For a local enhancement using mean and variance, there is one condition: σs(x, y) ≤ k2DG, where, MDG is global standard deviation, k2 a positive constant and σs(x, y) a measure of contrast at point (x, y). Then, which fact is true for k2 if its values is greater than 1.0?

Question

For a local enhancement using mean and variance, there is one condition:

Answer 1

For local enhancement using mean and variance, the condition is:

The variance within the local region must exceed a threshold for enhancement to be applied.

Explanation:

• Mean: The local mean adjusts the brightness of the neighborhood by computing the average pixel intensity in a region.
• Variance: The variance measures the spread of pixel intensities around the mean, indicating the level of contrast or texture within that region.

Key Condition:

• Threshold for Variance: Enhancement is typically applied when the variance in a local neighborhood is higher than a certain threshold. High variance indicates the presence of features such as edges or textures, which can be enhanced. Low variance, corresponding to smooth areas, does not require enhancement, as it may result in the amplification of noise or unnecessary contrast.

Thus, local enhancement is applied only when the local variance exceeds a certain threshold, ensuring that enhancement focuses on regions with sufficient contrast and detail.