# Bokeh Ref Iwa

#### ● Overview

This effect reproduces a camera lens blur. The input image is divided into several layers
based on the gradation of the Depth reference image, and the RGB values of each divided
layer are converted into exposure values, blurred using the Iris shape, and combined.
Higher speed is achieved by using the discrete Fourier transform. Before blurring,
a process of extending the parts of each layer that is hidden in the foreground with a
Median filter can be performed.

#### ● Input Port

- Iris : Connects the image to define the shape of the Iris. The image luminance values
  will be used for the effect. If no image is connected to the Iris port, no calculation will
  take place. It's possible to connect 8bit or 16bit RGBA images.
- Source : Connect the input image. If nothing is connected to the Source port, no
  calculation is performed.
- Depth : Connect the Depth reference image. The brightness of each pixel corresponds
  to the depth. The higher (brighter) the value, the farther away from the camera.

#### ● Parameters

- On-Focus Distance : If there's a layer in this position, it will look on focus and it will
  be composed normally. 0 represents the camera position. (Range 0.0-1.0)
- Bokeh Amount : Maximum size of blur (in scene units). When the focus position and
  the layer position are 1.0 away from each other, the Iris image is enlarged until the
  width of this image reaches this value.
- Hardness : The gamma value of the film. Used to convert between RGB value and
  exposure. This is equivalent to the increase in RGB value (0.0 to 1.0) when the exposure
  is increased 10 times. The lower the value, the more the highlights are emphasized.
  (Range 0.05-3.0)
- Distance Precision : The number of divisions of the depth reference image. The larger
  the value, the finer the gradation of the blur size, but the slower the processing.
  (Range 3-128)
- Fill Gap : Specifies whether to extend the further segmented layer pixels in order to fill gap.
- Use Median Filter : Specifies whether to use median filter for the extension.
  This option is recommended when the depth is distributed discretely.

#### ● Notes

- When rendering multiple frames, the Iris and the layers images, must be present within
  the range of all frames to be rendered.
- This effect uses a lot of RAM.

#### ● License Information

- This effect uses an open source library called Kiss FFT for the Fourier transform.

> This is the BSD-style license for the KissFFT.
> Copyright (c) 2003-2010 Mark Borgerding
> All rights reserved.
> Redistribution and use in source and binary forms, with or without modification, are permitted provided that
> the following conditions are met:
> * Redistributions of source code must retain the above copyright notice, this list of conditions and the following
> disclaimer.
> * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
> following disclaimer in the documentation and/or other materials provided with the distribution.
> * Neither the author nor the names of any contributors may be used to endorse or promote products derived
> from this software without specific prior written permission.
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