It is possible to compute data from videos in the Edit workspace by using the combination of a measurement tool, a marker with tracking activated and a data table. The computed data can then be extracted as a csv and used in other analytical software.
- Distance between two points
- Anlge tracking
Distance between two points
In the following example, you will see how to calculate the distance between the foot and the back of a cyclist. The same features can be applied to any video, as long as the camera is fixed (fixed position and no PTZ moveements), the target can be represented on a 2-dimensional plane and the points you want to track can be distinguished easily on the video (tip: to improve the reliability of the tracking, place amarker of a flashy color on those points)
- In the Edit workspace, start a new montage and add your video in the montage items list
- Select the drawing tool Marker and place it on the feet of the cyclist .
- Right click on the added Marker, select Tracking and choose the speed of the targeted point during the video playback.
- Select the Marker drawing tool and place it on the back of the cyclist.
- Use the drawing tool Measure to define a reference point on the video (tip: the default measure is 1 meter. Right-click > Set as reference to change the value. Tools > Options > Analyzer to change the unit).
- Add the drawing tool Data Table on your video
- Select the Data table, press on CTRL and select the two markers
- Right-click on the Data Table and select "Display distance between 2nd and 3rd drawing in this column"
- "Display offset (dX, dY)..." shows the horizontal and vertical distance between the two markers
- "Display offset dX..." shows the horizontal distance betwee the two markers
- "Display offset dX..." shows the vertical distance between the two markers
- Choose the frequencies of the entries in the data table and click on OK. In this example, as the video has 60 frames per second, a new entry every 30 fields is equivalent to 2 entries per second
- You can add more columns in the data table, that will automatically calculate relationships between entries. Right.click on the data table and select Insert column
- Interval speed: difference between current entry and previous entry
- Average speed: average of all the interval speed
- Interval length: distance between two entries
- Interval duration: time between to entries
- Data: another distance or position from another point
- Text: a free text field addition for labels or notes
- To export the data as a csv, right-click on the table and select Export Data
The data table can also retrieve the data from an angle. The processus is very similar to the distance between two points.
- Place an angle on the video
- Once the angle is positionned correctly, right-click on it and select Tracking > Slow/Medium/Fast speed
- Add a data table
- Select the data table, press on Ctrl and select the angle
- Right-click on the Data column and select Display angle