Create Overlays

Hey folks,

I have got a short question. I want to create a single image out of two separate images. Image #1 is an image of some nuclei and image #2 contains the nuclei outlines processed by CellProfiler. I can do that with the Image Calculator Node using the expression max(Image1, Image2). BUT this only works with white outlines. It does not work with colored (e.g. blue) outlines.

Do you have any ideas how to solve this problem?

Have a nice day!


the reason behind your problem is that colored images are actually three-dimensional (X,Y,Channel) whereas gray images are usually two-dimensional (X,Y). If you now want to combine the gray image (OrigBlue, that only has two dimensions, which can be verified either with the Table Cell View of the Image Reader or the Multi-Line-String renderer in the according data table (right click on column header)) with the colored image (NucleiOutlines, only the third channel actually has non-zero entries, that's why it appears blue) using the Image Calculator an error will be returned ("Images are not compatible") due to the different dimensions of the images. You can now either ensure, that the images to be combined are of the same dimensionality (using nodes like Cropper, Dimension Extender, Resampler etc.) or let the Image Calculator do that for you: Advanced Settings -> Adjust image dimensions (with NucleiOutlines selected as reference image).

The accordingly modified workflow is attached.



Martin, thank you very much! That helped me alot! smiley