Conversion options

Project conversion options can be set in File > Options > Gateway.

These are global preferences and will be applied to all scans added to the project.

Mask pixels

This function is designed to significantly reduce the splatter, or spray effect which arises when the laser scanner's beam switches from one object to another. It is able to locate lone pixels or pixels which have too few neighbors.

All non-boundary pixels have eight surrounding neighbors and so, in normal circumstances, a pixel would expect to find its nearest neighbors at similar ranges.

The options are as follows:

• Apply Mixed Pixel - Pixels that are at different ranges are flagged as being mixed pixels and are then masked out of the image. Enable this field to apply mixed pixel.

• Number of Neighbors (ranges from 1-8) - This value sets a threshold for required neighboring points. If the threshold value is not reached, a pixel is deemed noisy and masked out.

  The recommended value is 2.

• Threshold (degrees) - As an image is scanned by the algorithm, each pixel in turn becomes the center pixel with eight neighbors. Eight lines are then formed from the center pixel to its neighbors.

  The Rejection Angle is the angle formed between the view line (line between the center pixel and the origin) and each of the eight pixel lines.

  The recommended value is 5°.

Data masked out by this function will not be visible in 3D Modelling Windows, but will be coloured green in 2D Image Windows. The effect of the mask mixed pixels function is entirely reversible by modifying the conversion options and reconverting the scans.

In common with all these data points functions, the data is never actually deleted or modified, but is masked out and so easily restored.

Minimum field of view

The minimum azimuthal and elevation required for a scan to be processed. Scans not fitting this criteria will not be processed. This is often useful for bundled ptx scans which contain very small partials that are not of much value in isolation.

Dead angle

This enables the user to change the dead region cut-off zone in the base of the scan. The default settings remove the points in the area directly underneath the scanner, where the scanner may see its own tripod. This may be adjusted if a slightly higher viewing angle is required. To change, double-click the desired option and type the new value into the appropriate text fields or click the up and down arrows.

Individual scan settings

On review of the converted scans, several individual scans may require different conversion settings, for example a longer range setting.

To do this:

1. In the Registration panel, create a new group by right-clicking the project and selecting the New > Register Group.

2. Rename the group by right-clicking on the group and selecting Rename.

3. Type in the desired name and press Enter.

The group conversion options can be edited at the bottom of the properties window as shown below. Scans can be added to a group by selecting and dragging the scans onto the group node.