Paracatadioptric camera calibration based on the projecting relationship of the relative position between two spheres

2018 ◽  
Vol 78 (9) ◽  
pp. 12223-12249 ◽  
Author(s):  
Yalin Wang ◽  
Yue Zhao
2021 ◽  
Vol 2097 (1) ◽  
pp. 012027
Author(s):  
Zhongxin Liu ◽  
Zhiliang Wang ◽  
Chao Wang ◽  
Jinsong Zhang

Abstract This paper novel designed the local convergence configuration in the coaxial channels to study the two-phase flow (lubricating oil (continuous phase, flow rate Q c)/deionized water (dispersed phase, flow rate Q d)). Two geometric control variables, the relative position (x) and tapering characteristics (α), had the different effects on the droplet formation. The increase of relative position x caused the higher frequency and finer droplets, and the increase of convergence angle α, took the opposite effects. The results indicated that the equivalent dimensionless droplet length Ld/Wout and the flow rate ratio Qd/Qc had an exponential relationship of about 1/2. Similarly, it was found that the dispersed droplets generating frequency and the two-phase capillary number, CaTP = uTPμc/σ, had an exponential relationship. The advantage of the convergent configurations in micro-channel was the size and efficiency of droplet generation was very favorable to be controlled by α and x.


2006 ◽  
Vol 96 (6) ◽  
pp. 499-504 ◽  
Author(s):  
Brian A. Rothbart

The objective of this study was to determine whether a correlation exists between abnormal pronation and functional leg-length discrepancies. Visual assessment and a pelvic thrust maneuver were used to identify the functionally short leg in 56 indigenous Mexicans (20 males and 36 females; mean age, 33 years; mean weight, 59 kg; and mean height, 1.60 m). The Foot Posture Index was used with a modified stance position to identify the more pronated foot. The posterosuperior iliac spines were used to identify the “relative” position of the innominate bones. The raw data obtained from this study were evaluated using the McNemar test for paired proportions. A significant positive correlation was found between abnormal pronation and hip position and between hip position and functional leg-length discrepancy. These results are consistent with a theoretical ascending dysfunctional pelvic model: Abnormal pronation pulls the innominate bones anteriorly (forward); anterior rotation of the innominate bones shifts the acetabula posteriorly and cephalad (backward and upward); and this shift in the acetabula hyperextends the knees and shortens the legs, with the shortest leg corresponding to the most pronated foot. (J Am Podiatr Med Assoc 96(6): 499-507, 2006)


1895 ◽  
Vol 37 (3) ◽  
pp. 565-614 ◽  
Author(s):  
Robert Kidston

The Coal Measures of the South Wales Coal Field fall into three well-marked divisions:—I. The Upper Pennant or Upper Penllergare Series.II. The Lower Pennant Series.III. The White Ash Series.In 1885 I paid a visit to this Coal Field, with the object of studying its Fossil Flora, hoping by this means to ascertain the relative position of the Welsh Coal Measures to those of the other Coal Fields of Britain.


2014 ◽  
Vol 981 ◽  
pp. 364-367
Author(s):  
Guang Yu ◽  
Bo Yang Yu ◽  
Shu Cai Yang ◽  
Li Wen ◽  
Wen Fei Dong ◽  
...  

Projector calibration can be seen as a special case of the camera calibration. It can establish the relationship of the three dimensional space coordinates for points and projector image coordinates for points DMD by using a projector to project coding pattern. In camera calibration, ZHANG’s self-calibration was conducted in the maximum likelihood linear refinement. Operation process takes the lens distortion factors into account finding out the camera internal and external parameters finally. Using this algorithm to the projector calibration can solve the traditional linear calibration algorithm which is complex and poor robustness. Otherwise, it can improve the practicability of calibration method. This method can both calibrate the internal and external parameters of projector, which can solve the problem of independently inside or outside calibration.


1987 ◽  
Vol 115 ◽  
pp. 174-175
Author(s):  
J. R. Forster ◽  
J. L. Caswell

Detailed maps of 70 OH and H2O masers associated with star-forming regions have been made with the VLA at an angular resolution of ∼2″ arc. The absolute position accuracy is 0″.5 for both the OH and H2O observations, and the relative position accuracy of maser spots within a group is 0″.1 for each species. For about half of the sources compact H II regions are detected at 22 GHz with 0″.1 positional accuracy relative to the strongest H2O maser. Preliminary results are presented, with emphasis on the spatial relationship between the OH and H2O masers and compact H II regions.


2019 ◽  
Vol 9 (21) ◽  
pp. 4712 ◽  
Author(s):  
Qingya Li ◽  
Libao Yang ◽  
Weiguo Zhao ◽  
Zhen Shi ◽  
Zhenyu Liu

The factors affecting the re-orientation accuracy of the on-orbit replaceable optical unit were studied, and the mathematical models of the relationships between fit clearances of positioning mechanisms and the limits of rotation angles were deduced. When the relative position relationship of positioning mechanisms was determined, fit clearances were designed according to the requirement of the rotation angle limits, and the rotation angle limits were determined to ensure that the angles were within the index range. Theodolites were used to measure the re-orientation angles of the optical unit, and the errors between the measurement angles and the real angles were deduced. Then, the numerical simulation proved that the errors were within limits. The microgravity test environment was established, and the weight of the optical unit was unloaded by a suspension method to simulate the state of the optical unit when it was replaced on orbit. The test results confirmed the correctness of the design method.


Author(s):  
Zixiang Ding ◽  
Huihui He ◽  
Mengran Zhang ◽  
Rui Xia

Emotion cause identification aims at identifying the potential causes that lead to a certain emotion expression in text. Several techniques including rule based methods and traditional machine learning methods have been proposed to address this problem based on manually designed rules and features. More recently, some deep learning methods have also been applied to this task, with the attempt to automatically capture the causal relationship of emotion and its causes embodied in the text. In this work, we find that in addition to the content of the text, there are another two kinds of information, namely relative position and global labels, that are also very important for emotion cause identification. To integrate such information, we propose a model based on the neural network architecture to encode the three elements (i.e., text content, relative position and global label), in an unified and end-to-end fashion. We introduce a relative position augmented embedding learning algorithm, and transform the task from an independent prediction problem to a reordered prediction problem, where the dynamic global label information is incorporated. Experimental results on a benchmark emotion cause dataset show that our model achieves new state-ofthe-art performance and performs significantly better than a number of competitive baselines. Further analysis shows the effectiveness of the relative position augmented embedding learning algorithm and the reordered prediction mechanism with dynamic global labels.


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