scholarly journals Line of Sight and Image Motion Compensation for Step and Stare Imaging System

2020 ◽  
Vol 10 (20) ◽  
pp. 7119
Author(s):  
Jihong Xiu ◽  
Pu Huang ◽  
Jun Li ◽  
Hongwen Zhang ◽  
Youyi Li
Keyword(s):  
High Resolution ◽  
Motion Compensation ◽  
Imaging System ◽  
Control Flow ◽  
Image Motion ◽  
Line Of Sight ◽  
Pointing Accuracy ◽  
High Resolution Images ◽  
Pointing Control ◽  
And Control

In recent years, applications such as marine search and rescue, border patrol, etc. require electro-optical equipment to have both high resolution and precise geographic positioning abilities. The step and stare working based on a composite control system is a preferred solution. This paper proposed a step and stare system composed of two single-axis fast steering mirrors and a two-axis gimbal. The fast steering mirrors (FSMs) realize image motion compensation and the gimbal completes pointing control. The working principle and the working mode of the system are described first. According to the imaging optical path, the algorithm and control flow of the line of sight (LOS) and image motion compensation are developed. The proposed method is verified through ground imaging and flight tests. Under the condition of flight, the pointing accuracy of the target can be controlled within 15 m. The proposed algorithm can achieve effective motion compensation and get high-resolution images. This achieves high resolution and accurate LOS simultaneously.

Synthetic Wavelength Holography: Snapshot Non-Line-of-Sight Imaging with High-Resolution and Wide Field of View

2020 ◽  
Author(s):  
Florian Willomitzer ◽  
Prasanna Rangarajan ◽  
Fengqiang Li ◽  
Muralidhar Balaji ◽  
Marc Christensen ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Scattered Light ◽  
Field Of View ◽  
Line Of Sight ◽  
Wide Field ◽  
Navigation Systems ◽  
Small Probe ◽  
Wide Field Of View ◽  
Non Line Of Sight

Abstract The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by exploiting spectral correlations in scattered wavefronts. Our Synthetic Wavelength Holography (SWH) method is able to recover a holographic representation of hidden targets with high resolution over a wide field of view. The complete object field is recorded in a snapshot-fashion, by monitoring the scattered light return in a small probe area. This unique combination of attributes opens up a plethora of new Non-Line-of-Sight imaging applications ranging from medical imaging and forensics, to early-warning navigation systems and reconnaissance. Adapting the findings of this work to other wave phenomena will help unlock a wider gamut of applications beyond those envisioned in this paper.

High-resolution X-ray topographic images of dislocations in a silicon crystal recorded using an X-ray zooming tube

1998 ◽  
Vol 5 (3) ◽  
pp. 1079-1081
Author(s):  
Shigeru Kimura ◽  
Tatsuya Matsumura ◽  
Katsuyuki Kinoshita ◽  
Keiichi Hirano ◽  
Hiroshi Kihara
Keyword(s):  
High Resolution ◽  
Digital Imaging ◽  
Imaging System ◽  
Silicon Crystal ◽  
Stage Structure ◽  
Magnification Factor ◽  
Double Crystal ◽  
X Ray ◽  
Imaging Detector ◽  
High Resolution Images

A Be-window-type X-ray zooming tube is an X-ray digital imaging system whose magnification factor of X-ray images can be easily varied from 10 to 200, and whose spatial resolution is less than 0.5 µm. This zooming tube was used as an imaging detector in double-crystal X-ray topography to obtain high-resolution images of dislocations in a silicon crystal. X-ray interference images of about 5 µm were observed even though optimal performance of the X-ray zooming tube could not be achieved. The results indicate that the X-ray zooming tube might make a good detector for X-ray topography with minor improvements in its stage structure.

scholarly journals Surface evolution of the Anhur region on comet 67P/Churyumov-Gerasimenko from high-resolution OSIRIS images

2019 ◽  
Vol 630 ◽  
pp. A13 ◽  
Author(s):  
S. Fornasier ◽  
C. Feller ◽  
P. H. Hasselmann ◽  
M. A. Barucci ◽  
J. Sunshine ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Morphological Changes ◽  
Surface Evolution ◽  
Water Ice ◽  
Narrow Angle ◽  
Highly Active ◽  
Rosetta Mission ◽  
High Resolution Images ◽  
Comet 67P

Context. The southern hemisphere of comet 67P/Churyumov-Gerasimenko (67P) became observable by the Rosetta mission in March 2015, a few months before cometary southern vernal equinox. The Anhur region in the southern part of the comet’s larger lobe was found to be highly eroded, enriched in volatiles, and highly active. Aims. We analyze high-resolution images of the Anhur region pre- and post-perihelion acquired by the OSIRIS imaging system on board the Rosetta mission. The Narrow Angle Camera is particularly useful for studying the evolution in Anhur in terms of morphological changes and color variations. Methods. Radiance factor images processed by the OSIRIS pipeline were coregistered, reprojected onto the 3D shape model of the comet, and corrected for the illumination conditions. Results. We find a number of morphological changes in the Anhur region that are related to formation of new scarps; removal of dust coatings; localized resurfacing in some areas, including boulders displacements; and vanishing structures, which implies localized mass loss that we estimate to be higher than 50 million kg. The strongest changes took place in and nearby the Anhur canyon-like structure, where significant dust cover was removed, an entire structure vanished, and many boulders were rearranged. All such changes are potentially associated with one of the most intense outbursts registered by Rosetta during its observations, which occurred one day before perihelion passage. Moreover, in the niche at the foot of a new observed scarp, we also see evidence of water ice exposure that persisted for at least six months. The abundance of water ice, evaluated from a linear mixing model, is relatively high (>20%). Our results confirm that the Anhur region is volatile-rich and probably is the area on 67P with the most pristine exposures near perihelion.

scholarly journals Conceptual Design and Image Motion Compensation Rate Analysis of Two-Axis Fast Steering Mirror for Dynamic Scan and Stare Imaging System

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6441
Author(s):  
Jianjun Sun ◽  
Yalin Ding ◽  
Hongwen Zhang ◽  
Guoqin Yuan ◽  
Yuquan Zheng
Keyword(s):  
Motion Compensation ◽  
Imaging System ◽  
Flight Test ◽  
Transformation Method ◽  
Dynamic Imaging ◽  
Image Motion ◽  
Dual Band ◽  
Rate Equations ◽  
Rate Analysis ◽  
Dynamic Scan

In order to enable the aerial photoelectric equipment to realize wide-area reconnaissance and target surveillance at the same time, a dual-band dynamic scan and stare imaging system is proposed in this paper. The imaging system performs scanning and pointing through a two-axis gimbal, compensating the image motion caused by the aircraft and gimbal angular velocity and the aircraft liner velocity using two two-axis fast steering mirrors (FSMs). The composition and working principle of the dynamic scan and stare imaging system, the detailed scheme of the two-axis FSM and the image motion compensation (IMC) algorithm are introduced. Both the structure and the mirror of the FSM adopt aluminum alloys, and the flexible support structure is designed based on four cross-axis flexural hinges. The Root-Mean-Square (RMS) error of the mirror reaches 15.8 nm and the total weight of the FSM assembly is 510 g. The IMC rate equations of the two-axis FSM are established based on the coordinate transformation method. The effectiveness of the FSM and IMC algorithm is verified by the dynamic imaging test in the laboratory and flight test.

High-resolution ground-based coronagraphy using image-motion compensation

1992 ◽  
Vol 31 (22) ◽  
pp. 4405 ◽  
Author(s):  
D. A. Golimowski ◽  
M. Clampin ◽  
S. T. Durrance ◽  
R. H. Barkhouser
Keyword(s):  
High Resolution ◽  
Motion Compensation ◽  
Image Motion

scholarly journals Application of Photoacoustic Imaging for Lymphedema Treatment

2021 ◽  
Author(s):  
Yushi Suzuki ◽  
Hiroki Kajita ◽  
Shiho Watanabe ◽  
Keisuke Okabe ◽  
Hisashi Sakuma ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Three Dimensional ◽  
Lymphatic Vessels ◽  
Small Diameter ◽  
Detailed Structure ◽  
High Resolution Images ◽  
Major Application ◽  
Lymph Fluid

Abstract Background Lymphatic vessels are difficult to identify using existing modalities as because of their small diameter and the transparency of the lymph fluid flowing through them. Methods Here, we introduce photoacoustic lymphangiography (PAL), a new modality widely used for lymphedema treatment, to observe limb lymphatic vessels. The photoacoustic imaging system used in this study can simultaneously visualize lymphatic vessels and veins with a high resolution (0.2 mm) and can also observe their three-dimensional relationship with each other. Results High-resolution images of the lymphatic vessels, detailed structure of the dermal back flow, and the three-dimensional positional relationship between the lymphatic vessels and veins were observed by PAL. Conclusion The clear image provided by PAL could have a major application in pre- and postoperative use during lymphaticovenular anastomosis for lymphedema treatment.

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

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