scholarly journals Technique for Concurrent Internal Calibration during Data Acquisition for SAR Systems

2020 ◽  
Vol 12 (11) ◽  
pp. 1773
Author(s):  
Jens Reimann ◽  
Marco Schwerdt
Keyword(s):  
Image Quality ◽  
Data Acquisition ◽  
Real Data ◽  
Nominal Data ◽  
Calibration Scheme ◽  
Internal Calibration ◽  
Before And After ◽  
Sar Data ◽  
Selection Of

Nowadays, stringent requirements for the quality of SAR data products exist. The radiometric and image quality requirements can only be fulfilled by knowing the disturbances caused by the radar hardware itself. The internal calibration is a mechanism to estimate these disturbances from the real hardware. Unfortunately, most of the current internal calibration schemes interrupt the SAR data acquisition during internal calibration and hence cause a loss of azimuth samples and a degradation of the image quality. The calibration is thus often performed only before and after a data take. However, these two calibration events are hardly sufficient to estimate the instrument parameters during the whole acquisition especially for long data takes, which will become more common in future SAR system. In this paper, an internal calibration scheme is introduced which allows performing the internal calibration during nominal data acquisition by injecting a coded calibration signal into the receiver with very low power. This signal causes only minor degradation of the SAR image but can be retrieved from the data using adequate signal processing. This technique is described, the theoretical performance estimated, and finally demonstrated on real data from the TerraSAR-X mission. A selection of possible coding scheme is also analyzed with respect to their suitability for the proposed internal calibration scheme.

Small dose Contrast Venography as Venous Mapping in Predialysis Patients

2010 ◽  
Vol 11 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Yoo Dong Won ◽  
Ja Young Lee ◽  
Young Shin Shin ◽  
Young Soo Kim ◽  
Sun Ae Yoon ◽  
...  
Keyword(s):  
Image Quality ◽  
Small Dose ◽  
Small Diameter ◽  
Mapping Method ◽  
Dialysis Patients ◽  
Stage 4 ◽  
Significant Difference ◽  
Small Doses ◽  
Before And After

Purpose This study was designed to evaluate radiocontrast-induced nephrotoxicity (RIN), and the image quality and findings of venography using small doses of radiocontrast as a venous mapping method in pre-dialysis patients. Methods Twenty-eight patients with stage 4 and 5 chronic kidney disease underwent arm venography with 10–15 ml of dilute contrast medium. Image quality, venographic findings and glomerular filtration rate (GFR) before and after the procedure were evaluated. Results Mean GFR was 19.3±5.8 ml/min/1.73 m2 (7–30 ml/min/1.73 m2). Image quality of venography in the forearm and upper arm veins was good in all patients. Central veins were visualized well in 26 (92.8%) patients. Eight (28.5%) patients showed cephalic veins inadequate for creation of radiocephalic arteriovenous fistula (AVF) because of occlusion or small diameter veins. There was no significant difference in GFR between the pre- and post-study (19.3±5.8 vs. 19.2±6.2 ml/min/1.73 m2, p=0.693). RIN developed (GFR: 17 to 13 ml/min/1.73 m2) in only one patient but without sequelae, and the GFR completely recovered to baseline level 7 days after the study. Conclusion Small dose venography is safe and effective for venous mapping in pre-dialysis patients.

Typical errors when performing intraoral periapical x-rays, and their effect on image quality

2020 ◽  
pp. 36-44
Author(s):  
A.P. Arzhantsev
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Digital Image ◽  
Cone Beam ◽  
X Rays ◽  
Post Processing ◽  
X Ray ◽  
Selection Of ◽  
Periapical Radiography

During the study, intraoral periapical images were analyzed in 300 patients. The possibilities of using the methods of radiography and their influence on the quality of the obtained x-ray images were studied. The intraoral periapical radiography was compared with the results of orthopantomography and cone beam computed tomography. To identify the features of the mapping of zones of periapical destruction, 47 experimental x-ray studies were performed on skeletonized jaws with artificial defects in cortical plates. Often encountered errors are: an arbitrary choice of angles of inclination and the centration of the x-ray tube, the wrong location of the x-ray receiver in the patient's mouth, inaccurate installation or poor fixation of the patient's head, inefficient selection of physical and technical conditions of shooting, non-compliance with the conditions of the photo process with analog radiography or post-processing and printing digital image. The characteristic projection distortions of images resulting from these errors are analyzed and illustrated.

scholarly journals Tricks and Treats in Photomicrography

1995 ◽  
Vol 3 (6) ◽  
pp. 16-20
Author(s):  
H. Wolfgang Zieler ◽  
Walter C. McCrone
Keyword(s):  
Image Quality ◽  
Object Plane ◽  
Illumination System ◽  
Selection Of

Success in photomicrography depends, not only upon the acquisition of a technique, but also upon the selection of equipment. Unless the equipment is provided with certain facilities and controls, it is impossible to create optimum final image quality in the object plane.We shall direct our attention to that part of the equipment which - next to the performance of objective and eyepiece - has the greatest influence upon the quality of the image, viz., the illumination system.

scholarly journals Research on the Fairness of MPACC Selection Based on Examiner Heterogeneity

2021 ◽  
Vol 235 ◽  
pp. 03010
Author(s):  
Yan Wang ◽  
Zhuqian He ◽  
Jingjie Zheng
Keyword(s):  
Regression Model ◽  
Test Scores ◽  
Test Results ◽  
Before And After ◽  
The Relationship ◽  
Selection Of

The selection of MPACC (Master of Professional Accountant) is a key step in the training of senior accounting personnel. This paper examines the relationship between examiner heterogeneity and MPACC second test scores. We try to clarify the reason for the unfair phenomenon because of the heterogeneity of examiners in MPACC second test results and seek ways to solve this problem. The study found that the MPACC second test results are unfair. This unfairness is caused by the heterogeneity of the examiner. However, standardized algorithms balance the differences in MPACC examiner heterogeneity. The regression model was constructed by using the MPACC second test scores before and after standardization, which verified the existence of examiner heterogeneity and the effect of the standardized algorithm on the examiner heterogeneity. This article is based on the differences of MPACC second test scores due to examiner’s heterogeneity. We propose the application of standardized algorithm, which will play an important role in improving the quality of MPACC enrollment and promoting the training of senior accounting personnel.

scholarly journals IMPROVING PERFORMANCE OF FEATURE EXTRACTION IN SFM ALGORITHMS FOR 3D SPARSE POINT CLOUD

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 101-106
Author(s):  
F. Condorelli ◽  
R. Higuchi ◽  
S. Nasu ◽  
F. Rinaudo ◽  
H. Sugawara
Keyword(s):  
Point Cloud ◽  
Point Clouds ◽  
Low Density ◽  
Feature Points ◽  
Historical Archives ◽  
Before And After ◽  
Manual Selection ◽  
Art And Architecture ◽  
Selection Of

Abstract. The use of Structure-from-Motion algorithms is a common practice to obtain a rapid photogrammetric reconstruction. However, the performance of these algorithms is limited by the fact that in some conditions the resulting point clouds present low density. This is the case when processing materials from historical archives, such as photographs and videos, which generates only sparse point clouds due to the lack of necessary information in the photogrammetric reconstruction. This paper explores ways to improve the performance of open source SfM algorithms in order to guarantee the presence of strategic feature points in the resulting point cloud, even if sparse. To reach this objective, a photogrammetric workflow is proposed to process historical images. The first part of the workflow presents a method that allows the manual selection of feature points during the photogrammetric process. The second part evaluates the metric quality of the reconstruction on the basis of a comparison with a point cloud that has a different density from the sparse point cloud. The workflow was applied to two different case studies. Transformations of wall paintings of the Karanlık church in Cappadocia were analysed thanks to the comparison of 3D model resulting from archive photographs and a recent survey. Then a comparison was performed between the state of the Komise building in Japan, before and after restoration. The findings show that the method applied allows the metric scale and evaluation of the model also in bad condition and when only low-density point clouds are available. Moreover, this tool should be of great use for both art and architecture historians and geomatics experts, to study the evolution of Cultural Heritage.

Shifting students’ to experts’ complex systems knowledge

2003 ◽  
Vol 4 (2) ◽  
pp. 151-168 ◽  
Author(s):  
Ralf Hansmann ◽  
Harald A. Mieg ◽  
Helmut W. Crott ◽  
Roland W. Scholz
Keyword(s):  
Environmental Planning ◽  
Group Discussion ◽  
Scientific Models ◽  
Environmental Sciences ◽  
Group Discussions ◽  
Before And After ◽  
Expert Support ◽  
Selection Of

This paper includes three analyses concerning: expert support in the selection of impact variables for scientific models relevant to environmental planning, the quality of students’ individual estimates of corresponding impacts before and after a group discussion, and the accuracy of artificially‐aggregated judgments of independent groups. Participants were students of environmental sciences at ETH Zurich. The first analysis revealed that during participation in an environmental case study, students’ individual estimates of impacts of variables which have been suggested by experts increased, as compared to the estimates of impacts of additional variables, which have been selected by the students. The remaining analyses consider group discussions on the strength of particular environmental impacts. The quality of the estimates was analyzed referring to expert estimates of the impacts.

scholarly journals WILCOXON ANALYSIS TO COMPARE OPEN DISPLACEMENT LEVEL IN INDONESIA BEFORE AND AFTER IMPLEMENTED IN ASEAN ECONOMIC SOCIETY

2018 ◽  
Author(s):  
Indriyani Indriyani ◽  
Nur'Aeni ◽  
Novalia ◽  
Indriyani Mahmuddin Rabuha ◽  
Husna Purnama
Keyword(s):  
Human Resources ◽  
Free Flow ◽  
Skilled Labor ◽  
Job Seekers ◽  
Nominal Data ◽  
Employment Opportunities ◽  
Significant Difference ◽  
Before And After ◽  
Open Displacement

The ASEAN Economic Society (Indonesian: Masyarakat Ekonomi ASEAN (MEA)) is beginning to be implemented by 2015. This means that by 2015 a single market is formed and a production-based entity is supported by a free flow of goods, services, investments, capital and skilled labor. Free flow of skilled labor can be interpreted that all ASEAN citizens can go in and out to find work without any obstacle from the intended country. One of the preparations of the Indonesian government in facing the MEA is to improve the quality of human resources through the Masterplan of Acceleration and Expansion of Indonesian Economic Development (Indonesian: Masterplan Percepatan dan Perluasan Pembangunan Ekonomi Indonesia (MP3EI)) 2011-2025. Application of MEA should be viewed as a positive thing that is opening opportunity for job seekers in Indonesia for career abroad. Given the widespread employment opportunities, the Unemployment Rate (Indonesian: Tingkat Pengangguran Terbuka (TPT)) in Indonesia is declining.Wilcoxon analysis is a non parametric statistical analysis used to compare two nominal data groups correlated. In this study, wilcoxon analysis was used to compare TPT in Indonesia before and after the MEA was applied. TPT data used is TPT data before applied by MEA and TPT data after applied by MEA. The results showed that there was no significant difference between mean TPT in Indonesia before MEA was applied with average TPT in Indonesia after MEA was applied.

scholarly journals Iatrogenic Injuries During Puncture Procedures Applied To Breast

2021 ◽  
Vol 11 (1) ◽  
pp. 14-17
Author(s):  
Tamara Pavlova ◽  
Aleksandr Vasilyev
Keyword(s):  
Invasive Procedure ◽  
Diagnostic Procedures ◽  
Healthcare Facilities ◽  
Iatrogenic Injuries ◽  
Before And After ◽  
Malignant Breast ◽  
Quality Of Medical Care ◽  
Selection Of

Background: This article analyzes iatrogenic injuries of the breast that happen during puncture procedures. Methods and Results: We have analyzed the data of 2075 invasive diagnostic procedures related to both benign and malignant breast neoplasms, conducted in various healthcare facilities in the Russian Federation. A subcutaneous hematoma is the primary iatrogenic injury that occurs during breast puncture procedures conducted in Russian healthcare facilities. This is the most common complication during an ultrasound-guided CB (44.4%). The likelihood that this complication will occur is impossible to predict. Conclusion: The proper arrangements and patient follow-up before and after the biopsy, along with the selection of a proper invasive procedure for a pathologic neoplasm, will minimize the number of diagnostic iatrogenic injuries and improve the quality of medical care.

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