<p>I'm working on detecting optically overlapping galaxies for future astronomical surveys. I'm looking into feature extraction for HST images and have been computing the fourier transform of images in the hope to construct a metric signifying overlapping vs non-overlapping light profiles.</p>

<p>For example, I have the following image after having filtered out noise:</p>

<p><img src="https://i.sstatic.net/gCTF5.png" alt="Real Image"></p>

<p>I've been having trouble trying to interpret the results after taking the fourier transform, taking the magnitude of each element, and then plotting the logarithm of the magnitude.</p>

<p><img src="https://i.sstatic.net/i37KR.png" alt="Logarithm of the magnitude of the Fourier Transform"></p>

CC BY-SA 3.0
2015-02-23T18:51:30.857Z
I'm not sure what you're question is? Why have you chosen to use fourier transform for segmentation? If I look at the bottom picture, the fourier transform does not seem to be a very good feature.
Dieudonné
CC BY-SA 3.0
2015-02-27T22:27:03.320Z
The Fourier transform per se will not help you to find overlapping object. Where does this idea come from?
Walter
CC BY-SA 3.0
2015-03-05T21:43:53.167Z
It is just an idea at the moment but it doesn't seem very useful. Ideally, I would use with other features to input into a Machine Learning algorithm to predict overlapping or non-overlapping classes.
alvarezcl
<galaxy>
Fourier Transform of Galaxy Images
alvarezcl
# Fourier Transform of Galaxy Images

(Asked by: username_0 on 2015-02-23)

I'm working on detecting optically overlapping galaxies for future astronomical surveys. I'm looking into feature extraction for HST images and have been computing the fourier transform of images in the hope to construct a metric signifying overlapping vs non-overlapping light profiles.

For example, I have the following image after having filtered out noise:

![Real Image](https://i.sstatic.net/gCTF5.png)

I've been having trouble trying to interpret the results after taking the fourier transform, taking the magnitude of each element, and then plotting the logarithm of the magnitude.

![Logarithm of the magnitude of the Fourier Transform](https://i.sstatic.net/i37KR.png)

**Tags:** galaxy
> **Comments:**
> **username_1**: I'm not sure what you're question is? Why have you chosen to use fourier transform for segmentation? If I look at the bottom picture, the fourier transform does not seem to be a very good feature.  
> **username_2**: The Fourier transform per se will not help you to find overlapping object. Where does this idea come from?  
> **username_0**: It is just an idea at the moment but it doesn't seem very useful. Ideally, I would use with other features to input into a Machine Learning algorithm to predict overlapping or non-overlapping classes.  

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## 0 answers

