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PIXHIST3D-PLOT3(1)

NAME

pixhist3d-plot3 - output RGB color space utilization in 3D unix-plot form

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SYNOPSIS

pixhist3d-plot3 [file.pix] > file.plot3

DESCRIPTION

pixhist3d-plot3 reads a color pix(5) format image, either from the named file.pix or from standard input, and writes to standard output a point for each unique RGB color that occurs in the image. The points are emitted as a BRL extended three-dimensional UNIX plot (see libbv(3) and plot3(5)). Red, green, and blue lines are drawn along the edges of the color cube to mark the coordinate axes. The color space is sampled at a resolution of 128x128x128, i.e. the least significant bit of each color plane is ignored.

These plots are best viewed in an interactive 3D plot display program so the color cube can be rotated and examined from all angles. Anomalies in an image’s colors are often readily apparent, e.g. oversaturation resulting in intensity clipping.

The command takes no options.

EXAMPLES

Example 1. Visualize the color space of an image
pix-fb -i image.pix &
pixhist3d-plot3 image.pix | plot3-fb

Plot the set of colors used by image.pix as a 3D point cloud inside the RGB cube and display it on a framebuffer with plot3-fb(1). Running an interactive viewer that rotates the plot reveals clustering, gaps, and clipping in the image’s color usage.

Example 2. Save the color cube plot for later viewing
pixhist3d-plot3 < render.pix > render.plot3

Read render.pix from standard input and store the resulting 3D plot in render.plot3, which can subsequently be displayed or converted with other plot3(5) tools.

SEE ALSO

brlcad(1), pixhist3d(1), pixhist(1), plot3-fb(1), pix-fb(1), pix(5), plot3(5)

AUTHOR

BRL-CAD Team

This software is Copyright (c) 1989-2026 by the United States Government as represented by U.S. Army Research Laboratory.

BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org