Question

The constructive and destructive interference from the multiple scattering returns that occur within each resolution cell is called:

• A. $\text{Surface roughness}$
• B. $\text{Speckle}$
• C. $\text{Volume scattering}$
• D. $\text{Facet backscatter}$

Hint:

Speckle noise in radar and sonar imaging is caused by constructive and destructive interference of scattered waves within a resolution cell. It can be reduced using multi-look processing or adaptive filters.

Answer 1

The Correct Option is B

Step 1: Understanding constructive and destructive interference. When electromagnetic waves scatter from multiple surfaces or objects within a single resolution cell of an imaging system, they interfere with each other. This interference can be constructive (increased signal strength) or destructive (reduced signal strength).
Step 2: Defining speckle. Speckle is a granular noise pattern caused by coherent interference in radar and sonar imaging systems. It occurs due to: - Multiple scattering within a resolution cell. - Phase differences among scattered signals. - Coherent processing of signals.
Step 3: Explanation of other terms. - Surface roughness: Describes the physical texture of a surface that affects scattering. - Volume scattering: Occurs when signals scatter from multiple layers within a medium (e.g., forest canopy, ice layers). - Facet backscatter: Refers to scattering from small facets of an object rather than multiple interferences.
Step 4: Selecting the correct option. Since the phenomenon described in the question matches speckle, the correct answer is b. Speckle.