Printing quality control has been one of the challenges in the printing industry. Therefore, it is indispensable to find evaluation methods with high correlations with the human visual system to assess the quality of the printed images. Standard ISO/IEC 24790 is one of the recommended standards to achieve this goal. An evaluation procedure for graininess, a common defect in printing, has been presented in this standard; however, this procedure is suggested only for monochrome printed images. Hence, in this research, the graininess of coloured samples is evaluated based on the proposed method in this standard with considering the effect of the paper. For this purpose, fictitious graininess defects are designed and applied on coloured samples and are printed on different papers. A visual assessment is performed to examine the effect of colour and paper differences on graininess. Six different methods, including the method suggested in the standard and the proposed modified procedures, are used to evaluate graininess, and their results are compared to subjective results. Moreover, three other wavelets are studied besides the suggested one in the standard. To eliminate the effect of paper texture, a Gaussian filter is utilised. The results show that applying the Gaussian filter to images increases the correlation between computational procedure results and visual assessment results. Also, the results indicate that utilising haar wavelet slightly increases the correlation. The results demonstrate that besides assessing graininess in greyscale mode, evaluating graininess in RGB (red, green, blue) colour space results in a high correlation with the visual assessment results.

中文翻译：

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引入基于标准 ISO/IEC 24790 的新方法来评估彩色打印图像的颗粒度

印刷质量控制一直是印刷行业面临的挑战之一。因此，寻找与人类视觉系统高度相关的评估方法来评估打印图像的质量是必不可少的。标准 ISO/IEC 24790 是实现这一目标的推荐标准之一。本标准提供了颗粒度（印刷中常见的缺陷）的评估程序；但是，此过程仅建议用于单色打印图像。因此，在本研究中，考虑到论文的效果，根据本标准中提出的方法对彩色样品的颗粒度进行了评估。为此，设计了虚构的颗粒缺陷并将其应用于彩色样品，并打印在不同的纸张上。进行视觉评估以检查颜色和纸张差异对颗粒度的影响。六种不同的方法，包括标准中建议的方法和建议的修改程序，用于评估颗粒度，并将其结果与主观结果进行比较。此外，除了标准中建议的小波之外，还研究了其他三个小波。为了消除纸张纹理的影响，使用了高斯滤波器。结果表明，将高斯滤波器应用于图像增加了计算过程结果和视觉评估结果之间的相关性。此外，结果表明利用 haar 小波略微增加了相关性。结果表明，除了在灰度模式下评估颗粒度外，还在 RGB（红色、绿色、