The good news is you can keep the camera in your cell phone. The bad news is anyone who wants to can turn it off.

At least that's the way it might work if technology described by Hewlett-Packard makes it to market. A recent patent application from the computing giant describes a system in which digital cameras would be equipped with circuits that could be remotely triggered to blur the face in any images captured by the camera.

U.S. patent application 20040202382, filed in April 2003 and published in October 2004, describes a system in which an image captured by a camera could be automatically modified based on commands sent by a remote device.

In short, anyone who doesn't want their photo taken at a particular time could hit a clicker to ensure that any cameras or camera-equipped gadgets in range got only a fuzzy outline of their face.

Maurizio Pilu, an engineer in HP's Bristol, England, labs, says in the application that such a system would balance the proliferation of digital imaging capabilities with growing concerns about privacy.

"Increasing usage of portable camera devices means that the privacy issue of capturing images of subjects who would prefer not to be photographed has increased," according to the application. "Because portable cameras are small and are likely to be unseen by a subject, persons generally cannot choose to avoid being in the field of view of a small portable camera and are likely to have their pictures taken without their knowledge or consent."

A system that allowed people to selectively opt out of having their photo taken would address such privacy concerns without resorting to more draconian measures such as banning cameras, as numerous authorities have done with camera-equipped mobile phones.

The patent application covers technology that would have to be incorporated both into cameras and the "image inhibitor modules" that would signal "No photos of me, please," plus a system for spontaneously registering inhibitors with cameras. The in-camera technology includes sophisticated image-analysis software to selectively identify faces so they can be obfuscated.

An HP representative said the company had no current plans to commercialize the technology, which would require widespread adoption by camera makers and possibly government mandates to be financially practical.