Scene tracking is very similar to Camera Tracking for sports. It allows you to put Products on the pitch. The system keeps it on the same place while the camera moves.
Unlike Camera Tracking for sports, Scene Tracking is more universal type of tracking, but requires certain knowledge of the field to be provided by the user during calibration.
Scene Tracking requires license.
Calibration Editor
Press the Scene calibration editor button in the toolbar to open/close the editor.
Initial screen of the editor
- New – creates new Scene calibration.
- Open – opens an existing scene calibration. Scene calibration files have .scal suffix. Calibration folder is accessible via Start → Virtual Placement → App Directory → Scene Calibrations.
- Edit – edit current calibrations.
- Save/Save as – save current calibration into a file.
Panorama Calibration
Scene calibration consists of a Panorama and Metric. Metrics definition and calibration need the panorama to be built first.
Press Capture button to go to Panorama Sweeps screen.
Panorama Sweeps
This screen shows list of captured sweeps (represented by thumbnail of their first frame). Selected sweep is displayed in bigger size.
| UI | Description |
| Add new sweep. This will take you to the Panorama Sweep Capture screen. | |
| Select next sweep. | |
| Delete currently selected sweep. | |
| Generate panorama and go back to the Panorama Calibration screen. Panorama generating might take a while. |
Panorama Sweep Capture
This screen will help you to setup the camera and get ready for the next sweep capture.
| UI | Description |
| Start capturing sweep. | |
| Go back to Panorama Sweeps screen. | |
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Preview of camera zoom for this sweep. The preview is shown on the SDI output only, so the camera crew can see the requested zoom level. |
Guidelines for sweep capturing
- Zoom out the camera to the maximum for the first sweep
- Point the camera at the finish line or other significant point close to the camera.
- Start capturing sweep.
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- Don't change zoom level during the sweep.
- Follow the track with the camera.
- Keep the track focused during the sweep.
- Make sure there's no motion blur – when the light conditions are poor, make sure the pan is slow.
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We recommend to make the camera pan in counter clockwise direction.
When you return to the point where the pan started, press the Finish button.
Repeat the capture sweep procedure for another zoom level.
All sweeps should start at the same point.
When zoomed-in, we are more interested in advertisement and similar significant objects rather than mud/grass on the track.
| We need a minimum of 5 sweeps with different zoom settings, and as many as are necessary to cover the range from max zoomed out to as tight as you would want to go with virtual graphics. |
Panorama metric
The metric contains real world coordinates of few significant points and images of placement of these points. The metric can contain wire-frame model of the track.
By default, the calibration contains empty metric
- Import – Import metric from a file (.met file).
- Export – Export metric to a file.
- Edit – Edit current metric. Go to the Panorama Metric Designer screen.
- Calibrate – Calibrate the metric. Available only when a metric has been defined.
- Done – Return back to the Panorama Calibration screen.
Panorama Metric Designer
This screen helps you to design metric for the environment.
It contains following controls:
Model preview. When a wireframe for the model has been imported, top view of the track is shown.
Additionally it contains all added model points. The points are clickable so you can verity their location in the video preview.
Currently selected point is displayed in red.
Add a metric point. Define its position in the Model point editor.
Remove currently selected metric point.
Model point editor. Shows real world coordinates of the point [in meters].
Coordinate system origin is user-selectable (e.g. middle of the track, finish line etc.)
X,Y coordinates are on the surface of the environment, Z coordinate means altitude above the ground.
Point preview in the template image. You can change detail of the view by the Wide and Detail buttons.
Import wireframe from a file.
Finish metric definition and go back to the Panorama metric screen.
Wireframe
We accept .svg or .obj files with the wireframe model. Svg files can be used for planar models whereas .obj file format allows to define 3d wireframe models. Scale of the wireframe model must correspond to the real world environment. Origin of the wireframe model must correspond with the origin chosen for the metric points.
The wireframe serves for visual verification of the calibration quality only. It is highly recommended to have a simplified model the environment.
Guidelines for metric definition
- Localize several points in the environment. The points should be distributed along the whole track.
- Press Add point button
- Fill in coordinates of the point
- Click on the point in the panorama. The video zooms in to allow you fair position corrections.
Panorama Metric Calibration
The last step is locating the metric points in the video. The workflow and the look of the Calibration screen is very similar to the one in the Panorama Metric Designer.
Calibrating the points
- Select a point in the model preview (non-calibrated points are rendered in white, calibrated points in yellow, actually selected point in red color).
- Click the point in the panorama (the template preview in the toolbar will guide you).
The system switches to Detail view automatically to allow you fine positioning of the point in the video. - Select precise position of the point.
- Continue with the next point.
- Once you have all points placed in the video, press Calculate button (the process might take a while).
When the metric is successfully calibrated, the application starts rendering the wireframe, if defined. You can verify the quality of the calibration.
The point selected in the video is rendered as a cross. Projection of the real world point into the video is rendered as a circle. In ideal case these two points point to the same spot in the video. The last step is locating the metric points in the video.
The workflow and the look of the Calibration screen is very similar to the one in the Panorama Metric Designer.
Scene Tracking Static Camera
Scene tacking can also be used with a fixed camera, this enables the user to account for lens distortion during tracking. Calibration process is very similar to the dynamic camera workflow.
Calibrating the Static Camera
- Select static from camera type.
- Capture single frame from incoming video feed.
- Select lens distortion in order to apply a line to the captured frame. This line should be placed near the edge of the image.
- The line can then be adjusted using the Slider provided (shown in the image below)
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Note: The position of the line can sometimes vary depending on the image and also the lenses that are used on the cameras. |