Effect of Dot Percentage and Phase on Perspective Recognition of Rosette Pattern

In screening process, rosette pattern is formed by halftone dot array. It is inevitable to appear on the rosette pattern in the image using the halftoning process. In this report, the effect of dot percentage and phase of dot array on visibility of rosette pattern is analyzed by numerical method such as FFT. The result is compared with the result of perceptive recognition experiment about rosette pattern in the image. It is shown from this study that the rosette pattern is recognized clearly by the observers when the halftone dot percentage is around 30. The perceptive recognition intensity of rosette pattern, however, vary with the phase of dot array.