1. An image data processing device that generates driving image data used to drive an image display device, the image data processing device comprising: an image memory that sequentially stores input image data of multiple frames; a write control module that controls a writing operation into the image memory; a read control module that controls a reading operation from the image memory; and a driving image data generation module that generates the driving image data from read image data sequentially read from the image memory, the driving image data generation module generating the driving image data by replacing at least part of the read image data with regard to selected pixels with mask data, where the mask data is set corresponding to a pixel value of the read image data in each of the selected pixels to be replaced with the mask data.