The Importance of Gamma Correction in the Acquisition, Display and Hardcoy of Digital Images

1997 ◽  
Vol 3 (S2) ◽  
pp. 343-344
Author(s):  
John M. Mackenzie
Keyword(s):  
Digital Imaging ◽  
Digital Images ◽  
Gamma Correction ◽  
Critical Problem ◽  
Linear Portion ◽  
Gamma Functions ◽  
Recorded Image ◽  
Log Linear ◽  
Logarithmic Functions

Digital imaging is replacing conventional photography in many applications. As the quality of digital images improves, more applications for this technology will be found. This talk will examine the importance of gamma correction in digital imaging.Although many researchers believe that digital imaging will soon replace photography, it is probably more correct to think of digital imaging as an enhancement to photography. The most critical problem with translating our knowledge of photography to digital imaging is that photography operates exclusively via logarithmic functions. The exposure versus density curves common to photography have an x axis that is logarithmic. The development curves for film and paper are also logarithmic. The slope of the log-linear portion of this curve is designated gamma. All operations normally performed in the darkroom whether processing film or prints manipulate the gamma functions to achieve the best recorded image. The first rule that should be obvious is that every image has a different optimal gamma and every different image medium (whether graded photographic paper or the density of print on a digital image printer) will change that optimal gamma.

Digital Imaging for Photographic Collections: Foundations for Technical Standard

2000 ◽  
Vol 29 (1) ◽  
Author(s):  
Robin Dale
Keyword(s):  
Image Quality ◽  
Digital Imaging ◽  
Digital Images ◽  
National Endowment ◽  
Technical Standard ◽  
Digital Form ◽  
Project Report

The goal of this project report, sponsored by The National Endowment for the Humanities, Division of Preservation and Access, is “to offer some guidance to libraries, archives, and museums in their efforts to convert photographic collections to digital form.” To date, there are no standards for measuring the quality of digital images created from photographs. Therefore, this report is primarily concerned with developing tools to measure image quality. Other technical and managerial issues related to digital imaging projects in general are also addressed.

scholarly journals Primena digitalne video tehnike u ortopediji

2006 ◽  
Vol 53 (4) ◽  
pp. 99-104
Author(s):  
C. Vucetic ◽  
D. Milovanovic ◽  
B. Dulic ◽  
I. Dimitrijevic ◽  
N. Kalezic ◽  
...  
Keyword(s):  
Medical Devices ◽  
Digital Imaging ◽  
Digital Images ◽  
Digital Technologies ◽  
Surgical Patient ◽  
Clinical Use ◽  
Digital Imaging Technology ◽  
Case Documentation ◽  
Care Information

Digital video technologies are new and powerful tools with wide applications in orthopedic. Already integral to several common medical devices, digital images can be used for case documentation and presentation as well for diagnostic and surgical patient care information. Digital technologies allow easy manipulation of photographic, video and graphic materials in ways that were impossible with conventional techniques. Educational presentation has been transformed by use of computers and digital projectors. Understanding the basic foundations of digital imaging technology is important for effectively creating digital images, videos and presentations. In this review, we are going to discuss some of the issues that are raised by digital imaging in orthopedics, digital image processing, as well as, we are giving some recommendations for good quality of pre-, post- and intra-operative photographs in clinical use.

scholarly journals Ethics and Digital Imaging

2006 ◽  
Vol 14 (1) ◽  
pp. 40-41 ◽  
Author(s):  
J. M. Mackenzie ◽  
M. G. Burke ◽  
T. Carvalho ◽  
A. Eades
Keyword(s):  
Digital Imaging ◽  
Scientific Community ◽  
Digital Images ◽  
Image Resolution ◽  
Print Advertisements ◽  
The Past ◽  
Time Required ◽  
The Cost ◽  
Publication Quality

The amazing growth of digital imaging in the past several years has blurred the line between "real" images and those that are digitally enhanced. In most of our movies and print advertisements, we see amazing effects that create images that look real but are not.For the last several decades film has been the predominant method that scientists employ to record the images viewed through their microscopes. Film has been readily accepted as a valid, archival recording medium because it was difficult to alter once the exposure was made and the film or print developed. The improvements in computer power and image resolution, coupled with environmental considerations, have spurred the scientific community to replace photographic processes with digital images. Processes that took hours and days are now performed in minutes. Imaging programs like Adobe Photoshop can perform all of the same photographic steps that required a darkroom, and then can do much more. The image can be “burned” onto a CD or DVD disk which is difficult to alter. Printer technology has advanced so rapidly that inkjet prints rival photographic prints. Images are often distributed digitally and viewed on displays that continue to improve. As the hardware for digital imaging improves, the quality of digital images is approaching photographic quality for a fraction of the cost, and publication quality images are produced in a fraction of the time required for film-based photography.

scholarly journals Digital Imaging for TEM - Part III Characterizing Digital Images

1995 ◽  
Vol 3 (1) ◽  
pp. 12-13
Author(s):  
Anthony D. Buonaquisti
Keyword(s):  
Digital Imaging ◽  
Digital Images ◽  
Imaging System ◽  
Hard Copy ◽  
High Quality ◽  
Image Storage ◽  
Output Device ◽  
Recent Interest ◽  
Digital Imaging System

Last months issue of this publication contained the second article article in this series on digital imaging far TEM - and listed factors that may be stimulating the recent interest in digilal imaging for TEM. Most of the factors are concerned with issues of functionality. A digital imaging system can enhance TEM operation, image storage, image processing and communication. Significantly, the surge in interest was not linked to claims that digital images have better detail than images captured using sheet film. This is a pivotal issue for some microscopists. Nevertheless, my experience has been that many rnicroscopists, even skeptical microscopists, are surprised at the quality of output from a modern digital imaging system when using a high quality output device to produce hard copy images.

scholarly journals Exploratory Monitoring of the Quality and Authenticity of Commercial Honey in Ecuador

Foods ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 105 ◽  
Author(s):  
Lorena Salvador ◽  
Michelle Guijarro ◽  
Daniela Rubio ◽  
Bolívar Aucatoma ◽  
Tanya Guillén ◽  
...  
Keyword(s):  
Honey Bees ◽  
Reducing Sugars ◽  
Conductivity Measurement ◽  
Principal Component ◽  
Economic Importance ◽  
Critical Problem ◽  
Spectroscopic Analyses ◽  
Chemical Threats ◽  
Raman And Ir Spectroscopy

Honey is one of the oldest sweetening foods and has economic importance, making this product attractive to adulteration with cheap sugars. This can cause a critical problem in the honey industry and a possible health risk. The present work has the aim of evaluating the authenticity of honey commercialized in two different provinces of Ecuador (Pichincha and Loja) by performing physicochemical and spectroscopic analyses. For this study 25 samples were collected from different places and markets and characterized by water, sucrose, reducing sugars and electric conductivity measurement. Also, their Raman and Infrared (IR) spectra were recorded and analysed using a Principal Component Analysis (PCA) in order to verify the quality of the honeys. In addition, a screening of several pesticides was performed in order to verify possible chemical threats to human health and honey bees. It was found that 8 samples have a deviation from the Standard established parameters. Two of them have a high difference in the content of sucrose and reducing sugars, which are located deviated from all the other samples in the PCA of the applied vibrational spectroscopy (IR/Raman), shaping two clear clusters. The results show that Raman and IR spectroscopy is appropriate techniques for the quality control of honey and correlates well with the physicochemical analyses.

scholarly journals Digital imaging outperforms traditional scoring methods of spittlebug tolerance in Urochloa humidicola hybrids

2020 ◽  
Author(s):  
Luis M. Hernandez ◽  
Paula Espitia ◽  
Valheria Castiblanco ◽  
Juan A Cardoso
Keyword(s):  
Correlation Coefficient ◽  
Digital Imaging ◽  
Digital Images ◽  
Breeding Program ◽  
Alternative Methods ◽  
Screening Methods ◽  
Plant Tolerance ◽  
Scoring Method ◽  
Plant Damage ◽  
Visual Scoring

AbstractAmerican spittlebug complex (Hemiptera: Cercopidae) is a critical pest for existing Urochloa humidicola cultivars in the neotropical savannas. The U. humidicola breeding program of the International Center for Tropical Agriculture aims to increase tolerance to spittlebugs. To develop U. humidicola genotypes with superior tolerance to spittlebugs than existing cultivars, adequate screening methods ought to be deployed. Currently, visual scores of plant damage by spittlebugs is the standard method to screen for variation in plant tolerance. However, visual scoring is prone to human bias, is of medium throughput and relies of the expertise of well-trained personnel. In this study, we compared estimations of plant damage from two alternative methods (SPAD measurements and digital images) and visual scoring from an inexpert evaluator with the plant damage estimated from an expert. This information should instruct if different methods could be implemented in the U. humidicola breeding program. Time needed to evaluate damage was recorded for each method. Lin’s correlation coefficient, Pearson’s correlation coefficient and broad sense heritability values were also calculated. Overall, damage estimated from digital images showed the highest throughput (twice as fast as visual scoring from an expert); high correlations with visual scoring (r > 0.80, p < 0.0001); and heritability values for plant damage as good or better (> 0.7) than those obtained by visual scoring from an expert. Our results indicate that digital imaging is a phenotyping method that might improve the efficiency of breeding for increased tolerance to spittlebugs in U. humidicola.HighlightDigital imaging outperformed standard scoring method of spittlebug tolerance in Urochloa humidicola, suggesting that this method might improve the efficiency of breeding for such stress.

scholarly journals Screening and dotting virtual slides: A new challenge for cytotechnologists

CytoJournal ◽  
2013 ◽  
Vol 10 ◽  
pp. 22 ◽  
Author(s):  
Walid E. Khalbuss ◽  
Jackie Cuda ◽  
Ioan C. Cucoranu
Keyword(s):  
Digital Imaging ◽  
Digital Images ◽  
Imaging Modality ◽  
Virtual Slide ◽  
Current User ◽  
Digital Display ◽  
Whole Slide Imaging ◽  
Image Viewer ◽  
Virtual Slides ◽  
Glass Slides

Digital images are increasingly being used in cytopathology. Whole-slide imaging (WSI) is a digital imaging modality that uses computerized technology to scan and convert entire cytology glass slides into digital images that can be viewed on a digital display using the image viewer software. Digital image acquisition of cytology glass slides has improved significantly over the years due to the use of liquid-based preparations and advances in WSI scanning technology such as automatic multipoint pre-scan focus technology or z-stack scanning technology. Screening cytotechnologists are responsible for every cell that is present on an imaged slide. One of the challenges users have to overcome is to establish a technique to review systematically the entire imaged slide and to dot selected abnormal or significant findings. The scope of this article is to review the current user interface technology available for virtual slide navigation when screening digital slides in cytology. WSI scanner vendors provide tools, built into the image viewer software that allow for a more systematic navigation of the virtual slides, such as auto-panning, keyboard-controlled slide navigation and track map. Annotation tools can improve communication between the screener and the final reviewer or can be used for education. The tracking functionality allows recording of the WSI navigation process and provides a mechanism for confirmation of slide coverage by the screening cytotechnologist as well as a useful tool for quality assurance. As the WSI technology matures, additional features and tools to support navigation of a cytology virtual slide are anticipated.

METHODOLOGY FOR FORMING A DATABASE OF REFERENCE IMAGES OF BONE MARROW CELLS FOR THE AUTOMATED DIAGNOSIS OF ACUTE LEUKEMIA IN ONCOHEMATOLOGY

2021 ◽  
pp. 84-89
Author(s):  
Ольга Александровна Медведева ◽  
Святослав Николаевич Простаков ◽  
Николай Николаевич Тупицын ◽  
Александра Дмитриевна Палладина
Keyword(s):  
Bone Marrow ◽  
Acute Leukemia ◽  
Bone Marrow Cells ◽  
Digital Images ◽  
Automated Image Analysis ◽  
Medical Decision ◽  
Reference Images ◽  
Computer Microscopy ◽  
Marrow Cells

В статье представлено описание факторов, влияющих на качество формирования базы эталонных изображений клеток костного мозга для диагностики острых лейкозов с применением методов компьютерной микроскопии. Отмечена важность контроля качества подготовки препаратов и микроскопа для применения в автоматизированных системах анализа изображений. Рассмотрены особенности регистрации цифровых микроскопических изображений клеток костного мозга в системах компьютерной микроскопии. Исследовано влияние фокусировки оптической системы микроскопа и уровня освещения препарата на формирование цифровых изображений клеток костного мозга. Установлены требования к условиям регистрации цифровых изображений, используемых в автоматизированных системах микроскопического анализа препаратов костного мозга. Предложена концептуальная модель базы эталонных изображений костного мозга, являющаяся основой для разработки инструментов эффективного распознавания клеток костного мозга в системах компьютерной микроскопии. Следование указанным требованиям к регистрации изображений призвано обеспечить надлежащее качество эталонной базы, что имеет непосредственной влияние на повышение точности и достоверности медицинской диагностики с применением методов компьютерной микроскопии. Результаты работы могут быть использованы в системах поддержки принятия врачебных решений при диагностике острых лейкозов The article describes the factors affecting the quality of the formation of a database of reference images of bone marrow cells for the diagnosis of acute leukemia using computer microscopy methods. The importance of quality control of specimen and microscope preparation for use in automated image analysis systems is noted. The features of registration of digital microscopic images of bone marrow cells in computer microscopy systems are considered. The effect of focusing of the optical system of the microscope and the level of illumination of the specimen on the formation of digital images of bone marrow cells is investigated. The requirements for the conditions of registration of digital images used in automated systems of microscopic analysis of bone marrow preparations have been established. A conceptual model of the base of reference images of bone marrow is proposed. It is the basis for the development of tools for effective recognition of bone marrow cells in computer microscopy systems. Following the specified requirements for image registration is designed to ensure the proper quality of the reference base of images, which has a direct impact on improving the accuracy and reliability of medical diagnostics using computer microscopy. The results of the work can be used in medical decision support systems for the diagnosis of acute leukemia

Generative Learning Model to Teach Adult Learners Digital Imagery

2011 ◽  
pp. 357-364
Author(s):  
Maria H.Z. Kish
Keyword(s):  
Adult Learners ◽  
Web Sites ◽  
Digital Imaging ◽  
Digital Images ◽  
Digital Imagery ◽  
Design Concepts ◽  
Software Packages ◽  
Duquesne University ◽  
Adobe Photoshop ◽  
University Course

Adults learning about digital imagery or digital imaging software to create and manipulate images for personal and professional purposes is increasingly popular. Since 2001, the Duquesne University course, Digital Imagery for Teachers, has been taught to adults who teach or present to other adults or children. The course focuses on helping participants create and edit digital images, create and animate illustrations in movies, and implement design concepts for creating Web sites for their own students. The software packages used are Adobe Photoshop, Macromedia Flash, and Macromedia Dreamweaver.

Digital Imaging Exposure-Time Optimisation of Tripod-Camera Vibrating Systems Based on MTF

2008 ◽  
Author(s):  
Giulio Fanti ◽  
Roberto Basso
Keyword(s):  
Image Quality ◽  
Exposure Time ◽  
Digital Image ◽  
Digital Imaging ◽  
Digital Images ◽  
Noise Sources ◽  
Initial Analysis ◽  
Vibrating System ◽  
Time Optimization ◽  
Vibrating Systems

The problem of exposure-time optimization in digital images acquired by a tripod-camera vibrating system is examined in this paper and an initial analysis is presented. The different noise sources concerning both the acquisition sensor in the camera and external vibrations were studied and quantified in some specific cases. The digital image quality is then discussed in terms of the MTF function evaluated at 50% level in order to define what the optimum ranges of exposure-times are.

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