The following topics are also important when deeper study into Classifying objects is considered.
Classifying Objects in Images Using Deep Learning
Mahotas
URL: http://luispedro.org/software/mahotas/
Another package for image processing is Mahotas, including better and more complex image processing techniques that can help achieve better accuracy, although they may come at a high computational cost. However, many image processing tasks are good candidates for parallelization. More techniques on image classification can be found in the research literature, with this survey paper as a good start: http://ijarcce.com/upload/january/22-A%20Survey%20on%20Image%20Classification.pdf.
Other image datasets are available at http://rodrigob.github.io/are_we_there_yet...
