In this paper we propose an approach to retrieve the absolute geometry of an acoustic sensor network, consisting of spatially distributed microphone arrays, from reverberant speech input. The calibration relies on direction of arrival measurements of the individual arrays. The proposed calibration algorithm is derived from a maximum-likelihood approach employing circular statistics. Since a sen...

A keratometer, also known as an ophthalmometer, is a diagnostic instrument for measuring the curvature of the anterior surface of the cornea, which is used to assess the amount and axis of astigmatism. A very popular and reliable type of manual, one-position keratometer (commonly known as a Bausch and Lombtype keratometer) is shown in Figure 1. Although this type of keratometer rarely goes out ...

In this paper, we present a new method for camera calibration using concentric circles. We demonstrate that camera calibration is possible using two views of a concentric circle with known size. A new method to determine the position of the projected center of the circle is introduced. Based on the accurate estimation of the projected circle center of two sets of 3-D concentric circles, the pro...

With the rapid development of three-dimensional (3D) modelling, camera calibration is paid more and more attention. In this article, we analyse the influence factors in the calibration: the camera and lens, the shape of control points, photography model and the scale between calibration object and measurement. Appropriate model can get the right result quickly, and the position of the model in ...

Unmanned aerial vehicles (UAVs) are autonomous or remote control controlled air without a pilot. UAVs platforms capable of carrying non-metric photogrammetric equipment. In this study; the effect two different calibration values camera available on DJI Phantom 4 Pro equipment to ortho-photo maps obtained from flight heights was investigated. An area within campus Gebze Technical University chos...

The light-pen coordinate measuring machine (LPCMM for short) is portable and flexible to measure features including invisible ones in-situ. Since different styluses are needed to measure different features and even during the process of measuring a single workpiece with complicated configurations, to improve the system measurement accuracy it is beneficial to calibrate the stylus tip center pos...

We propose a practical method for calibrating the position and the Radiant Intensity Distribution (RID) of light sources from images of Lambertian planes. In contrast with existing techniques that rely on the presence of specularities, we prove a novel geometric property relative to the brightness of Lambertian planes that allows to robustly calibrate the illuminant parameters without the detri...