computer vision - Exact measurement of translation and rotation of marker objects using OpenCV/EmguCV -

-

i measure displacement of object between 2 images. displacement can in image plane. result should give displacement, if possible in sub pixel accuracy.

there assumptions, should make easier, didn't me far:

  • the camara objective virtualy distortion free (telecentric) , oriented perpendicular object plane
  • the object plane never changes
  • the flat marker object (could known image, e.g. play card) in object plane, isn't scaled or warped -> rotational , translational changing.

my first approach take feature recognition example emgucv, find first object in first image, take relevant piece of picture, use template , search in second image. did work, little unsatisfactory. there scaling , warpping in homography matrix (probably because of points, assigned wrong) , placing accuracy quite bad.

i tried once demo of commercial image processing software halcon , worked charm in sub pixel accuracy. there can sort of least square fit of template image searching object in. result affine transform matrix , precise.

is there comparable in emgucv/opencv?

thank in advance!

edit:

found solution in emgucv in function

cameracalibration.estimaterigidtransform(pointf[] src, pointf[] dest, bool fullaffine);

with fullaffine set false. problem before was, using 

features2dtoolbox.gethomographymatrixfrommatchedfeatures();

from matching example.

found solution in emgucv in function

cameracalibration.estimaterigidtransform(pointf[] src, pointf[] dest, bool fullaffine);

with fullaffine set false. problem before was, using

features2dtoolbox.gethomographymatrixfrommatchedfeatures();

from matching example.

the problem left small scaling still produced estimaterigidtransform, able calculate out of result.


Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more