feature-detection

问题 I want to track an object(for example, a moving ball) in a video. Referring to opencv tutorial - 'Features2D + Homography to find a known object', I have been able to track my object in a still image by providing a reference image. I plan to use a reference image to detect the moving object from the first frame of input video. For the next frame the object detected in previous frame should act as a reference image and so on. But I don't know how to find back an object from its descriptor. An

问题 I created a form on a website that allows users to upload files. Users can also drag and drop files onto this form. However, on some devices, it is simply not possible to drag and drop files (e.g. on my iPhone). So I only want to display the text "Drag and drop files here" only on devices on which it makes sense. Is there a way to detect whether the device supports drag and drop files in principle? A workaround could be to detect if a mouse pointer is moving. In this case, I would guess it is

来源： https://stackoverflow.com/questions/53151595/how-to-build-a-custom-opencv-js-with-opencv-contrib

来源： https://stackoverflow.com/questions/53151595/how-to-build-a-custom-opencv-js-with-opencv-contrib

来源： https://stackoverflow.com/questions/53151595/how-to-build-a-custom-opencv-js-with-opencv-contrib

问题 Problem So I am fairly new to Computer Vision in general. I am currently trying to calculate a homography by analyzing 2 images. I want to use the homography to correct the perspective of 1 image to match the other. But the matches I am getting are just bad and wrong. So the homographic warp I do is completely off. Current state I am using EmguCV for wrapping opencv in C#. I got as far as that my code seems to work "properly". I load my two images and declare some variables to store

问题 Problem So I am fairly new to Computer Vision in general. I am currently trying to calculate a homography by analyzing 2 images. I want to use the homography to correct the perspective of 1 image to match the other. But the matches I am getting are just bad and wrong. So the homographic warp I do is completely off. Current state I am using EmguCV for wrapping opencv in C#. I got as far as that my code seems to work "properly". I load my two images and declare some variables to store

问题 I am starting a new project that will be targeting MSVC , GCC (latest) , GCC 4.3 ARM and more. The waf build system we have built has C++11 feature detection of the compiler. I now have preprocessor macros for all features in compiler that I am targeting for C++11 , for example #ifdef WAF_FEATURE_CXX_STRONGLY_TYPED_ENUMS . I can therefore compile different code for what the compiler supports. As GCC nearly supports it all be MSVC isn't even close (even with MSVC 11) This got me thinking about

问题 is there a way to detect if calling play() on a video element is allowed without a user gesture? On Android Chrome this warning is given: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture. So on Chrome Android a user gesture is required to start the playback of a video, while it isn't on desktop Chrome. Is there a way to detect which behavior I will get? I want to have slightly different behavior in my app depending on if calling play programatically

问题 is there a way to detect if calling play() on a video element is allowed without a user gesture? On Android Chrome this warning is given: Failed to execute 'play' on 'HTMLMediaElement': API can only be initiated by a user gesture. So on Chrome Android a user gesture is required to start the playback of a video, while it isn't on desktop Chrome. Is there a way to detect which behavior I will get? I want to have slightly different behavior in my app depending on if calling play programatically