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This paper presents a general constructive algorithm to recover external camera parameters from a set of pairwise partial camera calibrations embedded in the structure named Camera Dependency Graph (CDG) [1] that encompasses both the feasibility and the reliability of each calibration. An edge in CDG and its weight account for the existence and for the quality of the essential matrix between the two...
The dynamic range of natural scenes usually exceeds the dynamic range of imaging sensors by several orders of magnitude. To overcome information loss multiple-slope cameras allow acquisition of images at extended dynamic ranges. However the response curve still has to be adapted to the scene. We present a new auto exposure control for multiple-slope cameras. The proposed method derives an optimum...
This paper presents a method for finding the surface normals and reflectance of an object from a set of images obtained under different lighting conditions. This set of images, assuming a Lambertian object, can be approximated by a three dimensional linear subspace, under an orthographic camera model and without shadows and specularities. However, a higher dimensional subspace is needed when images...
We present a new framework for the acquisition of full spherical videos using a high-speed rotating linear or area sensor equipped with a fish-eye lens. The high capture rate of the sensors allows us to reach high frame rates on the resulting videos. We describe the image processing workflows from the raw data to the full spherical frames, and we show experimental results of non-parallax panoramic...
An efficient hardware architecture for the acceleration of an integrated 3D reconstruction method is presented, targeting demanding dynamic Integral Imaging applications. It exploits parallel processing and features minimized memory operations by implementing an extended-access memory scheme. Its reduced data throughput, thanks to optimized data utilization, makes it suitable for single FPGA device...
Using only shadow trajectories of stationary objects in a scene, we demonstrate that a camera can be calibrated robustly. We require at least two vertical objects to be visible in the image casting shadows on the ground plane. Using properties of these cast shadows, the horizon line (or the line at infinity) of the ground plane is robustly estimated. This leads to pole-polar constraints on the image...
This work addresses the problem of human head pose estimation from single view images. 3D rigid head pose is estimated combining Active Appearance Models (AAM) with Pose from Orthography and Scaling with ITerations (POSIT). AAM shape landmarks are tracked over time and used in POSIT for pose estimation. A statistical anthropometric 3D model is used as reference. Several experiences were performed...
In this text we will present a novel solution for active perception built upon a probabilistic framework for multimodal perception of 3D structure and motion — the Bayesian Volumetric Map (BVM). This solution applies the notion of entropy to promote gaze control for active exploration of areas of high uncertainty on the BVM so as to dynamically build a spatial map of the environment storing the largest...
Integral Imaging is a highly promising technique for delivering full parallax autostereoscopic images. A straight-forward approach for producing high quality photorealistic Integral Images or Integral Image sequences is the use of Ray-Tracing techniques. However, Ray-Tracing tasks are time consuming and in most cases scene renderings greatly deviate from performing in real time. In this work, we describe...
This paper uses as starting point the transformation matrix defined in the homogeneous space that associates the points of a 2D plane (that represents the model) with those of another 2D space (the image one), this transformation characterizing the camera capture process. This transformation (an homography from 2D to 2D) is coming from previous work and is used within the scope of the SimulFoot project...
This article presents a method for cooperative reconstruction of three-dimensional scenes using multiple views. Although the use of multiple views is one of the most applied in the 3D scenes interpretation, its use with a single mobile robot does not guarantee the perfect localization of the environment, due to odometry errors. Also, the reconstruction of dynamic environments is not allowed for a...
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