CHARGE TRANSFER DEVICE INCORPORATING LAPLACIAN THRESHOLDING WITH A TIME DELAY AND INTEGRATION IMAGING ARRAY

摘要

A charge transfer device incorporating Laplacian thresholding with an imaging array (1) operated in delay and integration mode to generate an array of charge packets corresponding to the light intensity at the picture elements of an irradiating image. The charge packets are gated in parallel to a line image storage array (7) that stores n rows of charge packets in a columnar relation. A replicator circuit (11) generates a replicated sum charge for each column of charge packets of the line image storage array. Each replicated sum charge corresponds to the sum of the n charges stored in a column (13) at a particular instant in time and the charge stored at the (n+ 1)/2 position of each column is the middle charge for the associated replicated sum charge. Parallel delay gating electrodes (15) gate a row of replicated sum charges to an area average serial shift register (17) at the same time that a row of corresponding middle charges is gated into a focused element serial shift register (9). The serial shift registers are gated synchronously in a serial fashion and, as the registers (9, 17) are gated, the endmost n replicated sum charges are summed by a horizontal summer (26) and 1/n2 of the sum is subtracted by a comparator (23) from an associated central charge stored in the focused element serial shift register (9). The difference is the Laplacian for the central charge. The output of the focused element serial shift register, the summer output, and the Laplacian uare useful for subsequent image processing.