American Telephone & Telegraph Co., At&t Bell Laboratories

At&t Bell Laboratories

Adrianus Ligtenberg

Mehdi Hatamian

Glenn Lawrence Cash

Jay Henry O'Neill

Hemant Bheda

A system for reducing image data redundancies through progressive sub-band coding. The image is separated into a selected plurality of sub-bands, and the sub-band with the largest non-redundant data content is chosen and used to predict the data in the other sub-bands. Only prediction error information of the predicted sub-bands encoded and transmitted together with the encoded chosen sub-band. An overall performance error signal can also be evaluated at the encoder's end and used to further improve performance. The sub-band encoding can be performed recursively to still further reduce the encoded data.

Progressive sub-band image coding system

A fast pipeline adder comprising a plurality of registered adder rows. In one embodiment, additions in the pipeline are realized in reclocked half adders. In another embodiment, modified adders are employed which accept two carry inputs and develop two carry outputs. The resulting number of individual cells is reduced to approximately half of those in the prior embodiment. In still another embodiment, switch means are included in each cell to delete the reclocking and in still another embodiment, the adders in the diagonal of the pipeline adder are provided with additional inputs to permit use of the pipeline adder in recursive addition applications. In still another embodiment, the cells are permitted to output the inverse of the intended signal, reducing thereby the physical realization of the cells and increasing the speed of the cells.

Pipeline arithmetic adder and multiplier

An orthogonal transform processor comprising a rotator circuit, a look-up table and a communicator circuit. The rotator circuit performs the complex multiplications required of a rotator, the necessary coefficients are supplied by the look-up table, and the communicator circuit is charged with the task of accepting input signals, supplying the rotator with the signals necessary for each iteration, and delivering the resultant output signals. The rotator is realized with a matrix of spatially adjacent interconnected multiplier and adder modules, where each module comprises a portion of each of the multipliers necessary in the rotator.

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Rumson, NJ, United States of America

Adrianus Ligtenberg