Certified Photogrammetrist Aerial Triangulation & Bundle Adjustment 1 — Questions and Answers
Question 1: What is the primary purpose of aerial triangulation in photogrammetry?
- To determine the exterior orientation parameters of photographs without ground control at every photo (Correct answer)
- To measure the altitude of the aircraft during flight
- To calculate the focal length of the camera
- To generate color-balanced orthophotos automatically
Correct answer: To determine the exterior orientation parameters of photographs without ground control at every photo
Aerial triangulation determines exterior orientation parameters by using a network of tie points and sparse ground control, eliminating the need for ground control at every photograph.
Question 2: In bundle adjustment, what is minimized during the least-squares solution?
- The number of ground control points
- The sum of squared residuals of image coordinate measurements (Correct answer)
- The flying height above terrain
- The overlap percentage between adjacent photos
Correct answer: The sum of squared residuals of image coordinate measurements
Bundle adjustment minimizes the sum of squared residuals of image coordinate measurements, simultaneously solving for camera positions, orientations, and object point coordinates.
Question 3: What are tie points in aerial triangulation?
- Ground-surveyed control monuments
- Points measured in overlapping images that link photos together without known ground coordinates (Correct answer)
- GPS receiver locations on the aircraft
- Fiducial marks on the film frame
Correct answer: Points measured in overlapping images that link photos together without known ground coordinates
Tie points are image features measured in overlapping photographs that geometrically connect the photo block without requiring ground-surveyed coordinates.
Question 4: Which type of ground control point provides both horizontal position and elevation?
- Horizontal-only control
- Vertical-only control
- Full control (3D) (Correct answer)
- Photo-identifiable point
Correct answer: Full control (3D)
Full control points (3D) provide X, Y, and Z coordinates, fully constraining the photogrammetric network in all three dimensions.
Question 5: What does the term 'block of photographs' refer to in aerial triangulation?
- A single stereopair used for mapping
- A collection of overlapping photographs covering an entire project area (Correct answer)
- The physical film magazine in the camera
- A set of control points in a rectangular arrangement
Correct answer: A collection of overlapping photographs covering an entire project area
A block of photographs is the entire collection of overlapping images that covers a mapping project area, processed together in a single triangulation solution.
Question 6: Self-calibrating bundle adjustment simultaneously solves for which additional unknowns?
- Aircraft velocity and heading
- Camera interior orientation parameters (additional parameters) (Correct answer)
- Ground control point coordinates
- Image scan resolution
Correct answer: Camera interior orientation parameters (additional parameters)
Self-calibrating bundle adjustment adds camera interior orientation parameters—such as principal point offset, radial distortion, and decentering distortion—as additional unknowns in the solution.
Certified Photogrammetrist Aerial Triangulation & Bundle Adjustment 1
What is the primary purpose of aerial triangulation in photogrammetry?