You can find a lot of good examples and tutorials about the sobel edge detection algorithm (e.g. http://angeljohnsy.blogspot.com/2011/12/sobel-edge-detection.html). The link above contains a matlab example.

Dear Ram

I think you want to find the Grayscale values for after performing the sobel edge detector! If you want this,

get the index of matrix of white marked edges. Just mark the original image with different color on following index.

Just have a look on the following links.

Regards

Ehtesham

http://www.mathworks.com/help/hdlcoder/examples/edge-detection-and-image-overlay.html?searchHighlight=edge%20detection

http://www.mathworks.com/help/visionhdl/ref/frametopixels.html

Do you want to know how to compute Sobel edge detector having the Sobel matrix M and the image intensity I?

If so, you just need to convolve these two. In Matlab is conv2(I,M);

If you want to know how the convolution works, a simple example is in Wikipedia: https://en.wikipedia.org/wiki/Kernel_(image_processing)

If you want to find the edges of the image after applying the Sobel edge detector. Then, you need to threshold the values. So, the edges are image_sobel > threshold. Many already built-in detectors usually convert the values, so that, the image_sobel contains 1's where edges are and 0's where there are no edges.

Hope this helps.

we can also use shape based features in edge detection

Many of programming languages, which are having image processing capabilities, provide a predefined function for sobel edge detection. The following link explains how to write code in python(opencv) without using predefined function (sobel edge detection). It enables you to write your own code for sobel edge detection. Hence, you can get deeper knowledge on sobel edge detection and write your own code in any programming language. http://naveenideas.blogspot.com/2018/02/sobel-edge-detection.html

Hope, It may help to you.