12.1.10.6.4. Face Detection

This demo shows how a simple image processing example can be demonstrated. The itom grabber OpenCVGrabber captures your webcam. Then live your face and eyes are detected and marked in the live plot.

from itom import dataObject
from itom import dataIO
from itom import ui
import cv2
import numpy as np
import gc

Face detection method.

def detectFace(img, cascade):
    rects = cascade.detectMultiScale(img, scaleFactor=1.3, minNeighbors=4)
    if len(rects) == 0:
        return []
    rects[:, 2:] += rects[:, :2]
    return rects

Eye detection method.

def detectEyes(img, cascade):
    eyes = cascade.detectMultiScale(img)
    if len(eyes) == 0:
        return []

    if eyes.shape[0] > 2:
        eyes = eyes[0:1, :]

    return eyes

Draw detected rectangle method.

def drawRects(img, faces, color):
    for x1, y1, x2, y2 in faces:
        rect = shape.createRectangle((x1, y1), (x2, y2), index=11)
        rect.color = color
        win.plot.call("updateGeometricShape", rect)

Draw detected eyes method.

def drawEyes(img, eyes, color):
    cnt = 21
    for x, y, w, h in eyes:
        eye = shape.createEllipse((x, y + h), (x + w, y), index=cnt)
        eye.color = color
        try:
            win.plot.call("updateGeometricShape", eye)
        except AttributeError:
            break
        cnt = cnt + 1

Acquire an image from the webcam.

def snap():
    # image acquisition
    if "cam" in globals():
        d = dataObject()
        cam.disableAutoGrabbing()
        cam.acquire()
        cam.getVal(d)
    else:
        return

    img = np.array(d)

    win.plot["source"] = img

    # detect face and eyes
    faces = detectFace(img, faceCascade)
    eyes = detectEyes(img, eyeCascade)

    # overlay rect and eyes
    drawRects(img, faces, rgba(255, 0, 0, 255))  # in color red
    drawEyes(img, eyes, rgba(0, 255, 0, 255))  # in color green

Close GUI and stop webcam.

def guiClosed():
    tDetect.stop()
    global cam, win
    del win
    del cam
    gc.collect()

Open a simple GUI, connect the webcam and starte the live face detection.

win = ui(
    "FaceDetect.ui",
    ui.TYPEWINDOW,
    childOfMainWindow=True,
    deleteOnClose=True,
)

faceCascade = cv2.CascadeClassifier()
eyeCascade = cv2.CascadeClassifier()

faceCascade.load("haarcascades/haarcascade_frontalface_alt.xml")
eyeCascade.load("haarcascades/haarcascade_eye_tree_eyeglasses.xml")

cam = dataIO("OpenCVGrabber", 0, "gray")
cam.startDevice()
cam.disableAutoGrabbing()

tDetect = timer(100, snap)

win.connect("destroyed()", guiClosed)

# start GUI
win.show(0)