What Is the Set of Images of an Object Under All Possible Illumination Conditions?
International Journal of Computer Vision
International Journal of Computer Vision
A Multi-Frame Structure-from-Motion Algorithm under Perspective Projection
International Journal of Computer Vision - Special issue on computer vision research at NEC Research Institute
When Shadows Become Interreflections
International Journal of Computer Vision - Special issue on computer vision research at NEC Research Institute
International Journal of Computer Vision
From Few to Many: Illumination Cone Models for Face Recognition under Variable Lighting and Pose
IEEE Transactions on Pattern Analysis and Machine Intelligence
A New Structure-from-Motion Ambiguity
IEEE Transactions on Pattern Analysis and Machine Intelligence
Shadow Graphs and Surface Reconstruction
ECCV '02 Proceedings of the 7th European Conference on Computer Vision-Part II
Representations for Recognition Under Variable Illumination
Shape, Contour and Grouping in Computer Vision
Shadows, Shading, and Projective Ambiguity
Shape, Contour and Grouping in Computer Vision
Comparing Images under Variable Illumination
CVPR '98 Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition
Illumination Cones for Recognition under Variable Lighting: Faces
CVPR '98 Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition
Illumination Modeling and Normalization for Face Recognition
AMFG '03 Proceedings of the IEEE International Workshop on Analysis and Modeling of Faces and Gestures
ICPR '98 Proceedings of the 14th International Conference on Pattern Recognition-Volume 2 - Volume 2
Shadow Graphs and 3D Texture Reconstruction
International Journal of Computer Vision - Special Issue on Texture Analysis and Synthesis
The Local Projective Shape of Smooth Surfaces and Their Outlines
International Journal of Computer Vision
Shadow compensation in 2D images for face recognition
Pattern Recognition
On seeing and rendering colour gradients
Proceedings of the 4th symposium on Applied perception in graphics and visualization
Visual equivalence: towards a new standard for image fidelity
ACM SIGGRAPH 2007 papers
Shape Estimation Using Polarization and Shading from Two Views
IEEE Transactions on Pattern Analysis and Machine Intelligence
The assumed light direction for perceiving shape from shading
Proceedings of the 5th symposium on Applied perception in graphics and visualization
A novel photometric method for real-time 3D reconstruction of fingerprint
ISVC'10 Proceedings of the 6th international conference on Advances in visual computing - Volume Part II
Object recognition based on photometric alignment using ransac
CVPR'03 Proceedings of the 2003 IEEE computer society conference on Computer vision and pattern recognition
Classification of photometric factors based on photometric linearization
ACCV'06 Proceedings of the 7th Asian conference on Computer Vision - Volume Part II
Micro perceptual human computation for visual tasks
ACM Transactions on Graphics (TOG)
Auto-calibrating photometric stereo using ring light constraints
Machine Vision and Applications
Hi-index | 0.00 |
Since antiquity, artisans have created flattened forms, often called ``bas-reliefs,'' which give an exaggerated perception of depth when viewed from a particular vantage point. This paper presents an explanation of this phenomena, showing that the ambiguity in determining the relief of an object is not confined to bas-relief sculpture but is implicit in the determination of the structure of any object. Formally, if the object's true surface is denoted by z_true=f(x,y), then we define the ``generalized bas-relief transformation'' as z=\lambda f(x,y) +\mu x +\nu y with a corresponding transformation of the albedo. For each image of a surface f(x,y) produced by a light source, there exists an identical image of the bas-relief produced by a transformed light source. This equality holds for both shaded and shadowed regions. Thus, the set of possible images (illumination cone) is invariant over generalized bas-relief transformations. When \mu=\nu=0 (e.g.\ a classical bas-relief sculpture), we show that the set of possible motion fields are also identical. Thus, neither small motions nor changes of illumination can resolve the bas-relief ambiguity. Implications of this ambiguity on structure recovery and shape representation are discussed.