pamarith

performs arithmetic operations on two PAM/PNM images

TLDR

Add two images

$ pamarith -add [image1.pam] [image2.pam] > [result.pam]

Subtract images

$ pamarith -subtract [image1.pam] [image2.pam] > [result.pam]

Multiply images

$ pamarith -multiply [image1.pam] [image2.pam] > [result.pam]

Find difference

$ pamarith -difference [image1.pam] [image2.pam] > [result.pam]

Minimum of images

$ pamarith -minimum [image1.pam] [image2.pam] > [result.pam]

SYNOPSIS

pamarith -function pamfile1 pamfile2

DESCRIPTION

pamarith performs arithmetic operations on two PAM/PNM images. Images must have the same dimensions. Used for compositing, masking, and image comparison.

PARAMETERS

-add

Add pixel values.

-subtract

Subtract pixel values.

-multiply

Multiply pixel values.

-divide

Divide pixel values.

-difference

Absolute difference.

-minimum

Minimum of each pixel.

-maximum

Maximum of each pixel.

-mean

Average of pixels.

-and, -or, -xor

Bitwise operations.

EXAMPLE

$ # Find difference between images
pamarith -difference old.ppm new.ppm > diff.ppm

# Blend two images
pamarith -mean image1.ppm image2.ppm > blended.ppm

CAVEATS

Images must be same size. PAM format preferred. Output may need scaling for display.

HISTORY

pamarith is part of Netpbm, a toolkit for image manipulation dating back to the late 1980s.