Certified Photogrammetrist Stereo Compilation & 3D Modeling 3

Question 1

What is 'nadir' in aerial photogrammetry?

Accepted Answer

The point on the ground directly below the camera's perspective center (ground nadir), or its image (photo nadir)

Answer

The point on the photograph with minimum distortion due to radial lens distortion

Answer

The highest point in the flight block

Answer

The principal point of the camera calibration

Question 2

What causes 'layover' in radar imagery, and can it affect photogrammetric products?

Accepted Answer

In radar, layover occurs when tall objects lean toward the sensor; in photogrammetry, the analogue is relief displacement

Answer

Layover is caused by atmospheric haze and degrades photogrammetric accuracy uniformly

Answer

Layover is exclusive to multispectral sensors and does not affect photogrammetric products

Answer

Layover in photogrammetry refers to GPS signal multipath errors

Question 3

What is the purpose of 'edge matching' in stereo compilation projects?

Accepted Answer

Ensuring that map features compiled in adjacent stereomodels connect seamlessly at model boundaries

Answer

Matching the color histogram of adjacent photographs

Answer

Aligning GPS trajectories from two different flight days

Answer

Connecting control points across different coordinate zones

Question 4

What is 'stereoscopic exaggeration' in photogrammetric viewing?

Accepted Answer

The perceived amplification of vertical relief when the eye base is larger relative to the B/H ratio than normal human vision

Answer

The enhancement of image contrast in stereo viewing systems

Answer

The distortion introduced by incorrect lens calibration

Answer

The color enhancement applied to improve feature discrimination

Question 5

In stereo compilation, what is the function of the 'model coordinate system'?

Accepted Answer

An arbitrary local 3D coordinate system defined by the relative orientation of a stereopair, before absolute orientation is applied

Answer

The final geographic coordinate system of the mapping project

Answer

The coordinate system of the IMU unit on the aircraft

Answer

The pixel coordinate system of the scanned image

Question 6

What is 'parallax bar measurement' used for in analogue stereo photogrammetry?

Accepted Answer

Measuring x-parallax differences between points to compute relative elevations

Answer

Measuring the y-parallax to detect relative orientation errors

Answer

Measuring the principal distance of the analogue plotter

Answer

Calibrating the stage movement of a comparator