Sight line and view

Sight line and Sight view

Pixpro Sight line and Sight View functions can be used to determine direct line of sight and blind spots on a reconstructed surface. This can be used in various security and monitoring applications.

To use these functions a Digital Elevation Map is necessary to have in the project. All the visibility calculations and measurements are done on the Digital Elevation Map layer. Orthophoto layer can also be present to make the scene more realistic.

When a DEM layer is enabled two icons will appear in the toolbar.

icon is for Sight Line

icon is for Sight View

Sight Line function

Sight line functionality allows the user to determine if there is a direct line of sight between two points on the reconstructed surface and get all the appropriate measurements.

To activate Sight Line drawing press on the Sight Line button in the toolbar. Left mouse click anywhere on the DEM surface to place the first point. Do the same to add a second point to which a direct sight should be measured. After adding the second point, results and calculations appear in the Tools panel on the right side of the software window.

Below an Example of Sight Line being used.

The measurements associated with the Sight line placement can be seen in the tools panel:

Tools panel is divided into sections:

• Viewers Eyes Position

Provides a selection of preset values for the height of the first point and the option to enter a precise custom value.

• Target Position

Provides a field to enter the target height value (the second point of the line).

• Calculations - displays calculated line measurements:

Distance 2D - two dimensional distance of the drawn line as seen directly from above.

Sight Line - three dimensional distance between the first and second line points.

Slope Angle - angle of the drawn line in relation to the gravitational plane.

Bearing Angle - drawn line bearing angle in relation to north.

• Occlusions - displays information about the obstacle that breaks the line of sight.

Distance to Obstacle - distance measure to the obstacle that breaks the line of sight.

Max Obstacle Height - height of the obstacle that breaks the line of sight.

• Visibility - displays an indicator that shows if the direct sight is broken or not.

Settings button - opens up a window for settings related to the Sight Line function.

Blind Zone at the Beginning - allows entering a length value according to which a certain portion of the obstacles will be ignored. For example if a 1 meter blind zone is entered, all objects that break the direct sight in the Beginning part of the line will be ignored.

Blind Zone at the End - allows entering a length value according to which a certain portion of the obstacles will be ignored. For example if a 1 meter blind zone is entered, all objects that break the direct sight in the ending part of the line will be ignored.

Minimal Obstacle Height - allows entering the minimal height value that will be considered enough to break the direct sight. If a 1 meter height is entered, and the direct sight is broken by only 50 centimeters, these objects will be ignored and direct sight will be displayed as unbroken.

Sight View function

Sight view allows the user to simulate a camera with certain field of view settings and preview blind spots on the reconstructed surface.

Areas that are visible will be colored green on the DEM while areas that are obscure will be colored red. To begin using the tool press Sight View icon in the toolbar.

Left mouse click on the 3D view to designate the point of interest. A line will appear afterwards. Add the second point to the approximate area of interest, there is no need to be precise as the simulation position can be adjusted after the initial input.

Below an example of the tool being used.

In the tools panel various simulation options can be entered.

• Viewers Eyes Position

Provides a selection of preset values for the height of the first point and the option to enter a precise custom value.

• Target Position

Target Height can be entered. This will determine the center of the target above ground in the designated place on the DEM.

• Viewing Parameters

Viewing Direction - bearing angle in relation to the north can be entered.

Distance - distance that determines the maximum simulated length of the FOV (field of view) frustum can be entered.

• Camera Parameters

Horizontal and vertical FOV values can be entered.

To finish using either of the tools press OK button, otherwise no other function will be available when sight functions are active.