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In the area of signal processing the transforms are typically used because they offer specific point of view on the signal, revealing its properties, suitable for example for its better decomposition [4]-[6], [15]. An obvious example is the Fourier transform so much suited for acoustic signals treatment and for many other physical signals [5]. However, the digital signal may not have any ref[...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2007/4

» Digital filtering by discrete trigonometric transforms realized with generalized convolution

In this paper we present considerations, which form an appropriate background for justification a hypothesis that digital filtering based on any transform belonging to the family of discrete trigonometric transforms (DTTs) may be efficiently realized possibly at the cost of some slight and usually fully acceptable approximation with the so-called fast generalized convolution instead of less [...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2008/4

» Efficient image watermarking in the transform domain with the discrete trigonometric transforms

In the area of the still image watermarking, the approach where the watermark is introduced in the transform domain is considered in numerous descriptions. Apart from the Fourier and wavelet transform the discrete cosine transform (DCT) is mentioned quite often [1,3-5,10-12]. However, the commonly used DCT, is in fact one member of a larger set of 16 discrete cosine and sine transforms [2, 6] also referred to as the discrete trigonometric transforms (DTTs). In this context, the DCT commonly proposed for watermarking is the two dimensional DCT of type II-even (in short: DCT IIe), while there are all together four even DCTs, four odd DCTs, and similarly eight respective discrete sine transforms (DSTs) - four even and four odd [2,6], thus there are 16 DTTs in total. In the presen[...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2009/3

» Discrete trigonometric transform (DTT) fi lters

Finite impulse response (FIR) fi ltering, based on fi lter characteristics defi ned in the Fourier transform domain (frequency domain) is one of the most basic and fundamental procedures within the area of digital signal processing [8]. On the other hand the discrete trigonometric transforms (DTTs) seem to attract some attention in the context of fi ltering similar to the well known convolution, which is the result of the convolutionmultiplication property described for the case of the symmetric convolution proposed by Martucci [1]. Some examples of such applications may be found in [4, 7, 9]. In this paper novel approach based on the generalized convolution matrix defi ned for the DTTs [2-4] is proposed and documented with a set of computational examples. The concept exploits[...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2010/3