Sum the image horizontally. Untested code:
verticalProfile = sum(rgbImage(:,:,3), 2); % Collapse across columns.
% Then find out where it's not black
nonBlackRows = verticalProfile ~= 0;
% Now find the starting and stopping points
props = regionprops(nonBlackRows, 'PixelIdxList');
% Now crop
for k = 1 : length(props)
row1 = props(k).PixelIdxList(1);
row2 = props(k).PixelIdxList(end);
imageList{k} = rgbImage(row1:row2, :, :);
end
Each image is in a cell of the cell array. They might all have different sizes.
