This disclosure provides systems, methods and apparatus for parallel dithering images are disclosed. In one aspect, a display device includes: a front substrate; a backplate opposing the front substrate; an array of display elements associated with the front substrate; and an array of processing units associated with the backplate. Each of the processing units is configured to process data for one or more of the display elements for dithering an image. Each of the processing units is spatially arranged to correspond to the one or more display elements for which it is configured to process data. The array of processing units can perform a faster dithering process than a single processor sequentially performing all computation for dithering. Further, the position of the array of processing units allows effective image data processing in an active-matrix type display device while utilizing the space of the backplate thereof.