Finished exercise 4 on sheet3

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

ccv/sheet3/lab_pyramid.h

@@ -0,0 +1,41 @@
+#ifndef SHEET3_LAB_PYRAMID_H
+#define SHEET3_LAB_PYRAMID_H
+
+#include <opencv2/opencv.hpp>
+#include "gauss_pyramid.h"
+
+class lab_pyramid {
+private:
+    cv::Mat _inputImage_lab;
+    cv::Mat _imageChannels[3];
+    gauss_pyramid _pyramids[3];
+public:
+    const static int COLOR_L = 0;
+    const static int COLOR_A = 1;
+    const static int COLOR_B = 2;
+
+    /**
+     * Initializes a LAB pyramid.
+     *
+     * @param image_filename the filename of the image that should be used
+     */
+    lab_pyramid(cv::String image_filename);
+
+    /**
+     * Creates the gaussian pyramids for all channels with the given number of layers each.
+     *
+     * @param number_of_layers number of layers for gaussian pyramid
+     */
+    void create_pyramids(int number_of_layers);
+
+    /**
+     * Before this method can be called, pyramids have to be created via create_pyramids.
+     *
+     * @param channel the channel you want to get (COLOR_L, COLOR_A or COLOR_B)
+     * @return the gaussian_pyramid for the given channel
+     */
+    gauss_pyramid get_pyramid(int channel);
+};
+
+
+#endif //SHEET3_LAB_PYRAMID_H