[Python] camera can't open while running a flask app from docker on a windows system...

i get this error when trying to open a camera from a flask app running in docker:

172.17.0.1 - - [17/Mar/2025 11:24:10] "GET / HTTP/1.1" 200 -
[2025-03-17 11:24:19,498] ERROR in app: Exception on /detect_faces [POST]
Traceback (most recent call last):
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 1511, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 919, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 917, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 902, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
File "/face_app/face_recognition_.py", line 114, in detect_faces_api
result = detect_faces(image_path, video_capture)
File "/face_app/face_recognition_.py", line 48, in detect_faces
small_frame = cv2.resize(frame, (0, 0), fx=0.25, fy=0.25)
cv2.error: OpenCV(4.11.0) /io/opencv/modules/imgproc/src/resize.cpp:4208: error: (-215:Assertion failed) !ssize.empty()


my code:

def detect_faces_api():

timestamp = int(time.time())
video_capture = cv2.VideoCapture(0,cv2.CAP_DSHOW)

image = request.files['image']
image_path = '/face_app/'+str(timestamp)+ '.jpg'
image.save(image_path)

result = detect_faces(image_path, video_capture)

video_capture.release()
cv2.destroyAllWindows()


i need to run this app in a Linux server once it's done can someone help me

the app works fine when running on my computer but i get this error in docker i did have video_capture = cv2.VideoCapture(0) first but i get the error

72.17.0.1 - - [14/Mar/2025 15:45:53] "GET / HTTP/1.1" 200 -
[ WARN:0@13.565] global cap_v4l.cpp:913 open VIDEOIO(V4L2:/dev/video0): can''t open camera by index
[ERROR:0@13.566] global obsensor_uvc_stream_channel.cpp:158 getStreamChannelGroup Camera index out of range
[2025-03-14 15:46:02,507] ERROR in app: Exception on /detect_faces [POST]
Traceback (most recent call last):
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 1511, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 919, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 917, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 902, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
File "/face_app/face_recognition_.py", line 113, in detect_faces_api
result = detect_faces(image_path, video_capture)
File "/face_app/face_recognition_.py", line 48, in detect_faces
small_frame = cv2.resize(frame, (0, 0), fx=0.25, fy=0.25)
cv2.error: OpenCV(4.11.0) /io/opencv/modules/imgproc/src/resize.cpp:4208: error: (-215:Assertion failed) !ssize.empty() in function 'resize'


i also tried cv2.VideoCapture(1), cv2.VideoCapture(2), cv2.VideoCapture(-1), cv2.VideoCapture(1,cv2.CAP_V4L2), and every thing

my dockerfile

FROM python:3.9-slim

RUN apt-get update && apt-get install -y \
build-essential \
cmake \
gfortran \
wget \
libboost-all-dev \
libatlas-base-dev \
libopenblas-dev \
liblapack-dev \
libx11-dev \
tesseract-ocr \
libgl1-mesa-glx \
libglib2.0-0 \
libsm6 \
libxrender1 \
libxext6 \
&& rm -rf /var/lib/apt/lists/*


COPY requirements.txt /face_app/
RUN pip install --no-cache-dir -r /face_app/requirements.txt

WORKDIR /face_app

COPY . /face_app

EXPOSE 5000

ENV NAME=World

CMD ["python", "face_recognition_.py"]


docker build -t docker-face-app .

how i run the app:

docker run -p 5000:5000 docker-face-app

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