F. J. MacWilliams and N. J. A. Sloane, "Pseudo-random sequences and arrays," Proc. IEEE, Vol. 64, No. 12, pp. 1715-1728, 1976. 16  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and O Mb 3 minimum and maximum values of embedding factor. These are the parameters determining the extent of watermark insertion. The image thus obatained is visible watermarked image . iv. Pseudo random binary sequence 0,1 of period N is generated using linear shift register [55, 56]. The period is equal to the number of pixels of the image. v. The watermark is generated by arranging the binary sequence into blocks of size 4 4 or 8 8. The size of the watermark is same as the size of the image. 13 Merge Dual Watermarked Image (I ) Find SNR Is Threshold ....

F. J. MacWilliam and N. J. A. Sloane, "Pseudorandom Sequences and Arrays", Proc. of the IEEE, Vol. 64, No. 12, Dec 1976, pp 1715-1729.

....sequences or m sequences) are certain binary sequences of the length N = 2 ra 1 with m denoting the order of the sequence. These sequences have been known for a long time in areas such as rangefinding, scrambling, fault detection, modulation, synchronizing, acoustic measurements, etc. [6, 8, 9]. To construct a MLS of a given length N, we need a primitive polynomial p(x) of a degree m. An example of such a polynomial is given by the following Expression: p(x) xm xn l , 0 n m (1) This polynomial specifies a linear feedback shift register (LFSR) as shown in Fig. la. The boxes ....

F.J. acWilliams, N.J.A. Sloane, "Pseudo-random sequences and arrays", Proc. Of the IEEE, Vol. 64, No. 12, 1715-1730, 1976.

.... 91 80 3092896 saraju mmsl.serc.iisc.emet.in K.R. Ramakrishnan Dept. of Electrical Engg. Indian Institute of Science Bangalore 560 012, India Phone: 91 80 3092441 krr ee.iisc.ernet.in Mohan Kankanhalli School of Computing National University of Singapore Kent Ridge, Singapore 119 260 Phone: 65 874 6738 mohan comp.nus.edu.sg ABSTRACT Digital watermarking is the technique in which a visible invisible signal (watermark) is embedded in a multimedia document for copyright protection. In this paper, we propose a watermarking scheme called dual watermarking . Dual ....

....commercial advant age and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission end or a fee. ACM Multimedia 99 Pert 2) 10 99 Orlando, FL, USA 1999 ACM 1 58113 239 5199 0010. 5.00 2. VISIBLE WATERMARKING OF THE In the visible watermarking the modification of the gray values of host image is based on its local as well as global statistics. The watermarking insertion process consists of the following steps. Both host image (one to be watermarked) ....

F. J. Macwilliam and N.J. A. Sloane, "Pseudorandom Sequences and Arrays", Proceedings of the IEEE, Dec. 1976, Vol.64, No. 12, pp. 1715-1729,

....quality factor) DCT high pass filtering. Since the watermark mask is almost perfectly (spectrally) white, the same is true about low pass filtering. In order to preserve this feature in raster format, the m sequence should be embedded in a commensurate diagonal manner. The folded m sequence of [5] is ideal for this purpose. The partitioning of the process into 8 8 blocks should pose no significant problems. The m sequence employed in Fig.1. was 4 times longer than the linear dimension of the image, with no discernible effects on the result. We have actually experimented with 8 8 blocks and ....

....effect on columns is that of decimation. Unique phase shifts as determined from Galois Field theory lead to the formation of columns, which are themselves m sequences. The resulting array is an unbalanced Hadamard Matrix. Alternatively, a long sequence can be folded diagonally into an array format [5]. In this manner, the desirable one dimensional autocorrelation property can be extended to two dimensions. The encoding and decoding performance of the Hadamard technique suffers from the image related effects because the correlations are performed on the (short and thus interference prone) row ....

. F.J. MacWilliams and N.J.A.Sloane. Pseudo-random Sequences and Arrays. Proc.IEEE, vol 64, 1715-1729, Dec.1976.

....effects. This results in distinct peaks attributable to each sequence and some cross correlation peaks. The latter can be constrained by the choice of sequences to be less than the square root of the length. Cross correlation between binary m sequences has been theoretically analysed [6,7]. The extension of the above theory to applications in two or more dimensions is straightforward. M sequences of composite length can be folded into m arrays. The original m sequence appears along the diagonal of such an array. Consequently, the array retains the shift and add property of the ....

F. J. Mac Williams, N. J. A. Sloane, Pseudo-random sequences and Arrays, Proc. IEEE, vol. 64, pp. 17151729, Dec 1976.

....an optimum technique with minimal image dependence. We will explore the effects on the watermark due to cropping and distortions such as skew, rotations, translations etc, and countermeasures against these. These may include bit swapping or diagonal raster folding of sequences into m arrays [12]. These operations are facilitated by our choice of extended m sequences of length 2 n . The desirability of tamperresistant watermarks could be a function of the application. Some implementations may be better served by retaining a distorted watermark as evidence of the illegal act This aspect ....

F.J.McWilliams and N.J.A.Sloane. "Pseudorandom Sequences and Arrays". Proc.IEEE(76), vol 64, p.1715-1729.

....n tuple appears exactly once contiguously on the cycle. Such cycles, rst discovered in 1894 by Flye St. Marie (see [5] have found applications in the study of pseudo random numbers, cryptography, nonlinear shift registers and coding theory, and a vast literature exists (see [1] 6 11] 14] [18]) For r; s 0 a (k r ; k s ; m; n) k de Bruijn torus is a k ary (k r k s ) toroidal array with the property that every k ary (m n) matrix appears exactly once contiguously on the torus (see Figure 1) In addition to the above we nd interesting applications in robot self location ....

.... r ; k s ; m; n) k de Bruijn torus is a k ary (k r k s ) toroidal array with the property that every k ary (m n) matrix appears exactly once contiguously on the torus (see Figure 1) In addition to the above we nd interesting applications in robot self location [19] pseudo random arrays [18], and the design of mask con gurations for spectrometers [13] For an interesting variation on this theme see [16] Even cloth patterns have used these designs, long before their mathematical properties were discovered (see [12] 0 0 0 1 0 0 1 0 1 0 1 1 0 1 1 1 Figure 1. A (4; 4; 2; 2) 2 de ....

F.J. MacWilliams and N.J.A. Sloane, Pseudo-random sequences and arrays, Proc. IEEE 64 (1976), 1715-1729.

....effect on columns is that of decimation. Unique phase shifts as determined from Galois Field theory lead to the formation of columns, which are themselves msequences. The resulting array is an unbalanced Hadamard Matrix. Alternatively, a long sequence can be folded diagonally into an array format [5]. In this manner, the desirable one dimensional autocorrelation property can be extended to two dimensions. The encoding and decoding performance of the Hadamard technique suffers from the image related effects because the correlations are performed on the (short and thus interference prone) row ....

. F.J. MacWilliams and N.J.A.Sloane. Pseudorandom Sequences and Arrays. Proc.IEEE, vol 64, 1715-1729, Dec.1976.

....and another for outof phase correlations. Another desirable feature is that cross correlation with different members of the same family of sequences is one or two valued. We will describe three different sequences for system probing: the familiar M sequence [10,11] the Legendre sequence [9,12], and a chirp like Distinct Sums sequence [7] 3.1 The Generalised M sequence Zierler [17] introduced the concept of M sequences and showed their advantages as a binary sequence. They are used in many areas for signal phase recovery in noisy environments like communication [10,6 which ....

F. J. Mac Williams, N. J. A. Sloane, Pseudo-random sequences and Arrays, Proc. IEEE, vol. 64, pp. 17151729, Dec 1976.

....functions into even and odd, or periodic and aperiodic components does not apply, because the embedding pattern has periodicity commensurate with that of the image. So far, the watermarks have been chosen from one and twodimensional array patterns based on m sequences or extended m sequences [5]. An m sequence basis is chosen because of their balance (zero mean) random appearance, optimal autocorrelation properties and constrained cross correlation. The water mark has been encoded by the choice of m sequences and their phases. 2 Method 3 The encoding method uses LSB addition for ....

....other. 7 Two dimensional patterns are generated by polynomials in two variables. This is equivalent to a twodimensional shift register. One dimensional polynomials have been studied extensively, whilst higher dimensional constructions have been devised ad hoc, with specific applications in mind. [5] is one of the few references which attempts to treat this problem and its extensions to base fields other than GF(2) 4.1 Some Two Dimensional Constructions The autocorrelation function of binary m sequence is two valued: 2 n 1 (in phase) 1 (out of phase) A two dimensional construction ....

[Article contains additional citation context not shown here]

. F.J. MacWilliams and N.J.A.Sloane. Pseudo-random Sequences and Arrays. Proc.IEEE, vol 64, 1715-1729, Dec.1976.

....to arrays have been employed while preserving their correlation properties. The following section summarises some of these. Subsequent sections illustrate three distinct array constructions in particular. 3.1. Review of some 2D Constructions Multiple folding and unfolding. MacWilliams and Sloane [17] and Green [11] folded an M sequence of composite length into a matrix diagonal and showed that the matrix has the same periodic autocorrelation as the M sequence. We have found that this also holds for polyphase sequences. For unfolding, this is true only if the unfolding diagonal makes a single ....

....reduces to a shift and add (Calabro and Wolf [3] This construction has no adjustable parameters that can be used to encode data. 3.3. Folding Arrays A sequence of composite length pq can be folded into an array of area pq if p and q are co prime as shown in figure 1. MacWilliams and Sloane [17] and also Green [11] folded an M sequence of composite length into a matrix diagonal and showed that the matrix has the same periodic auto correlation as the M sequence. For large lengths, a prime length sequence can be truncated to a composite length with almost perfect correlation. This is ....

F. J. MacWilliams, N. J. A. Sloane, "Pseudo-Random Sequences and Arrays", Proceedings of the IEEE, Vol 64, No.12, Dec.1976, pp. 1715-1729.

....a PRBA to the surface studied in order to achieve optimal resolution. Index Terms Biomedical signal analysis, image processing, optical measurements, pseudo noise processes. I. INTRODUCTION A BINARY stage shift register will produce a sequence which will repeat itself after at most elements [1]. Sequences of the maximum length are called pseudo random binary sequences (PRBSs) Pseudo Random Binary Arrays (PRBAs) are their two dimensional (2 D) analogon. The binary information of both sequences and arrays can be coded in a number of ways depending on the application field. Color coded ....

....of the maximum length are called pseudo random binary sequences (PRBSs) Pseudo Random Binary Arrays (PRBAs) are their two dimensional (2 D) analogon. The binary information of both sequences and arrays can be coded in a number of ways depending on the application field. Color coded PRBAs [1] [6] can conveniently be used in the modeling of three dimensional (3 D) scenes. To achieve this, an image in which a PRBA has been encoded is projected onto or reflected by the scene under investigation and subsequently recorded by a CCD camera. The major advantage of the use of PRBAs lies in ....

[Article contains additional citation context not shown here]

F. J. MacWilliams and N. J. A. Sloane, "Pseudo-random sequence and arrays," Proc. IEEE, vol. 64, pp. 1715--1729, 1976.

....m sequence was obtained by Fig. 6. Five Stage Linear Feedback Shift Register 12 5 4 3 decimating the m sequence from this polynomial with at factor of 7. The reader is referred to the paper by Robert Gold [5] for details on the characteristics and properties of Gold codes, and to refs. 6] [7] and [9] for more detailed treatment of m sequences. Each bit in the 8 bit switching sequence switches segments of length 16 or 15 in the 124bit sequence. The chipping rate of the composite sequence was selected to give similar characteristics as GPS codes when correlated over 0 6.5KHz. ....

F. J. MacWilliams, N. J. A. Sloane, "PseudoRandom Sequences and Arrays", Proceedings of the IEEE, Vol. 64, No. 12, December 1976, pp. 1715-1727.

....correlation outside the origin ( Delta 6= 0) is often ascribed to a peculiarity of maximum length pseudo random sequences, as generated by a Linear Feedback Shift Registers (LFSR) However, the above argument reveals that it is fundamentally related to the requirement of the DC value. See also [13] and [14] this appears as a smoothing. A first order two dimensional IIR spatial smoothing filter computes [11] w 2 (n) 1 Gamma fi 2 ) 2 Theta w 1 (n) fiw 2 (n Gamma e 1 ) fiw 2 (n Gamma e 2 ) Gamma fi 2 w 2 (n Gamma e 2 Gamma e 2 ) from an original w 1 . It can be shown ....

....and our experiments. Therefore, in our experiments, we created quasi white and absolutely DCfree watermarks through appropriate pseudo random sequences. An appropriate choice appeared to be binary watermarks, w(n) 2 f Gammak; kg with fi = 0 generated by a 2 dimensional LFSR maximal length sequence [13] [14] of length 2 14 Gamma 1 = 2 7 Gamma 1) 2 7 1) 127 Delta 129, with 127 and 129 being relatively prime. Such sequences have a negligibly small DC component: since P n w(n) Gamma1, we get D 0 = 1= 2 14 Gamma 1) Their spatial correlation function has the appropriate ....

F.J. McWilliams and N.J.A. Sloane, "Pseudo-Random Sequences and arrays", Proc . of IEEE, Vol. 64, No.12, Dec. 1976, pp. 1715-1729

....of q symbols, where q is a prime or a power of a prime. A (q n 1) term PRMVS is generated by an n position shift register with a feedback path specified by a primitive polynomial h(x) x n h n 1 . x n 1 . h 1 . x h 0 of degree n with coefficients from the Galois field GF(q) [8]. When q is a power of a prime, q=p m , the Galois field elements are expressed as the first q 1 powers of some primitive element, labeled here by the letter A: GF(q) 0,1,A,A 2 , A q 2 . Primitive polynomials over GF(q) 0,1,A,A 2 , A q 2 ....

F. J. MacWilliams and N. J. A. Sloane, "Pseudorandom Sequences and Arrays", Proc. IEEE, Vol. 64, No. 12, pp. 1715-1729, Dec. 1976.

....limit of 2x10 6 W cm 2 for aluminum [17] Positioning the sample slightly off the focus of the 75mm focal length lens increased the spot size and reduced the power density far below material damage. The laser diode was modulated using a pseudo random sequence (m sequence) of excitation pulses [18, 19]. This sequence turned the laser on and off a total of 4095 times. Laser pulse widths ranged from 800ns to 9600ns in duration and the complete pseudo random sequence lasted 2.1ms. The generated ultrasonic waves were detected with a piezoelectric transducer coupled to the sample s back surface, ....

F.J. MacWilliams, and N.J.A. Sloane, "PseudoRandom Sequences and Arrays," Proceedings of the IEEE, Vol. 64, No. 12 December 1976.

....at the focus on the order of 10 5 W cm 2 . For generating ultrasonic signals, either pseudo random or frequency modulated chirp sequences were used. The pseudo random sequence consisted of 2048 pulses of variable temporal length light pulses and was generated following MacWilliams, et al. [10] The code length for the total sequence was 2.3 ms, and it covered a bandwidth from 0.1 to 1.6 MHz. The chirp sequences consisted of varying the diode s output amplitude with a sinusoidal chirp of total length of 2 ms. The chirp covered a bandwidth from either 0.1 to 1 MHz or 0.5 to 1.5 MHz. The ....

F. J. MacWilliams and N.J.A. Sloane, "Pseudo-Random Sequences and Arrays," Proceedings of the IEEE, Vol. 64, No. 12 December 1976.

....while the second one acted as a competing source and was adjusted to produce different conditions of interference. Four equally powered excitation signals were used during the data collection. They included a Maximum Length (ML) pseudo random sequence, used to calculate the room impulse responses [4], a Gaussian noise representing a competing noise and two similar length utterances, produced by a male and a female, representing the target speech and interfering signals. Omni directional electret microphones (Panasonic MW 54) were employed in data acquisition at CAIP s laboratory. High quality ....

....response from the source to the nth sensor. Again the latter term of Eq. 2) is the cross correlation of impulse responses from focus and from source. In the experiments, the impulse responses from the desired focal point to each receiver in the array were measured using pseudo random sequences [3, 4]. The quality of the reconstructed signal obtained as output of the MFA was perceptually estimated as being improved more than 10 dB when compared to a single microphone using data of 46 microphones collected at CAIP Center. Behavior of the MFA using data collected in the Varechoic Chamber was ....

F.J. MacWilliams, N.J.A. Sloane, "Pseudo-Random Sequences and Arrays," Proc.IEEE, vol. 68, May 1980, pp. 593-619.

....limit of 2x10 6 W cm 2 for aluminum [17] Positioning the sample slightly off the focus of the 75mm focal length lens increased the spot size and reduced the power density far below material damage. The laser diode was modulated using a pseudo random sequence (m sequence) of excitation pulses [18, 19]. This sequence turned the laser on and off a total of 4095 times. Laser pulse widths ranged from 800ns to 9600ns in duration and the complete pseudo random sequence lasted 2.1ms. The generated ultrasonic waves were detected with a piezoelectric transducer coupled to the sample s back surface, ....

# F.J. MacWilliams, and N.J.A. Sloane, "PseudoRandom Sequences and Arrays," Proceedings of the IEEE, Vol. 64, No. 12 December 1976.

....if q N 1. 2 The proof follows from the Kronecker product form of the correlation matrix (10) by noting that the invertibility of the matrix VV T guarantees the invertibility of the correlation matrix. For details see [14] A useful class of PRMS are known as maximal length sequences (MLS) [10, 12]. One important property of MLS is known as the window property. Property 1 The Window Property: If a window of width M is slid along a q level maximal length sequence of degree M , all but one of the q M M tuples is seen exactly once over one period (length q M Gamma 1) of the sequence. ....

F. J. MacWilliams and N. J. A. Sloane, "Pseudo-random sequences and arrays," Proc. IEEE, Vol. 64, No. 12, pp. 1715-1728, 1976.

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F. J. MacWilliams and N. J. A. Sloane, "Pseudo-random sequences and arrays," Proc. IEEE, Vol. 64, No. 12, pp. 1715-1728, 1976. 16

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F.J. McWilliams and N.J.A. Sloane, "Pseudo-Random Sequences and arrays", Proc . of IEEE, Vol. 64, No.12, Dec. 1976, pp. 1715-1729

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F. J. MacWilliams, N. J. A. Sloane, Pseudorandom sequences and arrays, Proceedings of the IEEE 64 (12) (1976) 1715--1729.

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F.J. MacWilliams and Neil J.A. Sloane, "Pseudorandom sequences and arrays," Proceedings of the IEEE, vol. 64, no. 12, pp. 1715--1729, 1976.

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F.J. MacWilliams and N.J.A. Sloane, Pseudo-random sequences and arrays, Procccdings of the IEEE, 64 (1976), 1715-1729.

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