How To / Using Video Analysis
You can use the Video Analysis tool to create a graphical
representation
of the motion you see in a movie or picture*. This is ideal for
mathematically
analyzing
real world events.
A tutorial covering video analysis is available. Select Open from
the File menu, then look in the Experiments folder to access it.
Before you can analyze a video, you must add a movie to your page.
From the Insert menu, choose Movie and select the movie you want
added to your page. Supported movie
formats are Video clip (.avi) and QuickTime movies (.mov). These can be
movies that you capture directly from
a video input such as a
digital video camera or web camera
Now you can set up your movie for basic analysis:
Click
in the movie player. The video analysis tools will appear on the right
side of the movie player. A graph will also be displayed. See below. By
default the graph will display both the x and y
positions
versus time. If necessary, resize and move the graph to a desired
position.
- Set a scale for the analysis. For this, it is important to have
something
in the movie to set the distance. You could include a meter stick in
the
movie to function as a reference. Click
then click and drag the mouse from one end of the reference to the
other end. A pop-up dialog box will appear. Enter the Distance and the
appropriate Unit for the object you are using. For example, for a meter
stick, enter Distance-1, and Units-m.
- Click
.
- Click the Play button, and just before the object in the movie
begins
its
motion, click the Stop button. Click the Next Frame button and advance
the movie until the object is in motion.
- Move the mouse over the movie and use the cross hairs to identify
a
recognizable
point on the object.
- Click the mouse. A mark is left on the screen and the movie
advances
one
frame.
- Repeat steps 5 and 6 until you have marked the point you want to
analyze..
- Click the movie Play button to see the object move and the record
of
its
horizontal and vertical position.
- The graph shows the object's horizontal and vertical positions
vs.
time.
Use Logger Pro's various analysis
features
(including Curve Fits) to study the
object's
motion.
*Instead of marking one object across frames (time) as you would in
a movie, analysis of a picture allows you to mark
many points on one frame. This is useful in getting the points along a
curve, for example.
See Also:
Video Analysis Overview
Video Capture