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In imaging systems the detector arrays deliver at the output time-discrete signals, where the spatial frequencies of the object scene are mapped into the electrical signal frequencies. Since the spatial frequency spectrum cannot be bandlimited by the front optics, the usual detector arrays perform a spatial undersampling and as a consequence aliasing occurs. A means to partially suppress the backfolded alias band is bandwidth limitation in the reconstruction low-pass, at the price of resolution loss. By utilizing a bilinear detector array in a pushbroom-type scanner, undersampling and aliasing can be overcome. For modeling the perception, the theory of discrete systems and multirate digital filter banks is applied, where aliasing cancellation and perfect reconstruction play an important role. The discrete transfer function of a bilinear array can be imbedded into the scheme of a second-order filter bank. The detector arrays already build the analysis bank and the overall filter bank is completed with the synthesis bank, for which stabilized inverse filters are proposed, to compensate for the low-pass characteristics and to approximate perfect reconstruction. The synthesis filter branch can be realized in a so-called ‘‘direct form,’’ or the ‘‘polyphase form,’’ where the latter is an expenditure-optimal solution, which gives advantages when implemented in a signal processor. This paper attempts to introduce well-established concepts of the theory of multirate filter banks into the analysis of scanning imagers, which is applicable in a much broader sense than for the problems addressed here. To the author’s knowledge this is also a novelty.

Various methods for simulation of reticle systems will be described which have practical applications for the simulation of missile guidance systems. The reticle pattern, as well as the received image, is digitized using common picture processing equipment. The sampled representations of the reticle and image are converted to a polar coordinate system, and the data is then put into a vector string. Setting up a cyclic matrix with this vector string, one can describe the periodic system signal by cyclic convolution of reticle string and image string. A similarity transform to the Jordan form of a quadratic cyclic matrix, by means of the discrete Fourier matrix, reduces the amount of calculations required. This is a great advantage in digital simulation. For this linear discrete system approximation, the transfer function in the Z-domain can be deduced. This approach gives a better insight into the overall performance of the control system. The analysis also shows the limitations of reticles, which has resulted in the decline of this technique for guided missile applications.

Various methods for simulation of reticle-systems will be described, which have practical application for the simulation of missile guidance systems. The reticle-pattern, as well as the received image, is digitized using common picture processing equipment. The sampled representations, of the reticle and image, are converted to a polar-coordinate system, and the data is then put into a vector-string. Setting up a cyclic matrix with this vector-string, one can describe the periodic system-signal by cyclic convolution of reticle-string and image-string. For this linear discrete system approximation, the transfer function in the Z-domain can be deduced. A similarity transform to the Jordan form of a quadratic cyclic matrix, by means of the discrete Fourier matrix, reduces the amount of calculations required. This is an advantage in digital simulation.