How to use 'Picture Frame' command to measure the area of an image?

I have some pictures (of a lot of cells), and I want to measure the area of each cell. My tutor advised me to use Rhino to do it.
I am expecting to use picture frame to draw the out lines, and then show the area, or diameter.

Do you think it can?

A bit hard to say without actually seeing a picture, but I would say, yes, that should be possible.
Just try it and if you get stuck, come back with a specific problem and, if you can, a Rhino model with picture.

Thank you, I will try first.

Brazil-long-20x-6.jpg_meta.xml (9.2 KB)
for example this one, I am thinking of measuring the average cell size.

sorry, this is the file:


I guess I would use the curve commands to outline the cell shapes, make closed curves around each and then use Area on the curves to get a cell’s area in the image. Start with a file in microns (DocumentProperties > Units) and use the Scale2D tool to scale your picture frame correctly using the marker in the image.

CellsPG.3dm (1.2 MB)


In case you have many of these to do it might be worthwhile to try to automate this by using Grasshopper.
You can use the Photo Sampler component in Grasshopper to generate curves.
In the following thread @martynjhogg posted a definition that you could use to experiment with:

Just pointing to your picture and changing the size to fit with the size of the picture gave me the following:

(Grasshopper curves in the Rhino viewport on the left)

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The image sampler in GH is good for this sort of primitive edge detection.
The curves will have some noise on them if you zoom in so you may need to zoom in to see this and manually draw curves on top of them if you need smoother results.