Units of illuminance

Troland

The troland (symbol Td), named after Leonard T. Troland, is a unit of conventional retinal illuminance. It is meant as a method for correcting photometric measurements of luminance values impinging on the human eye by scaling them by the effective pupil size. It is equal to retinal illuminance produced by a surface whose luminance is one nit when the apparent area of the entrance pupil of the eye is 1 square millimeter. The troland unit was proposed in 1916 by Leonard T. Troland, who called it a photon. The troland typically refers to the ordinary or photopic troland, which is defined in terms of the photopic luminance: , where L is the photopic luminance in cd m−2 and p is pupil area in mm2. A scotopic troland is also sometimes defined: , where L′ is the scotopic luminance in cd m−2 and p is pupil area in mm2. Although named "retinal illuminance" (and originally named "photon" by Troland), trolands do not measure the actual photon flux incident on the retina; that quantity depends on the specific wavelengths of light that constitute the luminance used in the calculation. (Wikipedia).

Video thumbnail

We Love Opera! What is a trouser role in an opera?

A quick definition of "trouser role" in an opera Sometimes this is also called a "pants role" or a "breeches role." Want to go to the opera, but you're not sure you'll understand what's going on? "We Love Opera" is a video series from Socratica that will help you understand what opera i

From playlist Opera Glossary

Video thumbnail

Art is for everyone! What is TROMPE L'OEIL?

A quick definition of "trompe l'oeil." Art Lover: Louise McCartney Director: Michael Harrison Written and Produced by Kimberly Hatch Harrison ♦♦♦♦♦♦♦♦♦♦ Ways to support our channel: ► Join our Patreon : https://www.patreon.com/socratica ► Make a one-time PayPal donation: https://www.p

From playlist Art glossary

Video thumbnail

Japan tron dance

epic dancers tron like suits. it is a must see video

From playlist Amazing Stuff

Video thumbnail

Radium - Periodic Table of Videos

Radium is a famous element - but also very dangerous. More links in description below ↓↓↓ Support Periodic Videos on Patreon: https://www.patreon.com/periodicvideos A video on every element: http://bit.ly/118elements More at http://www.periodicvideos.com/ Follow us on Facebook at http:/

From playlist With Portuguese subtitles (Português) - Periodic Videos

Video thumbnail

Radian Illustrator (GeoGebra)

What is a radian? 🤔 Interactive dynamic radius wrapping exploration for Ss: https://www.geogebra.org/m/e3aamere #GeoGebra #MTBoS #ITeachMath #algebra #geometry #trigonometry #mathchat

From playlist Trigonometry: Dynamic Interactives!

Video thumbnail

The electrophysiology of human memory

Dr. Michael Kahana discusses his work aiming to identify the neural signals that underlie memory variability. Human memory function is highly variable, fluctuating between periods of high and low performance even within a given person. Neurosurgical patients with indwelling electrodes pre

From playlist Wu Tsai Neurosciences Institute

Video thumbnail

What Kind of Computation Is Cognition?

Recent successes in artificial intelligence have been largely driven by neural networks and other sophisticated machine learning tools for pattern recognition and function approximation. But human intelligence is much more than finding patterns or approximating functions. And no machine sy

From playlist Whitney Humanities Center

Related pages

Square metre | Candela | Nit (unit)