Mosaic Engineering, Inc.

(This page describes a new, non-blurring technology for optical anti-aliasing.  Please note however that we also supply conventional birefringent optical anti-aliasing filters and optical low-pass filters.)

Color aliasing persists as a difficult problem in digital imaging.  The first image here illustrates this problem, which can occur whenever an image is sharply focused onto a sensor that samples different colors at different points.  We offer a novel and proprietary optical filtering technology that eliminates these aliasing artifacts; the second image demonstrates the application of our technology:

Color aliasing, before correction.	With Mosaic Engineering's optical anti-alising correction.

Our filter works by an entirely different principle from that of standard birefringent antialiasing filters, and it offers significant advantages over conventional strategies:

• The filter does not blur or defocus images, which therefore retain all of their original sharpness.  Conventional antialiasing filters prevent color artifacts through blurring or spatial lowpass filtering, but this permanently destroys fine detail.
• As the images show, small details retain their original color with this approach.  Software postprocessing approaches to aliasing correction typically reduce small colored regions to shades of gray.
• No complex processing algorithms are involved.  Color interpolation can be implemented in simple hardware at extremely high speeds, making this approach well suited to live video applications such as cinematography.

The central component of our antialiasing approach is a special optical filter that is inserted into an imaging system's optical path.  The filter can be placed in front of the imaging lens, or between the lens and the image sensor.  The filter has the appearance of clear glass, and does not contain a polarizer or other darkening element; it can optionally be combined with an IR absorbing blue-green glass.  Examples of the filter are shown here:

Color interpolation is performed by a special processing algorithm that is matched to the characteristics of the optical filter.  The algorithm is extremely simple, and is easily implemented at very high speeds without complex software or hardware.

This technology is currently the subject of pending U.S. and international patent proceedings.  Please contact us for additional technical details.

This page illustrates a general purpose approach for single-shot color mosaic cameras.  We also have a number of specialized approaches specifically tailored to certain constrained optical imaging architectures, such as document and film scanning.  We would be pleased to discuss your digital imaging application with you; if you are encountering aliasing or sampling artifacts, we may be able to supply you with an OEM component that rectifies them.

Notes:

• Each of the example images above is a 400 × 276 pixel composite of sections from a much larger, eleven megapixel image taken with a Hasselblad 553ELX camera body and a Luma professional digital camera back.  The 11 MP images were acquired under normal studio photographic conditions with conventional strobe illumination, using a 120 mm Hasselblad lens focused on a scene at approximately three meters distance.  The Luma uses the 11 MP Dalsa FTF4027C CCD, which has 9 µm pixels and a Bayer-pattern color dye mosaic.
• The second image above was produced under exactly the same conditions as the first, except that we have used one of our proprietary optical antialiasing filters with the Hasselblad lens.  Note that no additional image processing software was used to generate this corrected image; the color interpolation algorithm for each of these images consisted of only a trivial, average-of-nearest-neighbors approach.