Book excerpt: Even after completing a course on Fourier transform, it is difficult for many students to mentally represent a function or an image in the frequency domain. Several technologies exclusively work in the frequency domain like television and magnetic resonance imaging (MRI), making an understanding of this issue essential. As such, this book depicts the transformation into the frequency domain in detail, covering topics from Fourier series to image filtering and enhancement. It also provides a progressive introduction to programming in Matlab, as well as detailed operations of Fourier series and Fourier transforms, convolution and filtering, with numerical applications on functions and images at each step of the data processing.