Evaluating Stars Temperature Through the B-V Index Using a Virtual Real Experiment…
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Color Theory for Painting Video: Color Perception
Color Theory For Painting Video: Color Perception • http://www.ted.com/talks/lang/eng/beau_lotto_optical_illusions_show_how_we_see.html • Experiment • http://www.youtube.com/watch?v=y8U0YPHxiFQ Intro to color theory • http://www.youtube.com/watch?v=059-0wrJpAU&feature=relmfu Color Theory Principles • The Color Wheel • Color context • Color Schemes • Color Applications and Effects The Color Wheel The Color Wheel • A circular diagram displaying the spectrum of visible colors. The Color Wheel: Primary Colors • Primary Colors: Red, yellow and blue • In traditional color theory, primary colors can not be mixed or formed by any combination of other colors. • All other colors are derived from these 3 hues. The Color Wheel: Secondary Colors • Secondary Colors: Green, orange and purple • These are the colors formed by mixing the primary colors. The Color Wheel: Tertiary Colors • Tertiary Colors: Yellow- orange, red-orange, red-purple, blue-purple, blue-green & yellow-green • • These are the colors formed by mixing a primary and a secondary color. • Often have a two-word name, such as blue-green, red-violet, and yellow-orange. Color Context • How color behaves in relation to other colors and shapes is a complex area of color theory. Compare the contrast effects of different color backgrounds for the same red square. Color Context • Does your impression od the center square change based on the surround? Color Context Additive colors • Additive: Mixing colored Light Subtractive Colors • Subtractive Colors: Mixing colored pigments Color Schemes Color Schemes • Formulas for creating visual unity [often called color harmony] using colors on the color wheel Basic Schemes • Analogous • Complementary • Triadic • Split complement Analogous Color formula used to create color harmony through the selection of three related colors which are next to one another on the color wheel. -
Module 09 Colour Index TABLE of CONTENTS 1. Learning Outcomes
Module 09 Colour Index TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction 3. Dependence of magnitudes on wavelength 3.1. UBV System of Johnson and Morgan 3.2. Colour Index 3.3. Colour-Colour Diagrams 3.4. Colour Excess 3.5. Reddening and Redshift 4. Summary 1. Learning Outcomes After studying this module, you should be able to Appreciate that the magnitude depends on the wavelength at which it is measured Understand the need of UBV photometric system Realize that the UBV system at present measures magnitudes at various wavelength bands other than the visual region Understand why magnitudes of stars at various wavelength bands of their spectra are not equal Grasp the concept of colour index Understand that the colour index follows the surface temperature of the star Realize the importance of colour-colour diagrams in describing stars 2. Introduction In the last module we introduced the concept of magnitudes. Apparent magnitude is a number assigned to a star (or any other celestial object) to indicate its brightness. Brighter stars are assigned lower magnitudes and fainter stars are characterized by higher magnitudes. Only stars brighter than 6th magnitude are visible to the unaided eye. Since brightness is a function of distance and the intrinsic brightness of a star, apparent magnitude does not allow us to compare stars with respect to their intrinsic brightness. Therefore, to compare brightness all stars are thought to be at a standard distance of 10 pc. The apparent magnitude at this distance is called the absolute magnitude of the star. It turns out that the difference between the absolute magnitudes of two stars is proportional to the ratio of their luminosities. -
Digital Refocusing with Incoherent Holography
Digital Refocusing with Incoherent Holography Oliver Cossairt Nathan Matsuda Northwestern University Northwestern University Evanston, IL Evanston, IL [email protected] [email protected] Mohit Gupta Columbia University New York, NY [email protected] Abstract ‘adding’ and ‘subtracting’ blur to the point spread functions (PSF) of different scene points, depending on their depth. In Light field cameras allow us to digitally refocus a pho- a conventional 2D image, while it is possible to add blur to tograph after the time of capture. However, recording a a scene point’s PSF, it is not possible to subtract or remove light field requires either a significant loss in spatial res- blur without introducing artifacts in the image. This is be- olution [10, 20, 9] or a large number of images to be cap- cause 2D imaging is an inherently lossy process; the angular tured [11]. In this paper, we propose incoherent hologra- information in the 4D light field is lost in a 2D image. Thus, phy for digital refocusing without loss of spatial resolution typically, if digital refocusing is desired, 4D light fields are from only 3 captured images. The main idea is to cap- captured. Unfortunately, light field cameras sacrifice spa- ture 2D coherent holograms of the scene instead of the 4D tial resolution in order to capture the angular information. light fields. The key properties of coherent light propagation The loss in resolution can be significant, up to 1-2 orders are that the coherent spread function (hologram of a single of magnitude. While there have been attempts to improve point source) encodes scene depths and has a broadband resolution by using compressive sensing techniques [14], spatial frequency response. -
Thanks for Downloading the Sample Chapters
Thanks for Downloading the Sample Chapters Here are the chapters included. The Quick Start chapter, the first in the book, which identifies five quick ways to up the video and audio quality of your webinars and videoconferences. Chapter 5: Simple Lighting Techniques. The easiest way to significantly improve the quality of video produced by webcams and smartphones is to add lighting. You don’t have to spend a fortune; in fact, my go-to setup cost $30. You can read about this and more in this chapter. Chapter 9: Working With Audio on Android Devices. How to add and control a microphone on Android devices. Chapter 14: Working with Onstream Webinars. Audio and video adjustment controls available in Onstream Webinars. After the chapters, I’ve inserted the introduction to the book, and then the table of contents, so you can see what else is covered in the book. Thanks for having a look. Quick Start: Do This, Don’t Do That Figure a. Check your upload speed well in advance; don’t just pray for the best. This chapter contains highlights from various chapters in the book, both as a quick-start reference and as an introduction to the materials covered in the book. As you can see in Figure a, it’s better to check your outbound bandwidth with a tool called Speedtest than to simply pray that your bandwidth is sufficient. Chapter 1 has tables detailing the recommended bitrate for various conferencing and webinar applications, and other, related tips. Note that Speedtest is available as an app for both iOS and Android platforms, so you can check there as well. -
Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
A Study of Two Open Clusters Containing Wolf-Rayet Stars
A STUDY OF TWO OPEN CLUSTERS CONTAINING WOLF-RAYET STARS by Stephen L. Shorlin A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF ASTRONOlMY AND PHYSICS SAINT MARY'S UMNERSITY MAY 1998 HALIFAX, NOVA SCOTIA Ostephen L. Shorlin, 1998 National Library Bibliothèque nationale I*m of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. nie Wellington Ottawa ON K1A ON4 Ottawa ON KIA ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loau, distribute or seU reproduire, prêter, distribuer ou copies of this thesis in microfoq vendre des copies de cette thèse sous paper or electronic formats. la fome de microfiche/nIm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimes reproduced *out the author's ou autrement reproduits sans son permission. autorisation- Abstract The results of UBV CCD photornetry are presented for a newly discovered open cluster, as well as new photornetry for thirty-seven members of the open cluster HM 1. The new open cluster, to be designated OCL 1104610, has a distance modulus of Vo - l'LIV = 15.5 & 0.2: corresponding to a distance of 12.61::: kpc, and is several Myr old. -
Publications of the Astronomical Society of the Pacific 107: 945-958, 1995 October
Publications of the Astronomical Society of the Pacific 107: 945-958, 1995 October Galaxy Colors in Various Photometric Band Systems M. Fukugita1 Institute for Advanced Study, Princeton, New Jersey 08540 Electronic mail: [email protected] K. Shimasaku2 Princeton University Observatory, Princeton, New Jersey 08544 Electronic mail: [email protected] T. ICHIKAWA Kiso Observatory, University of Tokyo, Kiso-gun, Nagano 397-01, Japan Electronic mail: [email protected] Received 1995 March 10; accepted 1995 June 14 ABSTRACT. A study is made of stellar and galaxy colors using a spectrophotometric synthesis technique. We show that use of good color response functions and a modem determination of the spectroscopic energy distribution for a Lyr gives synthetic stellar colors in a good agreement with photometric observations to about 0.05 mag. The synthetic method then is applied to study galaxy colors using the spectrophotometric atlas of Kennicutt (1992, ApJS, 79, 255), and a comparison is made with observed galaxy colors. The Κ correction is calculated and compared with that of Coleman, Wu, and Weedman (1980, ApJS, 43, 393). We then study colors of galaxies in various photometric band systems and obtain color transformation laws, which enable us to find offsets among different systems. We include 48 photometric bands in our study. 1. INTRODUCTION in addition to a good sample of galaxy SED over a wide range of wavelength. Continual efforts to obtain the SED of Colors of galaxies provide us with valuable information Vega (Oke and Schild 1970; Hayes and Latham 1975; Oke concerning their present-day composition of stars, and ac- and Gunn 1983; Kurucz 1979; Hayes 1985, hereafter re- cordingly it gives us hints about the formation and evolution ferred to as H85; Castelli and Kurucz 1994, hereafter re- of galaxies. -
White Paper the Twilight Zone
White paper The twilight zone …a journey through the magic realm of color spaces, gray shades, color temperatures, just noticeable differences and more Goran Stojmenovik Product Manager Barco Control Rooms division The whole story behind display specifications and human vision (2) Abstract Our world and the displays representing it are not black and white, as someone might think when seeing a display spec consisting only of luminance and contrast. There is much more, there is a whole world of gray shades, color spaces, color temperatures, contrast sensitivities, just noticeable differences. Knowing what “brightness” and “luminance” are and being able to distinguish them, knowing what influences on-screen contrast of a display, and knowing how the eye adapts to changes in luminance levels – these are factors you should have learned from the first part of this white paper. Here, we will go into deeper waters of human vision, to explain when we perceive a display as a good display, and what are the requirements posed by the human visual system to create a good display. Page 1 of 9 www.barco.com White paper The twilight zone Display requirements and human vision Gamma When we talk about brightness and contrast, we cannot THE GAMMA DETERMINES THE skip the famous “gamma.” For one specified contrast, BRIGHTNESS OF THE MID-GRAY we know it’s the brightest white and darkest black that SHADES matter. But, what about all the in-between? This is the region of the gray shades. They are produced by tilting the liquid crystal molecules with a voltage (in LCD displays), or by modulating the amount of time a certain DMD mirror is on during one frame (in DLP projection displays). -
Kelvin Color Temperature
KELVIN COLOR TEMPERATURE William Thompson Kelvin was a 19th century physicist and mathematician who invented a temperature scale that had absolute zero as its low endpoint. In physics, absolute zero is a very cold temperature, the coldest possible, at which no heat exists and kinetic energy (movement) ceases. On the Celsius scale absolute zero is -273 degrees, and on the Fahrenheit scale it is -459 degrees. The Kelvin temperature scale is often used for scientific measurements. Kelvins, as the degrees are now called, are derived from the actual temperature of a black body radiator, which means a black material heated to that temperature. An incandescent filament is very dark, and approaches being a black body radiator, so the actual temperature of an incandescent filament is somewhat close to its color temperature in Kelvins. The color temperature of a lamp is very important in the television industry where the camera must be calibrated for white balance. This is often done by focusing the camera on a white card in the available lighting and tweaking it so that the card reads as true white. All other colors will automatically adjust so that they read properly. This is especially important to reproduce “normal” looking skin tones. In theatre applications, where it is only important for colors to read properly to the human eye, the exact color temperature of lamps is not so important. Incandescent lamps tend to have a color temperature around 3200 K, but this is true only if they are operating with full voltage. Remember that dimmers work by varying the voltage pressure supplied to the lamp. -
Calculating Correlated Color Temperatures Across the Entire Gamut of Daylight and Skylight Chromaticities
Calculating correlated color temperatures across the entire gamut of daylight and skylight chromaticities Javier Herna´ ndez-Andre´ s, Raymond L. Lee, Jr., and Javier Romero Natural outdoor illumination daily undergoes large changes in its correlated color temperature ͑CCT͒, yet existing equations for calculating CCT from chromaticity coordinates span only part of this range. To improve both the gamut and accuracy of these CCT calculations, we use chromaticities calculated from our measurements of nearly 7000 daylight and skylight spectra to test an equation that accurately maps CIE 1931 chromaticities x and y into CCT. We extend the work of McCamy ͓Color Res. Appl. 12, 285–287 ͑1992͔͒ by using a chromaticity epicenter for CCT and the inverse slope of the line that connects it to x and y. With two epicenters for different CCT ranges, our simple equation is accurate across wide chromaticity and CCT ranges ͑3000–106 K͒ spanned by daylight and skylight. © 1999 Optical Society of America OCIS codes: 010.1290, 330.1710, 330.1730. 1. Introduction term correlated color temperature ͑CCT͒ instead of A colorimetric landmark often included in the Com- color temperature to describe its appearance. Sup- mission Internationale de l’Eclairage ͑CIE͒ 1931 pose that x1, y1 is the chromaticity of such an off-locus chromaticity diagram is the locus of chromaticity co- light source. By definition, the CCT of x1, y1 is the ordinates defined by blackbody radiators ͑see Fig. 1, temperature of the Planckian radiator whose chro- inset͒. One can calculate this Planckian ͑or black- maticity is nearest to x1, y1. The colorimetric body͒ locus by colorimetrically integrating the Planck minimum-distance calculations that determine CCT function at many different temperatures, with each must be done within the color space of the CIE 1960 temperature specifying a unique pair of 1931 x, y uniformity chromaticity scale ͑UCS͒ diagram. -
Calculating Color Temperature and Illuminance Using the TAOS TCS3414CS Digital Color Sensor Contributed by Joe Smith February 27, 2009 Rev C
TAOS Inc. is now ams AG The technical content of this TAOS document is still valid. Contact information: Headquarters: ams AG Tobelbader Strasse 30 8141 Premstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: [email protected] Please visit our website at www.ams.com NUMBER 25 INTELLIGENT OPTO SENSOR DESIGNER’S NOTEBOOK Calculating Color Temperature and Illuminance using the TAOS TCS3414CS Digital Color Sensor contributed by Joe Smith February 27, 2009 Rev C ABSTRACT The Color Temperature and Illuminance of a broad band light source can be determined with the TAOS TCS3414CS red, green and blue digital color sensor with IR blocking filter built in to the package. This paper will examine Color Temperature and discuss how to calculate the Color Temperature and Illuminance of a given light source. Color Temperature information could be useful in feedback control and quality control systems. COLOR TEMPERATURE Color temperature has long been used as a metric to characterize broad band light sources. It is a means to characterize the spectral properties of a near-white light source. Color temperature, measured in degrees Kelvin (K), refers to the temperature to which one would have to heat a blackbody (or planckian) radiator to produce light of a particular color. A blackbody radiator is defined as a theoretical object that is a perfect radiator of visible light. As the blackbody radiator is heated it radiates energy first in the infrared spectrum and then in the visible spectrum as red, orange, white and finally bluish white light. Incandescent lights are good models of blackbody radiators, because most of the light emitted from them is due to the heating of their filaments. -
Color Temperature and at 5,600 Degrees Kelvin It Will Begin to Appear Blue
4,800 degrees it will glow a greenish color Color Temperature and at 5,600 degrees Kelvin it will begin to appear blue. But light itself has no heat; Color temperature is usually used so for photography it is just a measure- to mean white balance, white point or a ment of the hue of a specific type of light means of describing the color of white source. light. This is a very difficult concept to ex- plain, because–”Isn’t white always white?” The human brain is incred- ibly adept at quickly correcting for changes in the color temperature of light; many different kinds of light all seem “white” to us. When moving from a bright daylight environment to a room lit by a candle all that will appear to change, to the naked eye, is the light level. Yet record these two situations shooting color film, digital photographs or with tape in an unbalanced camcorder and the outside images will have a blueish hue and the inside images will have a heavy orange cast. The brain quickly adjust to the changes, mak- ing what is perceived as white ap- pear white, whereas film, digital im- ages and camcorders are balanced for one particular color and anything that deviates from this will produce a color cast. A GUIDE TO COLOR TEMPERATURE The color of light is measured by the Kelvin scale . This is a sci- entific temperature scale used to measure the exact temperature of objects. If you heat a carbon rod to 3,200 degrees, it glows orange.