We show that for a plane imaged by an endoscope the specular isophotes are concentric circles on the scene plane, which appear as nested ellipses in the image. We show that these ellipses can be detected and used to estimate the plane's normal direction, forming a normal reconstruction method, which we validate on simulated data. In practice, the anatomical surfaces visible in endoscopic images are locally planar. We use our method to show that the surface normal can thus be reconstructed for each of the numerous specularities typically visible on moist tissues. We show results on laparoscopic and colonoscopic images.

翻译：我们证明，在内窥镜成像的平面上，高光等照度线是场景平面上的同心圆，并在图像中呈现为嵌套椭圆。研究表明，这些椭圆可以被检测并用于估计平面法线方向，从而形成一种法线重建方法，并通过模拟数据验证了其有效性。在实际应用中，内窥镜图像中可见的解剖表面具有局部平面性。利用该方法，我们展示了如何从湿组织表面常见的众多高光点中重建表面法线，并在腹腔镜和结肠镜图像中取得了实验结果。