Camera-phone boundary blurs, but images get sharper

CANNES, FRANCE - It can only be a matter of time before we talk of calling someone with our camera, as the resolution and capabilities of the imaging components in mobile phones continue to climb. At the 3GSM World Congress in Cannes, France, this week, manufacturers showed off a number of technologies that render the line between phones and cameras more blurry -- but make the pictures they produce ever sharper.

Cameras typically allow a great deal of control over factors such as exposure and focus at the moment the picture is taken, whereas phones typically have one control: take a picture. Some cameras try to give users the control they seek after the fact with a range of functions for editing stored images, but these are often limited in capability.

Two companies exhibiting in Cannes -- Scalado AB of Lund, Sweden, and DxO Labs SA of Boulogne, France -- demonstrated image processing software for camera phones that improves image quality in different ways.

Scalado demonstrated software to solve one of the hidden problems of image editing on mobile phones: lack of memory. While a two-megapixel image might only occupy a few hundred kilobytes of memory in compressed JPEG format, editing such images has traditionally involved decompressing them into a full-size bitmap image of about 6M bytes and performing operations on a copy of that image -- requiring around 12M bytes of memory in total. If this memory is not available, then editing photos may only be possible at greatly reduced resolution, defeating the object of putting a high-resolution camera in the phone in the first place, according to Pierre Elzouki, Scalado's vice president of business development.

The company's Caps software libraries perform operations such as color correction, picture rotation, image compositing and pixel editing directly on the compressed version of the image, reducing the memory required for editing the same two-megapixel image to less than a megabyte, he said. By reducing the requirement for memory and processor power in the phone, the software can cut phone costs by between $1 and $5, Elzouki said.

Scalado sells its software in several ways. Phone manufacturers can license the image processing code for use in their own applications. They can also license broader functions or complete applications such as Photo Twister, which distorts images in real time, swelling and shrinking parts of the image much like the curved mirrors in a funhouse. Finally, owners of smart phones based on Symbian OS can download such applications from online services such as Handango, Elzouki said.

DxO Labs showed its DxO Mobile Embedded Edition software running on an Omap DM275 imaging processor from Texas Instruments Inc. (TI). The software corrects for image defects such as noise, color imbalance and low contrast introduced by digital image sensors by applying a variety of mathematical techniques to a model of the image sensor, the company said.

At low light levels, noise becomes a problem with digital image sensors. DxO uses a recently developed mathematical technique in its DxO Noise software to reduce the effect of noise on the image, which allows cameras to produce the same image quality with just a quarter of the ambient light, according to the company, which demonstrated the software at TI's booth. Another program, DxO Contrast, applies varying contrast settings to different parts of the image, to make fine detail in shadows or bleached-out parts of the image more visible.