face_areas.py

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#!/usr/bin/env python
import roslib
roslib.load_manifest('face_contour_detector')
import rospy
from face_contour_detector.srv import *
from face_contour_detector.msg import *
import cv
import cv_bridge

## @package face_contour_detector.image_information.face_areas
#  Provides a function to estimate the face area positions. Also inits a rosservice with name "find_face_areas" if this file is run as main script.
#  @author Fabian Wenzelmann

## @brief Estimates the area for nose, mouth, left eye, right eye and the complete face.
#  @param mask cvMat of type "mono8". Everything that is black in this image is part of the head.
#  see srv/FindFaceAreas.srv
#  the positions of the areas are only estimated. The image is divided into five parts horizontally and three parts vertically.
#  The face positions are estimated using the following pattern:
#  @image html face_areas.png
def find_areas(mask):
    min_left = max_right = min_top = max_bot = None
    width, height = mask.width, mask.height
    width_range = range( width )
    height_range = range( height )
    for row in height_range:
        if row >= int( 0.8 * height ):
            break
        for col in width_range:
            if mask[row, col] <= 128:
                if min_left is None:
                    min_left = col
                if max_right is None:
                    max_right = col
                if min_top is None:
                    min_top = row
                if max_bot is None:
                    max_bot = row
                min_left, max_right = min(min_left, col), max(max_right, col)
                min_top, max_bot = min(min_top, row), max(max_bot, row)
    # add some spacing for hairline
    face_top = min_top
    min_top += int(width * 1/5.5)
    face_width, face_height = max_right - min_left, max_bot - min_top
    pos_x = lambda face_x: min_left + face_x
    pos_y = lambda face_y: min_top + face_y
    pos_img = lambda face_x, face_y: (min_left + face_x, min_top + face_y)
    fifth, third, sixth = 1/5.0, 1/3.0, 1/6.0
    left_eye_x, right_eye_x = int(fifth * face_width), int(3 * fifth * face_width)
    eye_top = int(third * face_height)
    eye_height = int(sixth * face_height)
    eye_width = int(fifth * face_width)
    
    nose_x = int(2 * fifth * face_width)
    nose_y = eye_top + int(eye_height / 6)
    nose_height = int(1.75 * fifth * face_height)
    nose_width = int(fifth * face_width * 0.75)
    
    mouth_width = int(1.5 * eye_width)
    mouth_x = int((nose_x + (nose_width / 2.0)) - (mouth_width /2.0))
    mouth_y = int(nose_x + nose_height + (1/24.0 * face_height))
    mouth_height = int((20/173.0) * face_height)
    
    left_eye_x, right_eye_x, eye_top = pos_x(left_eye_x), pos_x(right_eye_x), pos_y(eye_top)
    nose_x, nose_y = pos_x(nose_x), pos_y(nose_y)
    mouth_x, mouth_y = pos_x(mouth_x), pos_y(mouth_y)
    # not nice but works
    x_vals = [left_eye_x, right_eye_x, nose_x, mouth_x]
    y_vals = [eye_top, nose_y, mouth_y]
    x_vals = map(lambda v: _correct_pos(v, width), x_vals)
    y_vals = map(lambda v: _correct_pos(v, height), y_vals)
    left_eye_x, right_eye_x, nose_x, mouth_x = x_vals[0], x_vals[1], x_vals[2], x_vals[3]
    eye_top, nose_y, mouth_y = y_vals[0], y_vals[1], y_vals[2]
    
    left_eye = image_area("LeftEye".encode("ascii"), left_eye_x, eye_top, eye_width, eye_height)
    right_eye = image_area("RightEye".encode("ascii"), right_eye_x, eye_top, eye_width, eye_height)
    nose = image_area("Nose".encode("ascii"), nose_x, nose_y, nose_width, nose_height)
    mouth = image_area("Mouth".encode("ascii"), mouth_x, mouth_y, mouth_width, mouth_height)
    complete = image_area("Complete Face".encode("ascii"), min_left, face_top, face_width, height - face_top)
    return FindFaceAreasResponse(left_eye, right_eye, nose, mouth, complete)
    
def _correct_pos(val, max_):
    val = max(val, 0)
    val = min(val, max_)
    return val
    

def get_areas(req):
    bridge = cv_bridge.CvBridge()
    cv_img = bridge.imgmsg_to_cv(req.mask, "mono8")
    return find_areas(cv_img)

def init_area_node():
    rospy.init_node("face_area_server")
    s1 = rospy.Service("find_face_areas", FindFaceAreas, get_areas)
    rospy.spin()

if __name__ == "__main__":
    init_area_node()