How sobel edge detector as a first order derivative is turned to a 2 dim filter?

1. What is first-order derivative in edge detection?
2. How does the Sobel edge detection work?
3. What is the difference between first-order and second order derivative in edge detection?
4. What is Sobel derivative?

What is first-order derivative in edge detection?

In this method we take the 1st derivative of the intensity value across the image and find points where the derivative is maximum then the edge could be located. The gradient is a vector, whose components measure how rapid pixel value are changing with distance in the x and y direction.

How does the Sobel edge detection work?

The Sobel filter is used for edge detection. It works by calculating the gradient of image intensity at each pixel within the image. It finds the direction of the largest increase from light to dark and the rate of change in that direction.

What is the difference between first-order and second order derivative in edge detection?

The first-order derivatives are good to select the stongest edges by (hysteresis-)thresholding the gradient magnitude. The zero-crossings of the second-order derivatives are good for localization of the edge.

What is Sobel derivative?

The Sobel Operator is a discrete differentiation operator. It computes an approximation of the gradient of an image intensity function. The Sobel Operator combines Gaussian smoothing and differentiation.