You can also use mp4v fourcc = cv2.VideoWriter_fourcc(*’mp4v’) where the videowriter should look like this: out = cv2.VideoWriter(‘output.mp4’,fourcc, 15, size) But there are more codecs available for mp4. You can see the list of them by setting fourcc = -1, it will show a list like this: OpenCV: FFMPEG: format mp4 / MP4 (MPEG-4 Part … Read more
BGR and RGB are not color spaces, they are just conventions for the order of the different color channels. cv2.cvtColor(img, cv2.COLOR_BGR2RGB) doesn’t do any computations (like a conversion to say HSV would), it just switches around the order. Any ordering would be valid – in reality, the three values (red, green and blue) are stacked … Read more
If you read the documentation it is mentioned this function implements the algorithm of: Suzuki, S. and Abe, K., Topological Structural Analysis of Digitized Binary Images by Border Following. CVGIP 30 1, pp 32-46 (1985) OpenCV is open source if you want to see how this is implemented just need to read the code: https://github.com/opencv/opencv/blob/master/modules/imgproc/src/contours.cpp#L1655 … Read more
In my opinion the most universal way to store the keypoints is to first convert them to a data-interchange format like JSON. After you are able to do that conversion you have a lot of flexibility to store it. JSON is easily converted to a String and/or sent through a network connection. With OpenCV C++ … Read more
By default all gpu module functions are synchronous, i.e. current CPU thread is blocked until operation finishes. gpu::Stream is a wrapper for cudaStream_t and allows to use asynchronous non-blocking call. You can also read “CUDA C Programming Guide” for detailed information about CUDA asynchronous concurrent execution. Most gpu module functions have additional gpu::Stream parameter. If … Read more
You can use: cvGetWindowHandle() to obtain Widows handler. Then using regular windows API you can do anything you like
This can be done faster, by reshaping and swapping axes, and then repeating over all kernel elements, like this: im = np.arange(81).reshape(9,9) print np.swapaxes(im.reshape(3,3,3,-1),1,2) This gives you an array of 3*3 tiles which tessalates across the surface: [[[[ 0 1 2] [[ 3 4 5] [[ 6 7 8] [ 9 10 11] [12 13 … Read more
In order to be able to send an image via HTTP, you also need to encode its width, height and type. You need to serialize the Mat into a stream and encode that stream with libb64. On the other side you need to decode that stream and deserialize the image to retrieve it. I implemented … Read more
This is an update to my initial answer after I had a chance to play with this myself. Yes, it is possible to use CvVideoCamera with a view controller written in Swift. If you just want to use it to display video from the camera in your app, it’s really easy. #import <opencv2/highgui/cap_ios.h> via the … Read more
My development environment is set up as follows: android-ndk-r10d (install path: D:\adt-bundle-windows-x86_64-20140702\android-ndk-r10d\) OpenCV-2.4.10-android-sdk (install path: D:\CODE\OpenCV-2.4.10-android-sdk\), Download link OpenCV-2.4.10 (install path: D:\CODE\OpenCV-2.4.10\), Download link Building the nonfree module We actually only need to copy a few files from OpenCV-2.4.10 source code to OpenCV-2.4.10-android-sdk, namely: Copy the nonfree folder from OpenCV-2.4.10\sources\modules\nonfree\include\opencv2\ to OpenCV-2.4.10-android-sdk\sdk\native\jni\include\opencv2. Create a folder … Read more