Demosaicing

Obtain natural-looking images from RAW, with few digital artifacts

One of the most important and difficult steps in raw conversion is to reconstruct full-color RGB pixels from raw sensor values in an operation called "demosaicing". Photo Ninja incorporates a world-class demosaicing algorithm that yields a natural, photographic look with few digital artifacts.

Two modes are available. The standard algorithm is suitable for the majority of cameras that have adequately strong antialiasing filters in front of the sensor. This algorithm is relatively fast and yields excellent results. The enhanced mode is appropriate for cameras with weak or missing antialiasing filters. It is slower, but in many cases it can significantly reduce directional artifacts and moire patterns that would otherwise result because of the lack of antialiasing.

For most photographers, we recommend using cameras with antialiasing filters. Antialiasing substantially reduces the risk and severity of demosaicing artifacts and moire. Apparent softness can be effectively overcome with Photo Ninja's excellent sharpening filter, which uses deblurring technology that can effectively compensate for antialiasing blur.

Example 1

Photo courtesy of Greg Takacs

This is a pathological example that tortures most demosaicing algorithms. It was shot with a Nikon D70, known for its weak antialiasing filter. The fine vertical lines in the columns (shown at actual resolution) coincide exactly with adjacent sensor array positions. Because a standard Bayer-style sensor omits alternating samples, the vertical lines are converted to a checkerboard pattern where it is no longer easy to discern whether a pixel belongs to a vertical or horizontal feature. The rendering on the left is representative of the vast majority of commercial demosaicing algorithms, with maze artifacts and color errors. On the right, Photo Ninja's "Enhanced" demosaicing mode does an impressive job resolving the ambiguities. Results are not always this good, but Photo Ninja's enhanced mode generally performs better than alternatives.

Example 2

From a Canon D30, 2X magnification. Left: Conventional demosaicing. Right: Enhanced demosaicing.

Example 3

From a Canon 10D, 2X magnification. Left: Conventional demosaicing. Right: Enhanced demosaicing.