How can you increase the angular resolution of pixels in a 2 D image fourier transform

Hi,

i have been doing 2D Fourier transforms on tilted fringe images and I want to know how to increase the angular resolution of the fringes so that I can obtain the fringe angle from the 2D fourier transform. I have tried using interpolation methods like (imresize, interp2) but that didn't get me to the resolution that I needed. I have also tried using resample to increase the sampling rate but that didn't give the result I wanted. Do you know of any ideas that I can use to increase the angular resolution?

An example of an image of the tilted fringe is attached. Thanks!

Answer 1

[Image Analyst]

The pixel resolution is determined and fixed by the size of the image matrix. If you increase the image size using imresize() it will give you more pixels but don't be deceived that this gives you more resolution physically in the real world. You can increase the number of pixels all you want and it won't give you more real resolution. In other words, if an image is blurry, scaling up the number of pixels by a thousand in each dimension will not now suddenly let you resolve points a thousand times closer together. It will still be a blurry image, just bigger.

[Isaac Oguntoye]

Thanks @Image Analyst for the quick response.

So basically, the only way to obtain a higher resolution is to start with an image with a large size before performing a fourier transform on the image? Also, will this improve the angular resolution of the pixels?

[Image Analyst]

Yes, and yes. As long as the larger size was not just created by upsampling a smaller digital image. For example, you can use a 4000 x 5000 pixel camera instead of a 1080 x 1280 pixel camera. But you can't just turn a 1080 x 1280 digital image into a 4000 x 5000 digital image with imresize() and expect to have more real world resolution even though the number of rows and columns is more.

[Isaac Oguntoye]

Thanks @Image Analyst.