2.2.3. Building the FRIT from FRAT and DWT Thecontinuousridgelettransform[24]ofabivariatefunction f(x)is given by RT = R2 a,b,(x)f(x)dx. (9) However, the use of digital images necessitates the development of suitable variations of the ridgelets to deal with images in the digital domain. An orthonormal, invertible and discrete form of the ridgelet, called finite ridgelet transform was first proposed in Ref. [27]. The FRIT is obtained by performing DWT on each FRAT projection sequence with fixed value of k. ThisprocessispictoriallyrepresentedinFig.5.Mathematically