YEBIS Optic Based Post-Processing


Physically Accurate Optical Post-effects

A variety of optical effects are available, ranging from highly realistic to more dramatic.

Optical post-effects added as simulation results

Camera lens


As previously stated, with Depth of Field effects, YEBIS is able to recreate the feel of an actual camera or lens with photo-realistic optical effects.

In fact, YEBIS provides not only Depth of Field effects, but also integrates optical simulation based post effects.

In simple terms, it allows running a simulation of the camera or lens, and then applies this to the rendering results as a post-effect. Naturally, this is performed in real-time.

For example, with YEBIS Depth of Field effects, the results of F-stop number, focal position and focal length (f) can be calculated and applied. With an actual lens, moving the focal point forward and back changes the angle of view (focal length) slightly. It also changes the F-stop blur value in the out-of-focus area. YEBIS does not simply blur the images, but instead reproduces actual optical conditions.

What happens when the F-stop is set to its smallest number (F128) to achieve the effect of a pinhole camera? At F128, the diameter is at its smallest, resulting in a large depth of field. At the same time, diffraction of the incoming light due to the iris mechanism is dominant, lowering the optical resolution. This is a phenomenon unique to small diameter optical system, referred to as small aperture blur. YEBIS reproduces this optical effect by faithfully running an initial simulation.

In other words, the Depth of Field effect in YEBIS does not simply apply a blur post-effect, but simulates the scene as viewed through an actual lens, and then applies the results as a post-effect.

Moreover, since parameters such as F-stop, focal point and focal length (f) can be changed in real-time, effects such as zooming in/out of a spy camera as typically seen in movies, can be achieved as though a real life camera was used.

The YEBIS lens simulation does not simply handle Depth of Field effects, but can also reproduce other optical effects.

For example, depending on parameters such as the length and diameter of the lens tube and the state of the aperture, vignetting can be recreated.

Vignetting is a phenomenon in which the area surrounding the camera lens is darker than the center. It occurs in the lens tube itself when a small aperture lens is placed in a long lens tube. To the viewer, it appears simply as if a round black mask has been placed around the rendering effects, but with YEBIS, the optical effect of reduced light around the center is carefully reproduced.

Even greater photo-realism

YEBIS offers unique optical system post-effects not available in other systems.

The design of a lens optical system may not always function as predicted in real-life due to the fact that lenses are made of plastic and glass, and thus the light entering refracts when it strikes these surfaces and may, in some cases, even separate into component colors. YEBIS recreates the performance of an actual lens, even its undesirable qualities, to deliver the most realistic optical effects.

An easily understood example is that of Chromatic Aberration.


Chromatic Aberration

The wavelength of light varies depending on its color. Since different wavelengths result in different refraction rates, the focal point for each color within the light entering the lens also varies, and the colors separate. Photography with an actual lens sometimes results in such color shift. In the real world, photographic lenses can be made from a high quality anomalous dispersion glass to reduce chromatic aberration. YEBIS allows big Chromatic Aberrations to recreate the feel of using a cheap lens.

YEBIS does not simply cause a color shift, it creates what is called a Magnified Chromatic Aberration where the color shift increases towards the perimeter of the image. Used skillfully, it is possible to create the feel of photographing with a cheap lens or through a thick glass.

Another undesirable optical quality that YEBIS can recreate is Lens Distortion.

Lens Distortion is an optical phenomenon resulting in a swelling or shrinking towards the perimeter of the image. The swelling is referred to as barrel distortion, and shrinkage is referred to as pincushion distortion. The better the camera lens, the less these phenomena will occur. At first glance there may appear to be no application for this effect, however it is a useful way to make CG images appear less CG-like which we described in Motion Blur section (URL).


Lens Distortion

CG images are drawn by creating a 3D model in a virtual space and then projecting it from a particular perspective (camera) onto a 2D frame. This perspective projection conversion can also be referred to as 3D > 2D conversion. Perspective projection conversion has a side-effect whereby the closer to the edges of the image, the more the surface area expands in a manner similar to that seen in a Mercator projection. Conversely by applying this lens distortion, the sluggishness of the image perimeter is reduced, and the overall appearance is more real and less CG-like.

As described above, depending on how they are used, the recreation of undesirable lens qualities can produce rendering effects for an extra level of photo-realism.

Free Trial Version
Download the YEBIS Free Trial Version

The only currently downloadable platform is for Windows PC.

System Requirements

OS Windows 7 or later
Compiler Microsoft Visual Studio 2010
Compatible with DX SDK Since June 2010
Compatible hardware DirectX 10 or later

Update Notes

May 29, 2015
- “Natural Bone” : The effect parameters tweaking demo added.
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Apprication Form

If you wish to acquire a trial version for PlayStation®4, PlayStation®3, PlayStation®Vita, Xbox One, Xbox 360, Android, iOS, Linux, or other embedded equipment, please submit a request above.

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