A semi-automatic alignment method for math educational standards using the MP (materialization pattern) model

2021 ◽  
Author(s):  
Namyoun Choi
Keyword(s):  
Educational Standards ◽  
Alignment Method ◽  
Automatic Alignment

scholarly journals Percutaneous placement of lumbar pedicle screws via intraoperative CT image–based augmented reality–guided technology

2020 ◽  
Vol 32 (4) ◽  
pp. 542-547 ◽  
Author(s):  
Huan Liu ◽  
Junlong Wu ◽  
Yu Tang ◽  
Haiyin Li ◽  
Wenkai Wang ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Pedicle Screw ◽  
Pedicle Screws ◽  
Clinical Situation ◽  
Ct Image ◽  
Alignment Method ◽  
Intraoperative Ct ◽  
Screw Perforation ◽  
Automatic Alignment ◽  
Lumbar Pedicle

OBJECTIVEThe authors aimed to assess, in a bone-agar experimental setting, the feasibility and accuracy of percutaneous lumbar pedicle screw placements using an intraoperative CT image–based augmented reality (AR)–guided method compared to placements using a radiograph-guided method. They also compared two AR hologram alignment methods.METHODSTwelve lumbar spine sawbones were completely embedded in hardened opaque agar, and a cubic marker was fixed on each phantom. After intraoperative CT, a 3D model of each phantom was generated, and a specialized application was deployed into an AR headset (Microsoft HoloLens). One hundred twenty pedicle screws, simulated by Kirschner wires (K-wires), were placed by two experienced surgeons, who each placed a total of 60 screws: 20 placed with a radiograph-guided technique, 20 with an AR technique in which the hologram was manually aligned, and 20 with an AR technique in which the hologram was automatically aligned. For each K-wire, the insertion path was expanded to a 6.5-mm diameter to simulate a lumbar pedicle screw. CT imaging of each phantom was performed after all K-wire placements, and the operative time required for each K-wire placement was recorded. An independent radiologist rated all images of K-wire placements. Outcomes were classified as grade I (no pedicle perforation), grade II (screw perforation of the cortex by up to 2 mm), or grade III (screw perforation of the cortex by > 2 mm). In a clinical situation, placements scored as grade I or II would be acceptable and safe for patients.RESULTSAmong all screw placements, 75 (94%) of 80 AR-guided placements and 40 (100%) of 40 radiograph-guided placements were acceptable (i.e., grade I or II; p = 0.106). Radiograph-guided placements had more grade I outcomes than the AR-guided method (p < 0.0001). The accuracy of the two AR alignment methods (p = 0.526) was not statistically significantly different, and neither was it different between the AR and radiograph groups (p < 0.0001). AR-guided placements required less time than the radiograph-guided placements (mean ± standard deviation, 131.76 ± 24.57 vs 181.43 ± 15.82 seconds, p < 0.0001). Placements performed using the automatic-alignment method required less time than those using the manual-alignment method (124.20 ± 23.80 vs 139.33 ± 23.21 seconds, p = 0.0081).CONCLUSIONSIn bone-agar experimental settings, AR-guided percutaneous lumbar pedicle screw placements were acceptable and more efficient than radiograph-guided placements. In a comparison of the two AR-guided placements, the automatic-alignment method was as accurate as the manual method but more efficient. Because of some limitations, the AR-guided system cannot be recommended in a clinical setting until there is significant improvement of this technology.

Automatic alignment method and realization of space optical coupling

2018 ◽  
Vol 47 (1) ◽  
pp. 103009
Author(s):  
柯熙政 Ke Xizheng ◽  
罗静 Luo Jing ◽  
雷思琛 Lei Sichen
Keyword(s):  
Optical Coupling ◽  
Alignment Method ◽  
Automatic Alignment

Automatic Alignment Method Based on Sine Wave Magnetooptic Modulation in Spatial Wide-Angle Scale

2012 ◽  
Vol 39 (4) ◽  
pp. 0408002
Author(s):  
周召发 Zhou Zhaofa ◽  
杨志勇 Yang Zhiyong ◽  
张志利 Zhang Zhili
Keyword(s):  
Sine Wave ◽  
Wide Angle ◽  
Alignment Method ◽  
Automatic Alignment

Automatic alignment method for calibration of hydrometers

Metrologia ◽  
2004 ◽  
Vol 41 (2) ◽  
pp. S100-S104 ◽  
Author(s):  
Y J Lee ◽  
K H Chang ◽  
J C Chon ◽  
C Y Oh
Keyword(s):  
Alignment Method ◽  
Automatic Alignment

A marker-free automatic alignment method based on scale-invariant features

2014 ◽  
Vol 186 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Renmin Han ◽  
Fa Zhang ◽  
Xiaohua Wan ◽  
Jose-Jesus Fernández ◽  
Fei Sun ◽  
...  
Keyword(s):  
Alignment Method ◽  
Scale Invariant ◽  
Invariant Features ◽  
Automatic Alignment ◽  
Marker Free

High Precision Robust Automatic Alignment Method for Rotating Shaft

MAPAN ◽  
2016 ◽  
Vol 31 (3) ◽  
pp. 189-196 ◽  
Author(s):  
Jun Luo ◽  
Zhiqian Wang ◽  
Chengwu Shen ◽  
Shaojin Liu ◽  
Zhuoman Wen
Keyword(s):  
High Precision ◽  
Alignment Method ◽  
Rotating Shaft ◽  
Automatic Alignment

Computer-Controlled Hrem Alignment Using Automated Diffractogram Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 532-533
Author(s):  
G.Y. Fan ◽  
O.L. Krivanek
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
The Other ◽  
Full Information ◽  
Resolution Electron ◽  
Skilled Operator ◽  
Automatic Alignment ◽  
High Resolution Electron Microscope ◽  
Computer Controlled ◽  
Recorded Image

Full alignment of a high resolution electron microscope (HREM) requires five parameters to be optimized: the illumination angle (beam tilt) x and y, defocus, and astigmatism magnitude and orientation. Because neither voltage nor current centering lead to the correct illumination angle, all the adjustments must be done on the basis of observing contrast changes in a recorded image. The full alignment can be carried out by a computer which is connected to a suitable image pick-up device and is able to control the microscope, sometimes with greater precision and speed than even a skilled operator can achieve. Two approaches to computer-controlled (automatic) alignment have been investigated. The first is based on measuring the dependence of the overall contrast in the image of a thin amorphous specimen on the relevant parameters, the other on measuring the image shift. Here we report on our progress in developing a new method, which makes use of the full information contained in a computed diffractogram.

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