mvp1/scan_faces.py

#!/usr/bin/python

import io
import picamera
import cv2
import numpy as np
import datetime
import time
import os
from si_prefix import si_format
import Adafruit_CharLCD as LCD
import urllib2
import socket


# Set FPS (though RPi is probably to slow to meet it ;-)
FPS = 1.0
frameTimeDelta = datetime.timedelta(seconds=1.0/FPS)
dimTimeDelta = datetime.timedelta(seconds=10)

# Init LCD
lcd_rs = 27
lcd_en        = 22
lcd_d4        = 25
lcd_d5        = 24
lcd_d6        = 23
lcd_d7        = 18
lcd_backlight = 4

lcd_columns = 16
lcd_rows    = 2

lcd = LCD.Adafruit_CharLCD(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6, lcd_d7,
                           lcd_columns, lcd_rows, lcd_backlight)


# ip if config is needed over ssh. Username pi, Password: artwork1
try:
	ip = (([ip for ip in socket.gethostbyname_ex(socket.gethostname())[2] if not ip.startswith("127.")] or [[(s.connect(("8.8.8.8", 53)), s.getsockname()[0], s.close()) for s in [socket.socket(socket.AF_INET, socket.SOCK_DGRAM)]][0][1]]) + ["no IP found"])[0]
except Exception:
	ip = "No network"
	
lcd.clear()
lcd.message("Init scanner.\n{}".format(ip) )
time.sleep(6) # give some time to read the ip.

# Init camera
camera = picamera.PiCamera()
#~ camera.resolution = (1280, 720)
camera.resolution = (1920, 1080)

lcd.clear()
lcd.message("Init scanner..")

# Init classifier, various options:
#~ /usr/share/opencv/haarcascades/haarcascade_frontalface_default.xml (~22sec)
#~ /usr/share/opencv/haarcascades/haarcascade_frontalface_alt.xml (>25sec)
#~ /usr/share/opencv/haarcascades/haarcascade_frontalface_alt2.xml (~21sec)
#~ /usr/share/opencv/haarcascades/haarcascade_frontalface_alt_tree.xml (~14sec, seems to miss many faces)
classifier = cv2.CascadeClassifier('/usr/share/opencv/haarcascades/haarcascade_frontalface_alt2.xml')
lcd.clear()
lcd.message("Init scanner...")

prevFaceCount = 0
totalUse = 0 #in face-seconds

logfile = "/home/pi/scan_faces/scan_face.log"

def tail(filepath):
	"""
	Thanks: https://stackoverflow.com/a/41491521
	"""
	with open(filepath, "rb") as f:
		first = f.readline()      # Read the first line.
		f.seek(-2, 2)             # Jump to the second last byte.
		while f.read(1) != b"\n": # Until EOL is found...
			try:
				f.seek(-2, 1)     # ...jump back the read byte plus one more.
			except IOError:
				f.seek(-1, 1)
				if f.tell() == 0:
					break
		last = f.readline()       # Read last line.
	return last

# make sure log file exists
if not os.path.exists(logfile):
	with open(logfile,"w") as f:
		f.write("{},{},{}".format(time.time(), 0,0))

# get last line of log file and update 'total use' using that.
last = tail(logfile)
bits = last.split(",")
totalUse = float(bits[2])
print "Total use:", totalUse

log = open(logfile, "a")

lastFaceTime = datetime.datetime.utcnow()

while True:
	try:
		print(time.time(),"GO")
		start = datetime.datetime.utcnow()
		stream = io.BytesIO()
		camera.capture(stream, format='jpeg')
		print(time.time(),"captured")
		buff = np.fromstring(stream.getvalue(), dtype=np.uint8)
		image = cv2.imdecode(buff,1)
		gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
		print(time.time(),"grayed")
		faces = classifier.detectMultiScale(gray, 1.2, 5, minSize=(30,20))

		
		print(time.time(),"Found {} faces".format(len(faces)))
		
		end = datetime.datetime.utcnow()
		# take the frame as being representative of whole frame
		scanDuration = (end - start).total_seconds()
		totalUse += len(faces) * scanDuration
		
		lcd.clear()
		#~ lcd.message("viewers {:>8}\nview-min. {:>7.2f}".format(len(faces), totalUse/60))
		lcd.message("{:>7} viewers \n{:>7}view-sec".format(len(faces), si_format(totalUse,precision=1)))

		log.write("{},{},{}\n".format(time.time(), len(faces), int(totalUse)))
		log.flush()
		os.fsync(log.fileno()) 
		


		if len(faces) < 1 and end - lastFaceTime > dimTimeDelta:
			lcd.set_backlight(0)
		else:
			lcd.set_backlight(1)
		
		if len(faces) > 0:
			lastFaceTime = end
			
		
		content = urllib2.urlopen("https://artstats.rubenvandeven.com/artwork1/views.php?time=%d&count=%d&total=%d&duration=%f" % (int(time.time()), len(faces), int(totalUse), scanDuration) ).read()
			
		#~ if end - start < frameTimeDelta:
			
			#~ waitTime = frameTimeDelta - (end-start)
			#~ print("wait {}".waitTime.total_seconds())
			#~ time.sleep(waitTime.total_seconds())
	except Exception as e:
		print e