diff --git a/bv/uebung11_presence.m b/bv/uebung11_presence.m
new file mode 100644
index 0000000..f59366a
--- /dev/null
+++ b/bv/uebung11_presence.m
@@ -0,0 +1,75 @@
+A = imread('kobi.png');
+[L,N] = superpixels(A,500);
+figure
+BW = boundarymask(L);
+imshow(imoverlay(A,BW,'cyan'))
+
+%   Set color of each pixel in output image to the mean RGB color of the
+%   superpixel region.
+outputImage = zeros(size(A),'like',A);
+idx = label2idx(L);
+numRows = size(A,1);
+numCols = size(A,2);
+for labelVal = 1:N
+    redIdx = idx{labelVal};
+    greenIdx = idx{labelVal}+numRows*numCols;
+    blueIdx = idx{labelVal}+2*numRows*numCols;
+    outputImage(redIdx) = mean(A(redIdx));
+    outputImage(greenIdx) = mean(A(greenIdx));
+    outputImage(blueIdx) = mean(A(blueIdx));
+end
+
+figure
+imshow(outputImage)
+
+% 2.
+he = imread('hestain.png');
+imshow(he), title('H&E image');
+text(size(he,2),size(he,1)+15,...
+     'Image courtesy of Alan Partin, Johns Hopkins University', ...
+     'FontSize',7,'HorizontalAlignment','right');
+ 
+cform = makecform('srgb2lab');
+lab_he = applycform(he,cform);
+
+ab = double(lab_he(:,:,2:3));
+nrows = size(ab,1);
+ncols = size(ab,2);
+ab = reshape(ab,nrows*ncols,2);
+
+nColors = 3;
+% repeat the clustering 3 times to avoid local minima
+[cluster_idx, cluster_center] = kmeans(ab,nColors,'distance','sqEuclidean', ...
+                                      'Replicates',3);
+                                  
+pixel_labels = reshape(cluster_idx,nrows,ncols);
+imshow(pixel_labels,[]), title('image labeled by cluster index');
+
+segmented_images = cell(1,3);
+rgb_label = repmat(pixel_labels,[1 1 3]);
+
+for k = 1:nColors
+    color = he;
+    color(rgb_label ~= k) = 0;
+    segmented_images{k} = color;
+end
+
+imshow(segmented_images{1}), title('objects in cluster 1');
+imshow(segmented_images{2}), title('objects in cluster 2');
+imshow(segmented_images{3}), title('objects in cluster 3');
+
+mean_cluster_value = mean(cluster_center,2);
+[tmp, idx] = sort(mean_cluster_value);
+blue_cluster_num = idx(1);
+
+L = lab_he(:,:,1);
+blue_idx = find(pixel_labels == blue_cluster_num);
+L_blue = L(blue_idx);
+is_light_blue = imbinarize(L_blue);
+
+nuclei_labels = repmat(uint8(0),[nrows ncols]);
+nuclei_labels(blue_idx(is_light_blue==false)) = 1;
+nuclei_labels = repmat(nuclei_labels,[1 1 3]);
+blue_nuclei = he;
+blue_nuclei(nuclei_labels ~= 1) = 0;
+imshow(blue_nuclei), title('blue nuclei');