watershed: MATLAB vs. OpenCV

README.md

Compare watershed function of MATLAB and OpenCV (see this SO question).

compare_watershed.m

%% data
load watershedExample.mat
A = rgbImage(:,:,1);
marker = int32(cv.dilate(uint8(marker)));

%% MATLAB
L = watershed(A);
m = (marker > 0) | (L == 0);
m = im2uint8(m);
m(:,:,3) = 0;

figure(1)
surf(A, 'FaceAlpha',0.5, 'EdgeAlpha',0.25), hold on
warp(imfuse(rgbImage,m,'blend'))
hold off, axis tight vis3d
title('MATLAB watershed')
colormap(flipud(hot(64))), colorbar
rotate3d on

%% OpenCV (using https://github.com/kyamagu/mexopencv)
L = cv.watershed(rgbImage, marker);
m = (marker > 0) | (L == -1);
m = im2uint8(m);
m(:,:,3) = 0;

figure(2)
surf(A, 'FaceAlpha',0.5, 'EdgeAlpha',0.25), hold on
warp(imfuse(rgbImage,m,'blend'))
hold off, axis tight vis3d
title('OpenCV watershed')
colormap(flipud(hot(64))), colorbar
rotate3d on