scholarly journals High Sensitive Night-time Light Imaging Camera Design and In-orbit Test of Luojia1-01 Satellite

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 797 ◽  
Author(s):  
Zhiqiang Su ◽  
Xing Zhong ◽  
Guo Zhang ◽  
Yanjie Li ◽  
Xiaojun He ◽  
...  
Keyword(s):  
Integrated Design ◽  
Remote Sensing Data ◽  
High Sensitivity ◽  
Stray Light ◽  
Modulation Transfer ◽  
Night Time ◽  
Camera Design ◽  
Design Requirements ◽  
Imaging Performance ◽  
Better Than

Luojia1-01 satellite is the first scientific experimental satellite applied for night-time light remote sensing data acquisition, and the payload is an optical camera with high sensitivity, high radiation measurement accuracy and stable elements of interior orientation. At the same time, a special shaped hood is designed, which significantly improved the ability of the camera to suppress stray light. Camera electronics adopts the integrated design of focal plane and imaging processing, which greatly reduces the volume and weight of the system. In this paper, the design of the optical camera is summarized, and the results of in-orbit imaging performance tests are analyzed. The results show that the dynamic modulation transfer function (MTF) of the camera is better than 0.17, and the SNR is better than 35 dB under the condition of 10 lx illuminance and 0.3 reflectivity and all indicators meet the design requirements. The data obtained have been widely applied in many fields such as the process of urbanization, light pollution analysis, marine fisheries detection and military.

scholarly journals Analysis and Reduction of Solar Stray Light in the Nighttime Imaging Camera of Luojia-1 Satellite

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1130 ◽  
Author(s):  
Xing Zhong ◽  
Zhiqiang Su ◽  
Guo Zhang ◽  
Zhigang Chen ◽  
Yao Meng ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Light Signal ◽  
Stray Light ◽  
Direct Sunlight ◽  
Detection Failure ◽  
Imaging Camera ◽  
Secondary Scattering ◽  
Order Of Magnitude ◽  
Nighttime Light ◽  
Design Requirements

As one of the experimental payloads on Luojia-1 satellite, the nighttime imaging camera works with a high sensitivity to acquire nighttime light on earth. Solar stray light is a fatal problem for optical satellite works in the polar orbit, even for nighttime scene imaging, resulting in image saturation and light signal detection failure. To solve this problem, an analysis of the range of solar incident angles was conducted firstly. Based on the result, a special-shaped baffle was designed to avoid direct sunlight incidence. Moreover, the capability of stray light elimination of the lens was enhanced by an order of magnitude via optimizing the internal structure. An evaluation of secondary scattering stray lights into the camera from surrounding parts was performed based on a real satellite model. The results showed that the stray light elimination reaches a 10−10 order, meeting design requirements. Utilizing on-orbit images, the ability of satellites in illuminated areas to obtain artificial lights in dawn-dusk area was verified, proving the effectiveness of the stray light elimination design.

scholarly journals Retrieval of ozone profiles from GOMOS limb scattered measurements

2010 ◽  
Vol 3 (5) ◽  
pp. 4355-4382 ◽  
Author(s):  
S. Tukiainen ◽  
E. Kyrölä ◽  
P. T. Verronen ◽  
D. Fussen ◽  
L. Blanot ◽  
...  
Keyword(s):  
Imaging System ◽  
Signal To Noise Ratio ◽  
Stratospheric Ozone ◽  
Stray Light ◽  
Time Data ◽  
Night Time ◽  
Retrieval Method ◽  
Stellar Occultation ◽  
Infra Red ◽  
Better Than

Abstract. The GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite measures the vertical composition of the atmosphere using the stellar occultation technique. While the night-time data of GOMOS are proved to be of good quality, the daytime observations are more challenging due to poorer signal-to-noise ratio. In this paper we present an alternative technique, which uses GOMOS limb scattered radiances instead of the stellar signal, to retrieve stratospheric ozone profiles. Like for many other limb-viewing instruments, GOMOS observations contain stray light at high altitudes. We introduce a method for removing the stray light and demonstrate its feasibility by comparing the corrected radiances against those from the OSIRIS (Optical Spectrograph & Infra Red Imaging System) instrument. For the retrieval of ozone profiles, an onion peeling method is used. The first validation results suggest that the retrieval of stratospheric ozone is possible with a typical accuracy better than 10% at 22–50 km. GOMOS has measured about 350 000 daytime profiles since 2002. The new retrieval method presented here makes this large amount of data finally available for scientific use.

scholarly journals Photogrammetric Digital Surface Model Reconstruction in Extreme Low-Light Environments

2021 ◽  
Vol 13 (7) ◽  
pp. 1261
Author(s):  
Riccardo Roncella ◽  
Nazarena Bruno ◽  
Fabrizio Diotri ◽  
Klaus Thoeni ◽  
Anna Giacomini
Keyword(s):  
Image Quality ◽  
Image Quality Assessment ◽  
High Sensitivity ◽  
Sensor Technology ◽  
Surface Model ◽  
Night Time ◽  
Low Light ◽  
Reduction Techniques ◽  
Geometrical Information ◽  
Imaging Sensors

Digital surface models (DSM) have become one of the main sources of geometrical information for a broad range of applications. Image-based systems typically rely on passive sensors which can represent a strong limitation in several survey activities (e.g., night-time monitoring, underground survey and night surveillance). However, recent progresses in sensor technology allow very high sensitivity which drastically improves low-light image quality by applying innovative noise reduction techniques. This work focuses on the performances of night-time photogrammetric systems devoted to the monitoring of rock slopes. The study investigates the application of different camera settings and their reliability to produce accurate DSM. A total of 672 stereo-pairs acquired with high-sensitivity cameras (Nikon D800 and D810) at three different testing sites were considered. The dataset includes different camera configurations (ISO speed, shutter speed, aperture and image under-/over-exposure). The use of image quality assessment (IQA) methods to evaluate the quality of the images prior to the 3D reconstruction is investigated. The results show that modern high-sensitivity cameras allow the reconstruction of accurate DSM in an extreme low-light environment and, exploiting the correct camera setup, achieving comparable results to daylight acquisitions. This makes imaging sensors extremely versatile for monitoring applications at generally low costs.

Cuckoo Search Based Decision Fusion Techniques for Natural Terrain Understanding

2014 ◽  
Vol 5 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Arpita Sharma ◽  
Samiksha Goel
Keyword(s):  
Remote Sensing ◽  
Satellite Images ◽  
Remote Sensing Data ◽  
Cuckoo Search ◽  
Decision Fusion ◽  
Majority Voting ◽  
Natural Terrain ◽  
Terrain Features ◽  
Level Fusion ◽  
Better Than

This paper proposes two novel nature inspired decision level fusion techniques, Cuckoo Search Decision Fusion (CSDF) and Improved Cuckoo Search Decision Fusion (ICSDF) for enhanced and refined extraction of terrain features from remote sensing data. The developed techniques derive their basis from a recently introduced bio-inspired meta-heuristic Cuckoo Search and modify it suitably to be used as a fusion technique. The algorithms are validated on remote sensing satellite images acquired by multispectral sensors namely LISS3 Sensor image of Alwar region in Rajasthan, India and LANDSAT Sensor image of Delhi region, India. Overall accuracies obtained are substantially better than those of the four individual terrain classifiers used for fusion. Results are also compared with majority voting and average weighing policy fusion strategies. A notable achievement of the proposed fusion techniques is that the two difficult to identify terrains namely barren and urban are identified with similar high accuracies as other well identified land cover types, which was not possible by single analyzers.

Study of Ancient Land Boundaries at Tauric Chersonesos Using Satellite Images

2019 ◽  
Vol 25 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Edgar A. Terekhin ◽  
Tatiana N. Smekalova
Keyword(s):  
Remote Sensing ◽  
Information Systems ◽  
Geographic Information Systems ◽  
Satellite Images ◽  
Agricultural Land ◽  
Remote Sensing Data ◽  
Field Surveys ◽  
The 1960S ◽  
Better Than ◽  
Made In

Abstract The near chora (agricultural land) of Tauric Chersonesos was investigated using multiyear remote sensing data and field surveys. The boundaries of the land plots were studied with GIS (Geographic Information Systems) technology and an analysis of satellite images. Reliable reconstruction of the borders has been done for 231 plots (from a total of about 380), which is approximately 53% of the Chersonesean chora. During the last 50 years, most of the ancient land plots have been destroyed by modern buildings, roads, or forests. However, in the 1960s, a significant part of the chora was still preserved. Changes in preservation with time were studied with the aid of satellite images that were made in 1966 and 2015. During that period, it was found that the number of plots with almost-complete preservation decreased from 47 to 0. Those land plots whose preservation was better than 50% dropped from 104 to 4. A temporal map shows this decline in preservation. It was found that the areas of land plots could be determined accurately with satellite images; compared to field surveys, this accuracy was about 99%.

Experiment Study on Air-Deck Divided Decoupling Charge in the Subway Construction

2012 ◽  
Vol 226-228 ◽  
pp. 1500-1503
Author(s):  
Ren Shu Yang ◽  
Yu Long Che ◽  
Qiang Sun ◽  
Shao Min Zhang ◽  
Chuan Huo
Keyword(s):  
Reference Value ◽  
Experiment Study ◽  
Charge Structure ◽  
Excavation Process ◽  
Blasting Excavation ◽  
Design Requirements ◽  
Subway Construction ◽  
Smooth Blasting ◽  
Air Deck ◽  
Better Than

At present, smooth blasting are widely used in urban subway excavation. To improve smooth blasting effect in the blasting excavation process of urban subway, this paper took the fourteen section of Qingdao subway as the background, confirmed the reasonable interval of surrounding holes by combining the theoretical calculation and the actual scene; improved the smooth blasting effect obviously by changing the charge structure of periphery holes. The results of the experiment showed that adopted air-deck divided decoupling charge, when interval of surrounding holes was 350mm, and the minimum burden was 500mm, the smooth blasting effect was better, and the half eye tracking rate was beyond 85%, which meet the design requirements. The experiments proved that when adopted air-deck divided decoupling charge, the blasting effect was better than adopted concentrated charge, so there will be some reference value to the later engineering.

A rapid and accurate method for screening T-2 toxin in food and feed using competitive AlphaLISA

2021 ◽  
Vol 368 (6) ◽  
Author(s):  
Liwen Zhang ◽  
Qingyu Lv ◽  
Yuling Zheng ◽  
Xuan Chen ◽  
Decong Kong ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Accurate Method ◽  
Detection Methods ◽  
Cereal Crops ◽  
Detection Range ◽  
Highly Sensitive ◽  
Food And Feed ◽  
Good Repeatability ◽  
Feed Samples ◽  
Better Than

ABSTRACT T-2 is a common mycotoxin contaminating cereal crops. Chronic consumption of food contaminated with T-2 toxin can lead to death, so simple and accurate detection methods in food and feed are necessary. In this paper, we establish a highly sensitive and accurate method for detecting T-2 toxin using AlphaLISA. The system consists of acceptor beads labeled with T-2-bovine serum albumin (BSA), streptavidin-labeled donor beads and biotinylated T-2 antibodies. T-2 in the sample matrix competes with T-2-BSA for antibodies. Adding biotinylated antibodies to the test well followed by T-2 and T-2-BSA acceptor beads yielded a detection range of 0.03–500 ng/mL. The half-maximal inhibitory concentration was 2.28 ng/mL and the coefficient of variation was <10%. In addition, this method had no cross-reaction with other related mycotoxins. This optimized method for extracting T-2 from food and feed samples achieved a recovery rate of approximately 90% in T-2 concentrations as low as 1 ng/mL, better than the performance of a commercial ELISA kit. This competitive AlphaLISA method offers high sensitivity, good specificity, good repeatability and simple operation for detecting T-2 toxin in food and feed.

DESIGN ACTIVITY MODELING IN DISTRIBUTED KNOWLEDGE RESOURCES ENVIRONMENT

2011 ◽  
Vol 10 (01) ◽  
pp. 69-76 ◽  
Author(s):  
XUDONG DAI ◽  
XUEFEN MA ◽  
YOUBAI XIE
Keyword(s):  
Integrated Design ◽  
Knowledge Flow ◽  
Design Activity ◽  
Distributed Resources ◽  
Value Analysis ◽  
Knowledge Resources ◽  
Design Activities ◽  
Design Requirements ◽  
The Common ◽  
Different Levels

For the definition of knowledge flow, knowledge-flow control and knowledge-acquisition in integrated product design within distributed knowledge resources environment, this paper studies the structural modeling of design activity for integrated product design. The common features of integrated design in distributed resources environment are summarized as follows: centering on specific design requirements, organizing related design resources to perform design activities, outputting design results, carrying on value analysis of design results, and then making design decisions on the basis of value analysis. Based on the common features, a structural model of integrated design activities in distributed resources environment is built, which presents the structural expression of knowledge flow by defining the design requirements, the design resource input, the result output, the design activities, the relationship between the design activities, and the values of the design activities. Design activities at different levels are defined according to the design process models at different levels. A design activity that has been defined can be packaged into design components. The essence of integrated design lies in knowledge integration, which is to be realized by defining the input and output relationship between the design components and the knowledge components.

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