OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Fri, 04 Oct 2019 03:19:54 -0500template matching invariant to rotations and noisehttp://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/ IS any way to enhance the maximum value of similarity in case the template on image is rotated with different angle than the saved template
The problem here is in case there is stamp on image rotated with small angle the template matching returns maximum matching value with small value so the program cannot now if this value is due to rotation or noise or due to the stamp is not found in the image Wed, 02 Oct 2019 09:29:04 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/Comment by Kitnos for <p>IS any way to enhance the maximum value of similarity in case the template on image is rotated with different angle than the saved template </p>
<p>The problem here is in case there is stamp on image rotated with small angle the template matching returns maximum matching value with small value so the program cannot now if this value is due to rotation or noise or due to the stamp is not found in the image </p>
http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219153#post-id-219153Did you try using invariant descriptors to rotation like (SIFT (sift is patented for commercial use) ,SURF,ORB,...), i think it's the best method if you are trying to find the rotation of your image compared to a reference image.Wed, 02 Oct 2019 09:49:21 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219153#post-id-219153Answer by Czak for <p>IS any way to enhance the maximum value of similarity in case the template on image is rotated with different angle than the saved template </p>
<p>The problem here is in case there is stamp on image rotated with small angle the template matching returns maximum matching value with small value so the program cannot now if this value is due to rotation or noise or due to the stamp is not found in the image </p>
http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?answer=219152#post-id-219152There is no algorithm that is truly invariant to rotation of template, and to noise some algorithms may be more robust (i would advice zero normalised cross correlation with can be efficiently implemented using fft). And multiple minima can be avoided by cropping image before and find minima in croped sections, it will be helpfull if You Can make aditional test on localisation that would differenciate between minimas.Wed, 02 Oct 2019 09:49:11 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?answer=219152#post-id-219152Comment by Czak for <p>There is no algorithm that is truly invariant to rotation of template, and to noise some algorithms may be more robust (i would advice zero normalised cross correlation with can be efficiently implemented using fft). And multiple minima can be avoided by cropping image before and find minima in croped sections, it will be helpfull if You Can make aditional test on localisation that would differenciate between minimas.</p>
http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219231#post-id-219231It's hard to give any advice without seeing data. If you can post images that you want to match it will we easier. My expertice comes from reaserch on digital image correlation where there is loads of repetetive paterns and shear, rotation and non linear deformation, but scale remains same, and FFT base metods are very common in that field. Mayby resolution of template do not match resolution in image that you try to match? Mayby scale it to diffrent sizes and look for the results.Fri, 04 Oct 2019 03:19:54 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219231#post-id-219231Comment by gino0717 for <p>There is no algorithm that is truly invariant to rotation of template, and to noise some algorithms may be more robust (i would advice zero normalised cross correlation with can be efficiently implemented using fft). And multiple minima can be avoided by cropping image before and find minima in croped sections, it will be helpfull if You Can make aditional test on localisation that would differenciate between minimas.</p>
http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219225#post-id-219225I find some good [example](https://github.com/Smorodov/LogPolarFFTTemplateMatcher) of this algorithm.
in practice, I found that Fourier based template matching works not so well if there are some other patterns on the be-matched images.
I think the rotation invariant matching or object detection is important topics for the application of computer vision in real world but with very few spot lights.Fri, 04 Oct 2019 02:20:53 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219225#post-id-219225Comment by LBerger for <p>There is no algorithm that is truly invariant to rotation of template, and to noise some algorithms may be more robust (i would advice zero normalised cross correlation with can be efficiently implemented using fft). And multiple minima can be avoided by cropping image before and find minima in croped sections, it will be helpfull if You Can make aditional test on localisation that would differenciate between minimas.</p>
http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219165#post-id-219165Not exactly there is [Fourier Mellin transform](https://sthoduka.github.io/imreg_fmt/docs/fourier-mellin-transform/)Wed, 02 Oct 2019 13:53:40 -0500http://answers.opencv.org/question/219149/template-matching-invariant-to-rotations-and-noise/?comment=219165#post-id-219165