Wednesday, April 20, 2011
HDRI
I was exploring on flickr when I came across some interesting photos. I did a little research and found out they were done using a technique called HDRI (high dynamic range imaging) or HDR for short. Basically what you do is take multiple shots of the same image; one with a normal exposure, one underexposed, and one overexposed. Then you bring the images into some editing software (something like photomatix) and put the images on top of each other. The result is a single image that supposedly has a higher dynamic range than the human eye. I think the pictures look a lot like video game images only more realistic. You can do this with digital or film and it can be done with video. The video link is in the title. Here is a link for some HDR still images:
High Dynamic Range photography is very widely used in 3D illumination as a light source! Basically the HDR image "gathers" all the light values of a particular location in a very high range (so lots of detail at both ends) and that data is used to "light" the 3D model. (I can explain more if you are interested)
ReplyDeleteIt has been used to light films like The Matrix sequels, The Curious Case of Benjamin Button, Terminator: Salvation, District 9, and Avatar among others.
HDR technique comes from the research of Paul Devebec known as HDRI and Image-Based Lighting. It is now a standard part in visual effects production.
Programs like Maya, which we use in the 3D class are able to use HDR images for that purpose.