neural systems and rehabilitation engineering
Academic article
Keuchel, Jens; Schellewald, Christian; Cremers, Daniel; Schnoerr, Christoph. (2001) Convex Relaxations for Binary Image Partitioning and Perceptual Grouping. Lecture Notes in Computer Science (LNCS)
Academic article
Jónsdóttir, Kristbjörg Edda; Mathiassen, John Reidar Bartle; Schellewald, Christian; Volent, Zsolt; Rosten, Carolyn; Sunde, Leif Magne; Schrøder, Merete Bjørgan. (2021) Akustiske og visuelle verktøy kan bidra til dokumentasjon av fiskevelferd ved håndteringsoperasjoner. Norsk Fiskeoppdrett
Popular science article
Føre, Martin; Svendsen, Eirik; Frank, Kevin; Schellewald, Christian; Sunde, Leif Magne; Stahl, Annette; Alfredsen, Jo Arve. (2017) LAKSIT:Telemetri og maskinsyn for overvåkning og dokumentasjon av fiskevelferd i avlusningsprosesser. Norsk Fiskeoppdrett
Popular science article
Schellewald, Christian; Roth, Stefan; Schnoerr, Christoph. (2007) Evaluation of a convex relaxation approach to the quadratic assignment of relational object views. Image and Vision Computing
Academic article
Keuchel, Jens; Schnoerr, Christoph; Schellewald, Christian; Cremers, Daniel. (2003) Binary Partitioning, Perceptual Grouping, and Restoration with Semidefinite Programming. IEEE Transactions on Pattern Analysis and Machine Intelligence
Academic article
Schellewald, Christian; Stahl, Annette; Kelasidi, Eleni. (2021) Vision-based pose estimation for autonomous operations in aquacultural fish farms. IFAC-PapersOnLine
Academic article
Madshaven, Arild; Schellewald, Christian; Stahl, Annette. (2022) Hole Detection in Aquaculture Net Cages from Video Footage. Proceedings of SPIE, the International Society for Optical Engineering
Academic article
Cremers, Daniel; Schnoerr, Christoph; Weickert, J.; Schellewald, Christian. (2000) Learning Translation Invariant Shape Knowledge for Steering Diffusion-Snakes. The journal of artificial intelligence research
Academic article
Cremers, Daniel; Schnoerr, Christoph; Weickert, J.; Schellewald, Christian. (2000) Diffusion-snakes using statistical shape knowledge. Lecture Notes in Computer Science (LNCS)
Academic article
Schellewald, Christian; Keuchel, Jens; Schnoerr, Christoph. (2001) Image Labeling and Grouping by Minimizing Linear Functionals over Cones. Lecture Notes in Computer Science (LNCS)
Academic article
Høgstedt, Espen Berntzen; Schellewald, Christian; Mester, Rudolf; Stahl, Annette. (2024) Automated computer vision based individual salmon (Salmo salar) breathing rate estimation (SaBRE) for improved state observability. Aquaculture
Academic article
Schellewald, Christian. (2012) A Convex Relaxation Bound for Subgraph Isomorphism. International Journal of Combinatorics
Academic article
Lien, Andreas Myskja; Schellewald, Christian; Stahl, Annette; Frank, Kevin; Skøien, Kristoffer Rist; Tjølsen, Jan Inge. (2019) Determining spatial feed distribution in sea cage aquaculture using an aerial camera platform. Aquacultural Engineering
Academic literature review
Schellewald, Christian; Stahl, Annette. (2022) Irregularity Detection in Net Pens Exploiting Computer Vision. IFAC-PapersOnLine
Academic article
Nygård, Trym Anthonsen; Jahren, Jan Henrik; Schellewald, Christian; Stahl, Annette. (2022) Motion Trajectory Estimation of Salmon Using Stereo Vision. IFAC-PapersOnLine
Academic article
Svendsen, Eirik; Volent, Zsolt; Schellewald, Christian; Tsarau, Andrei; Bjorgan, Asgeir; Venås, Birger; Bloecher, Nina; Bondø, Morten Steen; Føre, Martin; Jónsdóttir, Kristbjörg Edda. (2021) Identification of spectral signature for in situ real-time monitoring of smoltification. Applied Optics
Academic article
Eilertsen, Espen; Asderis, Michalis; Papandroulakis, Nikos; Caharija, Walter; Frank, Kevin; kapelonis, Zacharias; Schellewald, Christian. (2022) Quantification of acoustic target shadowing for biomass estimation in aquaculture net-pens. OCEANS
Academic article
Yip, Mau Hing; Stahl, Annette; Schellewald, Christian. (2024) Robust Hole-Detection in Triangular Meshes Irrespective of the Presence of Singular Vertices. Computer-Aided Design
Academic article
Yip, Mau Hing; Schellewald, Christian; Gambin, Timmy; Stahl, Annette. (2024) Active Pose - Autonomous Hole-Filling Techniques for 3D Surface Reconstruction in Underwater Exploration. IFAC-PapersOnLine
Academic article
Føre, Martin; Frank, Kevin; Norton, Tomas; Svendsen, Eirik; Alfredsen, Jo Arve; Dempster, Timothy David; Eguiraun, Harkaitz; Watson, Win; Stahl, Annette; Sunde, Leif Magne. (2017) Precision fish farming: A new framework to improve production in aquaculture. Biosystems Engineering
Academic article
Schellewald, Christian; Saad, Aya; Stahl, Annette. (2024) Mouth Opening Frequency of Salmon from Underwater Video Exploiting Computer Vision. IFAC-PapersOnLine
Academic article
Stahl, Annette; Kvamsdal, Trond; Schellewald, Christian. (2016) Post-processing and visualization techniques for isogeometric analysis results. Computer Methods in Applied Mechanics and Engineering
Academic article

Books

Schellewald, Christian. (2007) A Bound for Non-subgraph Isomorphism. Springer
Anthology
Schellewald, Christian; Schnoerr, Christoph. (2005) Probabilistic Subgraph Matching Based on Convex Relaxation. Springer
Anthology
Schellewald, Christian. (2002) Unsupervised Image Partitioning with Semidefinite Programming. Springer
Anthology

Part of book/report

Høgstedt, Espen Uri; Schellewald, Christian; Stahl, Annette; Mester, Rudolf. (2025) A Multi-Purpose Tracking Framework for Salmon Welfare Monitoring in Challenging Environments.
Academic chapter
Skaldebø, Martin Breivik; Schellewald, Christian; Evjemo, Linn Danielsen; Amundsen, Herman Biørn; Xanthidis, Marios; Kelasidi, Eleni. (2024) Approaches Enabling Underwater Autonomy and Sensing in Sea-Based Aquaculture Settings.
Academic chapter

Report

Schellewald, Christian; Theoharis, Theoharis; Gebremariam, Kidane Fanta; Kvittingen, Lise. (2013) FP7-ICT D3.1 State-of-the-art Report on Deterioration Simulation; Deliverable Workpackage 3. presious
Research report
Føre, Martin; Frank, Kevin; Svendsen, Eirik; Schellewald, Christian; Sunde, Leif Magne; Alfredsen, Jo Arve; Stahl, Annette. (2017) Telemetri og maskinsyn for overvåking av trender i tilstander hos laks før, under og etter avlusning Prosjektrapport for prosjektet "Teknologi for nye datatyper og informasjon som beskriver situasjon og tilstand hos laksefisk i kommersielle merder (LAKSIT)" FHF Pnr. 901184. SINTEF Ocean AS
Research report
Schellewald, Christian; Roth, Stefan. (2002) Performance evaluation of a convex relaxation ap- proach to the quadratic assignment of relational object views. University of Mannheim
Research report
Kelasidi, Eleni; Schellewald, Christian; Yip, Mauhing; Remmen, Bjørnar Moe. (2020) Data capture and real-time data quality analysis - OC2020 A-033. SINTEF Ocean AS
Research report
Kelasidi, Eleni; Su, Biao; Thorbjørnsen, Eirik Storås; Moen, Endre; Schellewald, Christian; Yip, Mau Hing; Remmen, Bjørnar Moe; Mulelid, Mats. (2020) CAGEREPORTER - Development of technology for autonomous, bio-interactive and high-quality data acquisition from aquaculture net cages. SINTEF Ocean AS
Research report
Schellewald, Christian; Schnoerr, Christoph. (2002) Subgraph matching with semidefinite programming. University of Mannheim
Research report
Keuchel, Jens; Schnoerr, Christoph; Schellewald, Christian; Cremers, Daniel. (2002) Binary partitioning, perceptual grouping, and restoration with semidefinite programming. University of Mannheim
Research report

Student thesis or dissertation

Schellewald, Christian; Kazakauskas, Vilius. (2014) 3D Surface Matching Optimization Techniques and Registration of Large Data Sets. Tapir Akademisk Forlag
Master thesis
Fjorden, Thomas; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) AI-driven Analysis: Image based qualification of Scale Loss in Fish using Machine Learning and Computer Vision. Norges teknisk-naturvitenskapelige universitet
Master thesis
Wiik, Magnus; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) Assessing Re-Identification Capabilities of Salmon Body Parts Using AI-Based Computer Vision Methods. Norges teknisk-naturvitenskapelige universitet
Master thesis
Larsen, Sindre; Stahl, Annette; Schellewald, Christian; Mester, Rudolf; Høgstedt, Espen Berntzen. (2024) Objective Analysis of Melanin Spots as Welfare Signals in Atlantic Salmon Using AI-Based Computer Vision. Norges teknisk-naturvitenskapelige universitet
Master thesis
Schellewald, Christian. (2005) Convex Mathematical Programs for Relational Matching of Object Views. University of Mannheim
Doctoral thesis
Schellewald, Christian. (1996) Kriterien für quantenmechanische integrabilität. Institut of Physics, University of Dortmund
Master thesis
Høgstedt, Espen Berntzen; Stahl, Annette; Schellewald, Christian. (2023) Developing a deep learning pipeline for automated salmon welfare analysis by respiration frequency. Norges teknisk-naturvitenskapelige universitet
Master thesis
Schellewald, Christian; Roth, Stefan. (2001) Analysis of a Deterministic Annealing Method for Graph Matching and Quadratic Assignment Problems in Computer Vision. CVGPR--group, University of Mannheim
Master thesis
Schellewald, Christian; Winkler, Florian. (2003) Optimization techniques for the estimation of disparity in stereo images. CVGPR--group, University of Mannheim, Germany
Master thesis

Outreach