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 less 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 in the local region must be greater than a certain threshold for enhancement to be effective.

Explanation:

• Mean: The local mean computes the average intensity in a defined neighborhood, helping to adjust the brightness.
• Variance: The local variance measures the spread or deviation of pixel values around the mean, indicating how much detail (contrast or texture) exists in the region.

Condition:

• Threshold Variance: Local enhancement is generally applied when the variance is sufficiently high, indicating the presence of features like edges or textures. If the variance is too low (in uniform or smooth areas), enhancement may not be necessary, as it could lead to amplifying noise or no useful effect.

In summary, local enhancement using mean and variance requires the variance to be above a threshold to effectively enhance regions with sufficient contrast or detail.