Computing the HSV histogram

From: Costantino Grana (prydechiocciolatinpuntoit_at_invalid.inv)
Date: 03/22/05 

Date: Tue, 22 Mar 2005 17:05:52 +0100

In the MPEG-7 standard the HSV histogram is used to provide information on
the image colors. In particular, the HSV color space is quantized with 16 H
values and 4 S and 4 V values.

My question is if is there any way to quickly convert from RGB to a
quantized HSV color space, by means of a look up table. The direct way is
very slow, so I d'like to speed up the process a bit.

Thanks in advance, 

-- 
/* Costantino Grana                                */
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*&a:t--;printf("  \0/*"+a));while ((a^=3)||a[++s]);;}
/* Original code due to Chris Brown... impressive! */