Certified Photogrammetrist Stereo Compilation & 3D Modeling

Question 1

What is the 'y-parallax' in a stereopair, and what does excessive y-parallax indicate?

Accepted Answer

Residual vertical displacement after relative orientation; it indicates incomplete relative orientation

Answer

The vertical image displacement caused by relief; it indicates high terrain

Answer

The horizontal parallax difference used to measure elevation

Answer

The parallax introduced by atmospheric refraction

Question 2

In stereo compilation, what does 'absolute orientation' accomplish?

Accepted Answer

It scales, rotates, and positions the stereomodel into a real-world coordinate system using ground control

Answer

It removes y-parallax from the stereopair

Answer

It adjusts image contrast for better stereoscopic viewing

Answer

It determines the interior orientation of each camera

Question 3

What is 'x-parallax' used for in stereo photogrammetry?

Accepted Answer

Measuring elevation differences between points in a stereopair

Answer

Detecting y-parallax errors in the model

Answer

Aligning flight strips in a block adjustment

Answer

Determining the principal distance of the camera

Question 4

What is a 'floating mark' in analogue or softcopy stereo compilation?

Accepted Answer

A stereoscopic measuring mark that appears to float at a selected elevation within the stereomodel

Answer

A GPS receiver that drifts during flight

Answer

An unregistered control point that is not tied to the datum

Answer

A tie point that only appears in one photograph

Question 5

What are the six elements of exterior orientation for a single photograph?

Accepted Answer

X, Y, Z (position of perspective center) and ω, φ, κ (three rotation angles)

Answer

Focal length, principal point x, principal point y, radial distortion k1, k2, k3

Answer

Scale, rotation, translation (2D), and focal length

Answer

Latitude, longitude, altitude, roll, pitch, yaw (as GPS/IMU output only)

Question 6

What is the 'base-to-height ratio' (B/H ratio) in aerial stereophotogrammetry?

Accepted Answer

The ratio of the air base (distance between exposure stations) to the flying height, affecting depth measurement sensitivity

Answer

The ratio of flying height to camera focal length

Answer

The ratio of forward overlap to sidelap percentage

Answer

The ratio of image scale to map scale