Download - Calibration Guide
CALIBRATION
Calibration is required to calculate scene configuration
for each camera:
1. Position in 3D space
2. Orientation
3. (optional) Field of view(if you don’t know FOVfor your camera)
X
Y
Z
1
2
3
Calibration in iPi DMC is based onglowing marker tracking in 3D space
You can use a flashlight with its reflector removed, or
other small glowing object
Mini Maglite in candle mode is recommended
Step 1: run iPiRecorder and
• turn on Calibration mode checkbox(for Sony PS Eye cameras)
• or set Exposure to reasonably small value(for DirectShow-compatible web cameras)
Image from cameras should look dim in calibration mode
Step 2: record calibration video
a. Start video recording
b. First couple of seconds of calibration video should contain background only (no marker)
c. Then move slowly the marker through your entire capture volume (front-top-right-bottom-left-back-top-right-bottom-left)
00:02 00:04 00:06 00:08
00:10 00:12 00:14 00:16
00:18 00:20 00:22 00:24
No marker!Start from top and move the marker in a descending
spiral motion
00:26 00:28 00:30 00:32
00:34 00:36 00:38 00:40
00:42 00:44 00:46 00:48
Move the marker in a descending spiral motion
00:50 00:52 00:54 00:56
00:58 01:00 01:02 01:04
01:06 01:08 01:10 01:12
Marker should always be visible in all camerasand never obscured by human body
d. Put the marker to the ground at each corner and at the center of capture volume
Capture Volume
Step 3: stop recordingand check recorded video
At least first two seconds of video does not contain marker
There is no motion blur (image of marker looks like a round spot rather than an ellipse or a luminescent line)
Marker is always visible in all cameras and never obscured by human body
Step 4: process calibration video in iPiStudio
• Please refer to the video tutorial: Calibration_Tutorial.mp4
Resulting scene should look like this:
Green points designate correctly detected 3D marker positions. Red points designate misdetected marker positions.
10-20% of red points should be considered normal.Calibration should work correctly if you have at least 70% of green points.
Step 5: mark ground points
(at least three)
Go to frame where marker is on the ground and press Mark as ground button
The system uses ground points to calculate ground plane.
You need to define at least 3 ground points.
Step 6: set scene scalebased on the measured camera height
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Note: Height of camera can be used only if ground is marked. If ground plane is not
defined, use distance between camera #1 and #2 to set scene scale
Step 7:save result into *.scene.xml file
Click here to save scene parameters to
XML file