最近傍法による単純な数字認識.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

'''
最近傍法による単純な数字認識のサンプルプログラム
'''

import numpy as np


prototype_1 = np.array([[0., 0., 1., 0., 0.],
                        [0., 0., 1., 0., 0.],
                        [0., 0., 1., 0., 0.],
                        [0., 0., 1., 0., 0.],
                        [0., 0., 1., 0., 0.]])

prototype_9 = np.array([[0., 1., 1., 1., 0.],
                        [1., 0., 0., 0., 1.],
                        [0., 1., 1., 1., 1.],
                        [0., 0., 0., 1., 0.],
                        [0., 0., 1., 0., 0.]])


def recognize(weight, pattern):
    # retrieve nearness
    return np.vdot(weight, pattern) - 0.5 * np.vdot(weight, weight)


def run():
    input_pattern = np.array([[0., 1., 1., 1., 0.],
                              [0., 0., 0., 0., 0.],
                              [0., 1., 1., 1., 0.],
                              [0., 0., 0., 0., 0.],
                              [0., 0., 0., 0., 0.]])
    d1 = recognize(prototype_1, input_pattern)
    d9 = recognize(prototype_9, input_pattern)
    print d1
    print d9
    # select nearest neighbor (or reject)
    if d1 > d9:
        print "pattern likes 1"
    elif d1 < d9:
        print "pattern likes 9"
    else:
        print "pattern rejected"


if __name__ == '__main__':
    run()