IRBlur

Function
This function is an image-based version of the RBlur function, using a second image's alpha mask (by default) to control the amount of radial blurring occurs on an image. This is useful for faking motion blur effects. In this example, the extremely complex foreground objects, commonly known as cubes, are rendered on a beach in a 3D package with the depth information. The 3D image was composited over a background photo of the beach. A DepthKey was used to extract a matte of the depth supplied by the 3D render. This matte was then fed into the second image of the IRBlur to give a zooming effect.

Parameters
Type
Defaults
Function
x/yCenter
float
width/2, height/2 The center point of the blur.
iRadius
float
0 The distance from the Center that contains the blur sample area.
oRadius
float
width The outer edge for the blur area
aspectRatio
float
1 The aspect ratio of the pixels for anamorphic images.
damp
float
1 A gamma value on the blur
amplitude
float
.5 The amount of blur. This number can also be negative.
blurQuality
float
.25 The amount of samples. A quality of 1, the maximum, means 64 samples.
mirror
int
0 This will consider points past the center area if your amplitude is high enough when it is turned on.
stepBlend
float
5 This controls the blending between the amount of regions (see below). If you put this at 0, each step will have a constant blur value. If this is 1, there is a continuous blend between the different regions.
steps
int
1 This is the amount of regions. The intensity of the control image is divided up X amount of zones, with X being equal to regions. If you see stepping between the zones and stepBlend does not correct it, increase steps to a higher number. The more steps you use, the slower the process.
controlChannel
string
"a" The channel of the second image to use to control the amount of sharpen.
invert
int
0 Inverts the controlChannel.


Synopsis

image IRBlur( 
  image img,
  image controlImg, 
  float xCenter, 
  float yCenter 
  float iRadius,
  float oRadius,
  float aspectRatio,
  float damp,
  float amplitude,
  float blurQuality,
  int mirror,
  int steps,
  float stepBlend,
  const char * controlChannel,
  int invert,
 );


Script

image = IRBlur(
  img, 
  controlImg, 
  xCenter, yCenter, 
  iRadius, oRadius, 
  aspectRatio,
  damp, 
  amplitude,
  blurQuality,
  mirror,
  steps, 
  stepBlend
  "controlChannel",
  invert
);


Command Line

shake -irblur comntrolImg xCenter yCenter iRadius etc....


See Also

RBlur, DepthKey, About Transformations and Motion Blur