Revision: 76988
http://sourceforge.net/p/brlcad/code/76988
Author: brlcad
Date: 2020-08-30 18:39:17 +0000 (Sun, 30 Aug 2020)
Log Message:
-----------
document the weights for all the options including the new conversion modes
Modified Paths:
--------------
brlcad/trunk/doc/docbook/system/man1/pix-bw.xml
Modified: brlcad/trunk/doc/docbook/system/man1/pix-bw.xml
===================================================================
--- brlcad/trunk/doc/docbook/system/man1/pix-bw.xml 2020-08-30 18:38:46 UTC
(rev 76987)
+++ brlcad/trunk/doc/docbook/system/man1/pix-bw.xml 2020-08-30 18:39:17 UTC
(rev 76988)
@@ -21,7 +21,7 @@
<arg choice='opt'>-w <replaceable>width</replaceable></arg>
<arg choice='opt'>-n <replaceable>height</replaceable></arg>
<arg choice='opt'>
- <arg choice='opt'>-e <replaceable>ntsc|crt</replaceable></arg>
+ <arg choice='opt'>-e <replaceable>ntsc|crt|hdtv|hdr|avg</replaceable></arg>
<arg choice='opt'>
<arg choice='opt'><arg choice='plain'>-R
</arg><replaceable>r_weight</replaceable></arg>
<arg choice='opt'><arg choice='plain'>-G
</arg><replaceable>g_weight</replaceable></arg>
@@ -64,17 +64,41 @@
<varlistentry>
<term><emphasis remap='B'>ntsc</emphasis></term>
<listitem>
-<para> weighting used is based on the NTSC primaries and the
-D6500 alignment white.</para>
+<para>Weighting used is based on the NTSC primaries and white
+alignment. Conforming with Rec.ITU-R BT.601-7, this uses
+0.299/0.587/0.114 RGB weights. This gives a simplified linear
+conversion of perceived luminance that reflects human physiological
+sensitivity to green and least to blue.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis remap='B'>crt</emphasis></term>
<listitem>
-<para>weighting scheme used will be for "typical" CRT phosphor chromaticities
-and the D6500 white.</para>
+<para>Weighting scheme matches "historic" CRT phosphor chromaticities
+and a D6500 white alignment. Uses 0.26/0.66/0.08 RGB weights.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><emphasis remap='B'>hdtv</emphasis></term>
+ <listitem>
+<para>Weighting scheme matches "modern" HDTV display chromacities.
+Uses 0.2126/0.7152/0.0722 RGB weights per Rec.ITU-R BT.709</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis remap='B'>hdr</emphasis></term>
+ <listitem>
+<para>Weighting scheme matches high dynamic range (HDR) chromacities.
+Uses 0.2627/0.6780/0.0593 RGB weights per Rec.ITU-R BT.2020</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><emphasis remap='B'>avg</emphasis></term>
+ <listitem>
+<para>Weighting scheme simply takes the average of all three values
+(i.e., R + G + B / 3.0).</para>
+ </listitem>
+ </varlistentry>
</variablelist>
<para>
Individual color plane(s) can be selected via the
@@ -96,15 +120,10 @@
<para>will equally blend the red and blue color planes; because -G is omitted,
the green color plane is not considered.
(Had "-G0.0" been included in this example, the three colors would have been
weighted equally, as in the default condition.)</para>
-<para>pix-bw -R0.30 -G0.59 -B0.11 < <emphasis remap='I'>file.pix</emphasis>
> <emphasis remap='I'>file.bw</emphasis></para>
+<para>pix-bw -R0.3 -G0.6 -B0.1 < <emphasis remap='I'>file.pix</emphasis>
> <emphasis remap='I'>file.bw</emphasis></para>
<para>
-has the same effect as the
-<option>-ntsc</option>
-flag.
-<!-- .br -->
-[The
-<option>-crt</option>
-weights are: 0.26, 0.66, 0.08]</para>
+applies weights close to the <option>-ntsc</option> flag.
+</para>
</refsect1>
<refsect1 xml:id='see_also'><title>SEE ALSO</title>
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