Lenna: Difference between revisions

Lenna or Lena is the name given to a 512×512 pixel standard test image which has been in use since 1973,^[1] and was originally cropped from the centerfold of November 1972 issue of Playboy magazine. It is a picture of Lena Söderberg, a Swedish model, shot by photographer Dwight Hooker. 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 Lena Söderberg's actual name comes from the Playboy article where Playboy changed the original "Lena".

The picture's history was described in the May 2001 newsletter of the IEEE Professional Communication Society, in an article by Jamie Hutchinson:^[2]

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".^[3] Lenna was not however the first image to be published on the Internet or World-Wide Web; the first image published on the WWW was one of Les Horribles Cernettes.

Lenna was also 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]

David C. Munson, editor-in-chief, January 1996 IEEE Transactions on Image Processing, cited two reasons for the popularity of the image in research:^[5]

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.^[6]

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.^[5]

In a 1999 essay on reasons for the male predominance in computer science, Dianne O'Leary wrote:^[7]

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;^[8]

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 (November 1972) was its best-selling issue ever, having sold 7,161,561 copies as of May 2006,^[6][9] and the Lenna centerfold appears briefly in Woody Allen's film Sleeper released the following year.

• Lenna 97: A Complete Story of Lenna
• The Lenna Story - Contains a link to an un-cropped scan of the original Playboy photograph