Hi Inge Lentferink Workman, the best software I recommend is ImageJ Fiji. It is an open source and has lots of plug-ins, one of the best plug-ins I found is Weka Trainable, where you can automatically segment the area of interest, then use the "measure" to measure what you need. It is very easy software to use and has 1000's of videos on youtube that caould be very close to what you are looking to do. I hope this is helpful. https://imagej.net/software/fiji/

Dear Inge Lentferink Werkman ,

Look the link, maybe useful.

https://www.nature.com/articles/srep42383

Regards,

Shafagat

Dear Inge Lentferink Werkman,

Please try Cellprofler or Computational cell tracking, also I suggest you see links on the topic.

Article CellProfiler: Image analysis software for identifying and qu...

Article Computerized cell tracking: Current methods, tools and challenges

https://www.nature.com/articles/srep42383

Article Quantitative Determination of Cellular-and Neurite Motility ...

Best regards

Check https://www.sciencedirect.com/science/article/pii/S2468502X20300711

https://biology.uiowa.edu/keck/projects/motion-analysis-single-cells

Also check https://rupress.org/jcb/article/209/1/163/38075/Open-source-software-for-quantification-of-cell

https://www.frontiersin.org/articles/10.3389/fninf.2019.00015/full

Dear Inge Lentferink Werkman . See the following useful link: https://academic.oup.com/bioinformatics/article/24/14/1647/182235

Kindly see also the following good link: https://biology.uiowa.edu/keck/projects/motion-analysis-single-cells

Also check please the following good link: Article CellSeT: Novel Software to Extract and Analyze Structured Ne...

Cell_motility software as used here

Article Cell_motility: A cross-platform, open source application for...