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Vision methods are very commonly used in underwater robotics. However, the cameras must be enclosed in a sealed housing for which flat-pane windows are the most economical and hence most popular solution. But they cause non-trivial refraction-based distortions at the air-glass-water interface. Recently, a new model for underwater cameras calibration called Pinax was introduced, which combines aspects...
Refraction of light underwater is a major source of error for 3D reconstruction. Use of a physically correct camera model taking into account properties of the optical system is essential for understanding the reasons why errors occur and obtaining quantitative estimates of errors. It was proven that use of the single viewpoint model of the camera leads to significant distortions in reconstruction...
The Pacific Islands Fisheries Science Center deploys the Modular Optical Underwater Survey System (MOUSS) to estimate species-specific, size-structured abundance of commercially-important fish species in Hawaii and the Pacific Islands Regions. The MOUSS is an autonomous stereo-video camera system designed for in situ visual sampling of fish assemblages. This system is rated to 500 meters and its low-light...
A multi-view multi-target correspondence framework employing deep learning on overlapping cameras for identity-aware tracking in the presence of occlusion is proposed. Our complete pipeline of detection, multi-view correspondence, fusion and tracking, inspired by AI greatly improves person correspondence across multiple wide-angled views over traditionally used features set and handcrafted descriptors...
This paper presents a new calibration method for lenslet-based plenoptic cameras. While most existing approaches require the computation of sub-aperture images or depth maps which quality depends on some calibration parameters, the proposed process uses the raw image directly. We detect micro-images containing checkerboard corners and use a pattern registration method to estimate their positions with...
This article proposes a method for sensor calibration and obstacle detection in urban environments. The radar and 3D LIDAR were calibrated with relation to a stereo camera. Data from the radar, 3D LIDAR and stereo camera sensors were fused for the detection of obstacles and determination of their shapes. The data collected using both camera and 3D LIDAR are a point cloud that is segmented taking the...
Plasma arc cutting is a complex process with substantial interaction between process parameters. These manifest in deviations in the properties of the cut such as kerf width and kerf angle. Developing relationships between process parameters and aspects of the cut requires a large amount of data. This paper presents a novel method that applies computer vision to assess the kerf width against plasma...
The correct functioning of data measuring systems is impossible without timely metrological examination and calibration of measuring channels. Uncalibrated channels can transmit unreliable data, leading to the poor monitoring and incorrect decision making. The overview of the current research in the field of measuring channels calibration shows the low research activity in this area and highlights...
There is a continuous rise of the number of trains' passengers to transport, therefore a densification of traffic is studied. For safety reasons, it becomes necessary to know the wheel-rail contact condition, in traffic, as it affects driving variables as adherence. The latest determines passenger's safety and the proper functioning of train equipment but it is often deteriorated due to recurrent...
Calibration between Lidar sensor and RGB cameras can be applied to various fields such as object recognition and tracking, 2D-3D mapping, and simultaneous localization and mapping (SLAM). Different methods for calibrating Lidar sensor and RGB cameras have been proposed using special 3D markers or calibration patterns. However, most of these methods have disadvantages of longer processing time, and...
This study proposes a method for analysis and calibration of the geo-coding error in mapping of the moving targets, 'movers', detected in the Wide Area Motion Imagery (WAMI). To estimate the accurate position of the movers, an iterative Ordinary Least Squares (OLS) optimisation of the camera model parameters is performed. The OLS is set to minimise the Euclidean distance between the locations of the...
Consumer-grade RGB-D cameras capture RGB images along with per-pixel depth information, and because of their limited cost and ability to measure distances at a high frame rate, have been used in robotics and computer vision application. However, drawbacks include the repeatability and accuracy of RGB-D cameras for object detection and localization. This paper investigates and compares RGB-D cameras'...
We present a novel data set made up of omnidirectional video of multiple objects whose centroid positions are annotated automatically. Omnidirectional vision is an active field of research focused on the use of spherical imagery in video analysis and scene understanding, involving tasks such as object detection, tracking and recognition. Our goal is to provide a large and consistently annotated video...
To improve the accuracy of camera calibration, a novel method is proposed based on the calibration principle of Zhang's calibration method. Firstly, improve the accuracy of pixel point to the subpixel. Then, the cameras of binocular visual measurement system are calibrated by Zhang's calibration method preliminarily. Finally, in consideration of the lens radial distortion, the parameters are optimized...
We propose a method for geometric calibration of multifocus plenoptic cameras using raw images. Multi-focus plenoptic cameras feature several types of micro-lenses spatially aligned in front of the camera sensor to generate micro-images at different magnifications. This multi-lens arrangement provides computational-photography benefits but complicates calibration. Our methodology achieves the detection...
Hand-Eye Calibration (HEC) which is necessary in robotics is proposed to determine the relative transformations between the camera and the Inertial Measurement Unit (IMU) in this paper. We know HEC could be degenerated into the problem of solving an optimization issue for the homogeneous matrix composed of rotation and translation. After acquiring an initial estimation with Kronecker product and singular...
Because it is a prior step for multiple computer vision applications, camera calibration is a critical task and needs to be performed accurately. With the emergence of new multispectral systems, the need of simple and reliable crossmodality calibration techniques has arisen. In this paper, we present a new calibration process for visible/far infrared(IR) stereo setups. Our calibration board is made...
In this study, a visible-light based fast iris ellipse fitting based gaze tracking scheme is developed for wearable eye trackers. First, after image enhancement pre-processing of eye images, the two-level binarization identifies the iris contour, and the candidate points for ellipse fittings are selected from the binaried iris profile. Next, by fast Random Sample Consensus (RANSAC) ellipse fitting,...
The choice of poses for camera calibration with planar patterns is only rarely considered — yet the calibration precision heavily depend on it. This work presents a pose selection method that explicitly avoids singular pose configurations which would lead to an unreliable solution. Consequently camera poses are favoured that reduce the uncertainty of the calibration parameters most. For this purpose...
Digital impressions of teeth, obtained through intra-oral scanning, allow for more efficient and cost effective treatments of many dental indications. Current state-of-the-art intra-oral impression acquisition systems make use of a separate monitor to show the scanning progress, forcing the dentist to divert attention away from the scanner and the patient. In this paper, we present an augmented reality...
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