**What does the Image Calculator command do ?**

Performs arithmetic and logical operations between two images selected from popup menus. *Image1* or both *Image1* and *Image2* can be stacks. If both are stacks, they must have the same number of slices. *Image1* and *Image2* must be the same data type but they do not have to be the same size.

You can select one of 12 operators from the *Operation:* popup menu. Check *Create New Window* and a new image or stack will be created to hold the result. Otherwise, the result of the operation replaces some or all of *Image1*. Check “32-bit Result” and the source images will be converted to 32-bit floating point before the specified operation is performed.

With 32-bit (float) images, pixels resulting from division by zero are set to *Infinity*, or to *NaN* (Not a Number) if a zero pixel is divided by zero. The divide-by-zero value can be redefined in ** Edit>Options>Miscellaneous>Divide by Zero Value**.

Add | img1 = img1+img2 |

Subtract | img1 = img1-img2 |

Multiply | img1 = img1*img2 |

Divide | img1 = img1/img2 |

AND | img1= img1 AND img2 |

OR | img1 = img1 OR img2 |

XOR | img1 = img1 XOR img2 |

Min | img1 = min(img1,img2) |

Max | img1 = max(img1,img2) |

Average | img1 = (img1+img2)/2 |

Difference | img1 = ¦img1-img2¦ |

Copy | img1 = img2 |

Transparent Zero zero | pixels of img2 are transparent |