STEP-BY-STEP INSTRUCTION FOR EXAMPLE D

This example shows how to determine the displacement time history of a moving insect with the single image tracking (SIT) method and to determine positions and displacements of all insects in all the image frames. A group of images were acquired at 60 fps to capture moving fire ants on a tub bottom surface. The object to image ratio was determined as 2467.19 pix/m.

 

PART I: REMOVING BACKGROUND NOISE

Step 1: Create image file list

- Execute file “Edpiv.exe” - The start window is shown on the screen;

- Select menu “Edit \ File list” - Dialogue box “Creating file list” appears;

- Press “Input files” button - Dialogue box “Data file list” appears;

- Browse hard drives to find folder “…\ PIVsamples \ d_IndividualIsectTracking”;

- Arbitrarily select one of the Windows Bitmap (BMP) files in the folder;

- Press “Open” button - Dialogue box “Data file list” is closed;

- Press “Output file” button - Dialogue box “Data file list” appears again;

- Browse the hard drives to find an empty folder or create a new folder;

- Type a name for the file list in the edit box indicated by “File name”;

- Click “Save” button - Dialogue box “Data file list” is closed;

- Set “Recording type” to 3;

- Select menu “Create” to generate the image file list;

- Close the dialogue box to return to the start window.

Step 2: Open the image group

- Click menu “File \ Image group” in the start window - Dialogue box “Recording group” appears;

- Browse the file system to find the image file list created in step 1;

- Click “Open” - The first image of the first pair is shown in the picture frame;

Step 3: Removing background image

- Press button “Processing” in the start window to open “Image processing” window;

- Click menu “Edit \ Image group \ Average” Dialogue box “Settings for image group processing” appears;

- Set image sequence as start from 1 and end by 1228, and press “OK” button - The average image will be shown in the window;

- Click menu “Edit \ Image group \ BG removing \ Object dark ” - Dialogue box “Settings for image group processing” appears;

- Set “File name” to “Original” and “Image sequence” start from 1 and end by 1228, and then press “Ok” button; It takes about 50 seconds to complete the image processing, and the processed images are saved in the same folder of the list file. 

- Close EDPIV.

 

Example: raw and processed ant images

 

PART II: TRACKING AN INDIVIDUAL FIRE ANT

Step 1: Create image file list

- Execute file “Edpiv.exe” - The start window is shown on the screen;

- Select menu “Edit \ File list” - Dialogue box “Creating file list” appears;

- Press “Input files” button - Dialogue box “Data file list” appears;

- Browse hard drives to find the folder that contains the processed image (see Part I);

- Arbitrarily select one of the Windows Bitmap (BMP) files in the folder;

- Press “Open” button - Dialogue box “Data file list” is closed;

- Press “Output file” button - Dialogue box “Data file list” appears again;

- Browse the hard drives to find an empty folder or create a new folder;

- Type a name for the file list in the edit box indicated by “File name”;

- Click “Save” button - Dialogue box “Data file list” is closed;

- Set “Recording type” as 3;

- Select menu “Create” to generate the image file list;

- Close the dialogue box to return to the start window.

Step 2: Open the image group

- Click menu “File \ Image group” in the start window - Dialogue box “Recording group” appears;

- Browse the file system to find the image file list created in step 1;

- Click “Open” - The first frame of the image group is shown in the window.

Step 3: Input imaging scale and time interval

- Click menu “Edit / Scale & time” in the start window to open dialogue box “Imaging scale / time interval”;

- Input 2467 in edit box “Img/obj ratio [pix/m]”;

- Input 16666.7 in edit box “Time interval [mu-s]”;

- Press “OK” button to return to start window.

Step 4: Set tracking parameters

- Click menu “Edit / Evaluation settings” in the start window to open the “Evaluation settings” window;

- Press button “PTV and then press button “C” on the right - Dialogue box “PTV settings” appears;

- Set “Particle image identification” parameters as
Dmin:
2
Dmax:
20
Margin:
0
hreshold:
127

- Set “Particle position” to “Center of mass”;

- Set “Two-frame particle image tracking” parameters as
Size:
checked, 100 (Weighting), 200 (Defo limit)
Brightness:
checked,100 (Weighting), 200 (Defo limit)
Shape:
checked,100 (Weighting), 200 (Defo limit)
Orientation:
checked,100 (Weighting), 200 (Defo limit)
Single PTV: checked
Error detection: not checked

- Close dialogue box “PTV settings”;

- Search radius [pix]: 6

- Close “Evaluation settings” window.

Step 5: Tracking an insect image

- Press “Evaluation” button to open “Evaluation” window;

- Increase window size to clearly see the image details;

- Click menu “Start” in “Evaluation” window;

- Answer “Yes” to question “Do you want to start an evaluation?”

- Answer “Yes” to question “Current grid will be erased. Do you want to proceed?”

- Move the mouse to select the ant image at (74,66) and then click left mouse button;

- Set “Recording limit” to 1227, “Particle limit to “10000”, and press  button “OK”;

- Wait until the image pattern tracking is finished;

- Press “OK” button in the information box that notices end of the evaluation;

- Click menu “File \ Save data” to save the raw results in a file.

Step 6: Data postprocessing

- Click menu “Edit \ Single PIT/IPT \ Data on/off” to display the displacement time history in the window;

- Click menu “Edit \ Single PIT/IPT \ High/low-pass filter” to setup parameters as
High-pass filter: r=0
Low-pass filter: r=2

- Press button “OK” to complete the filtering;

- Click menu “File \ Save data” to save the processed time history in a file.

- Click menu “Edit \ Single PIT/IPT \ Postprocessing \ Gradient” and set 1 to both “forward step” and “backward step”, and press “OK” button to compute a speed time history from the displacement time history;

- Click menu “File \ Save data” to save the speed time history.

Step 6: Make plots with TECPLOT software

- Close EDPIV;

- Use TECPLOT to make plots.

 

Single ant trace:

 

Displacement time history:

 

Speed time history: