Question

Which of the following statements is/are correct regarding across-track scanning sensor of an airborne optical imaging system?

• A. The relief displacement will be along the direction of the flight line
• B. There is no relief displacement along the direction of the flight line
• C. The greater is the distance of the ground object from nadir, the lesser is the image scale compression
• D. Linear features have sigmoidal distortion

Hint:

Across-track scanners create sigmoidal distortions due to scanning geometry and do not cause relief displacement along the flight line.

Answer 1

The Correct Option is B, D

Across-track scanners scan perpendicular to the flight path. Therefore, relief displacement is across the track, not along it. So, (A) is incorrect and (B) is correct.
As distance from nadir increases, image scale compression increases — hence, (C) is false.
Linear features captured by across-track scanners often appear curved or sigmoidal due to geometric distortions inherent in scanning — making (D) correct.

Final Answer: \(\fbox{(B), (D)}\)