Common

Function
This function compares two images and extracts or hides common elements. Use this to do Difference mattes. The extracted elements are taken if the difference between the two images is less than the Tolerances you set. A similar function is ISubA, which will subtract two images and return the absolute value of these images.

Parameters
Type
Defaults
Function
clipMode
int
0 Toggles between foreground (0) and background resolution (1)
mode
int

0 - 5

0

Tells Shake what to do with common elements

0: "show" keeps common elements only, turning the rest black.

1: "hide" hides common elements, leaving different elements untouched.

2: "white" turn the image to black and white, keeping common elements white.

3: "black" is the inverse of "white".

4: "proportion" takes the difference between the values, averages them, and then inverts it.

Tol
float
0, rTol, rTol, rTol

The Tolerance values. If pixels between the two images are less than the Tolerance value, they are considered common.


Synopsis

image Common( 
  image Foreground, 
  image Background,
  int clipMode, 
  int mode, 
  float redTol, 
  float greenTol, 
  float blueTol, 
  float alphaTol
 );


Script

 image = Common( 
   Foreground, 
   Background,
   clipMode, 
   mode, 
   redTol, greenTol, 
   blueTol, alphaTol
 );


Command Line

shake -common image clipMode "mode" redTol etc...


Example

shake lisa.iff -solarize .5 -common lisa.iff 1 4 .1
shake lisa.iff -mmult -common lisa.iff 1 2

See Also
ISub, ISubA