Is it possible to set a maximum size of watershed regions? Or easily divide the regions after watershedding?

I am doing some cell segmentation. I have a code that finds groups of cells with fairly high accuracy. Once the regions are found I use watershedding to separate touching cells. This also works well, however some cells are definitely too large to be just one cell. My question is: Can I set a maximum size each watershed region can be so that larger clumps will split into smaller ones?

Note: I do not care about the number of cells on their own (otherwise I would just divide each region's area by the maximum cell area). I want to separate these clumps so that I can determine how close cells are to the airways (yellow) in the image (i.e. how many cells "belong" to each airway).

I have attached my original image as well as the processed image with the cell regions and airways overlayed in blue and yellow respectively.

Thank you in advanced for the help!

Eric

Answer 1

[Image Analyst]

Not sure how you define distance. Would bwdist() help? Or how about the Hausdorf distance https://en.wikipedia.org/wiki/Hausdorff_distance ?

Also not sure how you define which yellow blob the blue blobs "belong" to.

[Eric Chadwick]

Hello. I am not having trouble with assigning cells to airways. I have already done that with bwdist. What I am asking is how I can further break up the cell regions since I know for a fact my code is getting the general shape of cell clusters rather than individual cells. I'd like to know how I can further separate the regions given a maximum cell area.

[Eric Chadwick]

What I am thinking now is if there is a way to drop N evenly distributed markers onto a cell region where N is cell_region_area/max_cell_area rounded up, then I can use marker-based watershedding to divide that cell region into smaller areas.

Do you know of a way to make these markers?

[Image Analyst]

See marker controlled watershed segmentation demos here

http://blogs.mathworks.com/steve/2013/11/19/watershed-transform-question-from-tech-support/

http://www.mathworks.com/help/images/examples/marker-controlled-watershed-segmentation.html

[Eric Chadwick]

Hi there.

I checked out these links, but I can't seem to get them to work for my problem. I've created the seeds I want to use for watershed, but whenever I try the methods you suggest, I get a blank image. I have attached my image of seeds as well as the original I am trying to watershed.