Defly - firefly and hot pixel noise removal tool

Click image for full size Before/After comparision

Defly is an image filtering tool for removing fireflies (hot pixels) from Octane and other unbiased or computational renderings.

Even though Octane has a built-in noise reduction (that seems to be based on principle explained here) it's sometimes useful to be able to do filtering independently from rendering, to avoid lost details during animation or re-rendering animation, so I decided to keep this online for now.

Please report issues in comments below. Thank you.

Warning: Read agreement first! This program is provided as is with no any sort of warranties, so don't put your life on it.
As there've been not much users noticed program is for Windows only.

How to use:
Important note: jpg causes a little blur which reduces effectiveness!
Image should be rendered without any filtering for same reason!
This was not tested, but this tool should be useless for digital camera firefly removal.

1. Load image or sequence frame that has most fireflies and sharp details
and navigate (in lower viewport) with arrow buttoons to a place that suffers from fireflies most.

2. Adjust "Remove firefly" slider so that you remove all firefly and maybe a little of brighter noise as needed:

3. Adjust "Preserve detail" slider so that you gain back thin lines or other small details that were removed by previous step if you had any:
(do not overdo with "Remove firefly" as it will require more of "Preserve details" parameter which in turn will reduce effectiveness of first one)

4. If you are doing single image press "Save this image"... Entering file name don't forget to set extension as it will define file format.
If you are doing sequence do not save anything. Do not change parameters.
Open sequence frame that you want removal (sequence start and end filenames should appear beneath buttons)
to start with and press "Process frame range". Frame number and extension will be added automaticaly (*.png)

Hot pixel removal principle explained:
- Program processes all non-boundary pixels of image one by one on r,g,b channels as averaged value or separated.
- If pixel is more than inverted "Remove..." value brighter than surrounding (left, right, top, bottom) pixels it is replaced with their average value if following condition is met:
- The difference between brightest and darkest pixels around (8 neighbouring pixels) must be smaller than "Preserve..." value.
Simple - isn't it?

By downloading, storing or using this program you are entering the following agreement:

You use this program at your own risk! This program comes with no warranty whatsoever.
Author is not liable for any direct/indirect damages caused by operation or inoperation or quality of this program.
You may not sell or distribute this program for any reward.
You may not separate the program from "Readme.txt" file and/or remove agreement.

Defly v0.9
Copyright © 2010 Konstantins Visnevskis, All rights reserved.

Agree and Download (~1MB)


kwon hyuk jin

, 14-02-17 10:49:

Muhammet Emin Öner

, 16-12-16 17:58:
Hello friend!
Very useful utility, thanks!


, 17-06-15 04:08:
You sir, made my day.
Thank you for the tools.

Konstantins Visnevskis

, 04-06-14 17:11:
@tester Hi, unfortunately no. I made it long ago and there was no real demand so I left it as is. Not sure I even can compile it anymore.
Anyhow, I'm wondering, why something like this still is not implemented in Blender. The principle is really simple.


, 04-06-14 16:24:
hello, is there a mac version?


, 29-03-14 02:38:

Max Lesnik

, 29-10-12 14:45:
Спасибо огромное! Это офигенно! Сэкономил кучу часов рендера!


, 15-08-12 11:29:
compliments! it improves a lot my renderings!

Brian L.

, 05-08-12 21:00:
This sounds like a very useful tool! Saw your link from BlenderNation today. I'll check it out! Thank you!

Konstantins Visnevskis

, 10-03-12 18:21:
@Leonardo Chaparro
You're welcome.

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