Sunday, August 29, 2010

Color Calibration of Satellite Cameras


For those of you who do not know me, my name is Paul Matheson. I work with Nathan and Giordano at HP Labs. My background is in commercial print and I consider myself to be a printer. Hopefully I will be able to add something of value to this hallowed blog - if not, I am sure Nathan and Giordano will make me pay for several rounds at the Nuthouse so at least they'll get something of value out of me.
Several days ago I stumbled across this article explaining how satellite cameras are calibrated. It reminded me of Nathan's post about a revolutionary white reflectance standard for metrology - curiously enough, the post was entitled "Revolutionary White Reflectance Standard for Metrology." The original blog post is gone but I was able to find a couple of links to the blog, one of which included some of the text.
Unlike Nathan's post, Lake Tuz really is used for calibration. I knew that many satellites have cameras, but it never occurred to me that they would need calibrating or that image sensors in orbit degrade significantly. The thing that I enjoy most about this article is the fact that some smart person(s) figured out how to use unique geographic features as reflectance standards.
Science is cool.

Image of Lake Tuz from the Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth."