Hand gesture recognition (PCA) - Python


Staff member
I am trying to make hand gesture recognition by Principal Component Analysis (PCA) using python. I am following the steps in this tutorial: <a href="http://onionesquereality.wordpress....genfaces-and-distance-classifiers-a-tutorial/" rel="nofollow">http://onionesquereality.wordpress....genfaces-and-distance-classifiers-a-tutorial/</a>

Here is my code:

import os
from PIL import Image
import numpy as np
import glob
import numpy.linalg as linalg

#Step 1: put training images into a 2D array
filenames = glob.glob('C:\\Users\\Karim\\Desktop\\Training &amp; Test images\\New folder\\Training/*.png')
img = [Image.open(fn).convert('L').resize((90, 90)) for fn in filenames]
images = np.asarray([np.array(im).flatten() for im in img])

#Step 2: find the mean image and the mean-shifted input images
mean_image = images.mean(axis=0)
shifted_images = images - mean_image

#Step 3: Covariance
c = np.asmatrix(shifted_images) * np.asmatrix(shifted_images.T)

#Step 4: Sorted eigenvalues and eigenvectors
eigenvalues,eigenvectors = linalg.eig(c)
idx = np.argsort(-eigenvalues)
eigenvalues = eigenvalues[idx]
eigenvectors = eigenvectors[:, idx]

#Step 6: Finding weights
w = eigenvectors.T * np.asmatrix(shifted_images)  
w = np.asarray(w)

#Step 7: Input (Test) image
input_image = Image.open('C:\\Users\\Karim\\Desktop\\Training &amp; Test images\\New folder\\Test\\31.png').convert('L').resize((90, 90))
input_image = np.asarray(input_image).flatten()

#Step 8: get the normalized image, covariance, eigenvalues and eigenvectors for input image
shifted_in = input_image - mean_image
c = np.cov(input_image)
cmat = c.reshape(1,1)
eigenvalues_in, eigenvectors_in = linalg.eig(cmat)

#Step 9: Fing weights of input image
w_in = eigenvectors_in.T * np.asmatrix(shifted_in) 
w_in = np.asarray(w_in)

#Step 10: Euclidean distance
df = np.asarray(w - w_in)                # the difference between the images
dst = np.sqrt(np.sum(df**2, axis=1))     # their euclidean distances
idx = np.argmin(dst)                     # index of the smallest value in 'dst' which should be equal to index of the most simillar image in 'images'
print idx

The detected image should be the nearest from the training images to the test image, but the result is a completely different one, although for each test image there are 10 similar images in the training image.

Anyone can help?