Department of Radiology, Duke University, Durham, NC 27705, USA.
Acad Radiol. 2012 Feb;19(2):196-202. doi: 10.1016/j.acra.2011.10.011.
To determine the accuracy and reproducibility of a remote eye-tracking system for studies of observer gaze while displaying volumetric chest computed tomography (CT) images.
Four participants performed calibrations using three different gray-scale backgrounds (black, gray, and white). Each participant then observed a three-dimensional 10-point test pattern embedded in five Digital Imaging and Communications in Medicine (DICOM) datasets (test backgrounds): a full 190-section chest CT scan, 190 copies of a single chest CT section, and three 190-section datasets of homogeneous intensity (black, gray, and white).
Significant variances between participants, calibration backgrounds, and test backgrounds were observed. The least mean systematic error (deviation of recorded gaze position from target) was obtained when the calibration background and test background were black (27 pixels). Systematic error increased when displaying a test background that deviated from the calibration background intensity. Hence, the largest mean systematic error occurred when calibrating to a black background and displaying a white background (67 pixels). For complex chest CT volumes the white calibration background performed best (38 pixels). An angular analysis of the systematic error was performed and demonstrated that the systemic error primarily affects the vertical position of the estimated gaze position.
Our findings indicate a potential source of systematic error during gaze recording in a dynamic environment and highlight the importance of configuring the calibration procedure according to the brightness of the display. We recommend that investigators develop routines for postcalibration accuracy measurement and report the effective accuracy for the display environment in which the data are collected.
确定一种用于显示容积性胸部计算机断层扫描（CT）图像时观测者注视的远程眼动跟踪系统的准确性和可重复性。
4 名参与者使用 3 种不同灰度背景（黑色、灰色和白色）进行校准。然后，每位参与者观察嵌入在 5 个数字成像和通信医学（DICOM）数据集（测试背景）中的三维 10 点测试图案：一个完整的 190 节胸部 CT 扫描、190 个单个胸部 CT 切片的副本，以及 3 个均匀强度（黑色、灰色和白色）的 190 节数据集。
观察到参与者、校准背景和测试背景之间存在显著差异。当校准背景和测试背景为黑色时，记录的注视位置与目标之间的平均系统误差最小（27 像素）。当显示与校准背景强度偏离的测试背景时，系统误差会增加。因此，当校准到黑色背景并显示白色背景时，会出现最大的平均系统误差（67 像素）。对于复杂的胸部 CT 容积，白色校准背景表现最佳（38 像素）。对系统误差进行了角度分析，结果表明系统误差主要影响估计注视位置的垂直位置。
我们的研究结果表明，在动态环境中进行注视记录时存在潜在的系统误差源，并强调了根据显示器的亮度来配置校准程序的重要性。我们建议研究人员制定校准后准确性测量的常规程序，并报告收集数据的显示环境的有效准确性。
