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From Shrijeet Paliwal <shrij...@rocketfuel.com>
Subject Re: Image as input to M-R in Hadoop
Date Mon, 29 Nov 2010 22:49:36 GMT
This gentleman here (see below) is doing a hadoop streaming magic and
seems to be playing with the image features in map reducy way. Its not
using hadoop's java api though, so no help there.
Still you can check and see if the articles gives you some clues,
http://techportal.ibuildings.com/2009/11/02/precision-color-searching-with-gmagick-and-amazon-elastic-mapreduce/

PS: Pardon if the motivation in the article is orthogonal to yours.

-Shrijeet

On Mon, Nov 29, 2010 at 2:13 PM, Aravinth Bheemaraj
<b.aravinth@gmail.com> wrote:
> 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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