### Fixel FFT Wizard 21 July 2018

The Fourier Transform is one of the most powerful methods to analyze signals / data. It is widely used in the Image Processing world as on of the most used tool for any algorithms developer.
In this post we’ll cover the intuitive ideas behind it and how to use it for Image Restoration while avoiding the Math!

## Background

The Fourier Transform is one of the most powerful methods to analyze signals / data. It is widely used in the Image Processing world as on of the most used tool for any algorithms developer. It has a flavor specialized for Discrete Signals called Discrete Fourier Transform (DFT) which has a fast and efficient implementation called Fast Fourier Transform (FFT). We won’t dive into the Math and ideas behind the DFT but the basic idea is pretty simple.
For images the DFT means we can represent data either by values of each pixel in a spatial grid or have equivalent representation which is the energy of periodic 2D signal.
In Digital Image Processing there are operations easier to do in the Spatial representation (Image itself) and operations easier to do on the frequency domain.

## Applications

There are many applications for the DFT in Image Processing.
For instance, Frequency Separation, which is highly popular among Retouchers, can be easily analyzed (Implemented) using DFT.
Actually many filters (See for instance ) can (Or are) be implemented in the frequency domain which under some conditions is more efficient (Faster). For instance have a look at Custom Filter in Adobe Photoshop.

Affinity Photo even use FFT for Denoising (See FFT Denoise, Though it is more periodic pattern suppression, see below).

### Texture / Pattern Suppression

One of the task which is easier to do in the Frequency Domain is Texture / Pattern Suppression.
Many users use to retouch scanned images or images with periodic pattern they want to remove.

We won’t display full use case of that but you can read and watch many examples in the following resources:

All of them has the same basic idea:

1. Transform the Image into Frequency Domain
Apply FFT Filter on an image in Photoshop. The filter will actually be applied on the Luminosity Data of the image.
The Plug In will yield 3 Channels image where 2 channels are dedicated to the Amplitude and Phase of the Frequency Domain.
2. Adjust the Amplitude of the Fourier Transform
The user will adjust (Only) the Amplitude. Usually by removing energy which fits the unwanted pattern. This is basically applying manual Filtering of the image.
3. Transform the Adjusted Frequency Data into Luminosity Image
Once the Amplitude is adjusted the use will apply the Inverse Transform (IFFT) which will result in Luminosity (Grayscale) image with the removed data according to the user applied filtering.
4. Merge the Adjusted Luminosity Image with the Color Image of the Original Image
Now, the last step, is merging the Luminosity data with the color data of the original image. Usually by changing the blending mode to Luminosity.

## Fixel FFT Wizard Photoshop Plug In

Adobe Photoshop, to our knowledge, has never offered DFT Filter integrated into Photoshop. Hence all solutions were based on Plug In’s created by 3rd party. In some of the above resources you’ll find some of those 3rd party solutions (Plug In based) yet usually they are either not working on platforms, not updated or supported.

Yet there is demand for such solutions:

So we thought we could assist the community with a product which will be supported as a commercial product but will be offered for free (Pay as You Want).

### Installation

Once you download Fixel FFT Wizard you will have a ZIP file named Fixel FFT Wizard majorVersion.minorVersion.buildNumber (For examples Fixel FFT Wizard 1.0.000).
Inside this ZIP file you’ll find 5 files:

• Fixel FFT Wizard <majorVersion> PS.8bf (For example Fixel FFT Wizard 1 PS.8bf) - Adobe Photoshop Plug In for Windows.
• Fixel FFT Wizard <majorVersion> PS.plugin (For example Fixel FFT Wizard 1 PS.plugin) - Adobe Photoshop Plug In for macOS.
• Fixel FFT Wizard <majorVersion> UI.jsx (For example Fixel FFT Wizard 1 UI.jsx) - Adobe Photoshop Extend Script File (Used of the UI).
• Fixel FFT Wizard.url - Internet Link for This Page / Product Page.
• Installation Guide.txt - Text File with Installation Guide.

#### macOS Installation

• Make sure Photoshop is closed.
• Go to the following path Hard Drive/Applications/<Photoshop Version>/Presets/Scripts.
• Create a Folder named Fixel Algorithms.
You may be required for Administrator Rights to do so.
• Go to the path created above - Hard Drive/Applications/<Photoshop Version>/Presets/Scripts/Fixel Algorithms.
For instance, in case <Photoshop Version> is Photoshop CC 2018 the path becomes Hard Drive/Applications/Adobe Photoshop CC 2018/Presets/Scripts/Fixel Algorithms
• Copy the file Fixel FFT Wizard 1 UI.jsx into the folder above.
• Go to the following path Hard Drive/Applications/<Photoshop Version>/Plug-ins.
• Create a Folder named Fixel Algorithms.
You may be required for Administrator Rights to do so.
• Go to the path created above Hard Drive/Applications/<Photoshop Version>/Plug-ins/Fixel Algorithms.
For instance, in case <Photoshop Version> is Photoshop CC 2018 the path becomes Hard Drive/Applications/Adobe Photoshop CC 2018/Plug-ins/Fixel Algorithms.
• Copy the file Fixel FFT Wizard 1 PS.plugin into the folder above.
• Launch Photoshop. Find Fixel FFT Wizard 1 UI at the bottom of the Filter menu.

#### Windows Installation

• Make sure Photoshop is closed.
• Go to the following path C:\Program Files\Adobe\<Photoshop Version>\Presets\Scripts.
• Create a Folder named Fixel Algorithms.
You may be required for Administrator Rights to do so.
• Go to the path created above - C:\Program Files\Adobe\<Photoshop Version>\Presets\Scripts\Fixel Algorithms.
For instance, in case <Photoshop Version> is Photoshop CC 2018 the path becomes C:\Program Files\Adobe\Adobe Photoshop CC 2018\Presets\Scripts\Fixel Algorithms
• Copy the file Fixel FFT Wizard 1 UI.jsx into the folder above.
• Go to the following path C:\Program Files\Adobe\<Photoshop Version>\Plug-ins.
• Create a Folder named Fixel Algorithms.
You may be required for Administrator Rights to do so.
• Go to the path created above C:\Program Files\Adobe\<Photoshop Version>\Plug-ins\Fixel Algorithms.
For instance, in case <Photoshop Version> is Photoshop CC 2018 the path becomes C:\Program Files\Adobe\Adobe Photoshop CC 2018\Plug-ins\Fixel Algorithms.
• Copy the file Fixel FFT Wizard 1 PS.8bf into the folder above.
• Launch Photoshop. Find Fixel FFT Wizard 1 UI at the bottom of the Filter menu.

### Use

The use of the filter is pretty simple.
In order to avoid quantization errors the user should use 16 Bit / 32 Bit Mode in Photoshop.
The Plug In is actionable. Feel free to build actions around it to incorporate it into your work flow.

#### Forward FFT

In order to apply the Forward FFT do as following:

1. Make sure the selected Layer in the Layer panel it a bitmap layer.
2. Launch the UI by Filter -> Fixel FFT Wizard 1 UI (Should be at the bottom of the Filter Menu).
3. On the UI Click Forward FFT.
Pay attention that if you’re in 8 Bit Mode a warning window will appear (Select Yes to apply the filter in 8 Bit Mode).

The Filter will create a new layer called Forward FFT (temp) with its Red Channel selected as active channel.
The channels of the Forward FFT (temp) are the Amplitude (Red Channel) and Phase (Green Channel) of the image.
The Blue Channel consists the Luminosity Channel of the input image with some encoding.

By default the Forward FFT (temp) will come with Amplitude Channel (Red Channel) selected.
Hence in order to adjust the amplitude just draw over the layer with any tool you find appropriate.
Make sure you don’t alter any other channel but the Amplitude Channel (Red Channel).
Otherwise the Backward FFT won’t reconstruct the image correctly.

Don’t alter the Image Mode during the use of the filter.

#### Backward FFT

The Backward FFT filter will reconstruct the Luminosity Channel based on the adjusted Amplitude Channel.
In order to apply the Forward FFT do as following:

1. Activate the Forward FFT (temp) layer in Layer Panel.
2. Launch the UI by Filter -> Fixel FFT Wizard 1 UI (Should be at the bottom of the Filter Menu).
3. On the UI Click Backward FFT.
The Plug In will reconstruct the Luminosity Channel and set the Blending Mode to Luminosity.

### System Requirements

#### Operating System

• Windows Windows 7 x64 (Service Pack 1 Installed), Windows 10 x64.
• macOS macOS 10.10 and above.

We suggest the Operating System to be updated to its latest build.

#### Host Program

• Adobe Photoshop 64 Bit Photoshop CS6 64 Bit. Adobe Photoshop CC 2015 64 Bit, Adobe Photoshop CC 2017 64 Bit, Adobe Photoshop CC 2018 64 Bit

It should work on Adobe Photoshop CS5 64 Bit and all CC 64 Bit versions but we never validated it.

#### Hardware

• x64 Bit CPU (Intel or AMD) with SSE4 Support.
Basically any modern CPU created by Intel or AMD since ~2010.

## Summary

The reason we created Fixel FFT Wizard was reading about the need of people for FFT Plug In in Photoshop both for Windows and macOS.
Moreover, usually the use case were old photos with sentimental significance.
So we felt we could assist and created Fixel FFT Wizard to support those people who mostly use this for keep their memories with them.
Taking all these under consideration we decided to offer Fixel FFT Wizard for free for any user without any constraint on the use.

At the moment Fixel FFT Wizard is in Public Release Candidate state and once we finalize it we’ll put it behind Pay as You Want offer with free option always available.