In optical remote sensing, stray scattered or diffused radiance from outside the target entering the sensor’s field of view most commonly has what effect on the resulting image?

Introduction / Context:
Atmospheric scattering and sensor stray light add unwanted radiance to the signal that should represent only the target. This contamination acts like a veiling light (haze), diminishing the ability to distinguish bright and dark features and blurring fine detail.

Given Data / Assumptions:

• Stray radiance originates from outside the intended target area.
• The effect is approximately additive in radiance.
• Sensor optics and atmosphere both contribute.

Concept / Approach:
An additive haze term raises dark pixel values toward mid-tones without equivalently lifting highlights, compressing dynamic range (contrast). Multiple scattering and optical flare also smear edges and dampen high-frequency content, lowering perceived sharpness and measurable modulation transfer.

Step-by-Step Solution:
Model observed radiance: L_obs = L_target + L_haze.As L_haze grows, differences between dark and mid-tones shrink → reduced contrast.Stray light spreads energy across neighboring pixels → edge softening → reduced sharpness.Therefore, the correct effect is decreased contrast and decreased sharpness.

Verification / Alternative check:
Haze removal algorithms (dark object subtraction, atmospheric correction) explicitly reduce an estimated additive path-radiance term to restore contrast and some detail.

Why Other Options Are Wrong:

• Increasing contrast is inconsistent with additive haze.
• Sharpness generally does not improve in the presence of stray light.

Common Pitfalls:
Confusing random sensor noise with systematic veiling glare; misinterpreting contrast changes after histogram stretching as true contrast recovery.

Final Answer:
Reduces the contrast of the image and also its sharpness