added pseudocode of original msckf

pseudocode/pseudocode_image_processing

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+
+
+stereo callback()
+
+	create image pyramids
+		_Constructs the image pyramid which can be passed to calcOpticalFlowPyrLK._
+.
+	if first Frame:
+		*initialize first Frame ()
+
+	else:
+		*track Features ()
+
+		*addnewFeatures ()
+
+		*pruneGridFeatures()
+			_removes worst features from any overflowing grid_
+
+	publish features (u1, v1, u2, v2)
+		_undistorts them beforehand_
+
+addnewFeatures()
+	*mask existing features
+	*detect new fast features
+	*collect in a grid, keep only best n per grid
+	*stereomatch()
+	*save inliers into a new feature with u,v on cam0 and cam1
+
+
+track Features()
+	*integrateIMUData ()
+		_uses existing IMU data between two frames to calc. rotation between the two frames_
+
+	*predictFeatureTracking()
+		_compensates the rotation between consecutive frames - rotates previous camera frame features to current camera rotation_
+
+	*calcOpticalFlowPyrLK()
+		_measures the change between the features in the previous frame and in the current frame (using the predicted features)_
+
+	*remove points outside of image region
+		_how does this even happen?_
+
+	*stereo match()
+		_find tracked features from optical flow in the camera 1 image_
+		_remove all features that could not be matched_
+
+	*twoPointRansac(cam0)
+	*twoPointRansac(cam1)
+		_remove any features outside best found ransac model_
+
+
+
+
+twoPointRansac()
+	*mark all points as inliers
+	*compensate rotation between frames
+	*normalize points
+	*calculate difference bewteen previous and current points
+	*mark large distances (over 50 pixels currently)
+	*calculate mean points distance
+	*return if inliers (non marked) < 3
+	*return if motion smaller than norm pixel unit
+	*ransac
+		*optimize with found inlier after random sample
+
+	*set inlier markers
+
+initialize first Frame()
+
+	features = FastFeatureDetector detect ()
+
+	*stereo match ()
+
+	group features into grid
+		- according to position in the image
+		- sorting them by response
+		- save the top responses
+		- save the top responses
+
+
+stereo match ()
+
+	*undistort cam0 Points
+	*project cam0 Points to cam1 to initialize points in cam1
+
+	*calculate lk optical flow
+		_used because camera calibrations not perfect enough_
+		_also, calculation more efficient, because LK calculated anyway_
+
+	*compute relative trans/rot between cam0 and cam1*
+
+	*remove outliers based on essential matrix
+		_essential matrix relates points in stereo image (pinhole model)_
+		for every point:
+			- calculate epipolar line of point in cam0
+			- calculate error of cam1 to epipolar line 
+			- remove if to big