Applying gaussian mask in frequency domain c++ opencv

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ok thanx for replying...But if i want to multiply two spectrums without mulspectrum function of opencv then what should be my approach

And also how can i control the radius of filter in frequency domain

I don't understand your question. Why don't you want to use cv::mulSpectrums()?

Controlling radius of filter can be done when creating Gaussian kernel using cv::getGaussianKernel() in spatial domain.

What are you expecting to achieve when reinventing GaussianBlur?

Hi matman...thank you for your valuable time and sharing your knowledge..Now i am able to control the radius of filter using getGaussiankernel..

But i want to understand the underlying behaviour of cv::mulSpectrums() ..If you have any idea regarding this please share with me.

The source code for mulSpectrums is here

@matman , Thank you for replying and helping to solve my problem.

@matman, I want to implement bilinear interpolation using opencv but without using opencv resize function. I want to implement the algorithm with c++ and opencv. So will u please help me regrding this?