scholarly journals Detection Capability Verification and Performance Test for the High Resolution Imaging Camera of China’s Tianwen-1 Mission

2021 ◽  
Vol 217 (6) ◽  
Author(s):  
Wei Yan ◽  
Jianjun Liu ◽  
Xin Ren ◽  
Chunlai Li ◽  
Qiang Fu ◽  
...  

AbstractHigh-resolution optical cameras have always been important scientific payloads in Mars exploration missions, which can obtain detailed images of Martian surface for the study of geomorphology, topography and geological structure. At present, there are still many challenges for Mars high-resolution images in terms of global coverage, stereo coverage (especially for colour images), and data processing methods. High Resolution Imaging Camera (HiRIC) is a high-quality, multi-mode, multi-functional, multi-spectral remote sensing camera that is suitable for the deep space developed for China’s first Mars Exploration Mission (Tianwen-1), which was successfully launched in July 2020. Here we design special experiments based on the in-orbit detection conditions of Tianwen-1 mission to comprehensively verify the detection capability and the performance of HiRIC, from the aspects of image motion compensation effect, focusing effect, image compression quality, and data preprocessing accuracy. The results showed that the performance status of HiRIC meets the requirements of obtaining high resolution images on the Martian surface. Furthermore, proposals for HiRIC in-orbit imaging strategy and data processing are discussed to ensure the acquisition of high-quality HiRIC images, which is expected to serve as a powerful complementation to the current Mars high-resolution images.

2021 ◽  
Vol 217 (3) ◽  
Author(s):  
Qingyu Meng ◽  
Dong Wang ◽  
Xiaodong Wang ◽  
Wei Li ◽  
Xianwei Yang ◽  
...  

Author(s):  
Max T. Otten ◽  
Wim M.J. Coene

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.


2011 ◽  
Vol 28 (8) ◽  
pp. 1050-1062 ◽  
Author(s):  
Jean Tournadre ◽  
Bertrand Chapron ◽  
Nicolas Reul

Abstract This paper presents a new method to analyze high-resolution altimeter waveforms in terms of surface backscatter. Over the ocean, a basic assumption of modeling altimeter echo waveforms is to consider a homogeneous sea surface within the altimeter footprint that can be described by a mean backscatter coefficient. When the surface backscatter varies strongly at scales smaller than the altimeter footprint size, such as in the presence of surface slicks, rain, small islands, and altimeter echoes can be interpreted as high-resolution images of the surface whose geometry is annular and not rectangular. A method based on the computation of the imaging matrix and its pseudoinverse to infer the surface backscatter at high resolution (~300 m) from the measured waveforms is presented. The method is tested using synthetic waveforms for different surface backscatter fields and is shown to be unbiased and accurate. Several applications can be foreseen to refine the analysis of rain patterns, surface slicks, and lake surfaces. The authors choose here to focus on the small-scale variability of backscatter induced by a submerged reef smaller than the altimeter footprint as the function of tide, significant wave height, and wind.


2020 ◽  
Vol 642 ◽  
pp. A14 ◽  
Author(s):  
◽  
M. Anderson ◽  
T. Appourchaux ◽  
F. Auchère ◽  
R. Aznar Cuadrado ◽  
...  

Aims. The Spectral Imaging of the Coronal Environment (SPICE) instrument is a high-resolution imaging spectrometer operating at extreme ultraviolet wavelengths. In this paper, we present the concept, design, and pre-launch performance of this facility instrument on the ESA/NASA Solar Orbiter mission. Methods. The goal of this paper is to give prospective users a better understanding of the possible types of observations, the data acquisition, and the sources that contribute to the instrument’s signal. Results. The paper discusses the science objectives, with a focus on the SPICE-specific aspects, before presenting the instrument’s design, including optical, mechanical, thermal, and electronics aspects. This is followed by a characterisation and calibration of the instrument’s performance. The paper concludes with descriptions of the operations concept and data processing. Conclusions. The performance measurements of the various instrument parameters meet the requirements derived from the mission’s science objectives. The SPICE instrument is ready to perform measurements that will provide vital contributions to the scientific success of the Solar Orbiter mission.


1989 ◽  
Vol 8 ◽  
pp. 545-546
Author(s):  
John Davis

As a result of advances in instrumentation and techniques, from radio through to optical wavelengths, we have before us the prospect of producing very high resolution images of a wide range of objects across this entire spectral range. This prospect, and the new knowledge and discoveries that may be anticipated from it, lie behind an upsurge in interest in high resolution imaging from the ground. Several new high angular resolution instruments for radio, infrared, and optical wavelengths are expected to come into operation before the 1991 IAU General Assembly.


2020 ◽  
Author(s):  
Wei Yan ◽  
Jianjun Liu ◽  
Xiaoxia Zhang ◽  
Dawei Liu ◽  
Donghao Liu

<p>Mars is a planet in the solar system that is closer to the Earth and has the most similar natural environment to the Earth. It has always been the first choice for humans to go out of the Earth and Moon system for deep space exploration.</p><p>China’s First Mars Mission (HX-1) will be launched in 2020 with an orbiter and a lander rover. One of the scientific goals of our mission is to study the morphology and geologic structure of the Mars. In order to achieve this purpose, the orbiter is equipped with a High Resolution Imaging Camera (HiRIC) to obtain the high-resolution morphology data of typical regions and to study the formation and evolution of geologic structure. HiRIC consists of three TDI CCD line-scan detectors and two COMS area-array detectors. Each TDI CCD detector covers 5 spectral bands. Its main working mode is the panchromatic TDI CCD push-scan imaging with a maximum spatial resolution of 0.5m.</p><p>Ground scientific verification test is an effective way to comprehensively evaluate the performance, data quality of HiRIC, and to fully verify its on-orbit detection process and data processing methods. In this study, contents and results of ground scientific verification test for HiRIC is introduced. The engineering model is used here for image motion compensation effect evaluation test, focusing effect evaluation test, and outdoor field imaging test. The results show that, 1) HiRIC can calculate the image motion compensation parameters and control the camera imaging correctly according to the platform parameters of orbiter; 2) Focus processing is effective, and HiRIC can adapt to the high-resolution imaging needs of different orbit altitudes; 3) Clear image data can be obtained according to the on-orbit detection process in the outdoor field imaging test, and image data processing was correct. Image data quality, compression quality, and TDI CCD stitching accuracy all meet the requirements of the verification test. This test fully evaluated HiRIC's ability to obtain high-resolution image data of the surface of Mars.</p>


2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Michael J. Haugh ◽  
Richard Stewart

This paper describes the design, crystal selection, and crystal testing for a vertical Johann spectrometer operating in the 13 keV range to measure ion Doppler broadening in inertial confinement plasmas. The spectrometer is designed to use thin, curved, mica crystals to achieve a resolving power of E/ΔE>2000. A number of natural mica crystals were screened for flatness and X-ray diffraction width to find samples of sufficient perfection for use in the instrument. Procedures to select and mount high quality mica samples are discussed. A diode-type X-ray source coupled to a dual goniometer arrangement was used to measure the crystal reflectivity curve. A procedure was developed for evaluating the goniometer performance using a set of diffraction grade Si crystals. This goniometer system was invaluable for identifying the best original crystals for further use and developing the techniques to select satisfactory curved crystals for the spectrometer.


2000 ◽  
Author(s):  
David L. Dickensheets ◽  
Phillip A. Himmer ◽  
Robert A. Friholm ◽  
B. Jeffrey Lutzenberger

Sign in / Sign up

Export Citation Format

Share Document