3D acquisition of mirroring objects using striped patterns

Abstract

Objects with mirroring optical characteristics are left out of the scope of most 3D scanning methods. We present here a new automatic acquisition approach, shape-from-distortion, that focuses on that category of objects, requires only a still camera and a color monitor, and produces range scans (plus a normal and a reflectance map) of the target. Our technique consists of two steps: first, an improved environment matte is captured for the mirroring object, using the interference of patterns with different frequencies to obtain sub-pixel accuracy. Then, the matte is converted into a normal and a depth map by exploiting the self-coherence of a surface when integrating the normal map along different paths. The results show very high accuracy, capturing even smallest surface details. The acquired depth maps can be further processed using standard techniques to produce a complete 3D mesh of the object.

How to Compute the Pose of an Object Without a Direct View?

“…Modeling of specular or shiny surfaces is an important application in inspection of industrial parts, especially in the car manufacturing industry (control of wind shields and bodywork) but also in the control of optical lenses or mirrors, glasses of watches etc. Vision-based reconstruction of specular surfaces is usually based on acquiring images of known patterns or light sources, reflected in the surface to be reconstructed [3,4,6,7,11,14].…”

Reconstructing Gas Flows Using Light-Path Approximation

“…A common issue in point-pixel based solutions is ambiguity: a pixel corresponds to a ray from the camera while the specular surface can lie at any position along the ray. Tremendous efforts have been focused on adding additional constraints [15,21,25,27] for resolving this ambiguity. Bonfort and Sturm [4] use images captured by multiple calibrated cameras to reconstruct specular surface via space carving.…”

“…It is well-known that point-pixel correspondences are under-constrained even for single reflection or refraction. To resolve this ambiguity, additional constraints such as the planarity assumption [11,15,21], surface smoothness prior [25], surface integrability constraints [27], and most recently multi-view constraints [4,20] need to be imposed. The seminal work of Atcheson et al [2] uses 16 synchronized camcorders to capture the distorted wavelet noise patterns placed several meters away from the target flow.…”

Mesostructure from specularity using gradient illumination

“…Because the screen is not visible to the camera, a spherical mirror is moved in front of both components, in order to make them visible to each other. As such, the needed geometric relations can be obtained using known calibration techniques [Tarini et al 2005;Francken et al 2007]. In order to find the internal camera parameters and the mesostructure's supporting plane, we use a standard calibration toolbox which makes use of a checkerboard pattern [Bouguet 2006].…”