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Re: ISSUE-66 Change Proposal: be more explicit about potential repair techniques

From: Nicholas Stimpson <nicholas.stimpson@ntlworld.com>
Date: Thu, 11 Mar 2010 01:19:08 +0000
Message-ID: <4B98450C.9010500@ntlworld.com>
To: public-html@w3.org
On 11/03/2010 01:04, Nicholas Stimpson wrote:
> SUMMARY
>
> The spec is very vague about what image analysis techniques could be
> applied to images. This change proposal suggests including more detail
> about possible techniques.
>
>
> RATIONALE
>
> Currently the<img>  element section mentions that UAs "may also apply
> heuristics to help the user make use of the image when the user is unable
> to see it", but the only suggested heuristic is OCR.
>
> In practice, there are a host of other heuristics that could help a user
> make sense of an image, and they might be useful even to users who _can_
> see the image. We do all users a disservice by not being more explicit
> here. Being explicit could encourage significant competition amongst user
> agents, leading to a much better user experience for everyone.
>
> Since these heuristics are in many cases already implemented and 
> shipping,
> sometimes in multiple products from multiple vendors, and since recent
> advances in image recognition techniques have been fast and furious, it
> seems reasonable to mention these techniques as real possibilities.
>
>
> DETAILS
>
> Strike "when the user is unable to see it". Instead, start a new sentence
> before the "e.g", which says "This would be especially useful to users 
> who
> cannot see the image", and add the following after the "e.g." clauses, in
> a separate clause: "but it could also be useful to users who _can_ see 
> the
> image, but might not fully understand or recognise it".
>
> Move "optical character recognition (OCR) of text found within the image"
> to be the first bullet of a bulleted list, and add the following
> additional points:
>
>    * Facial recognition in photographs, especially facial recognition of
>      notable individuals or of individuals in the user's social network.
>
>    * Product or brand recognition in photographs or logos.
>
>    * Barcode recognition of any embedded barcodes.
>
>    * Bitmap to vector analysis for diagrams, allowing images to be
>      further analysed in specialised tools.
>
>    * Data extraction for graphs, allowing data to be reconstructed from
>      bar charts, pie charts, and the like, or allowing regression lines
>      to be fitted to x,y plots.
>
>    * Landmark recognition for photographs.
>
>    * 3D reconstruction of scenes based on multiple images, allowing a set
>      of images to be taken together and explored in context.
>
I think this is fine text and a good idea. I wonder however whether we 
do these ideas a disservice by labelling them as repair techniques for 
missing alt. Would it not be better to suggest that the information 
extracted be made available to users in addition to any information 
provided by alt. For instance, this text could be presented under an 
"Understanding and Interpreting Images" section separate from the alt 
requirements.
>
> IMPACT
>
> POSITIVE EFFECTS
>
> Adding such text could lead to a renewed level of competition in browsers
> as they find the best ways to expose such tools to users.
>
> Such competition would inevitably lead to improved accessibility across
> the board, as many of these analysis techniques could provide users with
> anything from a basic hint of the image's contents to fully-interactive
> reconstructions of the image in more accessible forms (especially in the
> case of text-in-image or graphs).
>
> NEGATIVE EFFECTS
>
> Makes the spec longer.
>
> CONFORMANCE CLASS CHANGES
>
> None.
>
> RISKS
>
> It is suggested that mentioning that user agents might be able to repair
> non-conforming pages could make authors less likely to write conforming
> pages, though it is not clear why this would apply here and not in the
> many other parts of the spec that mention repair techniques, especially
> the sections that explicitly mandate specific user agent repair
> techniques.
>
Received on Thursday, 11 March 2010 01:20:41 UTC

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