OCT/facetracker.py

from picamera.array import PiRGBArray
from picamera import PiCamera
from datetime import datetime
import time
import cv2
import sys
import imutils
import np
import math # for sqrt distance formula

# Create the haar cascade
frontalfaceCascade = cv2.CascadeClassifier("haarcascade_frontalface_default.xml")
profilefaceCascade = cv2.CascadeClassifier("haarcascade_profileface.xml")

face = [0,0,0,0]        # This will hold the array that OpenCV returns when it finds a face: (makes a rectangle)
center = [0,0]                # Center of the face: a point calculated from the above variable
lastface = 0                # int 1-3 used to speed up detection. The script is looking for a right profile face,-
                        #         a left profile face, or a frontal face; rather than searching for all three every time,-
                        #         it uses this variable to remember which is last saw: and looks for that again. If it-
                        #         doesn't find it, it's set back to zero and on the next loop it will search for all three.-
                        #         This basically tripples the detect time so long as the face hasn't moved much.


# initialize the camera and grab a reference to the raw camera capture
camera = PiCamera()
#camera.resolution = (160, 120)
camera.resolution = (640,480)
cameracenter = (camera.resolution[0]/2, camera.resolution[1]/2)
camera.framerate = 32
rawCapture = PiRGBArray(camera, camera.resolution)

# Fisheye corrections. See https://medium.com/@kennethjiang/calibrate-fisheye-lens-using-opencv-333b05afa0b0
DIM=(640, 480)
K=np.array([[363.787052141742, 0.0, 332.09761373599576], [0.0, 362.23769923959975, 238.35982850966641], [0.0, 0.0, 1.0]])
D=np.array([[-0.019982864934848042], [-0.10107557279423625], [0.20401597940960342], [-0.1406464201639892]])

def distance(p0, p1):
    return math.sqrt((p0[0] - p1[0])**2 + (p0[1] - p1[1])**2)

def search_rightprofile(i):
#    return profilefaceCascade.detectMultiScale(i,1.3,4,(cv2.CV_HAAR_DO_CANNY_PRUNING + cv2.CV_HAAR_FIND_BIGGEST_OBJECT + cv2.CV_HAAR_DO_ROUGH_SEARCH),(30,30))
    return profilefaceCascade.detectMultiScale(i)

def search_leftprofile(i):
    revimage = cv2.flip(i, 1) # Flip the image
#    return profilefaceCascade.detectMultiScale(i,1.3,4,(cv2.CV_HAAR_DO_CANNY_PRUNING + cv2.CV_HAAR_FIND_BIGGEST_OBJECT + cv2.CV_HAAR_DO_ROUGH_SEARCH),(30,30))
    return profilefaceCascade.detectMultiScale(i)

def search_frontface(i):
#    return frontalfaceCascade.detectMultiScale(i,1.3,4,(cv2.CV_HAAR_DO_CANNY_PRUNING + cv2.CV_HAAR_FIND_BIGGEST_OBJECT + cv2.CV_HAAR_DO_ROUGH_SEARCH),(30,30))
    return frontalfaceCascade.detectMultiScale(i)

def undistort(i, balance=0.0, dim2=None, dim3=None):
    # Sanity Check the source dimensions
    dim1 = i.shape[:2][::-1]  #dim1 is the dimension of input image to un-distort
    assert dim1[0]/dim1[1] == DIM[0]/DIM[1], "Image to undistort needs to have same aspect ratio as the ones used in calibration"

    if not dim2:
        dim2 = dim1
    if not dim3:
        dim3 = dim1

    scaled_K = K * dim1[0] / DIM[0]  # The values of K is to scale with image dimension.
    scaled_K[2][2] = 1.0  # Except that K[2][2] is always 1.0

    # This is how scaled_K, dim2 and balance are used to determine the final K used to un-distort image. OpenCV document failed to make this clear!
    new_K = cv2.fisheye.estimateNewCameraMatrixForUndistortRectify(scaled_K, D, dim2, np.eye(3), balance=balance)
    map1, map2 = cv2.fisheye.initUndistortRectifyMap(scaled_K, D, np.eye(3), new_K, dim3, cv2.CV_16SC2)
    return cv2.remap(i, map1, map2, interpolation=cv2.INTER_LINEAR, borderMode=cv2.BORDER_CONSTANT)

# allow the camera to warmup
time.sleep(0.1)
lastTime = time.time()*1000.0

# capture frames from the camera
for frame in camera.capture_continuous(rawCapture, format="bgr", use_video_port=True):
        # grab the raw NumPy array representing the image, then initialize the timestamp
        # and occupied/unoccupied text
    image = frame.array
    image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) # convert to greyscale
    image = undistort(image, 0.8)
    faces = ();
    
    faceFound = False        # This variable is set to true if, on THIS loop a face has already been found
                                # We search for a face three diffrent ways, and if we have found one already-
                                # there is no reason to keep looking.
    # First Scan
    if lastface == 1:
        faces = search_rightprofile(image)
        if faces != ():
            faceFound=True
            lastface = 1
    elif lastface == 2:
        faces = search_leftprofile(image)
        if faces != ():
            faceFound=True
            lastface = 2
    else:
        faces = search_frontface(image)
        if faces != ():
            lastface = 3
            faceFound=True

    # Second scan
    if not faceFound:
        if lastface == 1:
            faces = search_frontface(image)
            if faces != ():
                lastface = 3
                faceFound=True
        elif lastface == 2:
            faces = search_rightprofile(image)
            if faces != ():
                faceFound=True
                lastface = 1
        else:
            faces = search_leftprofile(image)
            if faces != ():
                faceFound=True
                lastface = 2

    # Third scan
    if not faceFound:
        if lastface == 1:
            faces = search_leftprofile(image)
            if faces != ():
                faceFound=True
                lastface = 2
        elif lastface == 2:
            faces = search_frontface(image)
            if faces != ():
                lastface = 3
                faceFound=True
        else:
            faces = search_rightprofile(image)
            if faces != ():
                faceFound=True
                lastface = 1


    if not faceFound:
        print("{}: no faces found.".format(time.time()*1000.0-lastTime))
        lastTime = time.time()*1000.0
        # clear the stream in preparation for the next frame
        rawCapture.truncate(0)
        continue; 

    print("{}: {} faces found. Type: {}".format(time.time()*1000.0-lastTime, len(faces), lastface))
        
    lastTime = time.time()*1000.0

    # Draw a rectangle around the faces
    for (x, y, w, h) in faces:
        cv2.circle(image, (int(x+w/2), int(y+h/2)), int((w+h)/3), (255, 255, 255), 1)

    # Temporary, save the image
    cv2.imwrite("tmp/img.{}.png".format(datetime.now().strftime("%Y%m%d.%H%M%S.%f")), image)

    # clear the stream in preparation for the next frame
    rawCapture.truncate(0)
   
    # Find teh centermost face
    curdistance = 1000000 # Outside the dimensions of the picture
    for f in faces:
        x,y,w,h = f
        tmpcenter   = [(w/2+x),(h/2+y)]        # we are given an x,y corner point and a width and height, we need the center
        tmpdistance = distance(tmpcenter, cameracenter)
        if(tmpdistance < curdistance):
            print("Face closer to center detected. New target location: ({}, {}) - distance: {}".format(tmpcenter[0],tmpcenter[1],tmpdistance))
            center = tmpcenter;