[access-uk] Re: Empty PDF Document?

  • From: Benjamin Hawkes-Lewis <bhawkeslewis@xxxxxxxxxxxxxx>
  • To: access-uk@xxxxxxxxxxxxx
  • Date: Sat, 23 Jun 2007 17:08:10 +0100

Screen readers don't do any optical character recognition (despite their name, they do not read the screen; they do not act like a sighted person). They do basically one of two things:


1. Other programs send information to the visual display. Screen readers intercept these messages, extracting text and pixel positions.

2. Other programs use special code to expose information about themselves and what they are doing and what you can do with them to the screen reader. Screen readers use that information to provide you with a spoken or braille interface.

Hence screen readers can't do anything useful with an photograph of a document.

There's more detailed information about screen readers at:

http://en.wikipedia.org/wiki/Screen_reader


--
Benjamin Hawkes-Lewis

Joan Muir wrote:
Yes, Peter, I think we're finding the concept hard to grasp. I suppose what I 
mean is that, if someone sighted can read the graphic image, why can't the 
screen reader which is acting as a sighted person?

I still think I would have difficulty in following it though. (smile).

Best wishes,

Joan.
----- Original Message ----- From: Peter Beasley To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 4:04 PM
  Subject: [access-uk] Re: Empty PDF Document?


  I realise that tom but my point is thatyou would be able to read it were you 
able to see.
----- Original Message ----- From: Tom Lorimer To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 3:46 PM
    Subject: [access-uk] Re: Empty PDF Document?


    Yes you would be able to see the braille and read it with sight, but as 
it's a photograph you wouldn't be able to feel the braille with your fingers.

    Many years ago I was once sent a photo copy of a sheet of braille which of 
course was useless, and trying to get the person who sent it to me to 
understand that I couldn't read dots on a photograph was a total waste of time.

    Tom.

----- Original Message ----- From: Peter Beasley To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 3:26 PM
      Subject: [access-uk] Re: Empty PDF Document?


That's what I can't understand Tom. If I could see, and was presented with a picture of a sheet of Braille, surely I would be able to see the braille. ----- Original Message ----- From: Tom Lorimer To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 2:35 PM
        Subject: [access-uk] Re: Empty PDF Document?


        The text has been saved to a graphic type file and no screen reader can 
read it. That's why it had to be scanned with OCR software.

        Just imagine someone taking a picture of a sheet of braille with a 
camera and sending it to you.
        The braille is all there in the picture, but try reading it and you'll 
begin to understand the difference.

        Cheers Tom.

----- Original Message ----- From: Peter Beasley To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 2:25 PM
          Subject: [access-uk] Re: Empty PDF Document?


I was going to ask the same thing. What is the difference between a page of text and an image of a page of text? ----- Original Message ----- From: Joan Muir To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 1:52 PM
            Subject: [access-uk] Re: Empty PDF Document?


            Yes, indeed. I'm most grateful to Peter. What I don't follow is why 
I got the message that it was empty. I don't understand the thing about images 
really.

            Best wishes,

            Joan.
----- Original Message ----- From: Peter Beasley To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 12:49 PM
              Subject: [access-uk] Re: Empty PDF Document?


              I printed it out and scanned it with k1000 for her.
----- Original Message ----- From: Amro Bilal To: access-uk@xxxxxxxxxxxxx Sent: Saturday, June 23, 2007 12:33 PM
                Subject: [access-uk] Re: Empty PDF Document?


Joan, it might well be a PDF image. Run it through an OCR prog such as FineReader and see if you get any better results.
                HTH,
                Amro
----- Original Message ----- From: Joan Muir To: access-uk@xxxxxxxxxxxxx Sent: Thursday, June 21, 2007 9:43 PM
                  Subject: [access-uk] Empty PDF Document?


                  Hi, Folks,

                  I received an email with a PDF attachment. However, when I 
opened the document I got the message: Alert: empty document. Yet the 
attachment said 64 point something or other kb. How can this be?

                  If someone would like to look at this I'd be happy to forward 
it to them as obviously I can't send it to the list.

                  Best wishes,

                  Joan.


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