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 window must be greater than a predefined threshold for enhancement to be applied.

Explanation:

• Mean: The local mean computes the average intensity of pixels in a neighborhood, which helps adjust brightness.
• Variance: The local variance measures the spread or contrast of the pixel intensities. A higher variance indicates more variation in pixel intensities, suggesting more detailed textures or edges.

Condition:

• Threshold Variance: Enhancement is applied only if the variance in the local region exceeds a certain threshold. Regions with high variance, indicating significant contrast or detail, are enhanced. Low-variance regions (smooth, uniform areas) typically do not need enhancement and may even benefit from being left unaltered to avoid enhancing noise.

In summary, enhancement using mean and variance requires the variance to exceed a certain threshold to ensure that only regions with sufficient detail or texture are enhanced.