EnglishFrenchSpanish

OnWorks favicon

pnmconvol - Online in the Cloud

Run pnmconvol in OnWorks free hosting provider over Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

This is the command pnmconvol that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


pnmconvol - general MxN convolution on a portable anymap

SYNOPSIS


pnmconvol convolutionfile [pnmfile]

DESCRIPTION


Reads two portable anymaps as input. Convolves the second using the first, and writes a
portable anymap as output.

Convolution means replacing each pixel with a weighted average of the nearby pixels. The
weights and the area to average are determined by the convolution matrix. The unsigned
numbers in the convolution file are offset by -maxval/2 to make signed numbers, and then
normalized, so the actual values in the convolution file are only relative.

Here is a sample convolution file; it does a simple average of the nine immediate
neighbors, resulting in a smoothed image:
P2
3 3
18
10 10 10
10 10 10
10 10 10

To see how this works, do the above-mentioned offset: 10 - 18/2 gives 1. The possible
range of values is from 0 to 18, and after the offset that's -9 to 9. The normalization
step makes the range -1 to 1, and the values get scaled correspondingly so they become 1/9
- exactly what you want. The equivalent matrix for 5x5 smoothing would have maxval 50 and
be filled with 26.

The convolution file will usually be a graymap, so that the same convolution gets applied
to each color component. However, if you want to use a pixmap and do a different
convolution to different colors, you can certainly do that.

At the edges of the convolved image, where the convolution matrix would extend over the
edge of the image, pnmconvol just copies the input pixels directly to the output.

Use pnmconvol online using onworks.net services


Free Servers & Workstations

Download Windows & Linux apps

  • 1
    AstrOrzPlayer
    AstrOrzPlayer
    AstrOrz Player is a free media player
    software, part based on WMP and VLC. The
    player is in a minimalist style, with
    more than ten theme colors, and can also
    b...
    Download AstrOrzPlayer
  • 2
    movistartv
    movistartv
    Kodi Movistar+ TV es un ADDON para XBMC/
    Kodi que permite disponer de un
    decodificador de los servicios IPTV de
    Movistar integrado en uno de los
    mediacenters ma...
    Download movistartv
  • 3
    Code::Blocks
    Code::Blocks
    Code::Blocks is a free, open-source,
    cross-platform C, C++ and Fortran IDE
    built to meet the most demanding needs
    of its users. It is designed to be very
    extens...
    Download Code::Blocks
  • 4
    Amidst
    Amidst
    Amidst or Advanced Minecraft Interface
    and Data/Structure Tracking is a tool to
    display an overview of a Minecraft
    world, without actually creating it. It
    can ...
    Download Amidst
  • 5
    MSYS2
    MSYS2
    MSYS2 is a collection of tools and
    libraries providing you with an
    easy-to-use environment for building,
    installing and running native Windows
    software. It con...
    Download MSYS2
  • 6
    libjpeg-turbo
    libjpeg-turbo
    libjpeg-turbo is a JPEG image codec
    that uses SIMD instructions (MMX, SSE2,
    NEON, AltiVec) to accelerate baseline
    JPEG compression and decompression on
    x86, x8...
    Download libjpeg-turbo
  • More »

Linux commands

Ad