基于最小二乘法的数字图像网点补偿方法研究

Digital Image Dot Compensation Based on Least Square Method

中文关键词: 喷墨印刷  网点扩大  网点补偿  最小二乘法

英文关键词: inkjet printing  dot gain  dot compensation  least square method

中文摘要:

      目的 网点大小在印刷传递过程中会不断发生变化,在数字图像中表现更为严重,为此研究控制网点扩大的方法以提高印刷品质量。 方法 测量喷墨打印机黑白模式下输出单色黑色靶的网点面积率,在 Matlab 软件平台下以最小二乘法为原理拟合实际与理想网点面积率获取网点扩大曲线,然后根据网点补偿原理推测本应输入网点值并得到网点补偿曲线,最后通过补偿曲线针对网点进行修正。结果 通过测量补偿前后输出色靶,结果表明网点扩大得到了有效控制,补偿前平均网点面积扩大率为 9 . 1% ,补偿后平均网点面积扩大率为 0 . 4% 。 结论 观察修正后色靶,图像亮度明显提升,阶调再现性得到了提高,该方法可有效提高数字图像的输出质量。

英文摘要:

      Objective The dot is always changing from the original to the substrate, especially in digital images. To study the method of controlling the dot gain is indeed beneficial in improving the quality of print. Methods The actual dot area of monochromatic black target with outputs was measured in monochrome mode. On the Matlab platform, the least square method was used to get dot gain curve by fitting the actual and ideal dot area, and then the dot compensation curve was obtained based on the estimated values. Finally, the curve was used to correct the dots. Results By measuring the dot area, the result showed that the target's average dot gain was 9. 1% before correction and was decreased to 0. 4% after correction. Conclusion Compared to the uncompensated printing, the compensated printing has a practical improvement in tone reproduction and brightness, which can effectively improve the printing output quality.