Define color points

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Define color points

Define color points

Define color points command starts the color point mode. This includes opening of the Color points menu and additional processing steps depending on the specified color point mode:

Ground ortho - creation of a ground model, preview of rectified images.

Point cloud - on-the-fly extraction of color values for each point, display of the point cloud.

The Color points menu allows you to create color points and to define different types of correction polygons that improve the quality of the final ortho mosaic or a colored point cloud.

Color points for the rectification of images or orthophoto production require a ground model. Therefore, the corresponding color point mode is only available, if ground points are loaded into TerraPhoto.

Color points for point clouds require a TerraScan project that manages the point cloud and a point cloud format that is able to store color values, image numbers, and normal vectors/dimensions for each point. The storage of all these attributes is only possible in TerraScan Fast binary format.

The concept of color points and commands of the Color points menu are described in detail in Chapter Color Points and Selection Shapes.

To start the color point mode for (ortho) rectification:

1. Select Define color points from the Rectify pulldown menu.

This opens the Color point setting dialog:

color_point_setting_ortho

2. Select Ground ortho in the Mode list.

3. Define settings and click OK.

This starts the color point mode.

SETTING

EFFECT

Rectification pixel

Intended pixel size of the final orthophoto mosaic.

Computation

Pixel size scale factor for color point computation. Color points and selection shapes do not need to be computed at the full resolution of the final orthophoto. It is recommended to use a factor of 2 or 3 in order to make computation processes faster.

Max ground triangle

Maximum triangle length in the ground model.

Bounding polygons

If on, the area available for color points is limited by the polygon(s) drawn on the given MicroStation level. The list contains all levels with elements in the design file.

View update

Method of updating the view display after modifications to color points and selection shapes:

On command - the display must be updated manually.

Automatic - the display is updated automatically after each modification.

Use object shapes

If on, object shapes on the given levels are used to create a true orthophoto preview.

Levels

Number(s) of MicroStation design file levels that contain 3D objects for true orthophotos. Separate several levels by comma. This is only active if Use object shapes is switched on.

Edge buffer

Distance from the edge of a 3D object within which object pixels are not rectified on the ground. The prevents, for example, roof pixels to be rectified on the ground next to buildings. This is only active if Use object shapes is switched on.

To start the color point mode for point clouds:

1. Select Define color points command from the Rectify pulldown menu.

This opens the Color point setting dialog:

color_point_setting_pointcloud

2. Select Point cloud in the Mode list.

3. Define settings and click OK.

This starts the color point mode.

SETTING

EFFECT

Pixel size

Approximate pixel size of raw images. Determines the size of a color point.

Use classes

Point classes used for color point creation. Exclude classes with non-planar objects, such as poles, wires, etc.

_select_classes

Opens the Select classes dialog which contains the list of active classes in TerraScan. You can select multiple source classes from the list that are then used in the Use classes field.

Use only planar points

If on, only points with dimension attribute Planar are used for color point creation.

View update

Method of updating the view display after modifications to color points and selection shapes:

On command - the display must be updated manually.

Automatic - the display is updated automatically after each modification.

To classes

Point classes for which color values are extracted on-the-fly for displaying points in the color point mode.

_select_classes

Opens the Select classes dialog which contains the list of active classes in TerraScan. You can select multiple source classes from the list that are then used in the To classes field.

Max distance

Maximum distance between a raw image and a laser point. Images outside that distance are not considered for color extraction.

Use depth maps

If on, depth maps files are included in the color extraction process.

Favor better quality images

If on, the quality attribute stored for raw images in an image list is considered in the color extraction process.

Favor cameras by class

If on, the settings in the TerraPhoto mission file related to favoring cameras for coloring points are considered in the color extraction process.

Display classes

Point classes that are displayed in color point mode.

_select_classes

Opens the Select classes dialog which contains the list of active classes in TerraScan. You can select multiple source classes from the list that are then used in the Display classes field.