scholarly journals Schmidt Telescopes as Discovery Instruments

1984 ◽  
Vol 78 ◽  
pp. 3-11
Author(s):  
L. Woltjer
Keyword(s):  
Image Quality ◽  
Wavelength Range ◽  
Large Field ◽  
Good Image Quality ◽  
Good Image ◽  
Basic Need

In 1930 B. Schmidt invented the telescope that bears his name. Eleven years later, there were already two dozen Schmidt telescopes with primaries of 25 cm or more in diameter (Dimitroff and Baker 1945). An invention spreading so rapidly must have fulfilled a basic need – the need for a large field with good image quality over a substantial wavelength range. Here I shall briefly review the role of the large Schmidt telescopes in contemporary astronomy.

scholarly journals Feasibility and Quality Determinants of 3D Sonography in Children With Hydronephrosis

2017 ◽  
Vol 34 (1) ◽  
pp. 31-36
Author(s):  
Hansel J. Otero ◽  
Juan J. Cerrolaza ◽  
Judyta Loomis ◽  
Amanda George ◽  
Elijah Biggs ◽  
...  
Keyword(s):  
Image Quality ◽  
Pediatric Patients ◽  
Motion Artifact ◽  
Infants And Toddlers ◽  
Average Quality ◽  
Good Image Quality ◽  
Kidney Size ◽  
Good Image ◽  
3D Sonography

The objective was to determine the image quality of 3D diagnostic medical sonography (DMS) in children with hydronephrosis. 3D DMS was assessed based on 24 pediatric patients. Image quality was evaluated by two radiologists and a sonographer in terms of rib shadowing, cut-off parenchymal edges, motion artifact, and overall quality. The interreader reliability and relation between image quality and other variables were calculated. The results were based on images of 32 hydronephrotic kidneys. The average quality scoring of the images was quite high. Rib shadowing, cut-off edges, and motion artifact were present in the majority of the cases. The interreader reliability for overall quality, rib shadowing, cut-off, and motion was quite high. There was a correlation between the Society for Fetal and Neonatal Urology’s hydronephrosis grade and higher cut-off edges. Larger kidneys were more likely to show cut-off, motion, and lower quality scores. In this cohort of infants and toddlers with hydronephrotic kidneys, 3D DMS demonstrated good image quality; however, artifacts were attributed to kidney size and severity of hydronephrosis.

Small Bodies of the Solar System

1984 ◽  
Vol 78 ◽  
pp. 229-232
Author(s):  
Charles T. Kowal
Keyword(s):  
Image Quality ◽  
Solar System ◽  
Surface Brightness ◽  
Current Work ◽  
Good Image Quality ◽  
Small Bodies ◽  
Good Image ◽  
Entire Field ◽  
Low Surface Brightness ◽  
Solar System Objects

Schmidt telescopes are ideal for many types of survey work, and this includes surveying the solar system. Schmidt cameras have the advantages of speed and wide fields for rapid coverage of large areas of the sky, and good image quality over the entire field. The small focal ratios also have the effect of enhancing low surface-brightness features. This is an advantage for studying cornetary tails and comae.Current work in the field of small solar system objects can be divided into three different areas: searching for new objects, recovering lost objects, and astrornetry of known objects. Each of these areas requires its own techniques.

scholarly journals Image Quality Analysis of PNG Images on WhatsApp Messenger Sending

Telematika ◽  
2012 ◽  
Vol 14 (1) ◽  
pp. 1-12
Author(s):  
Fahmi Anwar ◽  
Keyword(s):  
Image Quality ◽  
Quality Analysis ◽  
Good Image Quality ◽  
Image Quality Analysis ◽  
Test Driven Development ◽  
Good Image ◽  
Alpha Channel ◽  
End To End ◽  
Types Of Information ◽  
Gallery Image

Technology is growing rapidly, especially in communication with various types of information services such as internet-based messages. One of the most popular internet-based messages in Indonesia is WhatsApp Messenger. WhatsApp is a chat application that can be used on many platforms. Message sending on WhatsApp is carried out end-to-end encryption from the sender to the message recipient. The sending of messages in PNG images is secured using end-to-end encryption and compressed according to predefined rules. This study analyzes Image Compression and Alpha channel in PNG by comparing PNG images before being sent with PNG images that have gone through the sending process on WhatsApp using the test-driven development (TDD) method. The analysis results contain comparisons based on the RMSE, SSIM, PSNR, and MD5 hash values. Delivery with a gallery image attachment type using an image transparent background changes to a white image background. While those with a background other than transparent have good image quality because it has a PSNR value of more than 35 dB, and submissions with document attachment types do not experience changes in MD5 hash value and image quality.

scholarly journals The Canada-France-Hawaii Telescope

1982 ◽  
Vol 67 ◽  
pp. 21-32
Author(s):  
Pierre Y. Bely ◽  
Gérard Lelièvre
Keyword(s):  
High Resolution ◽  
Image Quality ◽  
Focal Plane ◽  
Good Image Quality ◽  
Good Image ◽  
Technical Details

AbstractVisiting astronomers have now used the CFH telescope for 18 months in the prime focus and coudé configurations. Many observers have reported very good image quality and high resolution plates have already been obtained. The general concepts and technical details of the telescope and observatory are discussed. The focal plane instrumentation includes more than 25 instruments and detectors, and these are also discussed.

scholarly journals Is hypnosis a valid alternative to spontaneous breathing general anesthesia for claustrophobic patients undergoing MR exams? A preliminary retrospective study

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Stefania Rizzo ◽  
Nicole Ferrera ◽  
Emanuele Pravatà ◽  
Roman Guggenberger ◽  
Steven Stern ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Image Quality ◽  
General Anesthesia ◽  
Spontaneous Breathing ◽  
Descriptive Statistics ◽  
Control Group ◽  
Good Image Quality ◽  
Good Image ◽  
Significant Difference

Abstract Background The purpose of our retrospective study was to assess the termination rate and the image quality of MR exams performed in claustrophobic patients under medical hypnosis, as compared to patients undergoing MR under spontaneous breathing general anesthesia. Methods Our study was approved by the ethics committee. The “hypnosis group” included consecutive patients that had previously interrupted an MR exam because of claustrophobia. The “control group” included patients undergoing MR under pharmacologic sedation. Two experienced radiologists assessed, randomly, independently and blinded the image quality of the two groups using a symmetrical Likert scale: 0 = non-diagnostic images; 1 = bad image quality; 2 = fair image quality; 3 = good image quality; 4 = very good image quality. Descriptive statistics was performed. Results Eighty patients were included, equally distributed between the two groups. Every patient was able to complete the MR exam. Ratings 3 and 4 represented the majority of ratings. Both readers rated the MR exams with score 3 or 4 in 66.25% (53/80) of MR exams. Only 5% (4/80) of MR exams were rated below score 2. The majority of the MR exams showed good or very good image quality. No significant difference was found in image quality between the two (p = 0.06) groups. The agreement between the two readers according to the k score was 0.105. Conclusions Medical hypnosis is a valid alternative to spontaneous breathing general anesthesia in patients unable to undergo MR due to claustrophobia, allowing good quality images.

scholarly journals Multiple Angle of Bisector Rinn Holder for Oral X-Ray

2018 ◽  
Vol 7 (4.26) ◽  
pp. 215
Author(s):  
Nik Amirul Khalid Bin Nik Dziauddin ◽  
Nor Fazli Adull Manan ◽  
Mohd Yusmialdil Putera Mohd Yusof ◽  
Jamaluddin Mahmud ◽  
Shahrul Azam Abdullah
Keyword(s):  
Image Quality ◽  
Design Stage ◽  
Radiographic Image ◽  
Good Image Quality ◽  
Good Image ◽  
X Ray

Multiple angle of bisector rinn holder is a film holder instrument that is yet to be developed that is able to use paralleling technique and bisecting angle technique in oral x-ray radiography. It is a device aimed to be able to use multiple techniques in oral radiography while getting a good image quality that helps the dentist in doing their work. This is a project that involves the development of the instruments and the effectiveness of the instruments compared to the existing one. The result of the radiographic image was compared and certain constraint was used to compare the instruments with the existing instruments. This project used CATIA V5 software for the design stage. In this project, the instrument was tested to validate the effectiveness where the testing was conducted at the faculty of dentistry. The outcome was the effectiveness of the instrument as compared to the existing instrument with other certain constraints.  

scholarly journals Combined Fully Contactless Finger and Hand Vein Capturing Device with a Corresponding Dataset

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5014 ◽  
Author(s):  
Christof Kauba ◽  
Bernhard Prommegger ◽  
Andreas Uhl
Keyword(s):  
Image Quality ◽  
Light Transmission ◽  
Recognition Performance ◽  
Recognition Rate ◽  
Vascular Pattern ◽  
Device Design ◽  
Good Image Quality ◽  
Good Image ◽  
Hand Vein ◽  
Vein Recognition

Vascular pattern based biometric recognition is gaining more and more attention, with a trend towards contactless acquisition. An important requirement for conducting research in vascular pattern recognition are available datasets. These datasets can be established using a suitable biometric capturing device. A sophisticated capturing device design is important for good image quality and, furthermore, at a decent recognition rate. We propose a novel contactless capturing device design, including technical details of its individual parts. Our capturing device is suitable for finger and hand vein image acquisition and is able to acquire palmar finger vein images using light transmission as well as palmar hand vein images using reflected light. An experimental evaluation using several well-established vein recognition schemes on a dataset acquired with the proposed capturing device confirms its good image quality and competitive recognition performance. This challenging dataset, which is one of the first publicly available contactless finger and hand vein datasets, is published as well.

scholarly journals The formation, structure and changes in filaments in active regions

1968 ◽  
Vol 35 ◽  
pp. 267-279 ◽  
Author(s):  
Sara F. Smith
Keyword(s):  
Fine Structure ◽  
Image Quality ◽  
Large Scale ◽  
Active Regions ◽  
Solar Observatory ◽  
Granular Structure ◽  
Solar Granulation ◽  
Good Image Quality ◽  
Good Image

During periods of good image quality the large-scale films of the Lockheed Solar Observatory obtained during 1966 and 1967 have proven to be especially useful for studying filaments and their relationship to the Hα fine structure observed in active regions. Structures with dimensions on the order of 1 sec of arc can frequently be resolved, as illustrated in Figure 1. The ‘solar vortices’ are clearly resolved into numerous individual fibrils. Bright Hα plage is resolved into a fine granular structure resembling the solar granulation. Filaments are usually seen as irregular dense collections of material which are occasionally resolved into finer striations which run parallel to the path of the filaments.

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