sed/awk Capitallize everything between patterns and lowercase small words - sed

Question

I did find a way to capitalize the whole document, with both sed and awk, but how to do it, if I want to convert everything inside patterns from CAPS LOCK to Capital?
For example, I have an HTML file, and everything (multiple occurrences) between <b> and </b> has to be converted from TITLE to Title, and if possible making small words (1 ~ 2 letters) in lowercase.
From This:
<div id="1">
<div class="p"><b>THIS IS A RANDOM TITLE</b></div>
<table class="hugetable">
...
</table>
<div class="p"><b>THIS IS ANOTHER RANDOM TITLE</b></div>
<table class="hugetable">
...
</table>
...
</div>
To this:
<div id="1">
<div class="p"><b>This is a Random Title</b></div>
<table class="hugetable">
...
</table>
<div class="p"><b>This is Another Random Title</b></div>
<table class="hugetable">
...
</table>
...
</div>

Answer 1

This is not the most beautiful solution but I think it works:
sed -r -e '/<b>/ {s/( .)([^ ]*)/\1\L\2/g}' -e 's/<b>(.)/<b>\u\1/' -e '/<b>/ {s/(\b.{1,2}\b)/\L\1/g}' data
Explanation:
1st expression (-e): If a line contains <b>:
Then for each word which has a space in front of it, keep the space and the first (already capitalized) character (\1) and then convert all the following characters of the word to lower case (\L\2)
2nd expression (-e): The first word after <b> is still uncapitalized, so select the first character after the bold tag <b>(.) and replace it uppercased <b>\u\1
3rd expression (-e): Again if a line contains <b>:
Then select words of 1 or 2 characters in length \b.{1,2}\b and replace them lowercased \L\1