OpenCV TUTORIAL #2 How to Change Resolution or Rescale Frame in OpenCV with Python

OpenCV with Python Series #2 : How to Change Resolution or Rescale Frame

Install OpenCV for Python on your system:

[xslnx]

I believe the scaling didnt work on your example because of the variable scale_percent in the function rescale_frame:
it is set up scale_percent = 75 always if im not mistaken, if you set its value to the passed argument "percent" it works
def rescale_frame(frame, percent=75):
scale_percent = percent
# rest of code

Let me know if im wrong, im learning python myself...

Also, great tut.. ill be following for more!

[hamadahiro]

Hi, good video thank you! Do you think that should the scale_percent variable in the 24th line be the percent parameter? That's works for me as it is by default 75% so it is not much different in your example.

[daniyalhussain]

Nice vids, but when I started this project my grayscale stopped working and now its also not resizing, so can I have some help, please.

[krdshow]

Nice video sir !!! Thankyou for this!! Can you please tell, how to change the brightness and contrast of real time web cam??

[haley]

I'm watching this on my 4:20 monitor. Thanks!

[shubhamchawdhary]

Thank you I'm search alot for this video❤️

[anitasigamani]

cv2.error: OpenCV(4.3.0) error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'cv::imshow'

[marcossoto]

Hi, thanks for the explanation ... I have done the source code test and I have realized that it only works for a webcam.
But what would the procedure be like for an ip type camera?

[achebepeter]

Really don't know if this is important, I feel when you added a factor of 500 and it refused to scale was because frame used in the argument of frame2 is redefined as rescale_frame(frame, percent=30) in stead of its original value in cap.read(). I hope I am correct.

[msds]

What if my objective is to reduce the frames per second? Say from 30 fps 1080p, I want to make it 2 fps (for analysis)?

[leohsusolid]

Hi Justin, May I ask you that how I can rescale the video stream on tkinter interface with canvas.create_image()? I tried to rescale with canvas.scale(), however, it obviously didn't work. If you are willing to give me some suggestions, I would really appreciate that! Thank you for the great videos sharing!

[gallilos]

but can u change resolution, inside the WHILE ?? can i change it on the fly or do i need to stop the running and begin from the start?? tnx

[anitasigamani]

can you tell how to sort this
cv2.error: OpenCV(4.3.0) error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'cv::imshow'

[ashovav]

Good video thank you! Have you ever tried to run the open cv object tracking on the raspberry pi 3? with a 480/360 camera resolution, object detection per frame takes around 150-200 ms, which is quite disappointing for an 4xARM7. Thank you. Terence

[fpgamachine]

Thanks for the video, it helped my a lot!

[sureshbabu_r]

Thanks for your nice video. Its possible to resolution switches one to another with automatically using script?. Kindly reply to me.

[shrinithamonica]

can you please upload a video on emotion recognition using facial expressions

[alan]

I used video as input instead of camera, why change_res didn't work but rescale worked?

[BrunoRibeiro-xcet]

Thank you very much man you helped me a lot <3

[배상은-lc]

Thank you! Does this work when I use VideoStream instead of VideoCapture as well? Thanks.