facedetect.py

#!/usr/bin/python
"""
Face and object detection using haar-like features.
Finds faces in a camera image or video stream and displays a red box around them.

Based on a python implementation by: Roman Stanchak, James Bowman
"""
import os,subprocess,glob,time
import cv2.cv as cv
from optparse import OptionParser

# Parameters for haar detection
# From the API:
# The default parameters (scale_factor=2, min_neighbors=3, flags=0) are tuned 
# for accurate yet slow object detection. For a faster operation on real video 
# images the settings are: 
# scale_factor=1.2, min_neighbors=2, flags=CV_HAAR_DO_CANNY_PRUNING, 
# min_size=<minimum possible face size

min_size = (5,5)
haar_scale = 1.2
min_neighbors = 2
haar_flags = 0

# detection image width i
# 70 fast frame rate 
# 90 - more accurate / smaller faces / further away
# 120+ slow

smallwidth = 90
pan =100
os.system('echo "0="' + str(pan) + ' > /dev/servoblaster')

def detect_and_draw(img, cascade, detected):

    global pan

    # allocate temporary images

    gray = cv.CreateImage((img.width,img.height), 8, 1)
    image_scale = img.width / smallwidth

    small_img = cv.CreateImage((cv.Round(img.width / image_scale), cv.Round (img.height / image_scale)), 8, 1)
    # gray = cv.CreateImage((img.width,img.height), 8, 1)
    image_scale = img.width / smallwidth
    # small_img = cv.CreateImage((cv.Round(img.width / image_scale), cv.Round (img.height / image_scale)), 8, 1)

    # convert color input image to grayscale
    cv.CvtColor(img, gray, cv.CV_BGR2GRAY)

    # scale input image for faster processing
    cv.Resize(gray, small_img, cv.CV_INTER_LINEAR)

    cv.EqualizeHist(small_img, small_img)

    if(cascade):
        faces = cv.HaarDetectObjects(small_img, cascade, cv.CreateMemStorage(0), haar_scale, min_neighbors, haar_flags, min_size)
        if faces:
	    if detected == 0:
		# os.system('festival --tts hi &')
		detected = 1
            for ((x, y, w, h), n) in faces:
                # the input to cv.HaarDetectObjects was resized, so scale the 
                # bounding box of each face and convert it to two CvPoints
                pt1 = (int(x * image_scale), int(y * image_scale))
                pt2 = (int((x + w) * image_scale), int((y + h) * image_scale))
                cv.Rectangle(img, pt1, pt2, cv.RGB(255, 0, 0), 3, 8, 0)
		print "Face at: ", pt1[0], ",", pt2[0], "\t", pt1[1], ",", pt2[1]
		# find amount needed to pan/tilt
		span = pt1[0] 
		mid = smallwidth /2
		
		if span < mid:
			 print "left", mid -span
			 pandir = -1
		else:
			 print "right", span - mid
			 pandir = 1
		pan = pan + pandir
		if pan > 180: 
			pan = 180
		if pan < 0: 
			pan = 0
		os.system('echo "0="' + str(pan) + ' > /dev/servoblaster')
	else:
		if detected == 1:
			#print "Last seen at: ", pt1[0], ",", pt2[0], "\t", pt1[1], ",", pt2[1]
			#os.system('festival --tts bye &')
			status = "just disappeared"
		detected = 0

    # fps = int ( (t/(cv.GetTickFrequency()) / 1000))
    # font = cv.InitFont(cv.CV_FONT_HERSHEY_SIMPLEX,1,1,0,3,8)
    # cv.PutText(img,"% fps" % fps,(img.width/2,img.height-10), font,255)
    cv.ShowImage("result", img)
    return detected

if __name__ == '__main__':
    parser = OptionParser(usage = "usage: %prog [options] [filename|camera_index]")
    parser.add_option("-c", "--cascade", action="store", dest="cascade", type="str", help="Haar cascade file, default %default", default = "../data/haarcascades/haarcascade_frontalface_alt.xml")
    (options, args) = parser.parse_args()

    cascade = cv.Load(options.cascade)
    
    cv.NamedWindow("result", 1)


    raspicam = 0

    if raspicam:
    	# fps = 1000 / tl
    	command = "raspistill -tl 65 -n -rot 180 -hf -o /run/shm/image%d.jpg -w 320 -h 240 -e bmp"
    	p=subprocess.Popen(command,shell=True)

    	# wait until we have at least 2 image files

    	while True:
	    files = filter(os.path.isfile, glob.glob('/run/shm/' + "image*jpg"))
	    if len(files) > 1:
		break
	    print "waiting for images"
	    time.sleep(0.5)
    else:
	#usb cam
	capture = cv.CaptureFromCAM(0)
	frame = cv.QueryFrame(capture)
	cv.SetCaptureProperty( capture, cv.CV_CAP_PROP_FRAME_WIDTH, 320 )
	cv.SetCaptureProperty( capture, cv.CV_CAP_PROP_FRAME_HEIGHT, 240 )

    if True:
	detected = 0
        frame = None
        while True:
        
    	    t = cv.GetTickCount() 
	    if raspicam:
		# restart raspistill when it exits
	    	if p.poll() is not None:
			print "restarting raspistill"
    			p=subprocess.Popen(command,shell=True)

	    	# list most recent images,
	    	# and get the 2nd most recent image
	    	# since this is the last complete one

	    	files = filter(os.path.isfile, glob.glob('/run/shm/' + "image*jpg"))
	    	files.sort(key=lambda x: os.path.getmtime(x))
	    	imagefile = (files[-2])
		 
	    	# print imagefile
	    	frame=cv.LoadImage(imagefile,cv.CV_LOAD_IMAGE_COLOR)


	    else:
		#usb cam
		frame=cv.QueryFrame(capture)

            detected = detect_and_draw(frame, cascade, detected)

	    # uncomment if you want some spare cpu - reduced from 7fps to 5fps
	    # time.sleep(0.1)

    	    t = cv.GetTickCount() - t
    	    fps = int (1000 / (t/(cv.GetTickFrequency() * 1000)))
	    # print fps

	    #exit when any key pressed
            if cv.WaitKey(10) >= 0:
                break

    cv.DestroyWindow("result")