中国科学技术大学：《计算机视觉》课程教学资源（PPT课件讲稿）第九章 单幅图像深度重建 Depthmap Reconstruction Based on Monocular cues

第九章单幅图像深度重建 Depthmap reconstruction based on monocular cues

第九章 单幅图像深度重建 Depthmap Reconstruction Based on Monocular cues

深度图

深度图

章节安排 基于单眼线索的深度重建 Shape From Shading Shape From Vanishing Point Shape From Defocus Shape From Texture

章节安排 ▪ 基于单眼线索的深度重建 ➢ Shape From Shading ➢ Shape From Vanishing Point ➢ Shape From Defocus ➢ Shape From Texture

Shape From Shading

Shape From Shading

What is Shading? Well not shadow We cant reconstruct shape from one shadow

What is Shading? ▪ Well… not shadow… ▪ We can’t reconstruct shape from one shadow…

What is Shading? Variable levels of darkness Gives a cue for the actual 3d shape There is a relation between intensity and shape

What is Shading? ▪ Variable levels of darkness ▪ Gives a cue for the actual 3D shape ▪ There is a relation between intensity and shape

Shading EXamples These circles differ only in grayscale intensity none flat gouraud phong Intensities give a strong feeling of scene structure

Shading Examples ▪ These circles differ only in grayscale intensity ▪ Intensities give a strong “feeling” of scene structure

What determines scene radiance? The amount of light that falls on the surface The fraction of light that is reflected (albedo Geometry of light reflection Shape of surface ei,Pi >Viewpoint (Be, p

What determines scene radiance? ▪ n

Albedo p A property of the surface Usually normalized1≥p≥0 Can be modeled as a single scalar for the entire surface or dependent on location Usually assumed to be a known scalar >s this a ball with uniform albedo or is this a 2 D circle with varying albe0?°°

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Surface normal Convenient notation for surface orientation A smooth surface has a tangent plane at every point We can model the surface using the normal ery point at eve

Surface Normal Convenient notation for surface orientation  A smooth surface has a tangent plane at every point  We can model the surface using the normal at every point