Hi AjayK,
We don't use 32 bit image types for BCG since this is a very rare application need. First of all, its unlikely anyone has a 32 bit camera that would be acquiring such images (most are 8 bit). Also, 32 bits usually implies color images and BCG is primarily used on monochrome images. There is an example for using a 16 bit BCG which you may find useful that I have attached as well.
You may also want to consider submitting product suggestions to our R&D department here:
http://sine.ni.com/apps/we/nicc.call_me?p_action=country&p_lang_id=US
Regards
Dan
National Instruments