Connecting the IS1200
The IS1200 is connected to Previzion over a standard RS232 interface. Connect the DB9 connector on the IS1200 power/serial dongle to the DB9 connector on the Previzion serial breakout labeled “Intersense”.
The IS1200 requires a 6-10V DC power supply, which is supplied by the Airtrack power output (labeled 6.5V OUT) or the included 6V wall power converter. A 3 pin Lemo to DC power jack adapter cable is provided.
To check that the IS1200 is installed and working, select Start->All Programs->Intersense VisTracker->InertiaCam Test. InertiaCamTest should detect and connect to the IS1200 within about 5-10 seconds. The IS1200 consists of both a camera and an inertial measurement unit (IMU); if both are properly detected then this will be displayed in the status box highlighted in the above image.
Reading the Scene
InertiaCamTest provides a live view of what the IS1200 is seeing through its 80 degree field of view camera. Recognized fiducials will have a green cross through the center of the marker and the marker number next to it, as shown. To properly recognize fiducials, two criteria are used.
- Diameter: fiducial distance must be between 5 and 20 times the diameter of the fiducial
- Exposure: fiducial must be not be overexposed or underexposed
This view is especially useful when setting up a target grid on a stage. The IS1200 can be placed in typical positions that will be encountered by the actual production camera, and checked for target visibility and tracking acquisition.
The scene update is typically a frame every few seconds with the Image Quality slider set to 40%. To increase the rate of image update, lower the quality slider. This has no effect on the tracking of the IS1200, as during tracking only the XY pixel positions and identities of the identified fiducial targets are sent over the serial line.
Setting the Exposure
Lighting on stages varies widely, so there are multiple exposure modes that can be used. These are selected with the Devices->Camera Exposure menu. There are 3 settings.
- Auto1 (Basic)
- Auto2 (Ignore Lights)
In the Manual mode, the shutter duration and gain can be manually adjusted with the sliders in the lower left hand corner. The default is Auto2, which works best for varying lighting levels. Manual mode is most useful in stage conditions.
If the exposure mode has been changed, it can be stored in the IS1200”s EEPROM with Devices->Camera Exposure->Save in EEPROM.
Exit the InertiaCamTest program with File->Exit. InertiaCamTest must be off before sfServer (the program that converts the XY fiducial information into 3D tracking data) can be started.