Improving data compression
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An Indian company claims to have a better solution than JPEG.
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Photo: Vino John
QUICKER DIAGNOSIS: The doctor can decide whether he is interested in a particular MRI image in four seconds and go to the next image that is being transmitted using ABO technology, claims Arvind Thiagarajan, who is the inventor of the technology at MatrixView.
TWEAK THE Jenson & Nicholson's advertising slogan, "Whenever you see colour, think of us... " and it would read "Whenever you think of storage and transmission, think of us ... " That is the way the Chennai based MatrixView Technologies (India) Private Limited aspires to project itself in the coming years.
Myriad applications
The company is gearing up to bring about a change in the way data is stored and transmitted. And if it does succeed, it may find its technology being embedded in digital cameras and also being used for storing and transmitting radiological data such as X-rays, ECGs, CT scans and MRI scans. Well, in a world that is rapidly going digital, the opportunities are endless.
"What makes our product — Adaptive Binary Optimization (ABO) — perform better is its ability to compress more without losing any data," claimed Mr. Arvind Thiagarajan, who is the inventor of the technology and the Chief Scientist at MatrixView. "We can compress ECGs 50-300 per cent more compared with conventional technology."
Better compression without losing any data is the most difficult part for anybody to believe at the first instant. The biggest surprise is that the technology is very simple. So simple that one wonders why nobody ever thought of it earlier. And Mr. Thiagarajan wondered too.
So how did Mr. Thiagarajan who had not specialised in image processing crack it when experts the world over missed it? "Not having specialised in image processing actually helped me," Mr. Thiagarajan said matter of factly. In the end, straightjacketing was missing and he could think out of the box.
But in the first place what leads to loss of data with conventional technology? Loss of data, according to him, is inevitable in the case of conventional compression technology (discrete cosine transformations) used in JPEG. Here, any sharp transition from black to white is rounded off to get a smoother transition and better compression but at the cost of data loss.
"The process of converting an image, say ECG, from spatial to frequency domain is complex. This complex conversion process by itself leads to loss of data," claimed Mr. Shivakumar Narayanan, Vice President (R&D) at Matrix.
"There are two types of losses — mathematical and visual. And if you are doing medical diagnosis using high-resolution images then data loss becomes unacceptable," said Mr. Narayanan.
In the case of echocardiograms (ECG), ABO technology can achieve a compression ratio that is 50-300 per cent superior to conventional technology. But the biggest advantage is that the doctors can see live (moving) images and this makes repeat ECGs redundant.
Progressive transmission
In the case of radiology images such as CT and MRI scans, the compression ratio is 10-50 per cent better than existing techniques such as JPEG. Again, the advantages go beyond better compression. "We use progressive transmission," Mr. Thiagarajan said. "In this case, the first image of a digital scan X-ray comes in the first four seconds. And the entire file of 10 MB size in five minutes. The doctor can come out with a diagnosis when only 30-40 per cent of the data has been transmitted."
While some developed countries wanted to get away from X-ray films and the associated problems of storage and archival, X-rays have not gone the digital way in India.
With a digital X-ray file being in the order of 10 MB, transmitting through a dial-up line will take nearly 30 minutes; it takes just five minutes with ABO. The Sri Sathya Sai Hospital in Bangalore will soon be going in for a digital X-ray machine as they have started using the Matrix technology to transmit data.
Or take the case of transmitting MRI scans. With 16 images in an MRI scan transmitted one after the other as separate files, the doctor can decide whether he is interested in a particular image in four seconds and go to the next image. "The doctor can decide on his diagnostic approach within one minute," claimed Mr. Thiagarajan.
Static transmission
Conventional technology uses static file transmission and the screen remains blank till the entire image is transmitted in full. "So one has to wait for ten minutes for every MRI image to be transmitted," he added.
The biggest gainers will be telemedicine and BPOs (Business Process Outsourcing) involved in medical radiological diagnostics. Already, the Chennai based CIMAR, which is involved in tele-radiology, is testing the ABO technology for CT and MRI scans.
The Sri Sathya Sai Hospital has started using MatrixView's solution for compressing and transmitting ECGs in their LAN for immediate attention by the doctors.
"The need to go in for repeat ECGs when more information is needed has been obviated with this technology," Dr. P.K. Dash, Head, Department of Cardiology at the hospital said. "Consultants can see live as well the recorded ECGs. We are happy with the quality of the images as there is no loss of data."
Outside India, the Singapore based National University Hospital has started a pilot study to compress radiological images.
The new regulation in the U.S. does not permit the physical transfer of original documents.
This opens up new avenues for Matrix to scan the documents and transmit the data digitally to India with no loss of data and better compression. "So we believe there is a huge opportunity for outsourcing business," said Mr. Thiagarajan.
Archiving documents
Archiving documents is another area where the company has achieved success. HSBC Precision Printing Ltd, a subsidiary of HSBC has adopted the Matrix technology for document scanning and archiving. HSBC plans to initially target the Hong Kong and China customers and later cover the Asia Pacific region.
The company is also planning to launch a zip solution for Internet transmission which the user can use to compress files better than what is possible now.
One big market that is growing at a high rate is digital photography. The company, according to Mr. Thiagarajan, is in discussion with digital camera manufacturers to have ABO embedded in the cameras.
"Today's 1GB storage card used in digital cameras can store 600 images of the highest resolution. By using our technology nearly 1000 images can be stored," he emphasised.
With a compression ratio that is 5-30 per cent better than JPEG for natural colour images, the company sees a huge market for digital photos.
Plans are underway to enter the digital video market by the end of the year. "Our ultimate aim is to make JPEG and other unzip formats obsolete," commented Mr. Thiagarajan. A tall order indeed. Only time will tell if he can actually achieve it.
How it works
REPETITION CODED Compression invented by MatrixView assigns a value of `1' for successively similar values (pixels) in an image. If the value in an image is different from the previous value, `0' is assigned and the corresponding original value is stored in a table called `Data Store'. This process is done for all the values in an image.
The collection of zeroes and ones is called a bit plane. At the end of the process, there is a `Data Store' table and a bit plane.
Such a process makes it possible to increase the compression without losing any data.
R. Prasad
in Chennai
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