RASTER OUTPUT TYPE SCANNING SYSTEM (ROS)

摘要

PROBLEM TO BE SOLVED: To modulate a radiation light beam is such a manner that the pixel clock of a raster output scanning system (ROS) executed pixel arrangement along a scanning line by calculating the pixel frequency shift so as to correct the nonlinearity of the scanning line in the ROS. SOLUTION: The pixel clock of the ROS system modulates the light beam radiated to execute the pixel arrangement along the scanning line. As one method, the pixel clock frequency shift is calculated in some cases in order to correct the nonlinearity of the scanning line in the ROS. A data smoothing polynominal is calculated relating to the nonlinearity of the pixels along the scanning line. The necessary frequency shift based on the polynominal for the first order or higher order is calculated and is then stored into a frequency shift look-up table. The calculated frequency shift from the frequency shift look-up table corrects the nominal pixel clock frequency and corrects the measured scanning linearity of ROS by the modulation of the light beam.