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Tag: opencv

How to convert color with OpenCV?

I am struggling with converting red color to another color, blue, yellow, green and so on. I’ve already achieved to convert red color to gray scale color as bellow. But what I really want to achieve is turn a color into another one but not gray scale. How should I change the code or any good reference? …

List available cameras OpenCV/Python

I have multiple webcams connected to my PC and I would like to select one camera based on its info (name, resolution etc.). Is there a way to list all the cameras available on a PC, instead of trying all the indices in cv2.VideoCapture()? Answer The answer is negative. OpenCV doesn’t have a method for l…

CUDA(GPU) as OpenCV backend

Am trying to use CUDA as backend for dnn module provided in opencv-4.1.1 , I have build opencv with CUDA enabled, nvidia drivers and CUDA is properly placed on system, here am using manjaro as development platform. am trying to load pre-trained YOLOv3 weights using cv2.dnn module, But it uses CPU as defualt i…

OpenCV Drawing Contour Error Assertion Failed

So I am trying to follow guide on how to scan a document in https://www.pyimagesearch.com/2014/09/01/build-kick-ass-mobile-document-scanner-just-5-minutes/ exactly on the step 2 process where i am supposed to find the contour and draw it to the image, i got an “Assertion Failed” error on drawConto…

How to read MKV bytes as video?

I am receiving fragment of MKV video in bytes. I need to take 1st frame of it for later processing without saving video in disk. For similar problem with image I use OpenCV or PIL and everything works fine, however, I am not able to do the same with video data. Any tips how to read video from bytes to