c# - OpenCV MatchTemplate on GPU -


in c# project need fast template matching algorithm. have opencv implementation. simplified code is:

 using opencvsharp;  using opencvsharp.cplusplus;  // ...   var image = new mat("image.png");  var template = new mat("template.png");   double minval, maxval;  point minloc, maxloc;  var result = image.matchtemplate(template, matchtemplatemethod.ccoeffnormed);  result.minmaxloc(out minval, out maxval, out minloc, out maxloc);  console.writeline("maxloc: {0}, maxval: {1}", maxloc, maxval);

i'd same calculations on gpu speed them significantly, cannot find example of how that. example on github commented out , doesn't seem working.

i've attempted port opencv's matchtemplate() function gpu before.

they give equations in their documentation method. called "normalized cross-correlation."

enter image description here

the naive approach port gpu (i did pixel shader). turned out slower opencv's cpu method. why? using method called "fast normalized cross-correlation" outlined in this paper j.p lewis ilm.

the trick correlation in frequency domain , take advantage of convolution theorem: point-wise multiplication in frequency domain equivalent convolution in spatial domain. means time complexity reduced, , have add fft.


Comments

Post a Comment

Popular posts from this blog

powershell Start-Process exit code -1073741502 when used with Credential from a windows service environment -

i'm running strange behavior powershell start-process call. here call: $process = start-process ` "c:\somepath\mybinary.exe" ` -passthru ` -credential $defaultcredential ` -wait ` -workingdirectory "c:\somepath" ` -loaduserprofile if ($process.exitcode -ne 0) { #do } this call return exit code - 1073741502 . after quick search, exit code seems related generic error when program not load required dll (aka. status_dll_init_failed ). when run without -credential $credential program runs correctly. in order isolate problem, manually launched some.exe in prompt target credential , runs smoothly. so problem seems come way start-process cmdlet launch process. i found potential solutions problem tried apply no luck : link , link . would have idea of what's going on here ? edit 1: run proc mon monitoring program activities when launched directly or via powershell script. problem seems occur when loading kernelbase
Read more

twig - Using Twigbridge in a Laravel 5.1 Package -

i'm trying create laravel 5.1 package uses twigbridge instead of .php views. can normal .php views display fine, when try make use of .twig templates i'm met error. possible use twigbridge templates when creating views laravel package or pretty stuck blade , php ? edit 1: loading twig template without extending works. it's when start using {% extends 'file' %} error comes out. i error error loading /virtual/laravel/packages/username/mypackage/src/views/sample.twig: template "templates.master" not defined () in "/virtual/laravel/packages/username/mypackage/src/views/sample.twig" @ line 1. my folders username |_ mypackage |_ src |_ controllers - samplecontroller.php |_ views |_ templates - master.twig - sample.twig twig template sample.twig {% extends 'templates.master' %} {% block content %} {{ parent()
Read more

c# - LINQ join Entities from HashSet's, Join vs Dictionary vs HashSet performance -

i have hashset's each stores t, have written test application compares different relation algorithms can think of, i'm not pleased results getting. does there exist more efficient ways of achieving object relations, once testing? using system; using system.collections.generic; using system.linq; using system.text; using system.threading.tasks; using system.diagnostics; namespace linqtests { class program { static void main(string[] args) { hashset<user> usertable = new hashset<user>(); hashset<userproperty> userpropertytable = new hashset<userproperty>(); #region lets create dummy data. console.writeline("please wait while creating dummy data, can take while..."); console.writeline(""); int rows = 1000000; for(int x = 0; x < rows; x++) { random rnd = new random(); // ad
Read more