Image processing for privacy and wide-view using error diffusion

A display device includes control electronics and a pixilated liquid crystal (LC) panel. The control electronics receives inputs of main image data for a main image and side image data for a side image. The control electronics outputs combined image data combining the main and side images such that an on-axis viewer perceives from the combined image the main image, and an off-axis viewer perceives from the combined image the side image. The output image data comprises data values chosen from a set of available output data values for the pixels selected from multiple sets of available data values depending on at least on the side image data. For a pixel currently being processed, the output data value is chosen from the selected set of available output data values for which a resulting luminance value is closest to a target luminance value for the current pixel.