Orthographic Projection

Function

This Step orthographically projects a 3D point cloud into a 2D depth map, which can avoid the perspective distortion in ordinary projection.

../../../../../_images/functional_description_1.png

Usage Scenario

This Step is usually used for measurement. It projects a 3D point cloud into a 2D depth map for further processing in succeeding measurement Steps.

Input and Output

../../../../../_images/input_and_output_1.png

Parameter Description

Hint

Please right-click and select Show all parameters to view all parameters of this Step.

Orthographic Projection Settings

Resolution
Parameter description: This parameter represents the number of pixels per unit length on the 2D image formed by the orthographic projection. The unit length is 1 meter.
Default value: 1000.0000
Notes: Please refer to tuning examples for the visualized output.
Mask Blank Border Width
Parameter description: A white frame will be added to the mask of the 2D image formed by the projection. This parameter specifies the width of the frame.
Default value: 100px
Notes: Please refer to tuning examples for the visualized output.

Specify Min Point

Parameter description: This parameter specifies the vertex with the minimum X and Y coordinates on the bounding box of the point cloud. Once a minimum point and a maximum point are specified, the orthogonal projection will be performed on the range between the maximum and minimum points.
Default value: Unselected
Notes: If you select this parameter, you will need to set the Min Point X Coordinate and Min Point Y Coordinate.
Min Point X Coordinate
Default value: 0.000000m
Tuning recommendation: If you run the project with the Specify Min Point unselected, reference values will be output in the log panel. You can adjust the parameter according to the reference values until the effect of the orthographic projection outputs a desired result. Generally, it is expected that there is no inference point cloud and only the area where the object is located is kept after the orthographic projection.
../../../../../_images/log_x_y.png
Min Point Y Coordinate
Default value: 0.000000m
Tuning recommendation: See Min Point X Coordinate.

Specify Max Point

Parameter description: This parameter specifies the vertex with the maximum X and Y coordinates on the bounding box of the point cloud. Once a minimum point and a maximum point are specified, the orthogonal projection will be performed on the range between the maximum and minimum points.
Default value: Unselected
Notes: If you select this parameter, you will need to set the Max Point X Coordinate and Max Point Y Coordinate.
Max Point X Coordinate
Default value: 0.000000m
Tuning recommendation: See Min Point X Coordinate.
Max Point Y Coordinate
Default value: 0.000000m
Tuning recommendation: See Min Point Y Coordinate.

Tuning Examples

Resolution

When the resolution is set to 1000, 700 and 400 respectively, the output masks after the orthographic projection are shown as below.

../../../../../_images/resolution_compare.png

Mask Blank Border Width

When the mask blank border width is set to 100, 400, and 700 respectively, the output masks after the orthographic projection are shown as below.

../../../../../_images/mask_blank_border_width_compare.png