The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Camera calibration has many applications in various computer vision fields such as pose estimation, robot navigation, trajectory tracking, and object recognition. Camera calibration involves (mostly) determining the intrinsic parameters of a camera so that problems or distortions caused by the camera's optics or manufacturing could be estimated for proper projection. There are already a number of...
Ear recognition is one of the new patterns of biometrics. Ear structure is believed to contain specific and unique anatomical markers, which can be used both to distinguish it from others. In this paper, we derive preliminary of Ear identification based on the geometric features on 3D ear surface for 2D ear image. Principal components analysis (PCA) is used in this study for feature extraction to...
This paper deals with the estimation of intrinsic and extrinsic parameters in a fundus camera system. These parameters are fundamental to retrieve three-dimensional reconstruction of eye's structure, in our case, retinal blood vessels. In this paper we used the Zhang's algorithm to estimate the intrinsic parameters of the optical system. Besides, an alternative method to estimate the extrinsic parameters...
In this paper the elimination of image distortion and subsequent estimation of intrinsic camera parameters, while extracting the real object dimensions from photographs is presented. Research analysis includes description of the basic concepts related to the camera calibration. Following the analysis, the most suitable calibration method has been chosen and implemented as a software solution. The...
We introduce the distributed camera model, a novel model for Structure-from-Motion (SfM). This model describes image observations in terms of light rays with ray origins and directions rather than pixels. As such, the proposed model is capable of describing a single camera or multiple cameras simultaneously as the collection of all light rays observed. We show how the distributed camera model is a...
In this paper we design a novel planar 2D fiducial marker and develop fast detection algorithm aiming easy camera calibration and precise 3D reconstruction at the marker locations via the bundle adjustment. Even though an abundance of planar fiducial markers have been made and used in various tasks, none of them has properties necessary to solve the aforementioned tasks. Our marker, X-tag, enjoys...
Wireless capsule endoscopy (WCE) is the prime diagnostic modality for the small-bowel. It consists in a swallowable color camera that enables the visual detection and assessment of abnormalities, without patient discomfort. The localization of the capsule is currently performed in the 3D abdominal space using radiofrequency (RF) triangulation. However, this approach does not provide sufficient information...
The trajectory tracking system of particle motion on sieve surface was designed by the combination of the analysis of image sequences based on binocular stereo vision and three-dimensional position reconstruction based on artificial neural network. Firstly, the calibration plane with uniformly distributed solid circles was placed in multiple positions within the effective field of view. The images...
A quad-head combined aerial camera is first introduced in this paper. Due to its multiple center projection at each exposure station, an image post-processing procedure including camera calibration, matching, self-calibration stitching and color balancing is proposed to generate the stitched virtual image, in which the mathematical models of geometric calibration and self-calibration algorithms are...
This paper presents a new approach for pedestrian detection in the context of Driver Assistance Systems (DAS). Given a camera with known intrinsic parameters, a flexible online calibration scheme that explores the expected road geometry is used to obtain the extrinsic parameters. With the full camera parameters, the expected geometry and size of a standing person is used to customize a baseline pedestrian...
Surveillance cameras are used in public and private security systems. Typical systems may contain a large number of different cameras, which are installed in different locations. Manual calibration of each single camera in the network becomes an exhausting task. Although we can find methods that semi-automatically calibrate a static camera, to the best of our knowledge, there is not a fully automatic...
Camera calibration is one of the essential components of a vision based tracking system where the objective is to extract three dimensional information from a set of two dimensional frames. The information extracted from the calibration process is significant for examining the accuracy of the vision sensor, and thus further for estimating its effectiveness as a tracking system in real applications...
Fisheye cameras prove a convenient means in surveillance and automotive applications as they provide a very wide field of view for capturing their surroundings. Contrary to typical rectilinear imagery, however, fisheye video sequences follow a different mapping from the world coordinates to the image plane which is not considered in standard video processing techniques. In this paper, we present a...
Camera calibration denotes the task of estimating the projective mapping between 3D world and the camera image plane. Most of the modern cameras have multiple image and video acquisition modes, which differ in image resolution, field of view or aspect ratio. Each mode should be treated as an independent device, and therefore independently calibrated. This straightforward solution implies the acquisition...
Professional TV studio footage often poses specific challenges to camera calibration due to lack of features and complex camera operation. As available algorithms often fail, we propose a novel approach based on robust tracking of ellipse and line features of a predefined logo. We further devise a predictive and iterative estimation algorithm, which incorporates confidence measures and filtering....
The main challenge in multi-view camera calibration is precise pose estimation of cameras, especially when their fields of view have very little overlap. This work proposes a very accurate multi-view camera calibration method that does not require cameras to share theirs fields of view. A rotating stage is used to move the calibration target along a known trajectory, consisting of pure rotation, through...
Lens distortion self-calibration estimates the distortion model using arbitrary images captured by a camera. The estimated model is then used to rectify images taken with the same camera. These methods generally use the fact that built environments are line dominated and these lines correspond to lines on the image when distortion is not present. The proposed method starts by detecting groups of lines...
Landing aerial crafts, such as helicopters, on the board of naval vessels of small or medium size is a difficult and risky task for pilots since the tonnages are not large enough which makes the ships always swinging along with ocean waves. Thus the landing areas are moving all the way with six degrees of freedom randomly. Even, this mission will become dangerous and deadly when the weather is stormy...
The aim of this study is to propose a three-dimensional visual localization method based on binocular cameras. This method would improve the system localization precision in infrared ray (IR) environment, including modified calibration method, a quick and exact distortion adjustment technique and geometric reconstruction method combining feedback compensation. A system has been established and verified...
Camera calibration is necessary in machine vision application field. Calibration model has nonlinear characteristics, and establishment of mathematical model is often a complicated process, but neural network can solve the complex nonlinear problem effectively, neural network has strong nonlinear approximation ability, adaptive network parameters and fast learning. This paper presents a neurocalibration...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.