Lenna

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Lenna or Lena is the name given to a standard test image originally cropped from a Playboy magazine centerfold picture of Lena Söderberg, a Swedish model who posed nude for the November 1972 issue. The image is probably the most widely used test image for all sorts of image processing algorithms (such as compression and denoising) and related scientific publications.

The anglicised version "Lenna" of Söderberg's name comes from the Playboy article; Playboy changed the original "Lena".

Contents 1 History 2 Impact 2.1 Controversy 3 See also 4 Notes 5 References 6 External links

[edit] History

The picture's history was described in the May 2001 newsletter of the IEEE Professional Communication Society, in an article by Jamie Hutchinson:^[1]

“

Alexander Sawchuk estimates that it was in June or July of 1973 when he, then an assistant professor of electrical engineering at the University of Southern California Signal and Image Processing Institute (SIPI), along with a graduate student and the SIPI lab manager, was hurriedly searching the lab for a good image to scan for a colleague's conference paper. They got tired of their stock of usual test images, dull stuff dating back to television standards work in the early 1960s. They wanted something glossy to ensure good output dynamic range, and they wanted a human face. Just then, somebody happened to walk in with a recent issue of Playboy. The engineers tore away the top third of the centerfold so they could wrap it around the drum of their Muirhead wirephoto scanner, which they had outfitted with analog-to-digital converters (one each for the red, green, and blue channels) and a Hewlett Packard 2100 minicomputer. The Muirhead had a fixed resolution of 100 lines per inch and the engineers wanted a 512 × 512 image, so they limited the scan to the top 5.12 inches of the picture, effectively cropping it at the subject's shoulders.

”

This scan, nonetheless, became one of the most used images in computer history, so much that the mysterious Lenna came to be dubbed the 'First Lady of the Internet'^[2] and one of the influential photographs that changed the course of history ^[3]

Lenna was not the first Playboy magazine image to be used to illustrate image processing algorithms. Lawrence G. Roberts used a 1960 Playboy image, with permission and attribution, in his 1961 MIT master's thesis on image dithering.^[4] Another interesting piece of trivia is that Lenna's issue (November 1972) was Playboy's best selling issue ever and sold 7,161,561 copies. ^[5]

[edit] Impact

David C. Munson, editor-in-chief, January 1996 IEEE Transactions on Image Processing, cited two reasons for the popularity of the image in research:^[6]

“

First, the image contains a nice mixture of detail, flat regions, shading, and texture that do a good job of testing various image processing algorithms. It is a good test image! Second, the Lena image is a picture of an attractive woman. It is not surprising that the (mostly male) image processing research community gravitated toward an image that they found attractive.

”

Lenna is so widely accepted in the image processing community that Söderberg was a guest at the 50th annual Conference of the Society for Imaging Science and Technology in 1997.^[7]

[edit] Controversy

The use of the image has produced some controversy, with some people concerned about Playboy magazine as the source of the image, and with the image being copyrighted.^[6]

In a 1999 essay on reasons for the male predominance in computer science, Dianne O'Leary wrote:^[8]

“

If a professor makes a sexist joke, a female student might well find it so disturbing that she is unable to listen to the rest of the lecture. Suggestive pictures used in lectures on image processing are similarly distracting to the women listeners and convey the message that the lecturer caters to the males only. For example, it is amazing that the "Lena" pin-up image is still used as an example in courses and published as a test image in journals today.

”

When the IS&T wanted to invite Söderberg to their meeting,^[9]

“

Playboy helped track down the Swedish native in Stockholm, where she helps handicapped people work on (non-networked) computers. Although Playboy is notorious for cracking down on illegal uses of its images, it has decided to overlook the widespread distribution of this particular centerfold. Says Eileen Kent, VP of new media at Playboy: "We decided we should exploit this, because it is a phenomenon."

”

Coincidentally, Playboy states the issue was its best-selling ever, having sold 7,161,561 copies as of May 2006.^[10]

The image had a sense of affection to many image processing scientists that one of them even wrote a sonnet about her.^[11]

O 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 filters took sparkle from your eyes
I said, "Heck with it. I'll just digitize."

[edit] See also

• Cornell Box - radiosity rendering standard test scene
• Utah teapot - 3D computer graphics test shape
• Stanford Bunny - 3D computer graphics test shape
• Tom's Diner - original test song for MP3
• Standard test image

[edit] Notes

[edit] References

• Gonzalez, Rafael C.; Richard E. Woods. Digital Image Processing (2nd ed.). ISBN 0-20-118075-8.  — image used numerous times in chapter 6

[edit] External links

• http://www.ee.cityu.edu.hk/~lmpo/lenna/Lenna97.html
• The Lenna Story - Contains a link to an un-cropped scan of the original Playboy photograph