====== Ghost Cleaning ======
\\
This page describes the desktop extension "Ghost Cleaning" for Mobile Mapping.\\

**Content Manager**\\
{{orbitgis:how_to_find.png?25&nolink |}} [[1910:desktop:workspace:main_toolbar|Main Toolbar]] > Extensions > Ghost Cleaning\\

===== Concepts =====

**Ghosts** : A ghost represents a collection of lidar points that should not be present in the pointcloud. The best examples are moving objects, like cars or people that are recorded in several positions and appear as erroneous points. 

**Ghost cleaning** : The process of removing unwanted objects from the pointcloud. Orbit achieves this goal automatically inside a defined area, by creating a ground surface on the fly and removing all objects above that surface inside a fence. The Ghost cleaning extension only finds, calculates and selects the points that need to be removed, the actual removal of the objects requires [[1910:desktop_ext:consolidation|Consolidation]] 

**Files & folders** : All created files and folders are saved in a new folder <name-of-opc-file>.ghostcleaning next to the [[1910:technology:supported_formats:pointcloud:opc|]] file. For each cleaning a new project folder will be created, see below "File menu drop-down".

   
===== Sidebar =====

 {{ :1910:desktop_ext:ghostcleaning_sidebar_1920.jpg?nolink|}} 
=== Project ===

**Select Point cloud Dataset** \\
Displays the available opc files in the Dataset List, from which to choose the one on which the ghost cleaning will be performed.

**File menu drop-down** \\
Choose where you want to store the cleaning results. A project represents an automatically created destination folder inside your runs pointcloud folder. \\
For each Ghost Cleaning a new project will be created. Writing new data in an existing project will overwrite existing data in that folder. \\
Options to create a new project, open a recent project, close or delete a project are available.

=== Fence ===

**Included** \\
Ghost Cleaning will be done inside the fence that is drawn or selected.

**Excluded** \\
Ghost Cleaning will be done outside the fence that is drawn or selected.

**Draw** \\
Draw a fence around the area to clean.\\
[[1910:technology:core:crs|Map CRS]] must be the same as the pointcloud resource CRS.

**Select** \\
Select an already available vector file to use as a fence. 
 
**Add** \\
Add a part to an existing fence.

**Delete** \\
Delete existing fence.

**Included Area - Excluded Area** \\
The area of the fence will be calculated and displayed.


=== Analyze ===
Define the parameters that will be used in the automatic detection of ghosts.

**Cell size** \\
The cell size of the DEM created to define the ground surface.

**Cell range max** \\
To be considered "ground" pixel height value should differ from the average height less than cell range max.

**Neighb horz range** \\
Amount of pixels around current one where **Neighb offset max** is applied.

**Neighb offset max** \\
The maximum difference pixel height value is allowed to have with the neighboring pixel to be considered "ground". 

**Ground offset min** \\
The minimum distance between the ground surface and a point, in order to consider that point a ghost.

**Ground offset max** \\
The maximum distance between the ground surface and a point, in order to consider that point a ghost.

=== Process ===

**Delegate to task manager** \\
See: [[1910:desktop:tabs:task_manager|]]

**Start Now** \\
Start the ghost detection. It will create separate .ops files for each project.

**Manual Adjustment** \\
Allows the manual editing of the points to be included in the selection, and as a result modifies the objects considered as a ghosts.
By pressing "Manual Adjustment" the [[1910:desktop:tools:clip|]] tool is opened, which allows manual selection inside the pointcloud.

=== Merge Projects ===

Creates a temporary pointcloud file necessary when the run is consolidated. Several projects can be used at once, the result will be an .opd file stored in the run's pointcloud folder. The function is envisioned to be run only one time for all the projects. To run "Merge Projects" a second time, the previous .opd file must be deleted. 

**Start** \\
Start the generation of the .opd file to be used in Consolidation extension.

=== View Settings ===

**Show Fence** \\
Choose to visualize the fence that is drawn or selected.