A new method to estimate rotation angle of a 3D eye model from single camera

2015 ◽  
Author(s):  
Theekapun Charoenpong ◽  
Thananan Jantima ◽  
Chamaporn Chianrabupra ◽  
Visan Mahasitthiwat
Keyword(s):  
Rotation Angle ◽  
New Method ◽  
Single Camera ◽  
Eye Model

A New Method of Dimensional Synthesis for Planar 4-Bar Path Generation With Prescribed Timing

1998 ◽  
Author(s):  
Wu Xin ◽  
Chu Jinkui ◽  
Wu Chen ◽  
Cao Weiqing
Keyword(s):  
Rotation Angle ◽  
New Method ◽  
Path Generation ◽  
Dimensional Synthesis ◽  
Angle Function ◽  
Mathematical Equations ◽  
Harmonic Components ◽  
Set Up ◽  
Path Synthesis ◽  
First Time

Abstract Mathematical equations for 4-bar path generation on an arbitrarily arranged mechanism are set up by using complex number and Fourier series theory in this paper. The harmonic components of path generation on the coupler are carried out by systematic study. According to the conception of Coupler Rotation-Angle Operator (in short CRAO) about coupler’s rotation-angle function, a new method of determining the position for a coupler point, real dimensions and installing dimensions of the linkage is established for the first time. Based on this thinking, the concrete steps of dimension synthesis for path generation with prescribed timing are formed, and the method of path synthesis by using harmonic characteristic parameters is developed and further prefect is made.

New Method Based on Improved Double Ball Bar for Measuring Geometric Motion Errors of Coordinate Measuring Machine

2018 ◽  
Vol 12 (2) ◽  
pp. 199-205
Author(s):  
Ping Yang ◽  
◽  
Yue Wu ◽  
Hui Yu ◽  
Yinbiao Guo
Keyword(s):  
Rotation Angle ◽  
Coordinate Measuring Machine ◽  
Influential Factors ◽  
New Method ◽  
Separation Algorithm ◽  
Double Ball Bar ◽  
Ball Bar ◽  
Measuring Machine ◽  
The Difference ◽  
Geometric Motion

In this paper, an optimized method of measuring the geometric motion errors of a coordinate measuring machine (CMM) is proposed. The method is based on an improved double ball bar (DBB) that acquires the motion and link errors of the CMM and its actual rotation angles through simultaneous circular tests. The improved DBB has embedded a ring encoder system to the bottom of a commercial DBB on an auxiliary platform. In addition, an improved motion and link error separation algorithm is established by considering the difference angle Δθ between the actual rotation angle and the theoretical rotation angle of the DBB. Both influential factors of the center offset of the DBB and Δθ are discussed through simulations. When geometric motion errors are compensated for and measured on a 400 mm × 400 mm × 150 mm CMM, the standard deviations of the roundness errors decrease to 1.9 μm and 1.5 μm on the XY and ZX planes, respectively.

A new method of calculating the rotation angle in pediatric forearm fractures using direct radiographs

2016 ◽  
Vol 30 (1) ◽  
pp. 11-16
Author(s):  
Baran Heval Komur ◽  
Tahir Mutlu Durmus ◽  
Serhat Mutlu ◽  
Olcay Guler ◽  
Harun Mutlu ◽  
...  
Keyword(s):  
Rotation Angle ◽  
New Method ◽  
Forearm Fractures

A new method to calculate corneal ablation depth based on optical individual eye model

Optik ◽  
2005 ◽  
Vol 116 (9) ◽  
pp. 433-437 ◽  
Author(s):  
Huanqing Guo ◽  
Zhaoqi Wang ◽  
Yang Wang ◽  
Qiuling Zhao ◽  
Yan Wang
Keyword(s):  
Ablation Depth ◽  
New Method ◽  
Eye Model

Estimating rotation angle from asymmetric projection of chest

2021 ◽  
pp. 1-9
Author(s):  
Zhonghang Wu ◽  
Pengfei Hou ◽  
Wei Li ◽  
Tianbao Zhu ◽  
Peipei Wang ◽  
...  
Keyword(s):  
Rotation Angle ◽  
Chest Radiographs ◽  
New Method ◽  
Radiographic Examination ◽  
Thoracic Cage ◽  
Technical Adequacy ◽  
Width Difference ◽  
Spinous Processes ◽  
Chest Examination ◽  
Two Sides

BACKGROUND: Manual or machine-based analysis of chest radiographs needs the images acquired with technical adequacy. Currently, the equidistance between the medial end of clavicles and the center of spinous processes serves as the only criterion to assess whether a frontal PA chest radiograph is taken with any rotation. However, this measurement is normally difficult to implement because there exists overlapping of anatomies within the region. Moreover, there is no way available to predict exact rotating angles even the distances were correctly measured from PA chest radiographs. OBJECTIVE: To quantitatively assess positioning adequacy of PA chest examination, this study proposes and investigates a new method to estimate rotation angles from asymmetric projection of thoracic cage on radiographs. METHOD: By looking into the process of radiographic projection, generalized expressions have been established to correlate rotating angles of thorax with projection difference of left and right sides of thoracic cage. A trunk phantom with different positioning angles is employed to acquire radiographs as standard reference to verify the theoretical expressions. RESULTS: The angles estimated from asymmetric projections of thoracic cage yield good agreement with those actual rotated angles, and an approximate linear relationship exists between rotation angle and asymmetric projection of thoracic cage. Under the experimental projection settings, every degree of rotation corresponds to the width difference of two sides of thoracic cage around 13–14 pixels. CONCLUSION: The proposed new method may be used to quantify rotating angles of chest and assess image quality for thoracic radiographic examination.

A New Method for Measuring 3D Rotation Angle of Spherical Joint

Measurement ◽  
2022 ◽  
pp. 110661
Author(s):  
Long Yang ◽  
Penghao Hu ◽  
Kunlong Ma ◽  
Jin Zhang ◽  
Xueming Dang ◽  
...  
Keyword(s):  
Rotation Angle ◽  
New Method ◽  
Spherical Joint

scholarly journals Vision Measurement Scheme Using Single Camera Rotation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Shidu Dong
Keyword(s):  
Coordinate System ◽  
Rotation Angle ◽  
Rotation Axis ◽  
Translation Vector ◽  
Single Camera ◽  
Calibration Data ◽  
Accelerometer Sensor ◽  
Vision Measurement ◽  
Measurement Scheme ◽  
Camera Rotation

We propose vision measurement scheme for estimating the distance or size of the object in static scene, which requires single camera with 3-axis accelerometer sensor rotating around a fixed axis. First, we formulate the rotation matrix and translation vector from one coordinate system of the camera to another in terms of the rotation angle, which can be figured out from the readouts of the sensor. Second, with the camera calibration data and through coordinate system transformation, we propose a method for calculating the orientation and position of the rotation axis relative to camera coordinate system. Finally, given the rotation angle and the images of the object in static scene at two different positions, one before and the other after camera rotation, the 3D coordinate of the point on the object can be determined. Experimental results show the validity of our method.

Selective Sampling and Orientation of Non-Homogeneous Tissues

1968 ◽  
Vol 26 ◽  
pp. 98-99
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Random Sampling ◽  
New Method ◽  
Microscope Examination ◽  
Small Areas ◽  
Selective Sampling ◽  
Large Numbers ◽  
Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

Structure and migration of planar defects in crystals observed in atomic scale

1978 ◽  
Vol 36 (1) ◽  
pp. 284-285 ◽  
Author(s):  
H. Hashimoto ◽  
Y. Sugimoto ◽  
Y. Takai ◽  
H. Endoh
Keyword(s):  
Electron Microscope ◽  
Rotation Angle ◽  
Crystal Surface ◽  
Electron Gun ◽  
Atomic Scale ◽  
Present Observation ◽  
Twist Boundary ◽  
Optical Magnification ◽  
Zinc Crystal ◽  
And Migration

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

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