Using Predefined Filter Types :: Linear Filtering and Filter Design (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Using Predefined Filter Types

The fspecial function produces several kinds of predefined filters, in the form of correlation kernels. After creating a filter with fspecial, you can apply it directly to your image data using imfilter. This example illustrates applying an unsharp masking filter to an grayscale image. The unsharp masking filter has the effect of making edges and fine detail in the image more crisp.

I = imread('moon.tif');
h = fspecial('unsharp');
I2 = imfilter(I,h);
imshow(I), title('Original Image')
figure, imshow(I2), title('Filtered Image')

Filtering Using imfilter Filter Design