Wednesday, May 04, 2005

An Indian's Trail Blazing Invention

Arvind Thiagarajan explains how he compressed data, on his way to a
path-breaking invention.

An invention that saves money, time and precious resources, and at the
same time also exemplifies simplicity.

"Conventionally, compression is done using complex transformations
such as Discrete Cosine Transformations (DCT) or data
transformations, wherein the whole image is converted into a frequency
signal and some of the high frequency details are filtered. Because of
that loss, we are able to get the data compressed. This is a
well-known method used all over the world.

"What I thought was a completely new approach where you keep the
data in the original form itself. It was challenging to code colours.
Although they look quite similar to human eyes, in reality, there are
minor variations in them. The pattern is not like single pixel colours
occurring continuously; it will be like, if one is in the 1st position, the
other is in the 5th and another in the 10th.

"So, the challenge was to put all of them together. I felt if we can do
that by rearranging the data, we can code them better. When we
rearrange the data, it is necessary that we need to maintain the original
order. That's where the technique of repetition coding using an index,
which we call it as bit- plane, originated.

"What we do is, we maintain a binary index to store the original
location of the data when we do the rearrangement and coding. So, at
the decompression stage, we can bring back the original data without
any loss because we had already indexed it. So, it's a perfectly
reversible technique, and very simple, too.

"I really don't know how I hit upon the idea. It was more of a practical
approach where intuition played a part. It was logical thinking that
helped me.

"Yes, I wondered why nobody in the world thought of this before
because it is such a simple thought. Thousands of papers are produced
all around the world on compression of data but, somehow, nobody has
thought of this fundamental problem."

Not only lossless, but more compression too

When Arvind Thiagarajan applied the compression technique on the
images from the hospital, he got 35 times lossless compression. The
compression was only 5 times in the traditional techniques like JPEG
and data was lost.

Click to Seefor more details


At 11:03 PM, Blogger nimbu said...

Thanks for the report!

I am a Community Development Engineer at MatrixView, and am so glad to see you report on Arvind!

More information on the power of ABO can be found in a white paper here:

Exciting blog!



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