Chung Adrian J, Deligianni Fani, Shah Pallav, Wells Athol, Yang Guang-Zhong
Royal Society/Wolfson Foundation Medical Image Computing Laboratory, Department of Computing, Imperial College London, London SW7 2BZ, UK.
IEEE Trans Med Imaging. 2006 Apr;25(4):503-13. doi: 10.1109/TMI.2006.871550.
This paper presents an image-based method for virtual bronchoscope with photo-realistic rendering. The technique is based on recovering bidirectional reflectance distribution function (BRDF) parameters in an environment where the choice of viewing positions, directions, and illumination conditions are restricted. Video images of bronchoscopy examinations are combined with patient-specific three-dimensional (3-D) computed tomography data through two-dimensional (2-D)/3-D registration and shading model parameters are then recovered by exploiting the restricted lighting configurations imposed by the bronchoscope. With the proposed technique, the recovered BRDF is used to predict the expected shading intensity, allowing a texture map independent of lighting conditions to be extracted from each video frame. To correct for disocclusion artefacts, statistical texture synthesis was used to recreate the missing areas. New views not present in the original bronchoscopy video are rendered by evaluating the BRDF with different viewing and illumination parameters. This allows free navigation of the acquired 3-D model with enhanced photo-realism. To assess the practical value of the proposed technique, a detailed visual scoring that involves both real and rendered bronchoscope images is conducted.
本文提出了一种基于图像的具有逼真渲染效果的虚拟支气管镜方法。该技术基于在观察位置、方向和照明条件选择受限的环境中恢复双向反射分布函数（BRDF）参数。支气管镜检查的视频图像通过二维（2-D）/三维（3-D）配准与患者特定的三维（3-D）计算机断层扫描数据相结合，然后通过利用支气管镜施加的受限照明配置来恢复阴影模型参数。利用所提出的技术，恢复的BRDF用于预测预期的阴影强度，从而允许从每个视频帧中提取与照明条件无关的纹理映射。为了校正遮挡伪影，使用统计纹理合成来重建缺失区域。通过使用不同的观察和照明参数评估BRDF，渲染原始支气管镜视频中不存在的新视图。这允许对获取的三维模型进行自由导航，并增强逼真度。为了评估所提出技术的实用价值，进行了一项涉及真实和渲染支气管镜图像的详细视觉评分。
