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From Aravinth Bheemaraj <b.aravi...@gmail.com>
Subject Re: Image as input to M-R in Hadoop
Date Mon, 29 Nov 2010 22:13:38 GMT
Michael, thanks a lot for your reply.

I got to compare the images based on pixels. So is it possible to process
the image based on Pixel values rather than XML records?

I have read somewhere that the class "InputFormat" can be customized to
handle images by extending "InputSplit" and "RecordReader". But I am unsure
of the methods which are to be overridden so that I can access pixels of the
image. Is there anyway you can help me with this?

Regarding the note, I am reading in a directory with multiple image files.

On Mon, Nov 29, 2010 at 4:08 PM, Michael Segel <michael_segel@hotmail.com>wrote:

> Hi,
> The short answer is yes you can process images in Hadoop.
> Think of the image as a multi-line byte stream.
> As to an existing class, I don't believe that it exists, but shouldn't be
> too difficult to cobble.
> (If you can read in XML records for processing you should be able to read
> in a file containing a series of images.)
> Note: I'm assuming that you're either reading in a directory w multiple
> image files, or an image file w multiple images. Otherwise you probably
> don't want to use Hadoop.
> > Date: Mon, 29 Nov 2010 14:56:35 -0500
> > Subject: Image as input to M-R in Hadoop
> > From: b.aravinth@gmail.com
> > To: general@hadoop.apache.org
> >
> > Hi,
> >
> > I am a beginner to Hadoop and I am looking for some help in implementing
> the
> > Mapper with an image as input. Is there any predefined Writable class for
> > processing image? If so, how do I use it?
> >
> > Also I have read somewhere that compressed formats cannot be processed in
> > Hadoop. If this is true, am I making any sense in saying that the JPEG
> > images (which are also compressed format) cannot be processed by Hadoop?
> > Please correct me if I have misunderstood this concept.
> >
> > Thanks,
> > --
> > Aravinth

Aravinth Bheemaraj
University of Florida

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