DxO AutoCLS: Perfect Color Uniformity for Smartphone Cameras

The proliferation of mobiles with cameras in recent years means that everyone is now a photographer, and people are increasingly aware of image quality. The mobile camera has improved enormously to become a major selling factor when choosing a phone.

Read on to find out how DxO AutoCLS tackles this tough problem, and why it is more successful than other current solutions.

Although users are generally remarkably tolerant of absolute color rendering, they are much more sensitive to relative color rendering — typically, a lack of uniformity, i.e. color that changes from the center to the corners of the image, independent of scene content, and referred to as color shading. End-users readily notice levels of color shading as low as 2%, yet current cameras often exhibit 30% or even worse. This is a major problem that affects virtually all current phone cameras, a fundamental flaw inherent in their compact design.

Learn more about the color shading problem.

Per-unit calibration attempts to measure the color uniformity of each phone and store this information so as to be able to compensate for the shading. It fails with many indoor illuminants and mixed lighting situations. At best, it is only ever partially successful; at worst, it may even make the perceived results worse. This technique is used in all the phones cited in the complaints from users here.

Using a hybrid filter can certainly improve results, but involves the bulk and cost of an extra component. What’s more, the additional filter cuts down some of the wanted light reaching the sensor, leading to increased noise under typical low-light conditions - again, something that even non-expert users are particularly sensitive to.

DxO Labs has introduced DxO AutoCLS, an innovative software-only adaptive solution to color shading that has already been adopted by several manufacturers. DxO AutoCLS runs in real time, so is available during preview and for video as well. It operates on the same processing flow as conventional overall Auto White Balance, but uses image statistics differently to calculate the appropriate color shading correction. DxO AutoCLS estimates the local color correction required by

DxO AutoCLS brings a number of advantages:

• Excellent color uniformity - best image quality
• Easy to integrate software library for ARM
• No impact on camera size
• Much lower cost than hybrid filters or per-unit calibration

DxO AutoCLS can be used in conjunction with a hybrid filter if required. DxO AutoCLS can also be delivered in silicon IP.

Contact us for more information about DxO AutoCLS.