scholarly journals A time-division correction method for adaptive optics system

2021 ◽  
Vol 2093 (1) ◽  
pp. 012038
Author(s):  
Guangfu Yuan ◽  
Lirong Zhao ◽  
Peijian Wu ◽  
Weijie Wang
Keyword(s):  
Adaptive Optics ◽  
Correction Method ◽  
Field Of View ◽  
Image Feature ◽  
Astronomical Observation ◽  
Multiple Point ◽  
Light Sources ◽  
Extended Target ◽  
Point Light ◽  
Adaptive Optics System

Abstract An adaptive optics system can measure and compensate the wavefront distortion caused by dynamic disturbance in real time. It is usually used for astronomical observation and other occasions. According to the current technology, it is only suitable for small field of view optical system or point target, but not for ground extended target detection. In order to solve this problem, a correction method is proposed: firstly, the sub aperture image of wavefront sensor is divided into several sub regions, each sub region corresponds to a certain light direction or field angle range; secondly, calculate the offset of the image feature points in each sub region, and an image with good correction effect in a field of view in this direction is obtained; the last step is to measure each sub region one by one and combine these images into a full frame image. Through comparison, it is found that the method proposed in this paper is essentially to divide the extended target into multiple point light sources for correction.

Field-of-view shifted Shack-Hartmann wavefront sensor for daytime adaptive optics system

2006 ◽  
Vol 31 (19) ◽  
pp. 2821 ◽  
Author(s):  
Chaohong Li ◽  
Hao Xian ◽  
Changhui Rao ◽  
Wenhan Jiang
Keyword(s):  
Adaptive Optics ◽  
Field Of View ◽  
Wavefront Sensor ◽  
Adaptive Optics System

Estimation of Position and Intensity of Multi-Light Sources Based on Specular Sphere

2018 ◽  
Vol 22 (4) ◽  
pp. 491-497
Author(s):  
Chao Xu ◽  
◽  
Hua Li ◽  
Cheng Han
Keyword(s):  
Mixed Reality ◽  
Specular Reflection ◽  
Multiple Point ◽  
Light Sources ◽  
Ambient Light ◽  
Sphere Surface ◽  
Illumination Estimation ◽  
Illumination Model ◽  
Novel Method ◽  
Point Light

Illumination estimation is an important research content in mixed reality technology. This paper presents a novel method for locating multiple point light sources and estimating their intensities from the images of a pair of reference spheres. In our approach, no prior knowledge of the location of the sphere is necessary, and the center of the sphere can be uniquely identified with the known radius. The sphere surface is assumed to have both Lambertian and specular properties instead of being a pure Lambertian or specular surface, which guarantees a higher accuracy than the existing approaches. The position estimations of multiple light sources are based on the fact that the specular reflection is highly dependent on highlights. One sphere is utilized to determine the directions of the light sources, and two spheres are used to locate the positions. The images of reference spheres are sampled and partitioned with multiple light sources in different positions. An illumination model is used to calculate the intensities of the ambient light and multiple light sources. Experiments on both simulation and synthetic images show that this method is feasible and accurate for estimating the positions and intensities of the multiple light sources.

Increasing the useful field of view of an adaptive optics system

1998 ◽  
Author(s):  
Mark R. Chun ◽  
Walter J. Wild ◽  
Fang Shi ◽  
Michael F. Smutko ◽  
Edward J. Kibblewhite ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Field Of View ◽  
Useful Field Of View ◽  
Adaptive Optics System

scholarly journals Temporal statistics of residual wavefront variance of an adaptive optics system

2019 ◽  
Vol 21 (12) ◽  
pp. 125606
Author(s):  
Jian Huang ◽  
Hong Zhou ◽  
Jinsheng Yang ◽  
Chao Liu ◽  
Hao Xian
Keyword(s):  
Adaptive Optics ◽  
Temporal Statistics ◽  
Adaptive Optics System

scholarly journals Improved Wavefront Reconstruction and Correction Strategy for Adaptive Optics System with a Plenoptic Sensor

2021 ◽  
pp. 1-1
Author(s):  
Jintian Hu ◽  
Chen Tao ◽  
Xudong Lin ◽  
Liang Wang ◽  
Qichang An ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Wavefront Reconstruction ◽  
Adaptive Optics System

scholarly journals FSD-BRIEF: A Distorted BRIEF Descriptor for Fisheye Image Based on Spherical Perspective Model

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1839
Author(s):  
Yutong Zhang ◽  
Jianmei Song ◽  
Yan Ding ◽  
Yating Yuan ◽  
Hua-Liang Wei
Keyword(s):  
Feature Matching ◽  
Field Of View ◽  
Image Feature ◽  
Feature Points ◽  
Matching Process ◽  
Feature Descriptors ◽  
Coordinate Mapping ◽  
Matching Performance ◽  
Perspective Model ◽  
Attitude Matrix

Fisheye images with a far larger Field of View (FOV) have severe radial distortion, with the result that the associated image feature matching process cannot achieve the best performance if the traditional feature descriptors are used. To address this challenge, this paper reports a novel distorted Binary Robust Independent Elementary Feature (BRIEF) descriptor for fisheye images based on a spherical perspective model. Firstly, the 3D gray centroid of feature points is designed, and the position and direction of the feature points on the spherical image are described by a constructed feature point attitude matrix. Then, based on the attitude matrix of feature points, the coordinate mapping relationship between the BRIEF descriptor template and the fisheye image is established to realize the computation associated with the distorted BRIEF descriptor. Four experiments are provided to test and verify the invariance and matching performance of the proposed descriptor for a fisheye image. The experimental results show that the proposed descriptor works well for distortion invariance and can significantly improve the matching performance in fisheye images.

Optimal control techniques for the adaptive optics system of the LBT

2008 ◽  
Author(s):  
G. Agapito ◽  
F. Quiros-Pacheco ◽  
P. Tesi ◽  
S. Esposito ◽  
M. Xompero
Keyword(s):  
Optimal Control ◽  
Adaptive Optics ◽  
Control Techniques ◽  
Adaptive Optics System
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