Efficient no-reference metric for sharpness mismatch artifact between stereoscopic views

This paper analyzes sharpness mismatch between stereoscopic views. Sharpness mismatch is a special binocular mismatch and can occur through e.g. focus mismatch between stereoscopic cameras, errors in post-processing or asymmetric coding for low-bandwidth transmission, where one view is subsampled or transmitted at a much lower rate. Although blurred edges in one view can be suppressed by the corresponding sharper edges in the other view according to the binocular suppression phenomenon, sharpness mismatch can still be perceived and cause eye strain for viewers. Subjective studies were carried out with a test video dataset, in which the stereoscopic views are asymmetrically blurred by Gaussian low-pass filters since defocus-based effects of lens aberrations can be modeled as Gaussian blur. Also, an efficient novel automatic no-reference approach to measure the probability of sharpness mismatch is presented in this paper. The sharpness mismatch score is estimated by measuring width deviations of edge pairs in each “edge-significant” depth plane based on depth edges in both views. The probability of sharpness mismatch (PSM) is then calculated considering the perceptibility of edge width deviations considering absolute depth at which the edges occur. This PSM metric is evaluated using the test video dataset and blurriness dataset of LIVE 3D Phase II database. The experimental results show that the proposed metric outperforms the state-of-the-art stereo 3D quality metrics on analyzing sharpness mismatch between stereoscopic views.     

纸张表面的喷墨扩展分析

借助墨滴观测仪和工业显微镜,获取了墨滴在撞击纸张前后的状态及数据。在测量喷墨记录点亮度数据的基础上,分析了纸张表面的喷墨记录点扩展。定义了喷墨记录点内外边缘对应的反射系数,并验证了其可行性。讨论了影响喷墨记录点大小、形状、模糊度的因素,计算了不同承印材料的墨滴扩展比。     

相变喷墨打印质量的分析

通过分析相变喷墨工作的原理,同时根据ISO 13660标准规定的质量指标及计算方法,选取记录点直径、圆整度、长宽比,线条宽度、线条边缘模糊度、线条边缘粗糙度等,作为质量检测要素。利用CCD捕获图像质量要素并使用图像质量分析与评价软件,客观、定量地分析了相变喷墨打印质量。测量结果表明:相变喷墨在普通纸张上可以实现高质量的打印结果;记录介质表面平滑度对相变喷墨打印的线条质量有一定程度影响。     

数字输出设备线条输出质量测评

为了研究数字输出设备线条的输出质量,设计制作黄、品、青、黑4色不同宽度的横、竖线条测试图样,在两台彩色喷墨打印机上进行彩喷纸和光泽照片纸的打印输出.对输出测试图样的线条属性进行了客观属性指标的测量.测试结果表明：输出的线条宽度总比设计的宽度大;线条的边缘粗糙度与线条的方向相关,竖线条的粗糙度较横线条的大;输出线条边缘的模糊度主要受色墨和纸张的相互作用影响,具有涂层的纸张往往会加剧纸张表面方向的色料扩散,从而增强了线边缘的模糊性.     

基于模板匹配法的散焦图像模糊度估计

提出一种新的散焦图像模糊度估计方法。由图像中的阶跃型边缘提取线扩展函数。根据匹配滤波可实现最优信噪比信号检测的思想,引入模板匹配的方法计算线扩展函数的标准差。由点扩展函数的圆周对称性从线扩展函数的标准差得到高斯型点扩展函数的标准差。实验结果表明,该方法能够准确地估计散焦模糊图像点扩展函数的标准差。将点扩展函数的标准差作为一种评价图像模糊度的测度。实验表明该测度符合人眼的视觉特性,可以很好地判定散焦模糊图像的模糊度。