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Integrated Hadamard Image Scanner

IP.com Disclosure Number: IPCOM000084613D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Chai, HD: AUTHOR [+2]

Abstract

In the electronic teleprocessing of optical images, it is frequently advantageous to transmit a "transformed" version of the image. Shown is a solid-state image scanner which produces a transformed electrical signal. The transform which is utilized is the "Hadamard" transform which, among other places, is explained in the Proceedings of the IEEE, Volume 57, Pages 58-68 (1969).

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Integrated Hadamard Image Scanner

In the electronic teleprocessing of optical images, it is frequently advantageous to transmit a "transformed" version of the image. Shown is a solid-state image scanner which produces a transformed electrical signal. The transform which is utilized is the "Hadamard" transform which, among other places, is explained in the Proceedings of the IEEE, Volume 57, Pages 58-68 (1969).

The Hadamard transform operates on a signal so that the information concerning one point in the image is distributed in time throughout the transmission. Utilizing the Hadamard transformation technique, noise bursts encountered during the transmission degrade the image as a whole but do not influence greatly any particular part of it. The transformation also decreases the dynamic range requirements of the transmission system.

A Hadamard transformation can be performed by multiplying the signal by certain binary encoded signals (a string of 1's and 0's) and summing the result. For example, if the video signal is decomposed into N samples x(1), x(2), x(3),
...x(k) ...x(n), the transform is the set of values y(1), y(2), y(3), ...y(1) ...y(n) obtained from the following procedure: y(1) = all x1 + a(12)X(2) + ... + a(1N) x(N) y(2) = a(21) x1 + a(22)X(2) + ... + a(2N) X(n) y(n) = a(N1) x1 + a(N2)x(2) + ... + a(NN) x(N) or in matrix form: (y) = ( A ) ( x ). where the "A" matrix is derived from a Hadamard matrix. An example is the following A matrix for N=7: 1 1 1 0 0 1 0 0 1 1 1 0 0 1 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 1 0 0 1 0 1 1 1 1 0 0 1 0 1

Note that the matrix is cyclic so that a row is obtained from its preceding row by a single right-hand shift.

Fig. 3 is an electrical equivalent circuit of a photodiode version of the Hadamard scanner. This equivalent circuit shows three cells labelled A, B, and
C. Each cell has two gates designated 31 and 32, a photodiode 33, a capacitor 34, a resistor 35, and a battery 36. Each gate operates as...