This paper presents the design of a real-time imaging system, with incorporated the correction of lens-distorted images. It may be used in medical applications (e.g. real-time X-ray image intensifiers), industrial robot vision products or consumer electronics. The system contains two different VLSI-circuits: a transformer and an interpolator. The transformer calculates an address that points to a pixel in the input image. Since this address hardly ever is an exact pixel position, a cubic-spline interpolator is used to calculate the pixel-intensity at the desired position.

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In' we have presented the principle of an X-ray detector based upon a screen coupled to an array of multiple CCD sensors. In2 we focus on the characterization of the image quality: resolution (MTF) and noise behavior in the overlap area. Simple (and cheap) low F# lenses likely show distortion which means that not all imaged pixels have the same magnification. This may affect resolution. Lenses with (some) barrel distortion have the benefit of less vignetting. The correction of distortion in combination with a rotation adjustment requires interpolation. Interpolation affects the noise properties so care must taken in order to avoid that the noise characterization of the reconstructed image mosaic i. e. the noise texture becomes spatially non uniform. We present an analysis of the influence of lens distortion and interpolation in cases of small rotation correction on the image mosaic. The image processing appears not to diminish the image quality provided the processing parameters are set correctly. The callibration of the imaging mosaic geometry is crucial. We therefore present a robust extraction algorithm. In this paper our main interest is on MTF and quantum noise properties. The lab. prototype hardware is designed such (cubic spline interpolation) that also the lens distortion can be compensated. For this purpose ASICs are designed by the company AEMICS. This enables relative cheap optical components with low F# and a short building length. We have obtained and will present radiographic exposures of static phantoms.

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