feature-detection

问题 I have a short question: When I do feature-matching in OpenCV, what does the distance attribute mean of DMatches in MatOfMatches ? I know that I have to filter matches with bigger distance because they aren't as good as them with lower distance. But what is the meaning of this attribute? Is it a kind of deviation? 回答1: In this context, a feature is a point of interest on the image. In order to compare features, you "describe" them using a feature detector . Each feature is then associated to

问题 I need to get the list of the x and y coordinates of the pixels that the feature matcher selects in the code provided. I'm using Python and OpenCV. Can anyone help me? img1=cv2.imread('DSC_0216.jpg',0) img2=cv2.imread('DSC_0217.jpg',0) orb=cv2.ORB(nfeatures=100000) kp1,des1=orb.detectAndCompute(img1,None) kp2,des2=orb.detectAndCompute(img2,None) img1kp=cv2.drawKeypoints(img1,kp1,color=(0,255,0),flags=0) img2kp=cv2.drawKeypoints(img2,kp2,color=(0,255,0),flags=0) cv2.imwrite('m_img1.jpg',img1kp

问题 What I have done : Taken input image and resized image to standard size as I have to compare it with template. converted in binary using threshold value. Detected connected component and displayed largest component. As it is whole hand.as shows here: Place image at same coordinates to check placement of finger for comparison with template image but their positioning is different purple one is template image I m doing comparison of image with Image subtraction method. These case will not able

问题 I am using HTML5 <input type="date" /> , which works fine in Chrome and I get the calendar popup to select the date. But in firefox it acts like a text box and no calendar pops up. After doing few research I see few solutions using webshims, modenizr, etc... but I do not want to use jQuery. Is there an alternative for this? How can I make it work in Firefox ? 回答1: EDIT : from Firefox 57, <input type="date"/> is partially supported. Firefox doesn't support HTML5's <input type="date"/> yet. You

问题 SURF is patented, as is SIFT. ORB and BRIEF are not patented, but their features are not scale-invariant, seriously limiting their usefulness in complex scenarios. Are there any feature extractors that can extract scale-invariant features as fast as SURF and are not so strictly patented as SURF and SIFT? 回答1: Although you already choose BRISK, you might find FREAK interesting. Author claims to have better results than BRISK and ORB. I should also add that ORB is scale-invariant but has some

问题 I am new to opencv and trying to implement image matching between two images. For this purpose, I'm trying to understand the difference between feature descriptors, descriptor extractors and descriptor matchers. I came across a lot of terms and tried to read about them on the opencv documentation website but I just can't seem to wrap my head around the concepts. I understood the basic difference here. Difference between Feature Detection and Descriptor Extraction But I came across the

问题 I am in the process of creating a small program which detects objects(small image) in the large image and I am using OpenCV java. As I have to consider rotation and scaling I have used FeatureDetector.BRISK and DescriptorExtractor.BRISK. Following approach is used to filter the match results to get the best matches only. I have two questions Is there a way to find the below min_dist and max_dist with the loop I have used? Most important question - Now the problem is I need to use these

问题 I have a texture-heavy OpenGL game that I'd like to tune based on how much RAM the device has. The highest resolution textures I have work fine on an iPhone 4 or iPad2, but earlier devices crash in the middle of loading the textures. I have low-res versions of these textures, but I need to know when to use them. My current tactic is to detect specific older devices (3GS has a low-res screen; iPad has no camera), then only load the hi-res textures for IPad2 and above and iPhone 4 and above —

问题 IE10+ no longer supports browser detection tags to identify a browser. For detecting IE10 I am using JavaScript and a capability-testing technique to detect certain ms prefixed styles are defined such as msTouchAction and msWrapFlow . I want to do the same for IE11, but I am assuming that all the IE10 styles will be supported in IE11 as well. Can anyone help me identify IE11 only styles or capabilities that I could use to tell the two apart? Extra Info I don\'t want to use User Agent type