I have recently been playing with Hadoop and MapReduce-based algorithms. I created a simple MapReduced-based tool called huedistribution that is useful to me. huedistribution is actually a simple mapreduce-based algorithm to calculate distribution of Hue (color axis) values provided in a large data file. This data file is composed of lines which correspond to data obtained from segments of a range of images. I collect the data using another tool I developed called idext, Image Data Extraction Tool. huedistribution is designed to be run on Hadoop. You can check the source code here.