When the normType is NORM_MINMAX, cv::normalize normalizes _src in such a way that the min value of dst is alpha and max value of dst is beta. cv::normalize does its magic using only scales and shifts (i.e. adding constants and multiplying by constants). CV_8UC1 says how many channels dst has. The documentation here is pretty … Read more
OpenCV has region of interest functions which you may find useful. If you are using the cv::Mat then you could use something like the following. // You mention that you start with a CVMat* imagesource CVMat * imagesource; // Transform it into the C++ cv::Mat format cv::Mat image(imagesource); // Setup a rectangle to define your … Read more
“The reason why the early developers at OpenCV chose BGR color format is probably that back then BGR color format was popular among camera manufacturers and software providers. E.g. in Windows, when specifying color value using COLORREF they use the BGR format 0x00bbggrr. BGR was a choice made for historical reasons and now we have … Read more
I had the same problem. It seems that SIRF and SURF are no longer available in opencv > 3.4.2.16. I chose an older opencv-python and opencv-contrib-python versions and solved this problem. Here is the history version about opencv-python, and I use the following code : pip install opencv-python==3.4.2.16 pip install opencv-contrib-python==3.4.2.16 Edit For Anaconda User … Read more
Given your configuration, errors of 20-40mm at the edges are average. It looks like you’ve done everything well. Without modifying camera/system configuration, doing better will be hard. You can try to redo camera calibration and hope for better results, but this will not improve them alot (and you may eventually get worse results, so don’t … Read more
First of all: the function minMaxLoc finds only the global minimum and global maximum for a given input, so it is mostly useless for determining regional minima and/or regional maxima. But your idea is right, extracting markers based on regional minima/maxima for performing a Watershed Transform based on markers is totally fine. Let me try … Read more
This is from pylint. You can generate a pylint config file in the root of your project with this command: (I find this to be helpful if you work in a team or on different computers from the same repo) pylint –generate-rcfile > ~/.pylintrc At the beginning of the generated .pylintrc file you will see … Read more
From your question I guess you are using Ubuntu (or a derivate). If you use: apt-file search opencv.pc then you see that you have to install libopencv-dev. After you do so, pkg-config –cflags opencv and pkg-config –libs opencv should work as expected.
Let’s tackle each point one by one: My question is what actually are these keypoints? Keypoints are the same thing as interest points. They are spatial locations, or points in the image that define what is interesting or what stand out in the image. Interest point detection is actually a subset of blob detection, which … Read more
Since AR applications often run on mobile devices, you could consider also other features detector/descriptor: FREAK ORB