sift

co-ordinate of the matched SIFT keypoints

由 自作多情 提交于 2019-12-08 06:57:05
问题 I am doing a project with openCV, where I matched two images with the SIFT keypoints and got good match from the same using K nearest neighbor search. where k=2. Now I want to get the co-ordinate value of the SIFT keypoints which has good match in the image2 and also the co-ordinate value for the corresponding keypoints in Image2. Can any body help me with this. thanks. I find out the solution...It was very easy...silly me...I just converted the keypoints into CvPoints and from that I can

深度学习暑期学校（加拿大、蒙特利尔，2016.8.1-7）

由 半世苍凉 提交于 2019-12-08 00:21:00
learning to see.pdf @lutingting 2016-11-04 16:15 字数 10899 阅读 4087 SIFT特征提取及匹配 数字图像处理 图像特征提取 SIFT特征提取及匹配 1.SIFT（Scale-invariant feature transform）算子的核心思想 2.什么是尺度空间呢？ 2.1 一篇百度文库的文章关于尺度空间的分析 例子1 例子2 现实生活中的例子 2.2 SIFT中的尺度空间的概念 3.SIFT特征提取 3.1 尺度空间极值检测 3.1.1 尺度空间的建立（高斯金字塔的建立） 3.1.2 图像差分高斯金字塔（DoG）的建立 3.1.3 尺度空间中特征点的检测（DoG中极值点的检测） 3.2 关键点位置及尺度确定 3.3 关键点方向确定 3.4 特征向量生成 4.SIFT特征的匹配 5.下面是一些参考程序 5.1 5.2 1.SIFT（Scale-invariant feature transform）算子的核心思想 利用不同尺度的高斯核函数对图像进行平滑，即构造图像的尺度空间 比较不同尺度平滑后的图像差别，在某局部范围内，差别最大或者差别最小的像素点就是特征明显的点 由于SIFT特征的检测方式，使得它具有： 尺度不变性：在尺度空间内进行的特征点检测 2.什么是尺度空间呢？ 2.1 一篇百度文库的文章关于尺度空间的分析

SIFT Taylor Expansion working out subpixel locations

由 杀马特。学长 韩版系。学妹 提交于 2019-12-07 12:06:49
问题 I am trying to implement SIFT and am currently just trying to understand how it works before starting to implement it in MATLAB, i understand most of it except how to work out subpixel accuracy using Taylor Expansion: Above is the equation from the original paper. I have a few question on how it is applied. Are the derivatives worked out in each dimension seperatly and then the equation applied to x then y? Are the first and second derivates applied along the sigma axis aswell? I have tired

Opencv 3.0 - module object has no attribute 'xfeatures2d'

由 纵饮孤独 提交于 2019-12-06 18:12:30
问题 I have shifted from OpenCV 2.4.9 to 3.0 to make use of drawMatches and drawMatchesKnn function. I came to know that it does not come along with non-free algorithms like SIFT , SURF. So I installed opencv_contrib from https://github.com/Itseez/opencv_contrib by following steps cmake -DOPENCV_EXTRA_MODULES_PATH=/home/zealous/Downloads/opencv_contrib-master/modules /usr/local .. make -j5 make install I also cross checked in modules of opencv , xfeatures2d was there. Then when I tried to do >>>

Using SIFT descriptors to compare similarity between two images

由 梦想与她 提交于 2019-12-06 16:46:36
问题 I'm using the SIFT algorithm to determine the level of similarity between two images. I managed to get the list of descriptors for image but I cant seem to figure what to do next. My problem is that I have a different number of descriptors and their order is maybe not the same. What is the best way to compare these descriptors? Thanks. 回答1: Basic euclidean distance together with a heuristic that stipulated that a match is only accepted if it is significantly better than the second best match.

how to use SIFT features for bag of words in opencv?

由 ╄→尐↘猪︶ㄣ 提交于 2019-12-06 05:52:28
问题 I have read a lot of articles about implementing bag of words after taking sift features of an image, but I'm still confused what to do next. What do i specifically do? Thank you so much in advance for the guidance. This is the code that i have so far. cv::Mat mat_img = cropped.clone(); Mat grayForML; cvtColor(mat_img, grayForML, CV_BGR2GRAY); IplImage grayImageForML = grayForML.operator IplImage(); //create another copy of iplGray IplImage *input = cvCloneImage(&grayImageForML); Mat matInput

SIFT and SURF feature extraction Implementation using MATLAB

由 ╄→尐↘猪︶ㄣ 提交于 2019-12-06 04:18:59
问题 I am doing an ancient coins recognition system using matlab. What I have done so far is: convert to grayscale remove noise using Gaussian filter contrast enhancement edge detection using canny edge detector. Now I want to extract feature for classification. Features I thought to select are roundness, area, colour, SIFT and SURF. My problem is how I can apply SIFT and SURF algorithms to my project. I couldn't find built-in functions for both. 回答1: you can find a matlab implementation of SIFT

Similar image search using an image

由 萝らか妹 提交于 2019-12-06 02:32:47
问题 I am working on a project in which the two images will be checked for similarity like 'Google Image Search by image'. I searched through Google and also on various sites including stackoverflow and learnt about various techniques like histogram, sift, fourier transform, pixel grabbing, etc. The things are too complex for me to understand being a beginner in this field. My questions are: From where can i get started?? Is there any book available or a site which give tutorials for learning

SIFT Taylor Expansion working out subpixel locations

由 走远了吗. 提交于 2019-12-06 01:16:44
I am trying to implement SIFT and am currently just trying to understand how it works before starting to implement it in MATLAB, i understand most of it except how to work out subpixel accuracy using Taylor Expansion: Above is the equation from the original paper. I have a few question on how it is applied. Are the derivatives worked out in each dimension seperatly and then the equation applied to x then y? Are the first and second derivates applied along the sigma axis aswell? I have tired looking at previous implementations but cannot seam to find where they do this. Thanks in advance Faroq

Feature Extraction with Javascript

由 青春壹個敷衍的年華 提交于 2019-12-05 23:29:34
问题 I am wondering whether there is any open source or free library for Image feature extraction with Javascript? I am developing an app where I need to use an algorithm like SIFT. It is tough to implement in JS, and I couldn't find a good SIFT implementation in JS. I thought of implementing a feature extraction library in JS if one doesn't exist. Please can anybody help me to find a good solution or guide me to write one from scratch. Thanks, Keshan. 回答1: I'm not familiar with implementation for
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