face_recog.py

import numpy as np
import cv2

# instantiate the camera object and haar cascade
cam = cv2.VideoCapture(1)
face_cas = cv2.CascadeClassifier('./haarcascade_frontalface_default.xml')

# declare the type of font to be used on output window
font = cv2.FONT_HERSHEY_SIMPLEX

# load the data from the numpy matrices and convert to linear vectors
f_01 = np.load('face_01.npy').reshape((20, 50*50*3))    # Prashant
f_02=  np.load('face_02.npy').reshape((20, 50*50*3))    # Nil

print f_01.shape, f_02.shape

# create a look-up dictionary
names = {
    0: 'Prashant',
    1: 'Nil',

}

# create a matrix to store the labels
labels = np.zeros((40, 1))
labels[:20, :] = 0.0    # first 20 for Prashant (0)
labels[40, :] = 1.0 # next 20 for Nil (1)

# combine all info into one data array
data = np.concatenate([f_01, f_02]) # (40, 7500)
print data.shape, labels.shape  # (40, 1)

# the distance and knn functions we defined earlier
def distance(x1, x2):
    return np.sqrt(((x1-x2)**2).sum())

def knn(x, train, targets, k=5):
    m = train.shape[0]
    dist = []
    for ix in range(m):
        # compute distance from each point and store in dist
        dist.append(distance(x, train[ix]))
    dist = np.asarray(dist)
    indx = np.argsort(dist)
    sorted_labels = labels[indx][:k]
    counts = np.unique(sorted_labels, return_counts=True)
    return counts[0][np.argmax(counts[1])]

while True:
    # get each frame
    ret, frame = cam.read()

    if ret == True:
        # convert to grayscale and get faces
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        faces = face_cas.detectMultiScale(gray, 1.3, 5)

        # for each face
        for (x, y, w, h) in faces:
            face_component = frame[y:y+h, x:x+w, :]
            fc = cv2.resize(face_component, (50, 50))

            # after processing the image and rescaling
            # convert to linear vector using .flatten()
            # and pass to knn function along with all the data

            lab = knn(fc.flatten(), data, labels)
            # convert this label to int and get the corresponding name
            text = names[int(lab)]

            # display the name
            cv2.putText(frame, text, (x, y), font, 1, (255, 255, 0), 2)

            # draw a rectangle over the face
            cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 0, 255), 2)
        cv2.imshow('face recognition', frame)

        if cv2.waitKey(1) == 27:
            break
    else:
        print 'Error'

cv2.destroyAllWindows()