Visualization of virtual yarn images in new technology for predicting yarn quality and unevenness by quick and visual analysis method. Since the conventional methods for predicting yarn quality or irregularities were based upon statistics and signal processing method, they were all invisible and the mathematical induction system. Visualization technique is an analysis method to predict on-now condition of yarn quality through real yarn-shape image. Digital signals acquired by data auisition system are rendered to 3D shaped virtual yarn images with 3D graphic API, OpenGLulcorner. Those 3D virtual yarn images can be processed to make the virtual tapering board images with various models and visual effects for on-line measurement and characterization of yarn qualities.