Center for Devices & Radiol. Health, Food & Drug Adm., Rockville, MD.
IEEE Trans Med Imaging. 1992;11(4):496-506. doi: 10.1109/42.192685.
The design, implementation, and testing of a computational observer method for objective evaluation of ultrasound images are presented. The method uses digitized ultrasound B-scan images of a test phantom (the contrast-detail phantom), and is able to calculate the detectability of a target (signal) from its background (background noise). A quantitative detectability index, based on the measured signal-to-noise ratio of the image data, that is measured for both the human and the computational observer on the same scale is generated. It is shown that the computational observer (CO) method may be a more useful, objective way of evaluating ulrasound images and imaging systems than methods that rely solely on human observers. It may also be applicable to other types (i.e. other than ultrasound) of imaging systems which produce noisy images. The relevance of the CO method when compared to human observer two-alternative-forced-choice (2AFC) readings of the same data by showing a high correlation between the CO detectability results and those of human observers for the same set of images. The method is (1) quantitative, (2) reproducible, (3) absolute, (4) takes into account, and can calculate the value of TPF and FPF for each target, for the given system, and (5) speeds up the evaluation of an image or imaging system (compared to using human observers), given the right conditions and equipment.
提出了一种用于客观评估超声图像的计算观测器方法的设计、实现和测试。该方法使用测试体模（对比细节体模）的数字化超声 B 扫描图像，能够从背景（背景噪声）中计算目标（信号）的可检测性。生成了一种基于图像数据测量的信噪比的定量可检测性指数，该指数是在相同的尺度上针对人类观测者和计算观测者同时测量的。结果表明，与仅依赖人类观测者的方法相比，计算观测器（CO）方法可能是一种更有用、客观的评估超声图像和成像系统的方法。它也可能适用于产生噪声图像的其他类型（即超声以外的）成像系统。通过显示 CO 可检测性结果与人类观察者对同一组图像的 2AFC 读数之间的高度相关性，比较 CO 方法与人类观察者的相关性。该方法具有以下特点：（1）定量，（2）可重现，（3）绝对，（4）考虑到并可以计算给定系统中每个目标的 TPF 和 FPF 的值，（5）在给定条件和设备下，与使用人类观察者相比，加快了对图像或成像系统的评估。
