Demosaicing and Aliasing Correction
Pp. 149-190 (42)
M. Guarnera, G. Messina and V. Tomaselli
Acquisition of color images requires the presence of different sensors for different color
channels. Manufacturers reduce the cost and complexity by placing a color filter array (CFA)
on top of a single image sensor, which is basically a monochromatic device, to acquire color information
of the true visual scene. Since each image sensing element can detect only one color
of illumination, the missing information must be filled in. The color interpolation process (also
called demosaicing) aims to reconstruct the full resolution image acquired by the sensor, by calculating
the missing components. Picture quality is strictly related to the peculiarity of demosaicing
process. Due to the aliasing phenomenon, such as false colors and zipper effects, the color interpolation
has to guarantee the rendering of high quality pictures avoiding artifacts. In this chapter we
review some solutions devoted to demosaicing and antialiasing. Demosaicing algorithms can be
basically divided into two main categories: spatial-domain and frequency-domain. Demosaicing
solutions are not always able to completely eliminate false colors and zipper effects, thus imaging
pipelines often include a post-processing module, with the aim of removing residual artifacts.
Some of these techniques are also described.
Advanced System Technology - Catania Lab, STMicroelectronics, Italy.