Volume rendering produces informative two-dimensional (2D) images from a 3-dimensional (3D) volume. It highlights the region of interest and facilitates a good comprehension of the entire data set. However, volume rendering faces a few challenges. First, a high-dimensional transfer function is usually required to differentiate the target from its neighboring objects with subtle variance. Unfortunately, designing such a transfer function is a strenuously trial-and-error process. Second, manipulating/visualizing a 3D volume with a traditional 2D input/output device suffers dimensional limitations. To address all the challenges, we design NUI-VR\(^2\), a natural user interface-enabled volume rendering system in the virtual reality space. NUI-VR\(^2\) marries volume rendering and interactive image segmentation. It transforms the original volume into a probability map with image segmentation. A simple linear transfer function will highlight the target well in the probability map. More importantly, we set the entire image segmentation and volume rendering pipeline in an immersive virtual reality environment with a natural user interface. NUI-VR\(^2\) eliminates the dimensional limitations in manipulating and perceiving 3D volumes and dramatically improves the user experience.

体积渲染从 3 维 (3D) 体积生成信息丰富的二维 (2D) 图像。它突出显示了感兴趣的区域，并有助于更好地理解整个数据集。然而，体积渲染面临一些挑战。首先，通常需要一个高维传递函数来区分目标与其具有细微差异的相邻对象。不幸的是，设计这样的传递函数是一个艰苦的试错过程。其次，使用传统的 2D 输入/输出设备操作/可视化 3D 体积会受到尺寸限制。为了应对所有挑战，我们设计了 NUI-VR \(^2\)，这是一个在虚拟现实空间中启用自然用户界面的体渲染系统。NUI-VR \(^2\)结合体积渲染和交互式图像分割。它通过图像分割将原始体积转换为概率图。一个简单的线性传递函数将在概率图中突出显示目标。更重要的是，我们在具有自然用户界面的沉浸式虚拟现实环境中设置了整个图像分割和体积渲染管道。NUI-VR \(^2\)消除了操纵和感知 3D 体积时的尺寸限制，显着改善了用户体验。