How might you do this image analysis?

In the search for the Malaysian airliner that disappeared, there's a satellite imaging company that's heading a crowdsourcing effort to find it by putting their "live" satellite imagery online for the public to pore over:

https://browse.digitalglobe.com/ima...41001024AC00&imageHeight=1024&imageWidth=1024


My idea is to program something that looks at a picture and strips any/all pixels of a color that comprises more than 10% of the picture, stripping each picture of cloud and ocean data, then looking at what remains.

If you were to try doing something like this, how would you approach it? What language(s) and/or libraries might you use?

matlab + imagine processing package

Thanks both.