How to separate out echo targets in RiSCAN PRO

Understanding the "target" attributes

The "Target Count" and "Target Index" attributes can be combined to separate out the various echoes from a scan. Where a scan point is the only return, it is classified as a "single" target or echo. Where there were multiple echoes, they will be classified as either "first", "last", or "intermediate".

There are two attributes that relate to this:

• Target Count - the number of total echoes that this echo is from
• Target Index - the number of the echo of that laser shot, e.g. 2 of 4

Here are some examples:

Single target - i.e. the only echo from that laser shot - would have a target count of 1 and a target index of 1

Suppose there were 4 echoes from a laser shot. The first target would have a a target count of 4, and a target index of 1. The second target would have a target count of 4 and target index of 2. The fourth, or last, target would have a target count of 4 and a target index of 4 as well.

Examples

If you wanted to extract all of the first and single targets, you would use an attribute filter Target Index equal to 1:

If you want to get last and single targets, you would use Target Index equal to Target Count (i.e. the target index is the same value as the total number of targets, so it must be the last target):

Single targets will have a target count of 1, as they are the only echoes. Therefore, to extract just the last targets, add another row where Target Index greater than 1:

Combining or separating the pointclouds

You can choose to combine the results of the filter operations into a single pointcloud, or you can keep them separate.

Tick the "Combine data" box towards the bottom of the filter dialog to combine the output into a single file, which will be placed under the OBJECTS / POINTCLOUDS folder.

Untick this box to keep the files separate.

Use the suffix box to append a suffix to the end of the pointcloud name. Starting the suffix with a period (".") will allow you to multi-select the related pointclouds in the Project Manager.

Working with visible data in the 3D view

If you have got a number of scans open in a 3D view, and have hidden some points, and then you want to create pointclouds from the visible points but keep them in separate scan positions, you can select all of the visible points, then choose "Copy selection with filter settings...":

and then ensure that no filter is selected and all "point attributes in output file" are selected. Make sure to disable "Combine data", and add a suffix if you need one:

This will copy the visible points into separate pointclouds under each scan position.