Boots – shoes – and leggings
Patent
1989-02-09
1991-01-22
Shaw, Dale M.
Boots, shoes, and leggings
G06F 700, G06F 1500
Patent
active
049875574
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a system for calculation of a sum of products in which data items of a time- or space-based array such as image data are multiplied individually by coefficients corresponding to a distribution curve and then the products obtained are added together.
(b) Description of the Related Art
There exists several known systems for calculation of a sum of products, such as a convolution integrator used for enhancement of the sharpness of image data, spatial filtering and the like, wherein n data items are sequentially fetched from a time-or space-based array of data and are multiplied individually by coefficients corresponding to a distribution curve. The n data multiplied by the coefficients are then added to output the sum. In such a system, the products of the n data items and the respective coefficients are obtained at one time, then added together, and finally the sum of the products is output. Subsequently, the data items are shifted, so that the shifted n data items can be multiplied by the corresponding coefficients. The obtained products are added together, and the sum is output. The operation described is executed successively. In this case, the n data items need to be multiplied at one time by their corresponding coefficients. To this end, an arithmetic unit for the sum-of-products operation of a systolic array type is used having n processors which are arranged in parallel for multiplication.
Assuming that n data items are fetched sequentially from a sequence of data a.sub.1, a.sub., a.sub.3, . . . a.sub.m, . . . and are multiplied at one time by coefficients k.sub.1 to k.sub.n, respectively, the products obtained are added together, and the sum is delivered as output Y. In this case, the output Y of the arithmetic unit for sum-of-products operation is as follows:
Output Y1 obtained first is 1) a.sub.n+1( 2) a.sub.n+i-1 ( 3) must be obtained at the same time, a systolic array is employed in which n processors serving as multipliers are connected in parallel. 4
The processors which are used as multipliers are required to perform at high-speed and are therefore expensive. Consequently, there is a problem in that if the number of coefficients to be multiplied is large, the arithmetic unit required for sum-of-products operation becomes very expensive.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a system for calculation of a sum of products in which the number of the processors used as multipliers is reduced. Accordingly, the system provides an inexpensive arithmetic unit for the sum-of-products operation.
To achieve the above object, the present invention provides a system for calculation of the sum of products in which n coefficients are multiplied by corresponding data items and the products obtained are then added together. The system comprises a processor array including n/d processors to which data items of a data sequence are input while being shifted. The processors multiply the input data items individually by the coefficients. The processor array adds together the outputs of the processors and outputs the sum obtained; an adder for adding the output of the processor array to a value stored in an intermediate storage unit which corresponds to a respective shift; and the intermediate storage unit stores the output of the adder in an address thereof corresponding to a respective shift. The same data sequence is input to the processor array d times, and the coefficients set in the processors are varied to respective predetermined values each time the data sequence is input. The reading of data from the intermediate storage unit and the writing of the output supplied from the adder being delayed by n/d cycles each time the data sequence is input. The output of the adder is then the result of addition of the products of the n coefficients and the data items.
Assuming that the sequence of data to be processed is a.sub.1, a.sub.2, a.sub.3, . . . , and that the number of proc
REFERENCES:
patent: 3961167 (1976-06-01), Mills
patent: 4489393 (1984-12-01), Kawahara et al.
patent: 4550437 (1985-10-01), Kobayashi et al.
Fanuc Ltd.
Shaw Dale M.
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