Re: Image Search Engine Input (General storage of extra data for use by Nutch)

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Re: Image Search Engine Input (General storage of extra data for use by Nutch)

Ed Whittaker
Hi,

My question is not strictly to do with image search but I can't help feeling
the issue is somewhat related in terms of where to store what: I want to
spell correct web pages prior to indexing and only index the corrected
terms. I still want to store the original errorful text so this can be given
in the summary and highlighted accordingly. Queries would similarly be
corrected at query time. (The need for an alignment is to recover spelling
mistakes and miskeys like "inthe" and "Nutc h" etc. although actually it's
more relevant to CJK languages.)

Of course, this would be trivial if we didn't want to highlight the terms in
the summary but to do highlighting we need to know where the original terms
are in relation to the corrected terms (i.e what we indexed). We therefore
need somewhere to store an alignment of the errorful original with the
corrected text. At the moment we're storing this as an extra field inside
the index but this is not a very elegant solution. Hence my related
question: is there a more appropriate location to store such data? And where
is the best place to do the spelling correction in the Nutch workflow? A
separate mapreduce job or inside the indexing reduce job as I'm doing now?

-Ed

On 3/30/07, Doug Cutting <[hidden email]> wrote:

>
> Steve Severance wrote:
> > I am not looking to really make an image retrieval engine. During
> indexing referencing docs will be analyzed and text content will be
> associated with the image. Currently I want to keep this in a separate
> index. So despite the fact that images will be returned the search will be
> against text data.
>
> So do you just want to be able to reference the cached images?  In that
> case, I think the images should stay in the content directory and be
> accessed like cached pages.  The parse should just contain enough
> metadata to index so that the images can be located in the cache.  I
> don't see a reason to keep this in a separate index, but perhaps a
> separate field instead?  Then when displaying hits you can look up
> associated images and display them too.  Does that work?
>
> Steve Severance wrote:
> > I like Mathijs's suggestion about using a DB for holding thumbnails. I
> just want access to be in constant time since I am going to probably need to
> grab at least 10 and maybe 50 for each query. That can be kept in the plugin
> as an option or something like that. Does that have any ramifications for
> being run on Hadoop?
>
> I'm not sure how a database solves scalability issues.  It seems to me
> that thumbnails should be handled similarly to summaries.  They should
> be retrieved in parallel from segment data in a separate pass once the
> final set of hits to be displayed has been determined.  Thumbnails could
> be placed in a directory per segment as a separate mapreduce pass.  I
> don't see this as a parser issue, although perhaps it could be
> piggybacked on that mapreduce pass, which also processes content.
>
> Doug
>