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.
Wearable devices have many applications, pedestrian navigation among them. In this case, the inertial measurement unit (IMU) is embedded in the wearable device. Moreover, inertial navigation systems (INSs) based on non-foot-mounted IMUs use the step-length-and-heading estimation approach. The latter requires the calibration of the empirical model to estimate the step length. In this work, we propose...
This paper deals with analyzing humidity field estimation, using one humidity sensor in the central area and eight separate temperature sensors in each corner. This technique can replace expensive techniques of humidity field measuring using nine humidity sensors.
Parkinson's disease is a common neurodegenerative disorder causing several motor symptoms. Gait disorders such as festination and freezing of gait are important clinical problems, since, despite their high impact on patients' quality of life, they are poorly understood and counteracted phenomena due to their episodic nature, heterogeneous manifestation, and drug resistance. Automatic and objective...
Structured light techniques have received increased attention for depth estimation as they are robust and accurate. In this paper, we propose a method for camera-projector calibration which is required for structured light based depth estimation. We also propose enhancements to the existing hierarchical orthogonal coding (HOC) technique. The proposed space calibration technique is simple and fast...
This paper describes an image processing method for an automatic determination of the position of a tennis player on a playground for further analysis of his motion. A testing code was written in C++ with use of OpenCV libraries. The processing chain consists of several image processing techniques such as a camera calibration, background subtraction or finding the largest contours. The main objective...
We present a method for removing specular highlight reflections in facial images that may contain varying illumination colors. This is accurately achieved through the use of physical and statistical properties of human skin and faces. We employ a melanin and hemoglobin based model to represent the diffuse color variations in facial skin, and utilize this model to constrain the highlight removal solution...
A minimal solution using two affine correspondences is presented to estimate the common focal length and the fundamental matrix between two semi-calibrated cameras – known intrinsic parameters except a common focal length. To the best of our knowledge, this problem is unsolved. The proposed approach extends point correspondence-based techniques with linear constraints derived from local...
Accurate estimation of camera matrices is an important step in structure from motion algorithms. In this paper we introduce a novel rank constraint on collections of fundamental matrices in multi-view settings. We show that in general, with the selection of proper scale factors, a matrix formed by stacking fundamental matrices between pairs of images has rank 6. Moreover, this matrix forms the symmetric...
Considering the key factors that affect the precision of strapdown inertial navigation system (SINS) and odometer integrated navigation system, an on-line calibration method based on Kalman filter aided by odometer is proposed. Dead reckoning (DR) algorithm and DR error model including odometer scale factor and odometer installation errors are given. Based on the error model, a closed-loop Kalman...
A methodology that allows the separation of Faraday Rotation (FR) distortion from system induced distortion for the calibration of spaceborne polarimetric data is proposed. The separation is based on the frequency dependency of the FR across the system bandwidth and relies on the commonly used assumption that system distortions are frequency independent. A calibration schema appropriate for the calibration...
The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene project into circles in the image, and three lines suffice to calibrate the camera up to an ambiguity between focal length and radial distortion. The calibration results highly depend on accurate circle...
In this paper, we present a method for fusing different frequency synthetic aperture radar (SAR) images for improving the accuracy of land subsidence estimation using differential interferometric SAR (DInSAR) technique. Our study area, Kansai International Airport, Osaka, Japan, consists of two landfilled islands, and the subsidence velocity of an island is much larger than that of the other one....
Heavy metals that are present in soil are poisonous to both plants and animals. Measuring the heavy metal concentrations in wetland soil are of great significance for the assessment of wetland ecosystem health. This study was conducted in the Taihu Lake wetland region of China, and is aimed at comparing the partial least squares regression (PLSR) as well as support vector machine regression (SVMR)...
This paper presents a modified rank-reduction (RARE) method for joint direction-of-arrival (DOA) estimation and gain-phase calibration with some partly calibrated uniform linear arrays. Through recursively building up RARE matrices, the proposed method can guarantee the estimated gain-phase coefficients being unique, so as to improve the stability of gain-phase calibration performance. Another advantage...
The quantity and diversity of data in Light-Field videos makes this content valuable for many applications such as mixed and augmented reality or post-production in the movie industry. Some of such applications require a large parallax between the different views of the Light-Field, making the multi-view capture a better option than plenoptic cameras. In this paper we propose a dataset and a complete...
The last years have seen a quick rise of digital photography. Plenoptic cameras provide extended capabilities with respect to previous models. Multi-focus cameras enlarge the depth-of-field of the pictures using different focal lengths in the lens composing the array, but questions still arise on how to select and use these lenses. In this work a further insight on the lens selection was made, and...
Stereo rectification is a crucial step for a number of computer vision problems and in particular for dense 3D reconstruction which is a very powerful characterization tool for microscopic objects. Rectification simplifies and speeds up the correspondence search in a pair of images: the search space is reduced to a horizontal line. It is mainly developed for perspective camera model: a projective...
Various modalities are used for the examination of the gastrointestinal (GI) tract. One such modality is Wireless Capsule Endoscopy (WCE), a non-invasive technique which consists of a swallowable color camera that enables the detection of GI pathology with only minimal patient discomfort. Currently, tracking of the capsule position is estimated in the 3D abdominal space, using radio-frequency (RF)...
Magnetometers are an integral part of attitude determination system for the low-Earth orbiting small satellites as they are lightweight, inexpensive and reliable. Yet using magnetometers for attitude determination is not straightforward because of the sensor errors. These errors limit the overall achievable attitude determination accuracy. Thus far different methods to cope with magnetometer errors...
Amplitude and phase imbalance (IQ imbalance) seriously degrades the performance of FMCW radar systems with quadrature demodulator. The non-ideality of the radar signals has two main effects: The single-channel IQ imbalance leads to an image peak in the FMCW spectrum, resulting in wrong detections. The IQ imbalance between channels affects the direction-of-arrival (DOA) estimation, as the array manifold...
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.