d-bw [-n | scale] < doubles > unsigned_charsD-BW(1)
NAME
d-bw - convert double-precision binary numbers to unsigned bytes
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SYNOPSIS
DESCRIPTION
d-bw reads a stream of machine-native double-precision (8-byte) binary floating point values from standard input, multiplies each by a scale factor, and writes the result as a stream of unsigned bytes (one 8-bit value each) to standard output. This is typically used to turn a floating point signal or single-channel image into raw 8-bit pixel data suitable for bw(5) imagery.
Each scaled value is clamped to the range 0 through 255: values above 255.0 are written as 255 and values below 0.0 are written as 0. When any clamping occurs, the count of high and low clips is reported on standard error.
The scale factor defaults to 1.0. Supplying a numeric scale argument multiplies every input value by that factor before conversion. The -n flag is shorthand for a scale of 255.0, which maps normalized data in the range 0.0 to 1.0 onto the full 0 to 255 byte range.
Because the input is raw binary, d-bw refuses to run when standard input is a terminal. The inverse conversion, from unsigned bytes back to binary doubles, is performed by u-d(1).
This command is deprecated and is scheduled for removal; it prints a deprecation warning on startup.
OPTIONS
- -n
-
Normalize the data by using a scale factor of 255.0, mapping input values in the range 0.0 to 1.0 onto the output range 0 to 255.
- scale
-
A numeric scale factor by which each input value is multiplied before being clamped and written as a byte. Defaults to 1.0. Mutually exclusive with -n.
EXAMPLES
Example 1. Convert a normalized double stream to a bw image
d-bw -n < ramp.d > ramp.bwReads doubles in the range 0.0 to 1.0 from ramp.d and writes a single-channel 8-bit bw(5) image, scaling each value across the full 0 to 255 range so it can be viewed with bw-pix(1) or pix-fb(1).
Example 2. Apply a custom gain
dmod -m 100 < signal.d | d-bw 2.5 > signal.bwProcesses a double-precision signal with dmod(1), then scales each sample by 2.5 while converting to bytes, brightening the result and reporting on standard error how many samples were clipped.
SEE ALSO
brlcad(1), u-d(1), bw-d(1), dmod(1), dconv(1), bw(5)
AUTHOR
BRL-CAD Team
COPYRIGHT
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