textbook (PDF of final draft is online) to use Python to do image analysis (including SIFT)
http://programmingcomputervision.com/

ASIFT
http://www.cmap.polytechnique.fr/~yu/research/ASIFT/demo.html



with python - opencv
http://docs.opencv.org/trunk/doc/py_tutorials/py_imgproc/py_contours/py_contours_begin/py_contours_begin.html
http://opencv-python-tutroals.readthedocs.org/en/latest/py_tutorials/py_imgproc/py_contours/py_contour_features/py_contour_features.html