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 in the local window must be greater than zero.

Explanation:

• Mean: The local mean helps adjust the brightness by calculating the average intensity of pixels within a neighborhood.
• Variance: The variance measures how much the pixel intensities deviate from the mean, indicating the level of contrast or texture.

Condition:

• Non-zero Variance: For meaningful enhancement to occur, the variance within the local window must be greater than zero. A zero variance means the region is uniform, without any contrast or texture, so enhancement wouldn't be useful or would lead to noise amplification in featureless areas.

In summary, local enhancement using mean and variance is applied only when there is non-zero variance, ensuring that the algorithm focuses on regions with detail or contrast for enhancement.