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POExplain this algorithm (Compare points in SURF algorithm)
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  1. POExplain this algorithm (Compare points in SURF algorithm)
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    copied!<p>I need to know if this algorithm is a known one:</p> <pre><code>void getMatches(IpVec &amp;ipts1, IpVec &amp;ipts2, IpPairVec &amp;matches, float ratio) { float dist, d1, d2; Ipoint *match; matches.clear(); for (unsigned int i = 0; i &lt; ipts1.size(); i++) { d1 = d2 = FLT_MAX; for (unsigned int j = 0; j &lt; ipts2.size(); j++) { dist = ipts1[i] - ipts2[j]; if (dist &lt; d1) // if this feature matches better than current best { d2 = d1; d1 = dist; match = &amp;ipts2[j]; } else if (dist &lt; d2) // this feature matches better than second best { d2 = dist; } } // If match has a d1:d2 ratio &lt; 0.65 ipoints are a match if (d1 / d2 &lt; ratio) { // Store the change in position ipts1[i].dx = match-&gt;x - ipts1[i].x; ipts1[i].dy = match-&gt;y - ipts1[i].y; matches.push_back(std::make_pair(ipts1[i], *match)); } } } </code></pre> <hr> <pre><code>class Ipoint { public: //! Destructor ~Ipoint() { }; //! Constructor Ipoint() : orientation(0) { }; //! Gets the distance in descriptor space between Ipoints float operator-(const Ipoint &amp;rhs) { float sum = 0.f; for (int i = 0; i &lt; 64; ++i) { //std::cout &lt;&lt; i &lt;&lt; "\n"; try { sum += (this-&gt;descriptor[i] - rhs.descriptor[i])*(this-&gt;descriptor[i] - rhs.descriptor[i]); } catch (char *str) { std::cout &lt;&lt; "Caught some other exception: " &lt;&lt; str &lt;&lt; "\n"; } } return sqrt(sum); }; //! Coordinates of the detected interest point float x, y; //! Detected scale float scale; //! Orientation measured anti-clockwise from +ve x-axis float orientation; //! Sign of laplacian for fast matching purposes int laplacian; //! Vector of descriptor components float descriptor[64]; //! Placeholds for point motion (can be used for frame to frame motion analysis) float dx, dy; //! Used to store cluster index int clusterIndex; }; </code></pre> <p>This compares the results of SURF algorithm. </p> <ol> <li>This is a nearest neighbor algorithm? That looks like the func is searching the nearest point of every point. </li> <li>Can I do the same using Quadtree or kd-tree?</li> <li>There is a better algorithm to compare to images points and know if them are the same or similar?</li> <li>Preferable I want to store them into mysql and build a kd-tree to compare 1 image through all images, that's possible?</li> <li>RANSAC is useful for anything in this task?</li> <li>There is any method to catch false positives?</li> </ol>
 

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