OpenCV Python View webcam feed before it takes a snap? - python

So my code should detect an object with opencv and once it detects it it should take a snap of it. Which it does fine....However it simply goes to the webcam and doesn't show me the webcam feed. When it detects the object it takes a snap and show the image.
What I want is to see the webcam feed until it detects the object....How can I do that?
Here's my code:
import cv2
cascade = cv2.CascadeClassifier('xcascade.xml')
cap = cv2.VideoCapture(1)
num = 0
while num<1000:
ret, img = cap.read()
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
cas = cascade.detectMultiScale(gray, 10, 10)
for(x,y,w,h) in cas:
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.rectangle(img,(x,y), (x+w,y+h),(255,255,0),5)
cv2.putText(img, 'Something',(x,y-120), font, 1.5, (0,255,255),5, cv2.LINE_AA)
num = num+1
cv2.imshow('img',img)
cv2.waitKey(1000)
cap.release()
cv2.desrtoyAllWindows()
break

You are only showing the image when a detection happens, you need to take your imshow outside the for loop.
import cv2
cascade = cv2.CascadeClassifier('xcascade.xml')
cap = cv2.VideoCapture(1)
num = 0
while num<1000:
ret, img = cap.read()
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
cas = cascade.detectMultiScale(gray, 10, 10)
for(x,y,w,h) in cas:
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.rectangle(img,(x,y), (x+w,y+h),(255,255,0),5)
cv2.putText(img, 'Something',(x,y-120), font, 1.5, (0,255,255),5, cv2.LINE_AA)
num = num+1
cv2.imshow('img',img)
cv2.waitKey(1000)
cap.release()
cv2.desrtoyAllWindows()
break
cv2.imshow('img',img)
cv2.waitKey(1000)

Related

How do I add an image overlay to my live video using cv2?

This is my code, I've looked at some tutorials but can't find what I'm looking for
I want to overlay the Frame.png image on my webcam. I tried to add the image directly but it didn't work either. If possible, Is there a way to add an image, not to overlay but to keep the image at a certain coordinate in the live webcam window
import cv2
import numpy as np
def detect_and_save():
alpha = 0.2
beta = 1-alpha
cap = cv2.VideoCapture(0)
sciframe = cv2.imread('Frame.png')
classifier = cv2.CascadeClassifier("haarcascade_frontalface_default.xml")
while True:
ret ,frame = cap.read()
overlay = frame.copy()
output = frame.copy()
gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
faces = classifier.detectMultiScale(gray,1.5,5)
cv2.putText(output, "HUD Test",(175, 50), cv2.FONT_HERSHEY_SIMPLEX, 2, (255, 50, 50), 3)
cv2
for face in faces:
x,y,w,h = face
cv2.rectangle(overlay,(x,y),(x+w,y+h),(255,200,0),-1)
cv2.rectangle(overlay,(x,y),(x+w,y+h),(255,0,0),1)
cv2.rectangle(overlay,(x,y-20),(x+w,y),(25,20,0),-1)
cv2.addWeighted(overlay,alpha,output,beta,0,output)
cv2.putText(output,"Human",(x+10,y-10),cv2.FONT_HERSHEY_SIMPLEX,
0.35, (0, 0, 255), 1)
if not ret:
continue
cv2.imshow("HUD",output)
key = cv2.waitKey(1)
if key == ord('q'):
break
elif key == ord('s'):
cv2.imwrite('./images/CID_{}.png'.format(time.strftime('%d%m%y_%H_%M_%S')),output)
cap.release()
cv2.destroyAllWindows()
if __name__ == "__main__":
import time
detect_and_save()
You can directly add one image on top of another one at any coordinate easily in opencv.
cap = cv2.VideoCapture(0)
im_height = 50 #define your top image size here
im_width = 50
im = cv2.resize(cv2.imread("Frame.png"), (im_width, im_height))
while (True):
ret, frame = cap.read()
frame[0:im_width, 0:im_height] = im #for top-left corner, 0:50 and 0:50 for my image; select your region here like 200:250
cv2.imshow("live camera", frame)
if cv2.waitKey(1) == ord("q"):
break
cap.release()
cv2.destroyAllWindows()

webcam image distorted in python

import cv2
import sys
faceCascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
video_capture = cv2.VideoCapture(0)
img_counter = 0
while True:
# Capture frame-by-frame
ret, frame = video_capture.read()
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
k = cv2.waitKey(1)
faces = faceCascade.detectMultiScale(
gray,
scaleFactor=1.5,
minNeighbors=5,
minSize=(30, 30),
flags=cv2.CASCADE_SCALE_IMAGE
)
# Draw a rectangle around the faces
for (x, y, w, h) in faces:
cv2.rectangle(frame, (x, y), (x+w, y+h), (0, 255, 0), 2)
# Display the resulting frame
cv2.imshow('FaceDetection', frame)
if k%256 == 27: #ESC Pressed
break
elif k%256 == 32:
# SPACE pressed
img_name = "facedetect_webcam_{}.png".format(img_counter)
cv2.imwrite(img_name, frame)
print("{} written!".format(img_name))
img_counter += 1
# When everything is done, release the capture
video_capture.release()
cv2.destroyAllWindows()
after running the code in python the image of my webcam turn into this
Your code works for me without any problems.
The output image looks like there is a problem with the data type of the input image.
Something similar was discussed here:
https://answers.opencv.org/question/174027/c-ycbcr422-to-rgb-convert-from-raw-data-file/
Can you please also post your input frame grayscale image?
What camera are you using?
try add this code after video_capture.read() and post output.
print(frame.dtype)
print(frame.shape)
Mine is: dtype - uint8, shape - (480, 640, 3).
You can have a problem with the number of channels (for example RGBA) and rectangle function.
These are just my ideas of what could be wrong. But for me, your code works fine.
br Jozef

Capturing Screenshot in When when Face is detected

i Have to make a code that caputres screenshot when a face is detected in a video so that the image can be used for image recognition dataset
i made a program that captures all frames but i need to make it capture only when a face is detected
import cv2
cap = cv2.VideoCapture('test.mp4')
count = 0
while cap.isOpened():
ret,frame = cap.read()
cv2.imshow('window-name',frame)
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x, y, w, h) in faces:
cv2.imwrite("frame%d.jpg" % count, frame)
count = count + 1
if cv2.waitKey(10) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows() # destroy all the opened windows
I just tried your code and it has 1 small mistake. You don't specify the XML classifier path correctly. I fixed the path using full path where the XML file is located and works successfully.
import cv2
import numpy as np
cap = cv2.VideoCapture('test.mp4')
#cap = cv2.VideoCapture(0) # I tried using webcam and works
count = 0
while cap.isOpened():
ret,frame = cap.read()
cv2.imshow('window-name',frame)
# Below you have to insert the full path of XML file, below is mine
face_cascade = cv2.CascadeClassifier('C:/ProgramData/Anaconda2/pkgs/opencv-3.2.0-np111py27_0/Library/etc/haarcascades/haarcascade_frontalface_default.xml')
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x, y, w, h) in faces:
cv2.imwrite("frame%d.jpg" % count, frame)
count = count + 1
if cv2.waitKey(10) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows() # destroy all the opened windows

OpenCV - Coloring a specific area during video capture?

Here is my code:
import cv2
import numpy as np
cap = cv2.VideoCapture(1)
fourcc = cv2.VideoWriter_fourcc('M','J','P','G')
framesize = (640,480)
out = cv2.VideoWriter('dump.avi',fourcc,60.0,framesize)
font = cv2.FONT_HERSHEY_SIMPLEX
while True:
ret, frame = cap.read()
gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
cv2.imshow('frame',frame)
cv2.rectangle(gray, (0,0),(640,480),(255,255,255),3)
cv2.putText(gray, "gray", (0,130),font, 5,(255,255,255),2, cv2.LINE_AA)
cv2.imshow('fr',gray)
Here I am trying to color a specific square area on the live image feed
#gray[100:105,110:115] = [255,255,255]
io = gray[37:111,107:194]
Here I am cloning an are into another
gray[200:200,270:283] = io
out.write(frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
out.release()
cv2.destroyAllWindows()
How can I color a specific area? As my attempt is not working.

auto detect face and take a snapshot with opencv

i'm working on face recognition project with my college. what i'm trying to take a snapshot and save it if the face is detected automatically before closing the webcam.
what I have now is open cam and wait if face is detected and press "q" to take snapshot and save the image.
Here is the code:
import numpy as np
import cv2
import time
#import the cascade for face detection
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
def TakeSnapshotAndSave():
# access the webcam (every webcam has a number, the default is 0)
cap = cv2.VideoCapture(0)
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
# to detect faces in video
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]
x = 0
y = 20
text_color = (0,255,0)
# write on the live stream video
cv2.putText(frame, "Press q when ready", (x,y), cv2.FONT_HERSHEY_PLAIN, 1.0, text_color, thickness=2)
# if you want to convert it to gray uncomment and display gray not fame
#gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# Display the resulting frame
cv2.imshow('frame',frame)
# press the letter "q" to save the picture
if cv2.waitKey(1) & 0xFF == ord('q'):
# write the captured image with this name
cv2.imwrite('try.jpg',frame)
break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
if __name__ == "__main__":
TakeSnapshotAndSave()
thank you in advance
I adapted your code to save 10 images just for testing, if you want infinite photos, just change the while condition. So in your code you were overwriting the current image so I changed the string parameter so that it was possible to take lots of pictures.
import numpy as np
import cv2
import time
#import the cascade for face detection
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
def TakeSnapshotAndSave():
# access the webcam (every webcam has a number, the default is 0)
cap = cv2.VideoCapture(0)
num = 0
while num<10:
# Capture frame-by-frame
ret, frame = cap.read()
# to detect faces in video
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]
x = 0
y = 20
text_color = (0,255,0)
cv2.imwrite('opencv'+str(num)+'.jpg',frame)
num = num+1
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
if __name__ == "__main__":
TakeSnapshotAndSave()
Perform imwrite() in the for (x,y,w,h) in faces: loop itself. If you use a constant filename, your last detected face will be saved and the rest will be overwritten

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