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How to Extract Faces from a Video Using Haarcascade?

I am using below script for haarcascade face detection.
My aim is to collect face shots on a video.
I would like to extract faces from a video.
Below script provides the detection of faces on a video.
How could I extract detected faces on a video?
import numpy as np
import cv2
#https://github.com/Itseez/opencv/blob/master/data/haarcascades/haarcascade_frontalface_default.xml
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
#https://github.com/Itseez/opencv/blob/master/data/haarcascades/haarcascade_eye.xml
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
cap = cv2.VideoCapture(0)
while 1:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
cv2.imshow('img',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break
cap.release()
cv2.destroyAllWindows()

opencv how to use cascade on screen recorder

So I'm new to opencv and after practicing with some face detectors and understanding how to use the library, I created my own cascade and it's supposed to identify icons on my computer such as logos and others.
first to make sure my cascade worked I wrote one the detects the icons from the images I took,I took a screenshot and processed it through the cascade as an image and worked fine. the code for that is
import numpy as np
import cv2
img = cv2.imread('body.jpg')
face_csc = cv2.CascadeClassifier('new_cascade.xml')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_csc.detectMultiScale(gray, 1.1 , 4)
for (x,y,w,h) in faces:
cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,0),3)
cv2.imshow('img',img)
cv2.waitKey(0)
after some time I wrote this for it to render my screen while detecting the icons the same way it did when I tried it on a screenshot:
import numpy as np
import cv2
from PIL import ImageGrab
fourcc = cv2.VideoWriter_fourcc(*'XVID')
face_csc = cv2.CascadeClassifier('new_cascade.xml')
out = cv2.VideoWriter("test_output.avi", fourcc, 5.0, (1366, 768))
while True:
img = ImageGrab.grab(bbox=(100, 10, 750, 750))
# convert image to numpy array
img_np = np.array(img)
# convert color space from BGR to RGB
frame = cv2.cvtColor(img_np, cv2.COLOR_BGR2RGB)
# show image on OpenCV frame
faces = face_csc.detectMultiScale(frame, 1.1 , 4)
cv2.imshow("stream", frame)
# write frame to video writer
out.write(frame)
for (x,y,w,h) in faces:
cv2.rectangle(frame,(x,y),(x+w,y+h), (255,0,0), 2)
roi_gray = frame[y:y+h, x:x+w]
roi_color = img_np[y:y+h,x:x+w]
if cv2.waitKey(1) == 27:
break
cv2.waitKey(0)
out.release()
but when running the code it doesn't show any errors but it also doesn't detect or identify any of the icons it just records my screen, I've tried debugging this for hours now to no avail, any ideas?

You should show and write the video after you draw rectangles, not before.
import numpy as np
import cv2
from PIL import ImageGrab
fourcc = cv2.VideoWriter_fourcc(*'XVID')
face_csc = cv2.CascadeClassifier('new_cascade.xml')
out = cv2.VideoWriter("test_output.avi", fourcc, 5.0, (1366, 768))
while True:
img = ImageGrab.grab(bbox=(100, 10, 750, 750))
# convert image to numpy array
img_np = np.array(img)
# convert color space from BGR to RGB
frame = cv2.cvtColor(img_np, cv2.COLOR_BGR2RGB)
# show image on OpenCV frame
faces = face_csc.detectMultiScale(frame, 1.1 , 4)
for (x,y,w,h) in faces:
cv2.rectangle(frame,(x,y),(x+w,y+h), (255,0,0), 2)
roi_gray = frame[y:y+h, x:x+w]
roi_color = img_np[y:y+h,x:x+w]
if cv2.waitKey(1) == 27:
break
cv2.imshow("stream", frame)
# write frame to video writer
out.write(frame)
cv2.waitKey(0)
out.release()

OpenCV 3.4.0.12 with Python3.5 AttributeError: 'cv2.VideoCapture' object has no attribute 'imread'

I'm trying out facial recognition for the first time with python 3.5 and OpenCV 3.4.0.12 and I get this error when I run my code.
File "/Users/connorwoodford/anaconda3/envs/chatbot/lib/python3.5/site-packages/spyder/utils/site/sitecustomize.py", line 101, in execfile
exec(compile(f.read(), filename, 'exec'), namespace)
File "/Users/connorwoodford/Desktop/temp.py", line 11, in <module>
ret, img = cap.imread()
AttributeError: 'cv2.VideoCapture' object has no attribute 'imread'
Code:
import cv2
import numpy as np
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('CascadeClassifier')
cap = cv2.VideoCapture(0)
while True:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for(x,y,w,h) in faces:
cv2.rectangle(img, (x+y), (x+w, y+h), (255,0,0), 2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color, (ex, ey), (ex+ew,ey+eh), (0,255,0), 2)
cv2.imshow('img',img)
k = cv2.waitkey(30) & 0xff
if k == 27:
break
cap.release()
cv2.destroyAllWindows()

Your eye_cascade is referring to wrong cascade file, it should end with .xml extension. You can download it from here haarcascade_eye.xml.
Also note that your call to cv2.rectangle is not in correct format.
change it from
cv2.rectangle(img, (x+y), (x+w, y+h), (255,0,0), 2)
to
cv2.rectangle(img, (x,y), (x+w,y+h), (255,0,0), 2)
All you need to make this work is to wrap the capture logic in a method. Full code goes as follows:
import numpy as np
import cv2
def sample_demo():
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
cap = cv2.VideoCapture(0)
while 1:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
cv2.imshow('img',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break
cap.release()
cv2.destroyAllWindows()
and simply call method sample_demo()
sample_demo()

NameError in Python

I am getting a NameError: name 'eyes' not found while trying to run an OpenCV project in Python on cmd. I am using Python 2.7 and OpenCV 2.4.13, which I think is not a problem.
import cv2
import numpy as np
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
cap = cv2.VideoCapture(1)
while True:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for(x,y,w,h) in faces:
cv2.reactangle(img, (x,y), (x+w,y+h), (255,0,0), 2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for(ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color, (ex, ey), (ex+ew,ey+eh), (0,255,0), 2)
cv2.imshow('img',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break
cap.release()
cv2.destroyAllWindows()
Error:
File "detect.py" , line 19, in
for(ex,ey,ew,eh) in eyes:
NameError: name 'eyes' is not defined

Problem of indentation, just like this one:
eyes is out of scope when you go out of the faces loop.
while True:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for(x,y,w,h) in faces:
cv2.reactangle(img, (x,y), (x+w,y+h), (255,0,0), 2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
# this one should be inside the 'faces' loop
for(ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color, (ex, ey), (ex+ew,ey+eh), (0,255,0), 2)
cv2.imshow('img',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break

OpenCV 3.0 Beta - Python - Face Detection via Webcam - code gives me error

I wrote and looked over this code multiple times and it seems right to me especially that it's very simple and straight forward (Took snippet out of opencv tutorial), however it is still giving me an error. I've checked the error and I understand that it's missing channels, however, I don't know how to fix it. Any help would be appreciated. I'm using Windows x64 and Spyder (from Anaconda distribution) as my IDE. Could it be hardware issue? (webcam)
#####################################################
# Face Detection (Video) #
#####################################################
import numpy as np
import cv2
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
video = cv2.VideoCapture(0)
ret, frame = video.read()
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = frame[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
cv2.imshow('Video', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
video.release()
cv2.destroyAllWindows()
Here's the error I get:
error: ..\..\..\..\opencv\modules\imgproc\src\color.cpp:5731:
error: (-215) scn == 3 || scn == 4 in function cv::cvtColor

i guess, you wanted a 'continuous detection, not a 'single shot' one, right ?
you're just some small changes away:
import numpy as np
import cv2
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
if face_cascade.empty(): raise Exception("your face_cascade is empty. are you sure, the path is correct ?")
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
if eye_cascade.empty(): raise Exception("your eye_cascade is empty. are you sure, the path is correct ?")
video = cv2.VideoCapture(0)
while(video.isOpened()):
ret, frame = video.read()
if frame not None:
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = frame[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2)
cv2.imshow('Video', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
video.release()
cv2.destroyAllWindows()