Johnson Paul V, Kim Joohwan, Banks Martin S
University of California, San Francisco, and University of California, Berkeley, Berkeley, CA, USA.
Vision Science Program, University of California, Berkeley, Berkeley, CA, USA.
J Vis. 2014 Dec 19;14(14):10. doi: 10.1167/14.14.10.
Color breakup is an artifact seen on displays that present colors sequentially. When the eye tracks a moving object on such a display, different colors land on different places on the retina, and this gives rise to visible color fringes at the object's leading and trailing edges. Interestingly, color breakup is also observed when the eye is stationary and an object moves by. Using a novel psychophysical procedure, we measured breakup both when viewers tracked and did not track a moving object. Breakup was somewhat more visible in the tracking than in the non-tracking condition. The video frames contained three subframes, one each for red, green, and blue. We spatially offset the green and blue stimuli in the second and third subframes, respectively, to find the values that minimized breakup. In the tracking and non-tracking conditions, spatial offsets of Δx/3 in the second subframe (where Δx is the displacement of the object in one frame) and 2Δx/3 in the third eliminated breakup. Thus, this method offers a way to minimize or even eliminate breakup whether the viewer is tracking or not. We suggest ways to implement the method with real video content. We also developed a color-breakup model based on spatiotemporal filtering in color-opponent pathways in early vision. We found close agreement between the model's predictions and the experimental results. The model can be used to predict breakup for a wide variety of conditions.
颜色分离是在顺序呈现颜色的显示器上出现的一种伪像。当眼睛在这样的显示器上跟踪一个移动的物体时，不同的颜色会落在视网膜的不同位置，这会在物体的前缘和后缘产生可见的彩色条纹。有趣的是，当眼睛静止而物体移动时也会观察到颜色分离。我们使用一种新颖的心理物理学方法，在观察者跟踪和不跟踪移动物体时都测量了颜色分离。在跟踪条件下，颜色分离比不跟踪条件下更明显一些。视频帧包含三个子帧，分别用于红色、绿色和蓝色。我们分别在第二个和第三个子帧中对绿色和蓝色刺激进行空间偏移，以找到使颜色分离最小化的值。在跟踪和不跟踪条件下，第二个子帧中Δx/3（其中Δx是物体在一帧中的位移）的空间偏移以及第三个子帧中2Δx/3的空间偏移消除了颜色分离。因此，无论观察者是否在跟踪，这种方法都提供了一种最小化甚至消除颜色分离的方法。我们提出了用真实视频内容实现该方法的途径。我们还基于早期视觉中颜色对立通路的时空滤波开发了一个颜色分离模型。我们发现该模型的预测结果与实验结果非常吻合。该模型可用于预测各种条件下的颜色分离。
