scholarly journals Calibration of a Stereo Radiation Detection Camera Using Planar Homography

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Seung-Hae Baek ◽  
Pathum Rathnayaka ◽  
Soon-Yong Park
Keyword(s):  
Visual Information ◽  
Radiation Detection ◽  
Research Problem ◽  
Distance Measurements ◽  
Calibration Algorithm ◽  
Calibration Pattern ◽  
Gamma Sources ◽  
Stereo Calibration ◽  
Geometric Relationship ◽  
Homography Transformation

This paper proposes a calibration technique of a stereo gamma detection camera. Calibration of the internal and external parameters of a stereo vision camera is a well-known research problem in the computer vision society. However, few or no stereo calibration has been investigated in the radiation measurement research. Since no visual information can be obtained from a stereo radiation camera, it is impossible to use a general stereo calibration algorithm directly. In this paper, we develop a hybrid-type stereo system which is equipped with both radiation and vision cameras. To calibrate the stereo radiation cameras, stereo images of a calibration pattern captured from the vision cameras are transformed in the view of the radiation cameras. The homography transformation is calibrated based on the geometric relationship between visual and radiation camera coordinates. The accuracy of the stereo parameters of the radiation camera is analyzed by distance measurements to both visual light and gamma sources. The experimental results show that the measurement error is about 3%.

scholarly journals Professional competencies formation in the field of aesthetic artwork evaluation

2020 ◽  
Vol 210 ◽  
pp. 22027
Author(s):  
Irina Vlasova ◽  
Yulia Ushanyova ◽  
Sergey Pisarenko
Keyword(s):  
Visual Information ◽  
Research Problem ◽  
Educational Process ◽  
Theory And Practice ◽  
Professional Competencies ◽  
Educational Technologies ◽  
Aesthetic Evaluation ◽  
Literary Sources ◽  
Analytical Work ◽  
The Relationship

The purpose of the article is a brief description of the author’s method for solving the problem of professional competencies formation for students studying in art and adjoining specialties related to the ability to carry out aesthetic evaluation of artworks and independently conduct educating and educational activities. This problem is particularly relevant in modern conditions, which are characterized by high transmission speeds of a large amount of visual information. The methodology is based on a system of forming professional tools for students to conduct analytical work in the field of aesthetic evaluation of artworks. The development of this methodology was carried out in accordance with modern didactic principles, such as the principles of science, the relationship between theory and practice, as well as the principle of visibility. These principles were transmitted at various levels of the educational process organization. To collect information, we used such methods as analyzing literary sources on the research problem, conducting surveys of students and teachers, and analyzing modern resources for storing and distributing images, namely, author’s works of art. The educational technologies described in the article can be applied in the process of training specialists in the field of architecture, all types of visual design, painting, graphics, sculpture, as well as specialists in the field of art and correctional pedagogy, art therapy.

scholarly journals Image Preprocessing for Outdoor Luminescence Inspection of Large Photovoltaic Parks

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2508
Author(s):  
Pascal Kölblin ◽  
Alexander Bartler ◽  
Marvin Füller
Keyword(s):  
Crystalline Silicon ◽  
Distortion Correction ◽  
Lens Distortion ◽  
Control Points ◽  
Low Contrast ◽  
Voltage Curve ◽  
Current Voltage Curve ◽  
Calibration Algorithm ◽  
Calibration Pattern ◽  
Grid Points

Electroluminescence (EL) measurements allow one to detect damages and/or defective parts in photovoltaic systems. In principle, it seems possible to predict the complete current/voltage curve from such pictures even automatically. However, such a precise analysis requires image corrections and calibrations, because vignetting and lens distortion cause signal and spatial distortions. Earlier works on crystalline silicon modules used the cell gap joints (CGJ) as calibration pattern. Unfortunately, this procedure fails if the detection of the gaps is not accurate or if the contrast in the images is low. Here, we enhance the automated camera calibration algorithm with a reliable pattern detection and analyze quantitatively the quality of the process. Our method uses an iterative Hough transform to detect line structures and uses three key figures (KF) to separate detected busbars from cell gaps. This method allows a reliable identification of all cell gaps, even in noisy images or if disconnected edges in PV cells exist or potential induced degradation leads to a low contrast between active cell area and background. In our dataset, a subset of 30 EL images (72 cell each) forming grid (5×11) lead to consistent calibration results. We apply the calibration process to 997 single module EL images of PV modules and evaluate our results with a random subset of 40 images. After lens distortion correction and perspective correction, we analyze the residual deviation between ideal target grid points and the previously detected CGJ after applied distortion and perspective correction. For all of the 2200 control points in the 40 evaluation images, we achieve a deviation of less than or equal to 3 pixels. For 50% of the control points, a deviation of of less than or equal to 1 pixel is reached.

scholarly journals Common self-polar triangle of separate circles for light field camera calibration

2021 ◽  
Vol 39 (3) ◽  
pp. 521-528
Author(s):  
Qi Zhang ◽  
Qing Wang
Keyword(s):  
Camera Calibration ◽  
Light Field ◽  
Linear Optimization ◽  
Real Data ◽  
Calibration Method ◽  
Calibration Algorithm ◽  
Calibration Pattern ◽  
The Common ◽  
Projection Center ◽  
Planar Homography

Due to the trade-off between spatial resolution and angular resolution of the light field, it is difficult to extract high precision corner points and line features from light fields for calibration. A novel calibration pattern of separate circles is designed, and a light field camera calibration method based on common self-polar triangle with respect to separate circles is proposed in this paper. First, we explore the uniquity and reconstruction of common self-polar triangle with respect to sperate circles. Then, based on projections of the multi-projection-center model on the plane and conic, the common self-polar triangle on the sub-aperture image is reconstructed and used to estimate planar homography. Finally, a light field camera calibration algorithm is then proposed, including linear initialization and non-linear optimization. Experimental results on both synthetic and real data have verified the effectiveness and robustness of the method and algorithm proposed.

scholarly journals Subset-based stereo calibration method optimizing triangulation accuracy

2021 ◽  
Vol 7 ◽  
pp. e485
Author(s):  
Oleksandr Semeniuta
Keyword(s):  
Stereo Vision ◽  
Principal Component ◽  
Calibration Method ◽  
Image Pair ◽  
Calibration Pattern ◽  
Stereo Calibration ◽  
Image Pairs ◽  
Industrial Cameras ◽  
Random Nature ◽  
Calibration Parameters

Calibration of vision systems is essential for performing measurement in real world coordinates. For stereo vision, one performs stereo calibration, the results of which are used for 3D reconstruction of points imaged in the two cameras. A common and flexible technique for such calibration is based on collection and processing pairs of images of a planar chessboard calibration pattern. The inherent weakness of this approach lies in its reliance on the random nature of data collection, which might lead to better or worse calibration results, depending on the collected set of image pairs. In this paper, a subset-based approach to camera and stereo calibration, along with its implementation based on OpenCV, is presented. It utilizes a series of calibration runs based on randomly chosen subsets from the global set of image pairs, with subsequent evaluation of metrics based on triangulating the features in each image pair. The proposed method is evaluated on a collected set of chessboard image pairs obtained with two identical industrial cameras. To highlight the capabilities of the method to select the best-performing calibration parameters, a principal component analysis and clustering of the transformed data was performed, based on the set of metric measurements per each calibration run.

Investigating the Multimodal Nature of Human Communication

2009 ◽  
Vol 23 (2) ◽  
pp. 63-76 ◽  
Author(s):  
Silke Paulmann ◽  
Sarah Jessen ◽  
Sonja A. Kotz
Keyword(s):  
Visual Information ◽  
Empirical Studies ◽  
Physical Property ◽  
Event Related Potentials ◽  
Accurate Information ◽  
Human Communication ◽  
Channel Condition ◽  
Prosodic Cues ◽  
Early Processing ◽  
Related Potentials

The multimodal nature of human communication has been well established. Yet few empirical studies have systematically examined the widely held belief that this form of perception is facilitated in comparison to unimodal or bimodal perception. In the current experiment we first explored the processing of unimodally presented facial expressions. Furthermore, auditory (prosodic and/or lexical-semantic) information was presented together with the visual information to investigate the processing of bimodal (facial and prosodic cues) and multimodal (facial, lexic, and prosodic cues) human communication. Participants engaged in an identity identification task, while event-related potentials (ERPs) were being recorded to examine early processing mechanisms as reflected in the P200 and N300 component. While the former component has repeatedly been linked to physical property stimulus processing, the latter has been linked to more evaluative “meaning-related” processing. A direct relationship between P200 and N300 amplitude and the number of information channels present was found. The multimodal-channel condition elicited the smallest amplitude in the P200 and N300 components, followed by an increased amplitude in each component for the bimodal-channel condition. The largest amplitude was observed for the unimodal condition. These data suggest that multimodal information induces clear facilitation in comparison to unimodal or bimodal information. The advantage of multimodal perception as reflected in the P200 and N300 components may thus reflect one of the mechanisms allowing for fast and accurate information processing in human communication.

Situational Factors Competing for Attention

2010 ◽  
Vol 22 (1) ◽  
pp. 2-13 ◽  
Author(s):  
Weiyu Zhang ◽  
Se-Hoon Jeong ◽  
Martin Fishbein†
Keyword(s):  
Task Performance ◽  
Visual Information ◽  
Situational Factors ◽  
Sexual Content ◽  
Sexually Explicit ◽  
Explicit Content ◽  
Audio Information

This study investigates how multitasking interacts with levels of sexually explicit content to influence an individual’s ability to recognize TV content. A 2 (multitasking vs. nonmultitasking) by 3 (low, medium, and high sexual content) between-subjects experiment was conducted. The analyses revealed that multitasking not only impaired task performance, but also decreased TV recognition. An inverted-U relationship between degree of sexually explicit content and recognition of TV content was found, but only when subjects were multitasking. In addition, multitasking interfered with subjects’ ability to recognize audio information more than their ability to recognize visual information.

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