[python] Car detection form video file

#! /usr/bin/python

import cv2

face_cascade = cv2.CascadeClassifier('cars.xml')

vc = cv2.VideoCapture('video2.avi')

if vc.isOpened():

    rval , frame = vc.read()

else:

    rval = False

while rval:

    rval, frame = vc.read()

    # car detection.

    cars = face_cascade.detectMultiScale(frame, 1.1, 2)

    ncars = 0

    for (x,y,w,h) in cars:

        cv2.rectangle(frame,(x,y),(x+w,y+h),(0,0,255),2)

        ncars = ncars + 1

  

    # show result

    cv2.imshow("Result",frame)

    cv2.waitKey(1);

vc.release()

//--------------------------------------------------------------------------------------------------
// more strong version

#! /usr/bin/python

import cv2

face_cascade = cv2.CascadeClassifier('cars.xml')

vc = cv2.VideoCapture('video2.avi')

if vc.isOpened():

    rval , frame = vc.read()

else:

    rval = False

roi = [0,0,0,0]

lastdetected = 0

detections = 0

while rval:

    rval, frame = vc.read()

    fheight, fwidth, fdepth = frame.shape

  

    # car detection.

    cars = face_cascade.detectMultiScale(frame, 1.1, 1)

    ncars = 0

    for (x,y,w,h) in cars:

      

        # do not detect cars in the sky.

        if x > fwidth*0.4 and x < fwidth*0.5 and y > fheight*0.25 and w > 30 and h > 30:

                if ( abs(x-roi[0]) < 20 ):

                    x = roi[0]

                if ( abs(y-roi[1]) < 20 ):

                    y = roi[1]

                if ( abs(w-roi[2]) < 20 ):

                    w = roi[2]

                if ( abs(h-roi[3]) < 50 ):

                    h = roi[3]

                roi = [x,y,w,h]

                ncars = ncars + 1

                lastdetected = 0

                detections = detections + 1

    # seen in the last 50 frames

    if lastdetected < 5:

         cv2.rectangle(frame,(roi[0],roi[1]),(roi[0]+roi[2],roi[1]+roi[3]),(0,0,255),2)

    lastdetected = lastdetected + 1

    

    # show result

    cv2.imshow("Result",frame)

    cv2.waitKey(1);

vc.release()