Real-time and accurate autofocusing of stationary and moving objects is an important problem in modern digital cameras. Depth From Defocus (DFD) is a technique for autofocusing that needs only two or three images recorded with different camera parameters. In practice, there exist many factors that affect the performance of DFD algorithms, such as nonlinear sensor response, lens vignetting, and ...

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A method for accurate depth measurement in depth from focus is presented. With depth from focus the 3D shape of objects can be measured. To do so, an image series with different distances between camera and object is evaluated to extract focused parts. Combining the results of an edge detection filter with the distance information at which the images have been acquired provides a depth image of...

Automatic camera calibration has remained a hard topic in computer vision since its inception due to its reliance on the image corresp ondence problem. This problem becomes even more pronounced when calibrating a depth image with a color image due to a lack of simple corresp ondences between the two modalities. In this work, we develop a completely automatic, very fast, online algorithm that de...

A growing number of modern applications such as position determination, object recognition and collision prevention depend on accurate scene analysis. The estimation of an object’s distance relative to an observers position by image analysis or laser scan techniques is thereby still the most time-consuming and expansive part. A lower-priced and much faster alternative is the distance measuremen...

Camera calibration is an important and sensitive step in 3D environment reconstruction by stereovision. Small errors in the initial estimation of the camera parameters (especially in the estimation of the principal point) could rise to high errors in the 3D measurements, which are increasing with the working distance. There are many general-purpose calibration methods for calibration of individ...

This thesis investigates the applicability of computer vision camera models in recovering depth information from images, and presents a novel camera model incorporating a modified pupil plane capable of performing this task accurately from a single image. Standard models, such as the ideal pinhole, suffer a loss of depth information when projecting from the world to an image plane. Recovery of ...

The accuracy is important for a 3D whole body scanning system. In order to analyze the measurement error, a set of dimension-certified measurement equipment whose true dimensions were certified was introduced. The calibration models of height, breadth and depth measurement between measured values and true dimensions were established respectively and relevant error envelopes were derived. A veri...

This paper proposes a fast and accurate calibration method to calibrate multiple multimodal sensors using a novel photogrammetry system for fast localization of EEG sensors. The EEG sensors are placed on human head and multimodal sensors are installed around the head to simultaneously obtain all EEG sensor positions. A multiple views' calibration process is implemented to obtain the transformat...