Assign bad polygons
Assign bad polygons command is used to define areas in images of one camera that are unusable for TerraPhoto processes. Such areas may occur, for examples, if a camera always sees a part of the aircraft or car on which the system is mounted.
Such areas are marked in one raw image by a polygon. Then, the polygon can be defined as “bad polygon” for a camera in the Camera dialog. Areas inside bad polygons are excluded from automatic tie point and color point searches, from rectification processes, and from the extraction of RGB colors for laser points.
The polygons are stored in the camera calibration files. The coordinates of the vertices of the polygons are listed for each polygon separately in the calibration file of the effected camera.
To assign a bad polygon:
2. Attach a raw image as raster reference using Attach files command from the File pulldown menu.
3. Select Modify attachment command from the Edit pulldown menu.
4. In the Modify attachment dialog, define the following values:
|Easting origin = 0.0000||Pixel size = 1.00000|
|Northing origin = 0.0000||Pixel size = 1.00000|
5. Select Fit / Selected command from the View pulldown menu. Place a data click inside a MicroStation top view in order to display the image.
6. Digitize a polygon around the area that can not be used from the images of the camera. Any MicroStation tool for creating shape elements can be used.
You may create several polygons that can be defined as bad polygons in one step.
7. Select the polygon using any MicroStation Selection tool.
8. Select Define Camera tool in order to open the Camera dialog.
9. Select the correct camera name in the Camera field.
10. Select Assign bad polygons command from the Tools pulldown menu.
This defines the selected polygon as bad polygon. The number of Bad areas is displayed in the Camera dialog.