sift

问题 I want get the SIFT feature for specified points. These points is gotten by hand not by KeyPoint Detector. My question is: I only know the position of the points but have no idea about the size and angle value. How should I set this value? Here is my code: int main() { Mat img_object = imread("img/test.jpg", 0); SiftDescriptorExtractor extractor; Mat descriptors; std::vector<KeyPoint> keypoints; // set keypoint position and size: should I set // size parameter to 32 for 32x32 patch? KeyPoint

问题 Ive been trying out SIFT/SURF from online resources and wanted to test it out myself. I first tried without the non-free libraries using this code: int _tmain(int argc, _TCHAR* argv[]) { Mat img = imread("c:\\car.jpg", 0); Ptr<FeatureDetector> feature_detector = FeatureDetector::create("SIFT"); vector<KeyPoint> keypoints; feature_detector->detect(img, keypoints); Mat output; drawKeypoints(img, keypoints, output, Scalar(255, 0, 0)); namedWindow("meh", CV_WINDOW_AUTOSIZE); imshow("meh", output)

问题 I followed this tutorial I have this code, but no log file was written. What am i missing? here is my code: https://github.com/elad2109/log4j_sift/blob/master/src/main/java/com/waze/rr_logger/SiftExampleLog4j.java import org.apache.log4j.Logger; import org.slf4j.LoggerFactory; public class SiftExampleLog4j { static org.apache.log4j.Logger logger = Logger.getLogger(SiftExampleLog4j.class); public void log() { BasicConfigurator.configure(); org.apache.log4j.MDC.put("session_id","MyGooApp");

问题 I am using sift algorithm in opencv code to get descriptors and keypoints from images.My code is Ptr<IplImage> image; vector<KeyPoint> keypoints; OutputArray des; Feature2D *descriptor_type = new SIFT() Mat image_mat(image); (*descriptor_type)(image_mat,noArray(),keypoints,des,false); Here I can get the keypoints of the image in vector < KeyPoint > .After that,I want to get the Octave of each KeyPoint for more details .But when I cout each keypoint octave value for one image,it seems so

问题 I am trying to use OpenCV to match images like these: img2 http://img849.imageshack.us/img849/8177/clearz.jpg And I need to find the best intersection of them. I tried using SURFDetector and matching using BruteforceMatcher, but finds descriptors not equal. Tell me please the correct way to solve problem. 回答1: Did you have a look to this code example? Here you can see how to find an object using SURF descriptors. Go to main(), and check the code step by step. You can try it with your images

问题 Is there any C/C++ implementation of SIFT that runs in realtime in a processor of ~2.2GHz and a RAM of 4GB? Or what is the lowest achievable runtime for extracting SIFT features and descriptors of ~2000 keypoints. The C++ implementation by Andrew Vedaldi takes around 3.5 seconds for 2000 keypoints. 回答1: Generaly NO. Exact implementation of SIFT can't run in real time even with modern PC. But there is a implementations on GPU http://cs.unc.edu/~ccwu/siftgpu/. The faster alternative is SURF,

问题 I'm trying to get started working with sift feature extraction using (C++) OpenCv. I need to extract features using SIFT, match them between the original image (e.g. a book) and a scene, and after that calculate the camera pose. So far I have found this algorithm using SURF. Does anyone know a base code from which I can get started, or maybe a way to convert the algorithm in the link from SURF to SIFT? Thanks in advance. EDIT: Ok, I worked out a solution for the sift problem. Now I'm trying

问题 i am using SIFT algorithm in matlab to determine the similarity between template image and a set of images, where in the end i have to determine the best match between set of images on the basis of SCORES,is it true to say that higher the score of an image the better the match? i am aware that when there is an exact match, the score is zero, but what if the image is similar? 回答1: I assume by SCORES you mean a similarity measurement between a pair of matched descriptors (e.g. euclidean

问题 I am trying to use vl_dsift to get the 128*1 feature vectors at every pixel. Therefore I want the resulting matrix to have size 128*(#OfPixels) However when I use it on an image of size (192*168) then the resulting descriptor gives size (128*31,185) with a binsize of 1 and a magnification factor of 1. I = imread('Faces\yaleB11_P00A-130E+20.pgm'); size(I) figure imshow(I) binSize = 1 ; magnif = 1 ; Is = vl_imsmooth(single(I), sqrt((binSize/magnif)^2 - .25)) ; [f, d] = vl_dsift(single(I), 'size

问题 Can any one explain to me where is this error come from? and what does it mean? and how can I fix that? Maybe my question is so general! sorry but I don't know what should I put more here! :P Error: Traceback (most recent call last): File "C:\test\7.4.3.bench.py", line 9, in <module> print imagesearch.compute_ukbench_score(src,imlist[:100]) File "C:\test\imagesearch.py", line 168, in compute_ukbench_score pos[i] = [w[1]-1 for w in src.query(imlist[i])[:4]] File "C:\test\imagesearch.py", line