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We present an interactive system for reconstructing surface normals from a single image. Our approach has two complementary contributions. First, we introduce a novel shape-from-shading algorithm (SfS) that produces faithful normal reconstruction for local image region (high-frequency component), but it fails to faithfully recover the overall global(More)
This paper addresses the problem of shadow extraction from a single image of a complex natural scene. No simplifying assumption on the camera and the light source other than the Lambertian assumption is used. Our method is unique because it is capable of translating very rough user-supplied hints into the effective likelihood and prior functions for our(More)
This article addresses the problem of <i>natural shadow matting</i>, the removal or extraction of natural shadows from a single image. Because textures are maintained in the shadowless image after the extraction process, our approach produces some of the best results to date among shadow removal techniques. Using the image formation equation typical of(More)
We address the problem of robust normal reconstruction by dense photometric stereo, in the presence of complex geometry, shadows, highlight, transparencies, variable attenuation in light intensities, and inaccurate estimation in light directions. The input is a dense set of noisy photometric images, conveniently captured by using a very simple set-up(More)
We propose a new method, video repairing, to robustly infer missing static background and moving foreground due to severe damage or occlusion from a video. To recover background pixels, we extend the image repairing method, where layer segmentation and homography blending are used to preserve temporal coherence and avoid flickering. By exploiting the(More)
We present a surprisingly simple system that performs robust normal reconstruction by dense photometric stereo, in the presence of large shadows, highlight, transparencies, complex geometry, variable attenuation in light intensity and inaccurate light directions. Our system consists of a mirror sphere, a spotlight and a DV camera only. Using this, we infer(More)
Representative surface reconstruction algorithms taking a gradient field as input enforce the integrability constraint in a discrete manner. While enforcing integrability allows the subsequent integration to produce surface heights, existing algorithms have one or more of the following disadvantages: They can only handle dense per-pixel gradient fields,(More)
Reconstructing transparent objects is a challenging problem. While producing reasonable results for quite complex objects, existing approaches require custom calibration or somewhat expensive labor to achieve high precision. On the other hand, when an overall shape preserving salient and fine details is sufficient, we show in this paper a significant step(More)
We present a simple interactive approach to specify 3D shape in a single view using "shape palettes". The interaction is as follows: draw a simple 2D primitive in the 2D view and then specify its 3D orientation by drawing a corresponding primitive on a <i>shape palette</i>. The shape palette is presented as an image of some familiar shape whose local 3D(More)
This paper presents a robust and automatic approach to photometric stereo, where the two main components, namely surface normals and visible surfaces, are respectively optimized by expectation maximization (EM). A dense set of input images is conveniently captured using a digital video camera while a handheld spotlight is being moved around the target(More)