Hi, you are getting such output because you are applying super-pixel over segmentation on the whole image. You can use the function roifilt2 to apply your filtering only to the ROI. Refer the code below.
I = imread('peppers.png');
BW = roipoly(I);
imshow(BW);
% Create function handle
f = @(x)superpixels(x,500);
% Apply 2-D superpixel oversegmentation on the ROI
if size(I, 3) == 3
J = roifilt2(rgb2gray(I), BW, f);
else
J = roifilt2(I, BW, f);
end
% Create the mask
mask = boundarymask(J, 8);
% Overlay the mask above the image
figure;imshow(labeloverlay(I, mask, 'Transparency', 0.3, 'Colormap', 'parula'));
Hope this helps!
