How to use the command "pamfunc" (with examples)

Pamfunc is a command-line tool that allows you to apply arithmetic and bit string functions to Netpbm images. With pamfunc, you can perform various operations, such as multiplication, division, addition, subtraction, minimum, maximum, as well as bitwise operations like AND, OR, XOR, left shift, and right shift. These operations can be useful for image manipulation, processing, and analysis.

Use case 1: Apply arithmetic function to a PAM image

Code:

pamfunc -multiplier|divisor|adder|subtractor|min|max n path/to/input.pam > path/to/output.pam

Motivation: This use case is helpful when you need to modify the intensities or values of every sample in a PAM image using arithmetic operations. You can adjust the brightness, contrast, or apply filters to enhance or manipulate the image.

Explanation:

• -multiplier|divisor|adder|subtractor|min|max: Choose the desired arithmetic function to apply. You can use -multiplier to multiply each sample by a constant value n, -divisor to divide each sample by n, -adder to add n to each sample, -subtractor to subtract n from each sample, -min to clip each sample to the minimum value of n, or -max to clip each sample to the maximum value of n.
• n: The constant value used in the arithmetic function.
• path/to/input.pam: The path to the input PAM image file.
• path/to/output.pam: The path to the output PAM image file.

Example output: Suppose we have an input image “input.pam” with 100x100 dimensions and apply the multiplication operator with a value of 1.5.

pamfunc -multiplier 1.5 input.pam > output.pam

The resulting output.pam image will have the same dimensions as the input image, and each sample will be multiplied by 1.5.

Use case 2: Apply bit string function to a PAM image

Code:

pamfunc -andmask|ormask|xormask|shiftleft|shiftright n path/to/input.pam > path/to/output.pam

Motivation: This use case is beneficial when you want to perform bitwise operations on the samples of a PAM image. It can be used for various tasks, such as extracting specific bits, applying masks, or performing shifts.

Explanation:

• -andmask|ormask|xormask|shiftleft|shiftright: Choose the desired bit string function to apply. You can use -andmask to perform a bitwise AND operation with n, -ormask to perform a bitwise OR operation with n, -xormask to perform a bitwise XOR operation with n, -shiftleft to shift each sample to the left by n bits, or -shiftright to shift each sample to the right by n bits.
• n: The bit string used in the bit string function.
• path/to/input.pam: The path to the input PAM image file.
• path/to/output.pam: The path to the output PAM image file.

Example output: Suppose we have an input image “input.pam” with 100x100 dimensions and apply the left shift operator with a value of 2.

pamfunc -shiftleft 2 input.pam > output.pam

The resulting output.pam image will have the same dimensions as the input image, and each sample will be shifted to the left by 2 bits.

Conclusion:

With the “pamfunc” command, you can easily apply arithmetic and bit string functions to Netpbm images, allowing for various image manipulation and processing tasks. Whether you need to adjust intensities, perform bitwise operations, or apply filters, pamfunc provides a flexible and powerful solution for image processing.