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U-Net: deep learning for cell counting, detection, and morphometry

An Author Correction to this article was published on 25 February 2019

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U-Net is a generic deep-learning solution for frequently occurring quantification tasks such as cell detection and shape measurements in biomedical image data. We present an ImageJ plugin that enables non-machine-learning experts to analyze their data with U-Net on either a local computer or a remote server/cloud service. The plugin comes with pretrained models for single-cell segmentation and allows for U-Net to be adapted to new tasks on the basis of a few annotated samples.

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Fig. 1: Pipelines of the U-Net software.
Fig. 2: Example applications of U-Net for 2D and 3D detection and segmentation.

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Data availability

Datasets F1-MSC, F2-GOWT1, F3-SIM, F4-HeLa, DIC1-HeLa, PC1-U373 and PC2-PSC are from the ISBI Cell Tracking Challenge 2015 (ref. 17). Information on how to obtain the data can be found at, and free registration for the challenge is currently required. Datasets PC3-HKPV, BF1-POL, BF2-PPL and BF3-MiSp are custom and are available from the corresponding author upon reasonable request. Datasets for the detection experiments partially contain unpublished sample-preparation protocols and are currently not freely available. After protocol publication, datasets will be made available on an as-requested basis. Details on sample preparation for our life science experiments can be found in Supplementary Note 3 and the Life Sciences Reporting Summary.

Change history

  • 25 February 2019

    In the version of this paper originally published, one of the affiliations for Dominic Mai was incorrect: "Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University, Freiburg, Germany" should have been "Life Imaging Center, Center for Biological Systems Analysis, Albert-Ludwigs-University, Freiburg, Germany." This change required some renumbering of subsequent author affiliations. These corrections have been made in the PDF and HTML versions of the article, as well as in any cover sheets for associated Supplementary Information.


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This work was supported by the German Federal Ministry for Education and Research (BMBF) through the MICROSYSTEMS project (0316185B) to T.F. and A.D.; the Bernstein Award 2012 (01GQ2301) to I.D.; the Federal Ministry for Economic Affairs and Energy (ZF4184101CR5) to A.B.; the Deutsche Forschungsgemeinschaft (DFG) through the collaborative research center KIDGEM (SFB 1140) to D.M., Ö.Ç., T.F. and O.R., and (SFB 746, INST 39/839,840,841) to K.P.; the Clusters of Excellence BIOSS (EXC 294) to T.F., D.M., R.B., A.A., Y.M., D.S., T.L.T., M.P., K.P., M.S., T.B. and O.R.; BrainLinks-Brain-Tools (EXC 1086) to Z.J., K.S., I.D. and T.B.; grants DI 1908/3-1 to J.D., DI 1908/6-1 to Z.J. and K.S., and DI 1908/7-1 to I.D.; the Swiss National Science Foundation (SNF grant 173880) to A.A.; the ERC Starting grant OptoMotorPath (338041) to I.D.; and the FENS-Kavli Network of Excellence (FKNE) to I.D. We thank F. Prósper, E. Bártová, V. Ulman, D. Svoboda, G. van Cappellen, S. Kumar, T. Becker and the Mitocheck consortium for providing a rich diversity of datasets through the ISBI segmentation challenge. We thank P. Fischer for manual image annotations. We thank S. Wrobel for tobacco microspore preparation.

Author information

Authors and Affiliations



T.F., D.M., R.B., Y.M., Ö.Ç., T.B. and O.R. selected and designed the computational experiments. T.F., R.B., D.M., Y.M., A.B. and Ö.Ç. performed the experiments: R.B., D.M., Y.M. and A.B. (2D), and T.F. and Ö.Ç. (3D). R.B., Ö.Ç., A.A., T.F. and O.R. implemented the U-Net extensions into caffe. T.F. designed and implemented the Fiji plugin. D.S. and M.S. selected, prepared and recorded the keratinocyte dataset PC3-HKPV. T.F. and O.R. prepared the airborne-pollen dataset BF1-POL. A.D., S.W., O.T., C.D.B. and K.P. selected, prepared and recorded the protoplast and microspore datasets BF2-PPL and BF3-MiSp. T.L.T. and M.P. prepared, recorded and annotated the data for the microglial proliferation experiment. J.D., K.S. and Z.J. selected, prepared and recorded the optogenetic dataset. I.D., J.D. and Z.J. manually annotated the optogenetic dataset. I.D., T.F., D.M., R.B., Ö.Ç., T.B. and O.R. wrote the manuscript.

Corresponding author

Correspondence to Olaf Ronneberger.

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The authors declare no competing interests.

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Integrated supplementary information

Supplementary Figure 1 The U-Net architecture in the example of a 2D cell segmentation network.

(left) Input: An image tile with 540×540 pixels and C channels (blue box). (right) Output: The K-class soft-max segmentation with 356×356 pixels (yellow box). Blocks show the computed feature hierarchy. Numbers atop each network block: number of feature channels; numbers left to each block: spatial feature map shape in pixels. Yellow arrows: Data flow

Supplementary Figure 2 Separation of touching cells by using pixelwise loss weights.

(a) Generated segmentation mask with one-pixel wide background ridge between touching cells (white: foreground, black: background). (b) Map showing pixel-wise loss weights to enforce the network to separate touching cells

Supplementary Figure 3 Training data augmentation through random smooth elastic deformation.

(a) Upper left: Raw image; Upper right: Labels; Lower Left: Loss Weights; Lower Right: 20μm grid (for illustration purpose only) (b) Deformation field (black arrows) generated using bicubic interpolation from a coarse grid of displacement vectors (blue arrows; magnification: 5×). Vector components are drawn from a Gaussian distribution (σ = 10px). (c) Backwarp-transformed images of (a) using the deformation field

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–3 and Supplementary Notes 1–3

Reporting Summary

Supplementary Software 1

Caffe_unet binary package (GPU version with cuDNN, Recommended). Pre-compiled binary version of the caffe_unet backend software for Ubuntu 16.04, cuda 8.0.61 ( and cuDNN 7.1.4 for cuda 8.0 ( At time of publication cuDNN download from the nVidia website requires free registration as nVidia developer

Supplementary Software 2

Caffe_unet binary package (GPU version no cuDNN). Pre-compiled binary version of the caffe_unet backend software for Ubuntu 16.04 and cuda 8.0.61 (

Supplementary Software 3

Caffe_unet binary package (CPU version). Pre-compiled binary version of the caffe_unet backend software for Ubuntu 16.04

Supplementary Software 4

The source code difference (patch file) to the open source caffe deep learning software ( commit hash d1208dbf313698de9ef70b3362c89cfddb51c520). Checkout the correspondingly tagged commit and apply the patch using “git apply” to get the full source for custom builds

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Falk, T., Mai, D., Bensch, R. et al. U-Net: deep learning for cell counting, detection, and morphometry. Nat Methods 16, 67–70 (2019).

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