【摘要】 计算机直接制版技术(CTP)的出现标志着印前工作流程的完全数字化,促进了印刷技术的进一步发展。为提高CTP印版网点参数测量的精度,针对调幅圆形网点提出了相应的网点参数测量方法。先对采集的CTP图像预处理,根据印版图像网点部分和非网点部分的R、G、B三通道特点,对印版图像进行灰度化处理。采用最大类间方差法的阈值分割技术从印版灰度化图像中提取出网点部分,完成印版网点面积率的测量;运用旋转投影法对印版网点二值图像进行加网角度测量;通过测量加网角度方向上相邻网点投影中心之间的距离,来进行加网线数测量;以霍夫圆变换为理论基础的圆检测技术,完成网点直径的测量更多还原

【Abstract】 The emergence of computer to plate technology(CTP) marks a complete digital pre-press workflow,and promotes the further development of printing technology.In order to measure the measurement accuracy of parameters of CTP plate outlets,the corresponding method for measuring the parameters of screen for AM circular screen,which is the most widely used in printing industry,was put forward in this study.The images data of the CTP plate was collected firstly,and then the collected images was denoised,then the image was grayed according to the RGB three channels characteristics in and out of dot area of plate image.Dot area was extracted from the plate gray images using the OTSU threshold segmentation,the dot area percentage was measured;the plate dot binary images were processed with rotating projection as the main method to measure the plate screen angles;the binary images were rotated with the plate screen angles,and then the distance between the adjacent dot projection center was measured,and the plate screen lines measurement was finished.The dot diameter was measured by using circle detection technology,which is on the theoretical basis of Circle Hough Transform.更多还原