The main limitation in employing orthogonal frequency division multiplexing (OFDM) system is high peak-toaverage power ratio (PAPR) of the transmitted signal. A new nonlinear companding algorithm that transforms the OFDM signals into the desirable statistics form defined by a linear piecewise function is proposed. The more adjustability in companding form and an effective trade-off between the ...

-Steganography method used in this paper is based on biometrics. And the biometric feature used to implement steganography is skin tone region of images. Here secret data is embedded within skin region of image that will provide an excellent secure location for data hiding. For this skin tone detection is performed using HSV (Hue, Saturation and Value) color space. Additionally secret data embe...

The windowed Fourier transform of a time signal is considered, as well as a way to reconstruct the signal from a su ciently densely sampled version of its windowed Fourier transform using a Gabor representation; followingGabor, sampling occurs on a two-dimensional time-frequency lattice with equidistant time intervals and equidistant frequency intervals. In the limit of innitely dense sampling,...

In this paper a 4 x 4 Daubechies transform based authentication technique termed as SADT has been proposed to authenticate gray scale images. The cover image is transformed into the frequency domain using 4 x 4 mask in a row major order using Daubechies transform technique, resulting four frequency subbands AF, HF, VF and DF. One byte of every band in a mask is embedding with two/four bits of s...

This paper provides comparison between two image compression technique such as DCT and DWT. Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) are the most commonly used transformation. DCT has high energy compaction property and requires less computational resources. On the other hand, DWT is multi-resolution transformation. PSNR and Compression ratio are one of the parameter...

It is known that LOG – EXP transform based image compression algorithm proposed by S.C.Huang, L.G.Chen and H.C.Chang offers high Compression Ratio (CR) and high image quality compared to JPEG for any specified value of Peak-Signal to Noise Ratio (PSNR). In this paper, a modified LOG – EXP transform based image compression algorithm obtained by using arithmetic coding in the place of Huffman cod...

In this paper, comparison of three Video compression techniques i.e. Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT) and Hybrid is done. DCT is applied to Rows, Columns and Rows*Columns separately to frames in a video with compression factor of 2, 4 and 8, whereas Discrete Wavelet Transform(DWT) is applied till 2 level of DWT decomposition and Hybrid-1 combining DCT and DWT 1 ...

Multiple description coding is one of the coding techniques used in the non-prioritized networks to transmit image. In this coding method, the image is split into two or more descriptions and compressed with a controlled level of redundancy. Because of the introduced controlled redundancy the image can be recovered from the other descriptions. Due to this there is a slight degradation in the re...

Large size images consist of multiple bands data which occupies large space. Image compression becomes important for such large image or data’s to reduce the bandwidth in transmission over a network and in storage space. Wavelet transform is an efficient tool with some limitations for various image processing applications. And these limitations are overcome by complex wavelet transform. In this...

To accommodate high performance and high bit rates for multimedia applications in present and future wireless communication systems, it is essential that modulation techniques applied in this scenario are able to support high data rates upto and above 200 Mbps. To meet the increased demand of higher bit rates, the wireless systems are incorporating the multi-carrier modulation techniques ,such ...