[BV] Aufgaben 1-3 fertiggestellt

Signed-off-by: Jim Martens <github@2martens.de>

bv/uebung5.m

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+% 1.
+% First the connected components are determined. Then an array with the
+% color values for the gray colors is defined (possible value range 0-255).
+% The distance of 20 between each color is chosen to make the difference
+% visible for the human eye.
+% Afterwards the 8 values are assigned to the pixels of the 8 components.
+crosses = imread('crosses.gif');
+figure (1), imshow(logical(crosses));
+cc = bwconncomp(crosses);
+pixelIDs = cc.PixelIdxList;
+colors = [60, 80, 100, 120, 140, 160, 180, 200];
+for i = 1 : 8
+    crosses(pixelIDs{i}) = colors(i);
+end
+figure (2), imshow(crosses);
+
+% 2.
+dots = imread('littledots.gif');
+dots_bw = dots;
+% The threshold 50 is determined by looking at imhist(dots).
+% The background is lighter and covers most of the image and
+% it therefore is represented by the largest spike.
+% The cells are a bit darker and the threshold is therefore on the direct 
+% left of the spike.
+%---
+% The cells get the value 1, because the bwconncomp function views black as
+% background and white as objects. Lastly the number of objects is
+% extracted from the cc_dots struct.
+for i = 1 : numel(dots_bw)
+    if dots_bw(i) < 49
+        dots_bw(i) = 1;
+    else
+        dots_bw(i) = 0;
+    end
+end
+dots_bw_l = logical(dots_bw);
+cc_dots = bwconncomp(dots_bw);
+numObjects_dots = cc_dots.NumObjects;
+figure (3), imshow(dots);
+figure (4), imshow(dots_bw_l);
+
+% 3. 
+turkeys = imread('turkeys.jpg');
+turkeys_bw = turkeys;
+% The threshold 48 is determined by looking at imhist(turkeys).
+% There are many spikes and the turkeys have different color values
+% belonging to them. The larger part of them is on the darker side. The
+% exact threshold was determined by try and error to see which value
+% provided the best results. Since there was no single threshold in which
+% only the turkeys remained, some morphological operations were necessary.
+% Once every white dot not belonging to the turkeys was removed, one large
+% dilate operation was necessary to connect the remaining dots in a way
+% that represents the turkeys.
+% ---
+% The last step is similar to the second exercise.
+for i = 1 : numel(turkeys_bw)
+    if turkeys_bw(i) == 48
+        turkeys_bw(i) = 255;
+    else
+        turkeys_bw(i) = 0;
+    end
+end
+se = strel('line', 3, 90);
+se_2 = strel('disk', 14);
+se_3 = strel('square', 3);
+se_4 = strel('line', 3, 0);
+turkeys_opened = imopen(turkeys_bw, se);
+t_opened2 = imopen(turkeys_opened, se_4);
+t_opened3 = imopen(t_opened2, se_3);
+t_dilated = imdilate(t_opened3, se_2);
+cc_turkeys = bwconncomp(t_dilated);
+numObjects_turkeys = cc_turkeys.NumObjects;
+figure (5), imshow(turkeys_bw);
+figure (6), imshow(t_dilated);