Segmenting a cat’s side profile and plotting a line on the edges

My goal is to segment the side profile of a cats head and plot a line on the edges of the cat’s face, The cats will have different backgrounds, colour and quality, and the feature (cat’s face edges) will be in different positions in each image.

I have experimented in python with opencv and scikit-image (manual region of interest) but I am unsure which method gives the best consistency.

What would be the most appropriate method for this?

result

Segmenting cells from a stained image of cells from microscope

I have an image which has stained cells and I have to segment all the cells.

But the problem is that the cell boundary is not very distinguished where there is staining done because of the stain.

Can someone kindly help me with segmenting the image and getting cell boundary?

please find the image here:

https://drive.google.com/open?id=1liPzqZz1AWEgdI5PKNguWXyj8Y70XEGa

I tried various filters like RidgeFilter, DerivativeFilter, GaussianFilter and combination of them.

I am using Mathematica 12.