The aliasing modeling problem for CCD-imagers

Modern CCD-imagers demonstrate outstanding resolution and sensitivity. But the discrete CCD structure introduces irregularities, named aliasing, in their contrast transfer functions CTF(νΔ) at a spacial frequency ν near the Nyquist frequency. Basing on the computer modeling, the paper estimates: - the aliasing influence on the contrast transfer functions for rectangular and sine-wave gratings; - the level of introduced by aliasing noises; - the distortions of point objects at their sizes near the pixel size Δ. The contrast transfer function CTF(νΔ) is estimated here as an average value for a whole grating’s image. For the sine-wave grating it results in CTF(νΔ) = (sin(πνΔ) / (πνΔ))2 instead of the sin(πνΔ) / (πνΔ), widely used in literature and valid only for an optimal phases between the image and matrix structure. Also here the minimal possible value for the contrast transfer function equal to sin(2πνΔ) / (2πνΔ) is introduced to reflect the limiting imager’s characteristic. The imager’s modeling helps to create super resolution CCD matrixes.