OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Mon, 29 Jun 2015 09:45:47 -0500Find the value of pixel around a circlehttp://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/ Hello,
I want to draw a circle that allows me to collect informations about my image. I have done a DFT, and I want to get the information of low and high frequencies with a circle.
The question is " how can I use the circle as a system of mesure ?"
If someone could explain it to me, it will be great.
Jeje20Mon, 29 Jun 2015 08:02:38 -0500http://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/Comment by LBerger for <p>Hello,</p>
<p>I want to draw a circle that allows me to collect informations about my image. I have done a DFT, and I want to get the information of low and high frequencies with a circle.
The question is " how can I use the circle as a system of mesure ?"
If someone could explain it to me, it will be great.</p>
<p>Jeje20</p>
http://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/?comment=65148#post-id-65148For Line there is lineIterator I don't find for circle.
But I think you can use distancetransform with L2_dist. You can apply distanceTransform to an image included a white disk center at frequency 0 with same size than your spectrum. Result will be an image with value decreasing from center to boundary. Then you can use this value to explore your spectrum like using a mask.
May be an another way is possibleMon, 29 Jun 2015 09:45:47 -0500http://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/?comment=65148#post-id-65148Comment by thdrksdfthmn for <p>Hello,</p>
<p>I want to draw a circle that allows me to collect informations about my image. I have done a DFT, and I want to get the information of low and high frequencies with a circle.
The question is " how can I use the circle as a system of mesure ?"
If someone could explain it to me, it will be great.</p>
<p>Jeje20</p>
http://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/?comment=65147#post-id-65147I think you shall start reading [this](http://homepages.inf.ed.ac.uk/rbf/HIPR2/fourier.htm); then ask what you do not understand... ;)Mon, 29 Jun 2015 09:36:50 -0500http://answers.opencv.org/question/65137/find-the-value-of-pixel-around-a-circle/?comment=65147#post-id-65147