The frequency domain plays an important role in image

processing to smooth, enhance, and detect edges of images. Although

image data typically does not include imaginary values, the fast Fourier

transform (FFT) has been used for obtaining spectra. In this paper,

the fast Hartley transform (FHT) is used to transform two-dimensional

image data. Because the Hartley transform is real valued, it does

not require complex operations. Both spectra and autocorrelations of

two-dimensional ultrasound images of normal and abnormal livers were

computed.