added function getNumberOfIntersections

matlab/getNumberOfIntersections.m

@@ -0,0 +1,38 @@
+
+function count = getNumberOfIntersections(signal, timestamps, value)
+
+    is_smaller_value = false;
+    is_bigger_value = false;
+    window_poi = [];
+    window_ts = [];
+    p_idx = 1;
+    for j = 1:length(signal)
+        %is measurement smaller?
+        if(signal(j) < value)
+            %was the last measurement bigger and the current smaller? 		
+            if(is_bigger_value == true)
+                window_poi(p_idx) = signal(j);
+                window_ts(p_idx) = interp1(signal(j-1 : j),timestamps(j-1 : j),value);
+                p_idx = p_idx + 1;			
+            end
+
+            is_smaller_value = true;
+            is_bigger_value = false;
+        else	
+            %was the last measurement smaller and the current bigger?
+            if(is_smaller_value == true)
+                window_poi(p_idx) = signal(j);
+                window_ts(p_idx) = interp1(signal(j-1 : j),timestamps(j-1 : j),value);
+                p_idx = p_idx + 1;					
+            end
+
+            is_smaller_value = false;
+            is_bigger_value = true;			
+        end	
+    end
+    
+    count = length(window_poi);
+end
+
+
+