SimpleCV has functions to detect blobs in an image. The following code uses the findBlobs() function to detect blobs in the image:

from SimpleCV import Image
import time
img=Image('/home/pi/book/test_set/7.1.02.tiff')
imgBin=img.binarize()
blobs=imgBin.findBlobs()
blobs.show(width=5)
time.sleep(5)

The input image (an aerial photograph of a plane in a hanger) and the detected blobs are as follows:

SimpleCV also has a findSkintoneBlobs() function that automatically finds skin-toned blobs from an image. The following program uses the findSkintoneBlobs() function on the live stream that is received from the camera:

from SimpleCV import Image, Camera

cam = Camera()
while 1:
  img=cam.getImage()
  skin =img.findSkintoneBlobs()

  if skin:
    for i in skin:
      print i.centroid()
    skin.draw(), skin.show()
  else:
    print "No Skin detected"

In the preceding program, we printed the centroids of the detected skin-toned blobs. However, the output is highly dependent on the skin tone of the subject person and the lighting conditions.