Sharpening image using first order derivative

what is the MATLAB code to sharpen an image using first order derivative?

[Jan]

The derivative of what?

[Nirmala M S]

The first order derivative using sobel or robert etc.,

Answer 1

[Image Analyst]

You can sharpen the image by adding the Laplacian to the original image. This can all be done in one convolution:

windowWidth = 3;
kernel = -1 * ones(windowWidth);
middleRow = ceil(windowWidth / 2);
kernel(middleRow, middleRow) = 2 * windowWidth ^ 2 - 1;
sharpenedImage = conv2(double(grayImage), kernel, 'same');
imshow(sharpenedImage, []);

[Nirmala M S]

Thanks...