Re: CAPTCHA image validation in web form

[Ralph Daugherty <rdjfc@xxxxxxxxxxxxx>]

It's most likely TIFF. The hard part is extracting the portion of the 
page image that contains the letters (i.e., lots of white space on the 
page) and converting to GIF, JPG, or PNG for HTML display. Or clipping 
the page that contains several letter combinations into multiple files 
and then converting, etc.

Even if already in GIF (I doubt it), would still be an interesting 
exercise to extract a CAPTCHA sized image containing the letters out of 
the page image.

I wrote software a long time ago to do things like that as part of an 
OCR I was writing and got it to a certain stage of development that did 
that and lots more before moving to the AS/400 in 1989. Never really had 
time to revisit since then. It's on my list now that some of that stuff 
could be useful as in things like this.

 rd


vhamberg@xxxxxxxxxxx wrote:
> RD
>
> Converting a spooled file to TIFF is really easy with InfoPrint Server or Host Print Transform, as I recall. Or maybe GIF - I don't remember.
>
> Vern
>
> -------------- Original message -------------- 
> From: Ralph Daugherty <rdjfc@xxxxxxxxxxxxx> 
>
> > That would be cool to use the iseries functionality to generate the 
> > images, but a quick search on iseries printing (AFP, InfoPrint Server, 
> > etc.) didn't indicate that a character could be rotated. Of course 
> > Postscript supports it and it's an addon to InfoPrint Server, per the 
> > IBM blurbs, and maybe the "precise character positioning and alignment" 
> > feature includes that, I don't know. 
> >
> > However, just wanted to clarify that the rotation that is done in 
> > most CAPTCHA's isn't that critical to busting OCR's, just slightly 
> > overlapping a couple of the characters will do it. So in that regard, 
> > the DDS AFP POSITION keyword I saw I think could definitely do that. 
> >
> > But then getting the spoolfile into some graphics format and 
> > clipping the characters out and converting into one of the HTML 
> > supported formats if for example it was in TIFF would probably require 
> > more effort than just generating the images with that Java program. :) 
> >
> > rd 
> >
> >
> > vhamberg@xxxxxxxxxxx wrote: 
> > > I've been thinking about native image generation as this thread continures. 
> > Seems one could generate oddly placed numbers into a spooled file using the 
> >
> > various font characteristics and rotation, then run the result through 
> > HPT or 
> >
> > InfoPrint Server to get a graphic image - we have a couple converter 
> > products 
> >
> > that could help in the effort, but this is not specifically a vendor plug. 
> > > There are also a TIFF library and a PNG library of functions that can be 
> > installed into PASE. Maybe these have some uses in such a process. 
> > > Eh? 
> > >
> > > Vern