Patent ID: 7598969

Claim:
A correction-data generating method for generating correction data used to correct an error in a block period in a projector having an electro-optical panel which includes a plurality of switching elements provided corresponding to intersections of a plurality of scanning lines and a plurality of data lines, and a plurality of pixel electrodes provided corresponding to the plurality of switching elements, the electro-optical panel sequentially selecting the scanning lines and applying phase-expanded image signals in each block, which include the plurality of data lines, in a period during which each of the scanning lines is selected, the method comprising: displaying on a screen gray levels corresponding to measurement levels of a plurality of measurement blocks to generate the correction data, each of the plurality of measurement blocks comprising a plurality of vertical lines; displaying on the screen gray levels corresponding to reference levels of a plurality of reference blocks which are provided among the plurality of measurement blocks and which are used as a basis to determine positions of the measurement blocks, each of the plurality of reference blocks comprising a plurality of vertical lines; generating an image signal by capturing an image on the screen using a video camera; comparing the image signal with a threshold to distinguish the measurement levels from the reference levels; detecting the measurement blocks based on the comparison result; and generating the correction data for each of the data lines based on a difference between only the image signal and the gray levels corresponding to the measurement levels of the measurement blocks that are not adjacent to the reference blocks.