User Manual for Tracker Testbed
Contents
1. OK Cancel a Figure 3 Dialog for specifying a directory for saving tracking results 10 Rpt This button toggles playback of previously logged files on off If Tracker Testbed has opened a previously recorded sequence trk file and Rpt mode is on then the tracker commands Track gt gt and Step gt will play back logged results for each frame If Rpt mode is turned off the Tracker Testbed will revert to its normal mode of operation and begin running the chosen tracking algorithm on the image frames 11 Predict Toggles motion prediction functionality on off When the target becomes occluded and motion prediction mode is on the Tracker Testbed will predict the target position Figure 4 green line based on the targets recent trajectory history red line The current motion prediction algorithm assumes the target will maintain its current speed in a straight line constant velocity prediction frame00187 jpg Kit on Log off Rpt Off Predict on a E Open lgorihel lt BrowsdTrect gt gt Step gt Stop Rewind Kit Log Rot Predict Debug oa ar 4 Pr Predict Motion Figure 4 When motion prediction mode is on a constant velocity path prediction is invoked with the object becomes occluded 12 Debug This button will activate the debug window as shown in Figure 5 It displays intermediate tracking results The upper left corner image shows the current image2. frame The upper right image shows clustered background feature points computed by the KLT feature tracker The lower left image shows the weighted foreground image used for tracking and the current bounding box of the object FPS 0 Zoom 1 00 score 0 75 oO Figure 5 Debug Display Window
3. logged sequence e Open a logged sequence Click the Open button and browse directories Open a trk file of previously logged tracking results e Track next frame Click Track gt gt or Step gt to play back the logged results Note that playback is much faster than tracking mode it is just playing previously stored results Optional Switch to track mode on the same sequence e Stop playback Click the Stop button to stop playback e Rewind to beginning Click Rewind to go back to the initial frame and object polygon e Switch to track mode Click Rpt to turn off playback mode and switch to regular tracking mode using this starting frame and polygon e Track Click Track gt gt or Step gt to begin tracking 3 Command Buttons Figure 1 shows the tracker command buttons located at the top of the main window The function of each button is described below 1 Open Enables the user to pick an image sequence or open a previously logged sequence Thus there are two kinds of input files to open e Image sequence files in one of the following format Windows bitmaps BMP DIB JPEG files JPG JPE Portable Network Graphics PNG Portable image format PBM PGM PPM Sun rasters RAS TIFF files TIF e Previously recorded track file trk This log file format contains video sequence file and polygon initialization information 2 Algorithm As sh
4. the RGB combination feature F w1 R w2 G w3 B wl w2 w3 are weight parameters The choice of w1 w2 w3 is to maximize peak difference between target bounding box and its biggest noise blob in neighborhood Algorithm Tracker Selection Histogram Ratio Shift Fg Bg Basic Meanshift B G G R B G R C Template Match by Corelation C Variance Ratio Feature Shift C Peak Difference Feature Shift Cancel Figure 2 Algorithm Dialog for choosing a tracking algorithm 3 lt lt Browse This button will cancel the tracking mood and browse the frames backwards 4 Track gt gt When a tracking sequence has been initialized and 4 points around the target have been clicked this button will invoke the tracker to run frame by frame over the sequence If the tracking testbed is currently in playback mode this button starts playback of a previously logged sequence 5 Step gt When a tracking sequence has been initialized and 4 points around the target have been clicked this button will run the tracker on the next frame in the sequence single step mode If the tracking testbed is currently in playback mode this button advances the playback of a previously logged sequence by a single frame 6 St op Stops a currently running Track gt gt action or playback action and pauses at the current frame 7 Rewind Rewinds the sequence to the initialization frame where 4 points defining the obj
5. User Manual for Tracker Testbed Version 2 2 Robotics Institute Carnegie Mellon University May 23 2005 1 Required DLL Library Three DLLs listed below are required to run the executable file They can be put in the same directory as CTracker exe or else registered in the windows system path e cv096 dll e highgui096 dll e cxcore096 dll 2 Main GUI window As shown in Figure 1 The main window displays the original image frame and a bounding box of the tracking result At the top of the main window is the tracker parameter status bar and command button bar frame00004 jpg Kit on Log off Rpt Off Predict off CE ET Figure 1 Main window of the Tracker Testbed 3 Quick Start Sample Usage Below are two sample usage scenarios of the Tracker Testbed 1 Track a new sequence e Open a new frame Click the Open button Figure 1 and browse directories Select the starting image frame for the tracking sequence The image is then displayed in the tracker main window e Tracker Initialization Click 4 points to define a polygon bounding the target object in the image e Track next frame Click Track gt gt to beginning tracking the object continuously through the sequence Alternatively click Step gt to track step by step one frame at a time e Optional Save output tracking results Click Log button before tracking to record tracking results to a log directory 2 Play a previously recorded
6. ect were clicked If the sequence has not yet been initialized with 4 points it will rewind to the first opened frame 8 KIP Toggles the Klt tracker component on off The Kit tracker computes sparse optic flow by detecting and matching corner features between pairs of frames in the sequence The computed two frame flow is used by the Tracker Testbed to do motion prediction in cases of object occlusion If the KIt tracker mode is off the Predict button will be disabled 9 Log Toggles logging of results When turned on this prompts the user to specify a log file directory Figure 3 When the tracker is run with logging turned on a series of output files specifying the bounding box and foreground mask of the tracked object in each frame are written to the specified log directory By default the log directory is RunPath tkLog Sequence_x The tracker creates two kinds of log files under the log directory a single trk file is generated for the initialization frame of the sequence and a sequence of rpt files are generated one for each subsequent frame in the sequence e trk file Specifies location of the first frame of the sequence and the initial object polygon e rpt file Includes tracking results bounding box and foreground mask for every tracked frame Specify Log Directory Log directory EACTracker website s oftware TrackerT estbed_v2 2 tkLog egtest01_1 Log format Version 2 1 mask in trk
7. own in Figure 2 this button prompts the user to choose a tracking algorithm Current version of the Tracker Testbed includes the following tracking algorithms Histogram Ratio Shift Tracking is based on the ratio between foreground target and background histograms values This algorithm emphasizes foreground pixels with colors that are well distinguishable from the background The number of color histogram bins can be defined in the dialog menu Basic Mean shift Basic mean shift algorithm based only on object color distribution This implementation uses a hard coded 8 8 4 index image of normalized B G G R R G B values Template Match by Normalized Correlation Tracking based on computing the normalized correlation coefficient R between a target template and the current frame where R x y sumx y T x y eI x x y y sqrt sumx y T x y 2e sumx y T x x y y 2 and I x y is the image pixel value at location x y T x y is the template pixel value at location x y T x y T x y 1 weh esumx y T x y mean template brightness gt 0 I xtx yty I x x y y 1 weh esumx y I x x y y mean patch brightness gt 0 Variance Ratio Feature Shift Tracking is based on the RGB combination feature F w1 R w2 G w3 B wl w2 w3 are weight parameters The choice of w1 w2 w3 is to maximize variance ratio between target bounding box and its neighborhood Peak Difference Feature Shift Tracking is based on
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