CBSegmentation algorithm

components/rgbd-sources/include/ftl/cb_segmentation.hpp

+#pragma once
+
+#include <opencv2/core.hpp>
+
+namespace ftl {
+
+/**
+ * @brief	Codebook segmentation and depthmap filling.
+ * @param	Input image width
+ * @param	Input image height
+ * 
+ * Codebook segmentation based on
+ *
+ * Kim, K., Chalidabhongse, T. H., Harwood, D., & Davis, L. (2005).
+ * Real-time foreground-background segmentation using codebook model.
+ * Real-Time Imaging. https://doi.org/10.1016/j.rti.2004.12.004
+ * 
+ * and fixed size codebook optimization in
+ * 
+ * Rodriguez-Gomez, R., Fernandez-Sanchez, E. J., Diaz, J., & Ros, E.
+ * (2015). Codebook hardware implementation on FPGA for background
+ * subtraction. Journal of Real-Time Image Processing.
+ * https://doi.org/10.1007/s11554-012-0249-6
+ * 
+ * Additional modifications to include depth maps as part of the
+ * background model.
+ */
+class CBSegmentation {
+public:
+	CBSegmentation(char codebook_size, size_t width, size_t height, float alpha, float beta, float epsilon, float sigma, int T_add, int T_del, int T_h);
+
+	/**
+	 * @brief	Segment image.
+	 * @param	Input image (3-channels)
+	 * @param	Output Mat. Background pixels set to 0, foreground pixels > 0.
+	 *
+	 * @todo	Template method on OpenCV type
+	 */
+	void apply(cv::Mat &in, cv::Mat &out, cv::Mat &depth, bool fill=false);
+	void apply(cv::Mat &in, cv::Mat &out);
+	
+protected:
+	class Pixel {
+	public:
+		int idx;
+		float r;
+		float g;
+		float b;
+		float i;
+		int d;
+		long t;
+		Pixel(const int &index, const uchar *bgr, const int &depth, const long &time);
+	};
+
+	class Codeword {
+	public:
+		float r;
+		float g;
+		float b;
+		float i_min, i_max;
+		long f, lambda, p, q;
+
+		float d_m;
+		float d_f;
+		float d_S;
+		
+		void set(CBSegmentation::Pixel &pixel);
+		void update(CBSegmentation::Pixel &pixel);
+
+		bool colordiff(CBSegmentation::Pixel &pixel, float epsilon);
+		bool brightness(CBSegmentation::Pixel &pixel, float alpha, float beta);
+		bool depthdiff(CBSegmentation::Pixel &pixel, float sigma);
+
+        inline int freq() { return f; }
+		inline long getLambda() { return lambda; }
+		inline long ctime() { return p; }
+		inline long atime() { return q; }
+	};
+
+	enum EntryType { H, M };
+
+	union Entry {
+		char size;
+		struct Data {
+			EntryType type;
+			CBSegmentation::Codeword cw;
+		} data ;
+	};
+
+	struct CompareEntry{
+		bool operator()(const Entry &a,const Entry &b) const{
+			return 	!((a.data.type == M && b.data.type == H) ||
+					(a.data.cw.f < b.data.cw.f));
+		}
+	};
+
+	bool processPixel(Pixel &px, Codeword *codeword=nullptr);
+	
+	size_t width_;
+	size_t height_;
+	size_t size_;
+
+	int T_h_;
+	int T_add_;
+	int T_del_;
+
+	float alpha_;
+	float beta_;
+	float epsilon_;
+	float sigma_;
+
+private:
+	long t_ = 1;
+    std::vector<Entry> cb_;
+};
+
+}
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