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Cellpose: a generalist algorithm for cellular segmentation


Many biological applications require the segmentation of cell bodies, membranes and nuclei from microscopy images. Deep learning has enabled great progress on this problem, but current methods are specialized for images that have large training datasets. Here we introduce a generalist, deep learning-based segmentation method called Cellpose, which can precisely segment cells from a wide range of image types and does not require model retraining or parameter adjustments. Cellpose was trained on a new dataset of highly varied images of cells, containing over 70,000 segmented objects. We also demonstrate a three-dimensional (3D) extension of Cellpose that reuses the two-dimensional (2D) model and does not require 3D-labeled data. To support community contributions to the training data, we developed software for manual labeling and for curation of the automated results. Periodically retraining the model on the community-contributed data will ensure that Cellpose improves constantly.

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Fig. 1: Model architecture.
Fig. 2: Visualization of the diverse training dataset.
Fig. 3: Example Cellpose segmentations for 36 test images.
Fig. 4: Segmentation performance of specialist and generalist algorithms.
Fig. 5: Model performance across image types and ROI statistics.
Fig. 6: Segmentation in 3D without 3D-labeled data.

Data availability

The manually segmented cytoplasmic dataset is available at and

Code availability

The reviewed version of Cellpose is available as Supplementary Software. The code, graphical user interface and updated versions are available at To test out the model directly on the web, visit Note that the test time augmentations and tiling, which improve segmentation, are not performed on the website to save computation time.


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This research was funded by the Howard Hughes Medical Institute at the Janelia Research Campus. We thank P. Tillberg and members of the Tillberg laboratory for advice related to expansion microscopy, and W. Sun for sharing calcium imaging data from mouse hippocampus. We also thank S. Saalfeld and J. Funke for useful discussions.

Author information

Authors and Affiliations



C.S. and M.P. designed the study. T.W. acquired data. M.M. manually segmented images. C.S., M.P. and T.W. performed data analysis. C.S. and M.P. wrote the manuscript, with feedback from T.W.

Corresponding author

Correspondence to Marius Pachitariu.

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Competing interests

The authors declare no competing interests.

Additional information

Peer review information Rita Strack was the primary editor on this article and managed its editorial process and peer review in collaboration with the rest of the editorial team.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Graphical User Interface (GUI).

Shown in the GUI is an image from the test set, zoomed in on an area of interest, and segmented using Cellpose. The GUI serves two main purposes: 1) easily run Cellpose ‘out-of-the-box’ on new images and visualize the results in an interactive mode; 2) manually segment new images, to provide training data for Cellpose. The image view can be changed between image channels, cellpose vector flows and cellpose predicted pixel probabilities. Similarly, the mask overlays can be changed between outlines, transparent masks or both. The size calibration procedure can be run to estimate cell size, or the user can directly input the cell diameter, with an image overlay of a red disk shown as an aid for visual calibration. Dense, complete manual segmentations can be uploaded to our server with one button press, and the latest trained model can be downloaded from the drop-down menu.

Extended Data Fig. 2 Effect of network architecture and training set exclusions.

a-d, Each analysis compares average precision relative to the standard 4-network average, full Cellpose architecture. The following changes were made: a, removed the style vectors; b, replaced residual blocks with standard convolutional layers; c, Replaced addition with concatenation on the upsampling pass; d, standard Unet architecture (in other words a, b and c combined). e, Performance on generalized data for the ‘generalist’ Cellpose model, and a version of the model trained without the ‘specialized’ data.

Extended Data Fig. 3 Prediction of median object diameter.

a, The style vectors were used as linear regressors to predict the diameter of the objects in each image. Shown are the predictions for 68 test images (specialized and generalized data together), which were not used either for training cellpose or for training the size model. b, The refined size predictions are obtained after running cellpose on images resized according to the sizes computed in a. The median diameter of resulting objects is used as the refined size prediction for the final cellpose run. cd, Same as ab for the nucleus dataset.

Extended Data Fig. 4 Example Stardist segmentations.

Compare to Fig. 4.

Extended Data Fig. 5 Example Mask R-CNN segmentations.

Compare to Fig. 4.

Extended Data Fig. 6 Other performance metrics.

ab, Boundary prediction metrics (precision, recall, F-score42) for: a, specialized and b, generalized data. All images of masks were first resized to an average ROI diameter of 30 pixels so that a common boundary width can be used across images. cd, Aggregated Jaccard Index43 for: c, specialized (n=11 test images) and d, generalized data (n=57 test images). **, p < 0.01; ***, p < 0.001; ****, p < 0.0001; Wilcoxon two-sided signed-rank test.

Extended Data Fig. 7 Benchmarks for dataset of nuclei.

a, Embedding of image styles for the nuclear dataset of 1139 images, with a new Cellpose model trained on this dataset. Legend: dark blue = Data Science Bowl dataset, blue = extra kaggle, cyan = ISBI 2009, green = MoNuSeg. b, Segmentations on one example test image. c, Accuracy precision scores on test data for Cellpose, Mask R-CNN, Stardist, unet3, and unet2 on n=111 test images.

Extended Data Fig. 8 Example cellpose segmentations for nuclei.

The predicted masks are shown in dotted yellow line.

Supplementary information

Supplementary Information

Supplementary Table 1.

Reporting Summary

Supplementary Video 1

xy projections through 3D volume with superimposed Cellpose3D ROI.

Supplementary Video 2

Rotating Cellpose3D ROI.

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Stringer, C., Wang, T., Michaelos, M. et al. Cellpose: a generalist algorithm for cellular segmentation. Nat Methods 18, 100–106 (2021).

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