Sobel and Prewitt operators decomposition

1. What is the difference between Sobel and Prewitt?
2. Why is Sobel called more emphasized filter than Prewitt?
3. How does the Prewitt operator work?
4. Is Sobel first derivative?

What is the difference between Sobel and Prewitt?

The difference between Prewitt and Sobel operator is the spectoral response. It is an appropriate way to estimate the magnitude and orientation of an edge. Prewitt approximation is applied on the derivatives of in- tensity function. Its results in edges where gradient of in- tensity function has maximum value.

Why is Sobel called more emphasized filter than Prewitt?

Prewitt operator is similar to the Sobel operator and is used for detecting vertical and horizontal edges in images. However, unlike the Sobel, this operator does not place any emphasis on the pixels that are closer to the center of the mask.

How does the Prewitt operator work?

The Prewitt operator is based on convolving the image with a small, separable, and integer valued filter in horizontal and vertical directions and is therefore relatively inexpensive in terms of computations like Sobel and Kayyali operators.

Is Sobel first derivative?

The Sobel method, or Sobel filter, is a gradient-based method that looks for strong changes in the first derivative of an image. The Sobel edge detector uses a pair of 3 × 3 convolution masks, one estimating the gradient in the x-direction and the other in the y-direction.