opencv - cv::SVM response one class for every sample -


i new in match faces , trying learn how use svm hog descriptors. wrote simple face recognizer svm, when activate , code returns 1

float *gethog(const cv::mat &image, int* count)//compute hog {     cv::hogdescriptor hog;     std::vector<float> res;     cv::mat img2;     cv::resize(image, img2, cv::size(64, 128));     hog.compute(img2, res, cv::size(8, 8), cv::size(0, 0));     *count = res.size();     float* result = new float[*count];     for(int = 0; < res.size(); i++)     {         result[i] = res[i];     }     return result; }  const int datasetlength = 10; float **gettraininigdata(int* setlen, int* veclen)//load samples of data {     char *names[datasetlength] = {         "../faces/s1/1.pgm",         "../faces/s1/2.pgm",         "../faces/s1/3.pgm",         "../faces/s1/4.pgm",         "../faces/s1/5.pgm",         "../faces/cars/1.jpg",         "../faces/cars/2.jpg",         "../faces/cars/3.jpg",         "../faces/cars/4.jpg",         "../faces/cars/5.jpg",     };      float **res = new float* [datasetlength];     for(int = 0; < datasetlength; i++)     {         std::cout<<names[i]<<"\n";         cv::mat img = cv::imread(names[i], 0);         res[i] = gethog(img, veclen);     }     *setlen = datasetlength;     return res; }  void test()//training , activate svm {     int setlen, veclen;     float **trainingdata = gettraininigdata(&setlen, &veclen);     float *labels = new float[datasetlength];     for(int = 0; < datasetlength; i++)     {         labels[i] = (i < datasetlength/2)? 0.0 : 1.0;     }     cv::mat labelsmat(setlen, 1, cv_32fc1, labels);     cv::mat trainingdatamat(setlen, veclen, cv_32fc1, trainingdata);      cv::svmparams params;     params.svm_type    = cv::svm::c_svc;     params.kernel_type = cv::svm::linear;     params.term_crit   = cv::termcriteria(cv_termcrit_iter, 100, 1e-6);     std::cout<<labelsmat<<"\n";      cv::svm svm;     svm.train(trainingdatamat, labelsmat, cv::mat(), cv::mat(), params);     cv::mat img = cv::imread("../faces/s1/2.pgm", 0);//sample train data, ansewer 1 every sample     auto desc = gethog(img, &veclen);     cv::mat samplemat(1, veclen, cv_32fc1, desc);     float response = svm.predict(samplemat);     std::cout<<"resp "<< response<<"\n"; }

what wrong code ?

ps sorry writing mistakes. english in not native language

  1. you don't have training data. note how dalal , triggs in original paper on hog (http://lear.inrialpes.fr/people/triggs/pubs/dalal-cvpr05.pdf) used thousands of examples train svm, have 5 negative , 5 positive.
  2. you haven't set c parameter (you need find value via cross validation) - need more data.
  3. possibly hog descriptors faces , cars not separable linear kernel, try rbf. unlikely issue since d&l use linear svm in paper.
  4. read this: http://www.csie.ntu.edu.tw/~cjlin/papers/guide/guide.pdf
  5. if haven't done yet, svm working simpler case (e.g. use image patches instead of hog).

Comments

Post a Comment

Popular posts from this blog

.htaccess - First slash is removed after domain when entering a webpage in the browser -

sometimes when hit address of webpage in browser, removes first slash after domain. examples: www.mywebsite.com/scripts/script_6.php -> trying load www.mywebsite.comscripts/script_6.php www.mywebsite.com/test.php -> trying load www.mywebsite.comtest.php after entering again, loads page. a .htaccess settings must wrong: rewritebase / errordocument 404 http://www.mywebsite.com/oops.php errordocument 401 /notallowed.php rewriteengine on # turn on rewriting engine #gzip <ifmodule mod_deflate.c> addoutputfilterbytype deflate text/text text/html text/plain text/xml text/css application/x- javascript application/javascript </ifmodule> #end gzip rewritecond %{http_host} ^mywebsite\.com rewriterule ^(.*)$ http://www.mywebsite.com$1 [r=permanent,l] directoryindex index6.php rewriterule ^termsofuse/?$ termsofuse.php [nc,l] # handle requests "adpolicy" rewriterule ^privacy-policy/?$ privacy-policy.php [nc,l] # handle requ...
Read more

Automatically create pages in phpfox -

i have array of information of places , wanna use them create multiple pages in phpfox site. first tried manually insert data in phpfox database (in tables of phpfox_pages , phpfox_pages_text ). the page shown in site when opening it's link, site says: the page looking cannot found. do know other tables should manipulate make work? or know plugin phpfox same? thanks, solved ( @purefan guide): "pages" has user if take @ phpfox_user table, you'll found out how fetch new records on that. there 2 ambiguous fields in table ( password & password_salt ). can use script create values fields: <?php function generaterandomstring() { $length = 164; $characters = '-_0123456789abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz'; $randomstring = ''; ($i = 0; $i < $length; $i++) { $randomstring .= $characters[rand(0, strlen($characters) - 1)]; } return $randomstring; } $ssalt = '';...
Read more

c# - Farseer ContactListener is not working -

i'm using farseer in xna project, have trouble contactlistener. created class contactlistener these 2 error messages , don't know how fix problems. the type or namespace name 'contactlistener' not found (are missing using directive or assembly reference?) the type or namespace name 'contactimpulse' not found (are missing using directive or assembly reference?) what wrong contactlistener class? class mycontactlistener: contactlistener { void begincontact(contact contact) { /* handle begin event */ } void endcontact(contact contact) { /* handle end event */ } void presolve(contact contact, ref manifold oldmanifold) { fixture fixturea = contact.fixturea; fixture fixtureb = contact.fixtureb; if (fixtureb.collisioncategories == category.cat10) { contact.enabled = false; } } void postsolve(contact contact, ref contactimpulse impulse) { /* handle post-solve event */ } }...
Read more