% Author: Dr. Joshua Morgan and Isabella Bagdasarian, TIME lab, UCR
% Use gradient (via derivative5, Peter Kovesi) to find phalloidin edges and
% threshold. Outputs an NxN double and NxN logical to be used for watershedding.
%PARAMETERS
%           Pth - NxN image (normally already filtered)
%           Po- NxN filtered phalloidin image
%           Db4e- NxN logical 
%           threshold- threshold parameter, single value 
%           areaopen- smallest size to preserve when performing bwareaopen,
%           single value

function [T, mask] = CytGradSeg(Pth, Po, Db4e, areaopen, threshold)
%Use gradient to segment out cytosolic region
    [gx, gy] = derivative5(Pth, 'x','y');
    G = gx.^2+gy.^2;
    
    G2 = adapthisteq(normalise(G),'NumTiles',[24 24],'NBins',1024);
    
    Pm = Po > threshold;
    Pmi = bwareaopen(Pm, areaopen);
    mask = imclose(Pmi,strel('disk',4));
    
    T = graydist(G2,Db4e,'quasi');
    T = normalise(T);
    T(~mask) = 1;
    T = imimposemin(T, Db4e);
end