VirtualDub: Kagayaki filter (Twinkling Soft Focus and Cross)

[ Japanese ] Kagayaki filter is the Twinking Soft Focus and Cross filter for VirtualDub, to enhance emotion of your starry and night footage. It works nicely for starry timelapse, night city and fireworks footage. It is also optimal when you use still-astrophotograpies in your movies. And it can work as general-purpose soft focus filter, not limited to night footages.

Demonstration

Please watch it HD and full-screen.

Download

[ Download Kagayaki Filter v0.6 / Source ]

This filter is a freeware. To install it, just UNZIP then copy the vdf and html files into "Plugins" sub-folder of your VirtualDub folder. If you don't have VirtualDub, you can get it at http://www.virtualdub.org/.

How to Use

Summary of the Processing

Summary of the processing of this filter is relatively simple: it just blend the source frame and blurred frame with screen blending (similar to add blending). Sorry but this filter is currently very heavy. I might want to make it lighter in the future.

Params

  • Blend Source and Blurred Frames: Standard mode.
  • Show Blurred Frame Only: Show the blurred frame without blending with the source frame.
  • Preprocessing: Some adjustments for the source frame before applying blur.
    • Cut-off Level: To cut-off background.
    • Tone Power: To optimize differences of magnitude of stars.
  • Twinkling: Twinkling in this filter is not just random but designed to have realistic feel.
    • Amplitude: Higher value results in stronger twinkling.
    • Freqency: Higer value results in quicker twinkling.
  • Soft Focus: Low quality and high quality modes. High quality mode is heavier.
    • Radius
    • Power: Lower value results in blunter blur. Higher value respects core of stars more.
    • Multiplier: Multiplier to brightness of blur.
  • Cross: Meaning of params are same as soft focus.
  • Final Color Adjustment: Final adjustments for the blurred frame. RGB balance adjustment, and color saturation adjustment.

Understanding the Processing

To understand the processing of this filter, you might want to try this:

  1. Set to Show Blurred Frame Only mode.
  2. Disable all of Twinkling, Soft Focus and Cross.
  3. Set Tone Power of Preprocessing to 1.0 (it means disabled.)
  4. Click Show preview and start previewing.
  5. Change Cut-off Level param and observe the preview.
  6. Change Tone Power param and observe the preview.
  7. Enable Soft Focus, change params and observe the preview.

Intention and Feature

Modern lenses are very sharp. Thus, when you shoot starry scenes, stars are sometimes too sharp and thus differences of magnitude of stars are not very clear. Thus, sometimes you use physical soft focus filter to enhance difference of magnitude of stars. However, effectiveness of physical soft focus filter is somewhat strong, even if you use weak version of soft focus filter. And if you want to enhance differences of magnitude of stars just slightly, it is not possible with physical soft focus filter.

And, digital processing makes it possible. My Kagayaki filter is a kind of digital soft focus filter. And unlike general purpose soft focus filters, this one is designed to have good results for starry footages. It can generate beautiful halo for stars, with enhancing differences of magnitude of stars naturally.

It also have an unique feature: twinkling! timelapse footage of starry scenes have much better quality compared with real time footage. But unlike real time footage, stars in timelapse footage do not twinkle. It is somewhat sad. But my Kagayaki filter now allows you to have twinkling in your starry timelapse, and also still-astrophotography!

Twinkling in my Kagayaki filter is not just random but designed to have realistic feel.

My Kagayaki filter is a powerful tool. But please understand that it is not perfect. It can enhance colors of stars, but it enhances false colors as well.

Sample Images

You may have wide range of effectiveness, from slight (natural) effectiveness to strong effectiveness. (All materials are used under permission.)

Starry Scene 1 (Source material by mockmoon)

kagayaki_starry1.jpg

If you want to have natural result, please disable cross effect, and use soft focus effect with weak effectiveness. Emotion could live in very slight differences, even with unnoticeable level. Thus, sometimes, very weak effectiveness is good to have.

To have natural feel of colors of stars, you might want to adjust RGB balance bluish and also slightly enhance color saturation.

Starry Scene 2 (Source material by me)

kagayaki_starry2.jpg

Example of very strong effectiveness. Somewhat similar to CG illustrations of a Japanese starry illustration artist?

Night City (Source material by mockmoon)

kagayaki_nightcity.jpg

Miniature-like image taken with tilt-shift lens. When you apply Kagayaki filter to night city scenes, area type light sources like windows and neon billboards tend to be blurred too much. So please carefully adjust params to have good result.

Fireworks (Source material by me)

kagayaki_fireworks.jpg

Sorry about poor quality because it was taken with a compact digital camera (Optio W80). It is noticeable that Kagayaki filter enhance colors of fireworks. To have natural enhancement of colors, disable cross effect and use soft focus effect with relatively weak effectiveness with higher color saturation. It is good to do because when you shoot fireworks as movies, it tends to have lower colorfulness than real life look.

Flowers (Source material by OpenSpace)

kagayaki_flower.jpg

It can work as general-purpose soft focus filter, not limited to night footages. When you use it as general-purpose soft focus filter, use it with low Power (possibly 1.0 to 2.0) and with weak multiplier. Note that it might work very heavy because of larger number of high brightness pixels.

To Have Better Results

Try Gradation Curves Filter

Gradation Curves Filter is very helpful tool to optimize result of my Kagayaki filter. You can get it from Alexander Nagiller's website.

Avoid Overexposure

If high brightness area (possibly by light pollution) is included in background, it is not possible to cut it off even with high cut-off level param. Kagayaki filter can not process those kind of source image well.

To avoid overexposure, you might want to lower your ISO. And then, apply Kagayaki filter. Finally, use Gradation Curves Filter to have exposure level you want to have.

About this Entry

This page contains a single entry by Tagoshu published on April 11, 2012 3:19 PM.

VirtualDub: Afterimage filter was the previous entry in this blog.

Timelapse: Flrefly-squid Hunters (TEST), Apr 21, 2012 is the next entry in this blog.

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