diff --git a/matlab/gtsam_examples/CameraFlyingExample.m b/matlab/gtsam_examples/CameraFlyingExample.m
index 258bd968b..1eb301b38 100644
--- a/matlab/gtsam_examples/CameraFlyingExample.m
+++ b/matlab/gtsam_examples/CameraFlyingExample.m
@@ -3,15 +3,26 @@ clc;
 clf;
 import gtsam.*
 
+%% define the options 
+options.fieldSize = Point2([100, 100]');
+options.cylinderNum = 10;
+options.poseNum = 20;
+options.monoK = Cal3_S2(525,525,0,320,240);
+options.stereoK = Cal3_S2Stereo(721,721,0.0,609,172,0.53715); % read from the VO calibration file
+options.imageSize = Point2([640, 480]');
+
 %% generate a set of cylinders and Samples
-fieldSize = Point2([100, 100]');
-cylinderNum = 10;
+cylinderNum = options.cylinderNum;
 cylinders = cell(cylinderNum, 1);
 
-% ToDo: it seems random generated cylinders doesn't work that well
-% use fixed parameters instead
+% It seems random generated cylinders doesn't work that well
+% Now it set up a circle of cylinders
+theta = 0;
 for i = 1:cylinderNum
-    baseCentroid = Point2([fieldSize.x * rand, fieldSize.y * rand]');
+    theta = theta + 2*pi / 10;
+    x = 20 * cos(theta) + options.fieldSize.x/2;
+    y = 20 * sin(theta) + options.fieldSize.y/2;
+    baseCentroid = Point2([x, y]');
     cylinders{i,1} = cylinderSampling(baseCentroid, 1, 5, 1);
 end
 
@@ -19,23 +30,21 @@ end
 % now is plotting on a 100 * 100 field
 figID = 1;
 figure(figID);
-plotCylinderSamples(cylinders, fieldSize, figID);
+plotCylinderSamples(cylinders, options.fieldSize, figID);
 
 %% generate camera trajectories
 K = Cal3_S2(525,525,0,320,240);
 imageSize = Point2([640, 480]');
-poseNum = 10;
-cameras = cell(poseNum, 1);
-trans = Point3();
-% To ensure there are landmarks in view, look at one randomly chosen cylinder 
-% each time.
-for i = 1:poseNum
-    cylinderIdx = max(min(round(cylinderNum*rand), 10), 1);
-    cameras{i} = SimpleCamera.Lookat(trans, cylinders{cylinderIdx}.centroid, ...
-        Point3([0,0,1]'), K);
-    
-    incT = Point3(5*rand, 5*rand, 5*rand);
-    trans = trans.compose(incT);    
+cameras = cell(options.poseNum, 1);
+% Generate ground truth trajectory r.w.t. the field center
+theta = 0;
+r = 30;
+for i = 1:options.poseNum    
+    theta = (i-1)*2*pi/options.poseNum;
+    t = Point3([30*cos(theta), 30*sin(theta), 10]');
+    cameras{i} = SimpleCamera.Lookat(t, ... 
+        Point3(options.fieldSize.x/2, options.fieldSize.y/2, 0), ...
+        Point3([0,0,1]'), K);    
 end
 
 %% visibility validation
@@ -46,25 +55,23 @@ visiblePoints3 = cylinderSampleProjection(cameras{1}, imageSize, cylinders);
 %plotProjectedCylinderSamples(visiblePoints3, cameraPoses{1}, figID);
 
 %% setp up monocular camera and get measurements
-%pts2dTracksMono = points2DTrackMonocular(cameras, imageSize, cylinders);
+pts2dTracksMono = points2DTrackMonocular(cameras, imageSize, cylinders);
 
 %% set up stereo camera and get measurements
 % load stereo calibration
 calib = dlmread(findExampleDataFile('VO_calibration.txt'));
 KStereo = Cal3_S2Stereo(calib(1), calib(2), calib(3), calib(4), calib(5), calib(6));
-poseNum = 10;
-camerasStereo = cell(poseNum, 1);
-trans = Point3();
-for i = 1:poseNum
-    cylinderIdx = max(min(round(cylinderNum*rand), 10), 1);
-    camerasStereo{i} = SimpleCamera.Lookat(trans, cylinders{cylinderIdx}.centroid, ...
-        Point3([0,0,1]'), KStereo);
-    
-    incT = Point3(5*rand, 5*rand, 5*rand);
-    trans = trans.compose(incT);    
-end
+camerasStereo = cell(options.poseNum, 1);
+% for i = 1:options.poseNum
+%     cylinderIdx = max(min(round(cylinderNum*rand), 10), 1);
+%     camerasStereo{i} = SimpleCamera.Lookat(trans, cylinders{cylinderIdx}.centroid, ...
+%         Point3([0,0,1]'), KStereo);
+%     
+%     incT = Point3(5*rand, 5*rand, 5*rand);
+%     trans = trans.compose(incT);    
+% end
 
-pts2dTracksStereo = points2DTrackStereo(camerasStereo, imageSize, cylinders);
+%pts2dTracksStereo = points2DTrackStereo(camerasStereo, imageSize, cylinders);
 
 % plot the 2D tracks