Certified Photogrammetrist Digital Photogrammetry & Point Clouds 3

Question 1

What is 'voxel-based' point cloud processing?

Accepted Answer

Processing point clouds in a 3D grid of volumetric cells (voxels) for efficient spatial analysis

Answer

Converting point clouds to 2D raster images for visualization

Answer

Applying color correction using HSV color model

Answer

Merging point clouds from multiple flight dates

Question 2

In digital photogrammetry, what is 'epipolar geometry' used for?

Accepted Answer

Constraining image matching to a 1D search along epipolar lines, reducing computation and false matches

Answer

Correcting color balance between adjacent strips

Answer

Defining the flight line spacing for a project

Answer

Converting pixel coordinates to geographic coordinates

Question 3

What is the purpose of 'thinning' or 'decimating' a point cloud?

Accepted Answer

Reducing point cloud size by removing redundant points while preserving surface representation

Answer

Increasing point density through interpolation

Answer

Adding color attributes to uncolored points

Answer

Splitting a large point cloud into manageable tiles

Question 4

In photogrammetric software, what does 'tie point extraction' (e.g., SIFT, SURF) accomplish?

Accepted Answer

Detecting distinctive image features and matching them across overlapping images for use in bundle adjustment

Answer

Extracting control points from a GIS database automatically

Answer

Scanning film negatives to produce digital images

Answer

Extracting building rooftops from aerial images using AI

Question 5

What is 'photogrammetric restitution' in the context of digital mapping?

Accepted Answer

The process of extracting planimetric and topographic features from stereo imagery for map compilation

Answer

The process of recovering financial costs from project overruns

Answer

Reconstructing damaged photographs from partial data

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Recovering deleted project files from backup storage

Question 6

Which file format is used to exchange dense point clouds with both geometry and per-point color information?

Accepted Answer

LAS/LAZ (with RGB fields) or PLY format

Answer

GeoTIFF

Answer

DXF polyline format

Answer

SHP (Shapefile)