Apache Mahout - Distributed Linear Algebra
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
KNIME - KNIME, the open platform for your data.
GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
WEKA - WEKA is a set of powerful data mining tools that run on Java.
Yandex.Images - search for images on the internet, search by image