How is the Laplacian used for Unsharp Mask?

1. How is Laplacian operator used for image sharpening?
2. Why Laplacian filter is used?
3. How does Unsharp Mask work?

How is Laplacian operator used for image sharpening?

The input gray image is first subjected to a Laplacian filter, which acts as the preprocessing block and then Adaptive Histogram Equalization (AHE) is applied to the image obtained after preprocessing as shown in Fig. 3. The Laplacian filter is an edge-sharpening filter, which sharpens the edges of the image.

Why Laplacian filter is used?

A Laplacian filter is an edge detector used to compute the second derivatives of an image, measuring the rate at which the first derivatives change. This determines if a change in adjacent pixel values is from an edge or continuous progression.

How does Unsharp Mask work?

The Unsharp Mask increases the image contrast along the edges of objects in a photo. The effect doesn't actually detect edges, but it can identify pixel values that differ from their neighboring pixels by a certain amount.