934 IEEE TRANSACTIONS ON COMPUTERS, VOL. c-28, NO. 12, DECEMBER [2] S. H. Fuller, V. R. Lesser, C. G. Bell, and C. H. Kaman, "The effects of emerging technology and emulation requirements on microprogramming," IEEE Trans. Comput., voL C-25, pp. 1000- 1009, 1976. [3] E. F. Moore, "Gedanken-experiments on sequential machines," in Automata Studies. Princeton, NJ: Princeton University Press, 1956. [4] S. Dasgupta, "The organization of microprogram stores," Comput. Surveys, vol. 11, pp. 39-65, 1979. [5] K. Hwang, "Fault-tolerant microprogrammed digital controller design," IEEE Trans. Industrial Electronics and Control Instrumentation, vol. IECI-23, 1976, pp. 200-206. [6] A. K. Agrawala and T. G. Rauscher, Foundations of Microprogramming. New York: Academic, 1976, p. 62. [7] E. E. Swartzlander, Jr., "Microprogrammed sequential machines," in New Components and Subsystems for Digital Design, Santa Monica, CA: Technology Ser- [8] 1979 tions and the resulting flow graphs are presented. The structure of the flow graphs enables one to develop computational algorithms for sequence length N = 8, 16, 32,*-. Haar Transform and Rationalized Haar Transform The HT and RHT of a data sequence {x(n)}T = {X(O)X(1) X(N - 1)} where N = 2 , n = positive integer and superscript T denotes transpose can be respectively defined as I {Yx(n)} vice Corp., 1975, pp. I 1 1-1 14. -, "Microprogrammed control for signal processing," 10th Workshop on Microprogramming, (IEEE # 77CH1266-6C), 1977, pp. 80-84. [HO(n)]{x(n)} (1) [ifO(n)]{x(n)}. {YR(n)}=j [HO(n)] and [Hio(n)] are the HT and RHT matrices of size (2" x 2n). {Yx(n)} and {YR(n)} are the corresponding transform vectors. Based on [1], [Ho(n)] and [Hlo(n)] can be expressed as Unified Matrix Treatment of Discrete Tramforms V. VLASENKO AND K. R. RAO Abstract-An unified matrix treatment is developed for some discrete transforms such as Haar (HT), rationalized Haar (RHT), rapid (RT), modified Wash-Hadamard (MWHT), HadamardHaar (HHT)r, and rationalized Hadamard-Haar (RHHT)If. For RT a technique for recovering the data sequence from the trans. form vector is presented. Index Terms-Discrete transforms, fast algorithms, Kronecker products. [Ho(n)] = -i Hl F r=n-l s=l [Is,z] [[P0][MS][B¶ .]] (D [[P'r][ffl2--r]] I [H-O(n)] = 2n2r=n-1 f] |,EMIr] 1 (2) (3) s= where r is the iteration number in the fast algorithm, s = number of blocks in each iteration, and ® is the Kronecker product: 0 [Ilr] = 0 - 0 2r 0 0 INTRODUCTION An unified matrix theory for various orderings of the Walsh0 Hadamard transform (WHT) has been presented recently [1]. -+ S This has been also extended to the calsal ordering (WHT)s 4 2r [2]. Such a matrix treatment is now developed for some other discrete transforms such as Haar (HT) [3]-[7], rationalized Haar s= 1 _ I (3 [H1], (RHT) [5], [7], rapid (RT) [8], [9], [15], modified WHT (MWHT) [BS2i u-ni I [I2--®] [of si s >1 [3], Hadamard-Haar (HHT), [4], [18] and rationalized Hadamard-Haar (RHHT), [17]. As before [1] this development is [I.] is un.it matrix of size (m x m), [H1] is the WHT matrix based on Kronecker products and permutation matrices. HT has been applied to character recognition, data compression, and 1] [HI]= [l image processing [3], [7], [18]. In view of its invariance to cyclic shift and to small rotations, RT has found applications in alphanumeric and Chinese character recognition [8], [9], [15]. As the s= 1 | [I2---1 ]® [0 2(1-r- j/2 WHT power spectrum can be computed faster using the MWHT = 2ir1/ [MS'] [3], [11], [16] and as the data sequence can be recovered faster s > 1 scale matrix [I2 n- r] through the phase and power spectra using the MWHT [16], the latter has gained some importance. WHT, of course, has been p,] I[P2n-r--1, 2] S = 1 l [P2n-r, 1 S > 1. utilized in various aspects of digital signal and image processing [3], [4], [10], [12]-[14], [18]. (HHT)T which serves as a compromise ] is the "perfect shuffle" matrix, which can be expressed for between WHT and HT has also been applied to image processing [P' N= 8 as [18]. Detailed development of the unified matrix treatment of these discrete transforms is not presented here as the techniques 1 0 0 0 0 0 0 0 are similar to those of the (WHT)h [1]. Only the matrix formula0 10 0 000 0 0 00 1 00 0 [P4,2] = 0 O 00 00 1 0 [P2,4] = [P4,2]TManuscript received March 10, 1978; revised May 11, 1979. 0 1 00 0 00 0 V. Vlasenko was a visiting Professor at the Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019 under the International 0 O 01 0 00 0 Research and Exchanges Board Scholarship during September 1977-June 1978. He 0 O 00 0 10 0 is now with the Odessa Polytechnic Institute, Odessa, USSR. K. R. Rao is with the University of Texas at Arlington, Arlington, TX 76019. .0 0 00 0 0 0 1 0018-9340/79/1200-0934$00.75 @) 1979 IEEE 935 IEEE TRANSACTIONS ON COMPUTERS, VOL. c-28, NO. 12, DECEMBER 1979 XM(l 0 2 3 4 5 6 7 (a) X(i) yR 0 0 2 2 3 3 4 4 5 5 6 6 7 7 (b) Fig. 1. Signal flow graphs for (a) HT and (b) RHT. Signal flow graphs for the fast computation of (1)-based on (2) and (3) are represented in Fig. 1(a) and (b), respectively. The notation and structure used in the flow graphs are the same as those in [1]. the recurrence relation [3] [H1(k)] [11(k)] [H(k + 1)] = [2k2I2k 15 k = 0, 1, 2, . (5) Modified Walsh-Hadamard Transform [H(O)] = 1 The idea of "perfect shuffle" for developing the fast algorithmic computation of WHT has been shown to yield good results [1], [2]. The signal flow graph for fast computation of (WHT)a [2] Analytical form of [H(k + 1)] can be expressed as based on [1] is shown in Fig. 2. This technique can be applied to 1 0 MWHT for developing its fast algorithm. H = [H(n)] 2 is The MWHT of {x(n)} [3] r=n- 1 {F(n)} = N [H(n)]{x(n)} 2r (4) . 1: ([P2] (9 s'l I ) f- where [H(n)] is the (2" x 2n) MWHT matrix, which is defined by Signal flow graph of (6) is shown in Fig. 3 for N = 8. (6) 936 IEEE X( i ) 0 natural orderr o TRANSACTIONS ON COMPUTERS, VOL. c-28, NO. 12, DECEMBER 1979 Walsh (sequency) order ca-sal order 0 wal (O,t) 2 cal(I,t) 2 4 -cal(2,t) 3 6 cal(3,t) -- 4 7 sol(4,t) 5 5 scl(3,t) 62 3 sal(2,t) 7 sol(l,t) r- Xr=O | r=2- -Permutation stage Fig 2. Signal flow graph for calsal ordeered Walsh-Hadamard transform (WHT),.. x i1 o F(i ) 0O 5, 2 2 2 2 3 3 - 4 4 2l 5 5 6 6 -- 7 2 7 Fig. 3. Signal flow graph for mo3dified Walsh-Hadamard transform. Hadamard-Haar Transform and Rationalized Hadamard-Haar Transform The Ith order Hadamard-Haar transform (HHT), is defined as [4], [18] *[[12.-k- l] (0 [H1]][P2, 2.-k- {L,(n)} where [l ([I2k] () [[P23--kl, 2] [RHH,(n)] = = I [HHI(n)]{x(n)} (7) [HH,(n)] [Go(l)] ® [HO(n 1)] and [Go(l)] is the (2' x 2') = Il] 2r [I2 ]II- r=n-l-l fI zE [IS2]j s=l - (WHT)h matrix. The rationalized version of (HHT), and its inverse can be expressed as [17] {L,(n)} = [RHH,(n)]{x(n)} (8) {x(n)} [RHH,(n)]f[P,(n)]{L,(n)} = ® is and the dia[RHH,(n)] [Go(l)] [fio(n 1)] [P,(n)] (3 [[P"r][BW2"-,] | ]- (10) Signal flow graphs of (9) and (10) are represented in Figs. 4 and 5, respectively (N = 8, 1 = 1). = where gonal matrix whose diagonal elements are negative integer powers of 2. Matrices [HH,(n)] and [RHH,(n)] can be expressed as [HH,(n)] = y l {[I2s] ® [[P2-5-k1, 2] [[I2n-k-1] 0) [H1]][P2,2-0-1l]) 0 I[[P2][M _ Z['r [B=n(-]}JS {[IS21 (3[Pr=[s]B2lr} ] ( Rapid Transform Although RT is not an orthogonal transform it has some interesting properties (apart from the computational simplicity), such as invariance to circular shift, to reflection of the data sequence and to the slight rotation and inclination of a two-dimensional pattern [8], [9]. Also there is some correspondence between periodicity and null subspace in the pattern and transform domains. These properties have led to its application in character recognition [8], [9], [15]. The algorithm for RT [8] can be described by X(r +) = X(r) + X)(N/2) N= O, 1 2 * 2 =y(rp) 12, DECEMBER 1979 IEEE TRANSACTIONS ON COMPUTERS, VOL. c-28, NO. 937 [P4,I [P2,4] X(i) 0' 2 3 ' 4' 5 ' 6 ' Fig. 4. Signal flow graph for XCi) [P2,2 ] (HHT)j, N = 8. [ ]P4 ] [.2,4] [P -2 ;p Li ) A 2 3 4 5 5 6 Fig. 5. Signal flow graph for XS+(N2) = X - and powers of odd elements along the main diagonal are constructed from (Nl2) =|P1) | p=0 1, 2,*--, N -1 (RHHT)j, N = 8. (11) K 0 [R(n)]= r =nfI 1 {[Mr(n)][I2n--] ... ... kp,o L k(N,2) - 1,0 nn (-1)k [M,(n)] = r 1 (13) (13) ( I1 (xt2) - I. 0 (14) -I k(N12)- 1,n- 1 A1/2 (15) X The matrix of states (15) can be used for computing the inverse RT. Signal flow graph for RT is shown in Fig. 6(a). Structure. of systems for RT and its inverse is shown in Fig. 6(b). 0 (_l1to.r ko,n Kl,n-lI kp,r where 1 nl+ I <<°0. The number of elements kp,+ 1 is Nk = N/2 log2 N, which can be arranged in a rectangular matrix (N/2 x n) as (12) (3 [Hl][P2, 2X-1]} np+l )o P,7 I 1 CONCLUSIONS In this paper the "perfect shuffle" method [1] was applied to several orthogonal linear and nonlinear transforms, which are widely used for digital signal processing. Analytical formulas which facilitate the computation of transform coefficients and the practical organization of signal processing algorithms were ob- 938 IEEE TRANSACTIONS ON COMPUTERS, VOL. c-28, NO. 12, DECEMBER 1979 X{; )I[diog [diog [Hl] 0 2 Y 4 5 6 Fr-O~~~~~4 k1r- (a'I) {X ..} ln-l} * -r--r -1-T Compute (I l -I pI pute I1 I y I DecisionI {KP {Kpo} l {Kp2} {Kpn--1 Construction of Matrix [kPr] (b ) Fig. 6. (a) Signal flow graph for the one >dimensional RT, N = 8. (b) Implementation of RT a nd its inverse. tained. A technique for recovery of input data for the RT was also presented. REFERENCES [1] B. J. Fino and V. R. Algazi, "Unified matrix treatment of the fast WalshHadamard transform," IEEE Trans. Comput., vol. C-25, pp. 1142-1146, Nov. 1976. [2] K. R. Rao, M. A. Narasimhan, and V. Devarajan, "Cal-sal Walsh-Hadamard transform," IEEE Trans. Acoust. Speech, Signal Processing, vol. ASSP-26, pp. 605-607, Dec. 1978. [3] N. Ahmed and K. R. 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Shiau, "Machine recognition of printed chinese characters [10] [11] [12] [13] [14] via transformation algorithms," Pattern Recognition, vol. 5, pp. 303-321, Dec. 1973. H. W. Jones, Jr., "A real-time adaptive Hadamard transform video compression," in SPIE's 20th Int. Tech. Symp., Aug. 23-27, 1976, San Diego, CA. N. Ahmed, K. R.- Rao, and A. L. Abdussattar, "BIFORE or Hadamard transform," IEEE Trans. Audio Electroacoust., vol. AU-19, pp. 225-234, Sept. 1971. J. A. Heller, "A real-time Hadamard transform video compression system using frame-to-frame differences," in Nat. Telecommun. Conf., Dec. 2-4, 1974, San Diego, CA. N. Ahmed, P. J. Milne, and S. G. Harris, "Electrocardiographic data compression via orthogonal transforms," IEEE Trans. Biomed. Eng., vol. BME-22, pp. 484-487, Nov. 1975. W. F. Nemcek and W. C. Lin, "Experimental investigation of automatic signature verification," IEEE Trans. Syst., Man, Cybern., vol. SMC-4, pp. 121-126, Jan. 1974. [15] M. A. Narasimhan and K. R. Rao, "Printed alphanumeric character recognition by rapid transform," in 9th Proc. Annu. Asilomar Conf. on Circuits, Systems Computers, Pacific Grove, CA, Nov. 3-5, 1975, pp. 558-563. [16] J. Ninan and V. U. Reddy, "BIFORE phase spectrum and the modified Hadamard transform," IEEE Trans. Acoust. Speech Signal Processing, vol. ASSP-23, pp. 594-595, Dec. 1975. [17] K. R. Rao, A. Jalali, and P. Yip, "Rationalized Hadamard-Haar transform," in 11th Proc. Asilomar Conf. Circuits, Syst., Comput., Nov. 7-9, 1977, Pacific Grove, CA, pp. 194-203. [18] K. R. Rao, M. A. Narasimhan, and K. Revuluri, "Image data processing by Hadamard-Haar transform," IEEE Trans. Comput., vol. C-24, pp. 888-896, Sept. 1975.