NON ROC MEASURES FOR EVALUATING IMAGE COMPRESSION

描述：当前使用ROC风格的观察者性能的趋势 评估图像压缩方案的研究效率很低，并且有很大的影响 限制了我们认证用于射线照相的特定技术的能力 图像。该项目的目标是开发更高效的自动化 用于评估图像压缩效果的技术，但这些技术 独立于任何特定的压缩方法。两种方法将是 被追捕。首先，我们将制定可应用于以下方面的保真措施 图像的原始版本和压缩版本之间的差异。 这些将不仅基于差异图像的大小，还将基于 也在此图像中的结构上，并应克服 更简单的衡量标准，如均方误差。我们将基于以下设计 这些措施基于关于哪些因素重要的貌似合理的假设。 而不是直接基于心理视觉理论。尽管这些措施 不能期望与观察者的表现高度相关，因为 较小的图像降级，它们应该有助于设置限制 关于诊断性能的预期损失。 其次，设计了一个可用于评估的数字体模 任何压缩技术和压缩比。这个幻影将会是 采用上述测评方法进行评价。使用幻影会更有效率 因为它可以对每种压缩技术执行一次，并将避免 为每个图像评估一种度量的必要性。 最后，我们将尝试应用这两种方法来分析 目前在我们的观察者性能研究中使用的图像 压缩和对图像分辨率的影响。作为这项工作的一部分，我们将关联 正在开发的针对ROC的物理测量结果来自这些研究。

DESCRIPTION: The current trend of using ROC style observer performance studies to evaluate image compression schemes is inefficient and has greatly limited our ability to certify particular techniques for use on radiographic images. The goal of this project is to develop more efficient automated techniques for evaluating the efficacy of image compression, but which are independent of any particular compression method. Two approaches will be pursued. First, we will develop fidelity measures which can be applied to the difference between an original and compressed version of an image. These will be based on not only the magnitude of the difference image but also on the structure in this image, and should overcome the limitations of simpler measures such as mean square error. We will base the design of these measures on plausible hypotheses about what factors are important rather than on psycho-visual theory directly. Although these measures cannot be expected to be highly correlated to observer performance, for small levels of image degradation they should be useful for placing limits on the expected loss of diagnostic performance. Secondly, a digital phantom will be designed which can be used to evaluate any compression technique and compression ratio. This phantom would be evaluated with the above measures. Use of a phantom would be more efficient since it could be done once for each compression technique and would avoid the necessity of evaluating a measure for each image. Finally, we will attempt to apply both methods to analyze the databases of images currently being used in our observer performance studies on image compression and on image resolution. As part of this we will correlate the physical measures being developed to ROC results from these studies.