Complex NSST in Text Localization
Jiu-Wen Zhang, Lu Zhang, Chunhui Liu, Min Dong · 2016
Text localization is a crucial course for image processing.In this paper, an algorithm for text localization based on Complex Nonsubsampled Shearlet transform (NSST) is proposed.Complex NSST is implemented by a projection followed NSST.The Projection operation converts the input image into its analytic one, and NSST composes the real component and imaginary component into multiscale and multidirectional subbands.The obtained relative phase and magnitudes are combined to get the new subbands.Then Dynamic thresholding, Morphological operations, logical AND operation, Voting-decision and Vertical and Horizontal Projections are used on the new subbands to achieve the final text regions.Compared with common wavelet transform, the complex wavelet transform has the properties of shift invariance, limited redundancy and low aliasing.At the same time, the added phase information delivers more accurate representation for image.Experiments show that the algorithm can accurately locates the text regions in an image.