“…Structural features describe the geometrical and topological characteristics of a text image pattern, such as directions, strokes, endpoints, the intersection of line segments, number of diacritical marks, loops, types of dots, zigzag, arcs, concavities, etc. Statistical features are extracted from the pixels’ statistical distribution, and they describe the set of characteristic measurements of a text image pattern, such as number of loops, segments, branching and crossing points, and diacritics and their positions [ 95 ], and they have low complexity and high speed [ 1 , 3 , 8 , 94 ]. Feature space transformations convert the pixel representation to a more compact form with less feature vector dimensionality [ 7 , 8 , 94 ] among the methods involving principal component analysis (PCA), Walsh Hadamard Transform, Fourier Transform, Wavelets, Hough Transform, Gabor Transform, Rapid Transform, and Karhunen Loeve Expression and moments [ 1 , 3 , 8 , 9 , 94 , 95 ].…”