Thursday, March 6, 2008

“Bump maps” vs “Shape from Shading”


There’s a small German company called OBE that’s been getting a lot of press regarding their “Shape from Shading” technology for detecting subtle changes in surface topology. I took a look at their web site and I have to say that it seems quite impressive.

But then the old grey matter begins to churn and I think to myself, “Haven’t I see this before somewhere?” So I did a little digging. Back in the last century I heard about a couple of very smart guys in the UK who were working on a technique they called a “bump map”. They chose this name because their technique was very useful for detecting subtle changes in surface topology. This
link will take you to an application description. (You’ll need to read the whole article to get an overview of their approach.)

As far as I can tell, both groups acquire multiple images of the same scene, with the incident light coming from a different direction in each image. Then they process the images to derive height information from the changes in shadows caused by the directionality of the light.

I can only think that this must be a great idea if it keeps popping up.

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