The earlier answers are good, but they won’t work for non-continuous matrices which arise when you want to serialize regions of interest (among other things). Also, it is unnecessary to serialize elemSize() because this is derived from the type value. Here’s some code that will work regardless of continuity (with includes/namespace) #pragma once #include <boost/archive/text_oarchive.hpp> … Read more
I think you may be thinking of tvecs_new as the camera position. Slightly confusingly that is not the case! In fact it is the position of the world origin in camera co-ords. To get the camera pose in the object/world co-ords, I believe you need to -np.matrix(rotation_matrix).T * np.matrix(tvecs_new) And you can get the Euler … Read more
cv::Mat::copyTo does one of two things depending on whether the output matrix has been initialized. If your output matrix is not initialized, using copyTo with a mask creates a new output matrix that is the same type as the input and all of the values are set to 0 over all channels. Once that happens, … Read more
This is my solution for python 3.7 and without using PIL import base64 def readb64(uri): encoded_data = uri.split(‘,’)[1] nparr = np.fromstring(base64.b64decode(encoded_data), np.uint8) img = cv2.imdecode(nparr, cv2.IMREAD_COLOR) return img i hope that this solutions works for all
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
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
The hierarchy returned by findContours has the following form: hierarchy[idx][{0,1,2,3}]={next contour (same level), previous contour (same level), child contour, parent contour} CV_RETR_CCOMP, returns a hierarchy of outer contours and holes. This means elements 2 and 3 of hierarchy[idx] have at most one of these not equal to -1: that is, each element has either no … Read more
I can suggest one of the following solutions: Using local high level features: OpenCV includes SURF, so: for each frame, extract SURF features. Then build feature Kd-Tree (also in OpenCV), then match each two consecutive frames to find pairs of corresponding features. Feed those pairs into cvFindHomography to compute the homography between those frames. Warp … Read more
The feature data you mention (position, laplacian, size, orientation, hessian) is insufficient for your purpose (these are actually the less relevant parts of the descriptor if you want to do matching). The data you want to look at are the “descriptors” (the 4th argument): void cvExtractSURF(const CvArr* image, const CvArr* mask, CvSeq** keypoints, CvSeq** descriptors, … Read more
This is a linker issue. Try: g++ -o test_1 test_1.cpp `pkg-config opencv –cflags –libs` This should work to compile the source. However, if you recently compiled OpenCV from source, you will meet linking issue in run-time, the library will not be found. In most cases, after compiling libraries from source, you need to do finally: … Read more