Hans Johnson
Associate Professor
Iowa City, Iowa, United States
Summary
🤩
Rockstar🎓
Top SchoolHans Johnson is an Associate Professor at the University of Iowa with 23 years of experience applying image analysis and high-performance computing to advance medical imaging research and clinical tools. He combines deep academic leadership—directing image processing initiatives and training students—with hands-on systems engineering, contributing performance and build-system improvements to core open-source toolkits like ITK, SimpleITK, MONAI, and ANTs. His work spans algorithm optimization, robust DevOps for scientific software, and scalable data handling, including contributions that modernized C++ codebases and improved build/test infrastructures for projects such as LAPACK and BART. Known for quietly improving reliability and reproducibility, he has a track record of fixing subtle compiler issues, deprecations, and performance bottlenecks that enable large-scale neuroimaging and MRI toolchains. Holding a Ph.D. in Electrical and Computer Engineering from the University of Iowa, he applies rigorous engineering practices to accelerate discovery and improve patient care through reproducible, high-performance imaging software.
23 years of coding experience
8 years of employment as a software developer
Ph.D., Electrical And Computer Engineering, Ph.D., Electrical And Computer Engineering at University of Iowa
Github Skills (65)
python10
image-processing10
simpleitk10
cmake10
build-automation10
numerical-optimization10
cpp10
optimization10
code-optimization10
develop10
architecture10
optimisation10
data-processing10
algorithm10
git10
Programming languages (20)
Github contributions (5)
InsightSoftwareConsortium/ITK
Dec 2002 - Dec 2022
Insight Toolkit (ITK) -- Official Repository. ITK builds on a proven, spatially-oriented architecture for processing, segmentation, and registration of scientific images in two, three, or more dimensions.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:850 reviews, 2718 commits, 1313 PRs in 20 years 3 months
Contributions summary:Hans primarily contributed to improving the performance and efficiency of the image processing toolkit, specifically within the domain of image analysis and processing. Their work focused on refactoring code, optimizing algorithms, and implementing improvements such as efficient memory handling and algorithm optimization within the core code. A significant part of their work involved making improvements to the FFTW library. The commits demonstrate expertise in optimizing image processing algorithms and underlying libraries for performance.
pythonitkcomputer-visionopen-sciencescientific
ANTsX/ANTs
Feb 2012 - May 2022
Advanced Normalization Tools (ANTs)
Role in this project:Back-end Developer
Back-end DeveloperContributions:1 review, 362 commits, 60 PRs in 10 years 4 months
Contributions summary:Hans contributed to the build process by adding VTK build and refactoring various aspects of the compilation and testing system. This involved modifications to CMake files, particularly the SuperBuild and ANTS configuration, indicating a focus on building and managing dependencies. The user also fixed issues related to compiler warnings, including the use of deprecated APIs, demonstrating an understanding of code quality and maintenance within the project.
antsnormalizationimage-registrationimage-segmentationmedical-image-processing
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