Significant features, consisting of flats and humps, have been observed inimpurity-ion ultraviolet line-emission profiles measured on the TJ-II flexibleheliac, thereby providing evidence for the existence of topological structuresin the plasma interior. The data for this study were collected using a fastspectroscopic scanning system with good spatial resolution capabilities; theywere analysed using an in-house developed pattern recognition algorithm. Thisalgorithm is capable of separating effects due to plasma fluctuations andnoise from those caused by two-dimensional structures. In the paper wedescribe the data collection system and the pattern recognition algorithm andwe analyse plasma radiation profiles from standard TJ-II configurations todemonstrate that this pattern recognition algorithm can identify real featuresin these. Next, we analyse profile data from a configuration scan made on theTJ-II and finally we report on the features found, their typical widths andsymmetry, as well as on the time evolution and correlation with the electrondensity.