Anil K Kandangath
Anyone familiar with digital image processing will surely recognize the image of Lena. While going through some old usenet discussions, I got to know that Lena has a history worth all the attention that has been paid to her over the years by countless image processing researchers.
Lena Sj??blom, (also spelled Lenna by many publications) was the Playboy playmate in November 1972 and rose to fame in the computer world when researchers at the University of Southern California scanned and digitized her image in June 1973. (Lena herself never know of her fame until she was interviewed by a computer magazine in Sweden where she lives with her husband and children).
According to the IEEE PCS Newsletter of May/June 2001, they were hurriedly searching for a glossy image which they could scan and use for a conference paper when someone walked in with a copy of Playboy. The engineers tore off the top third of the centerfold and scanned it with a Muirhead wire photo scanner (a distant cry from the flatbed scanners of today) by wrapping it around the drum of the scanner. (Now you know why the image shows only a small part of the entire picture.. discounting of course, the fact that the complete picture would raise quite a few eyebrows. Follow the link at the bottom of this article to see the complete picture.) At a maximum possible resolution of 100 lines per inch of their scanner, the researchers were able to scan only the top 5.12 inches of the image (to obtain a 512 x 512 pixel image) and the complicated scanning process also lost one line from the image. (The top line was replicated to obtain 512 rows) since the image was needed in a hurry. This distorted (the imperfect A/D converters also ensured that the image was slightly elongated) image soon became a standard when USC researchers began handing out the Lena image to test compression and encoding algorithms.
Over the years, the Lena image has been used so much that she is now dubbed the First Lady of the Internet! The Lena image is now considered the benchmark for testing and demonstration of image compression and transmission algorithms. While it was probably just a matter of chance that some researcher (probably someone who liked the image a lot for his personal reasons - note that I say his, not her), the image is now widely accepted as one that satisfied many of the requirements of a standard "test" image for image processing. The January 1996 IEEE Transactions on Image Processing has a note from the Editor-in-chief who says that "image contains a nice mixture of detail, flat regions, shading, and texture that do a good job of testing various image processing algorithms". Over the years, the image has attracted its fair share of controversy (from people who have demanded that the image be dropped from research and IEEE publications due to it's 'ignominous' origins) adoration(I found a poem by an unknown student of image compression, which I shall reproduce below) genorosity (from Playboy magazine which seems to have decided not to enforce it's copyright privileges over the image) and interest (Wired news wrote about her and Yahoo! India has a separate category for the Lena image in it's directory). Pursue the links below to find out more on Lena.
And finally, here's the poem dedicated to Lina, written by an anonymous admirer:
"0 dear Lena,
your beauty is so vast
It is hard sometimes to describe it fast.
I thought the entire world I would impress
If only your portrait I could compress.
Alas!
First when I tried to use VQ I found that your cheeks belong to only you.
Your silky hair contains a thousand lines Hard to match with sums of discrete cosines.
And for your lips, sensual and tactual
Thirteen Crays found not the proper fractal.
And while these setbacks are all quite severe I might have fixed them with hacks here or there
But when wavelets took sparkle from your eyes I said, "Skip this stuff. I'll just digitize."