To convert aspect ratio by simplifying the circuit and reducing the requisite of a memory and the band width, so as to reduce the cost, in a projective television image receiver.

The method of conversion of the aspect ratio in a random line access system of imager includes a stage of periodically receiving a specified number of input video lines, a stage of converting a specified number of input video lines into a vertical format so as to give converted video input having a part of a specified number of input video lines, and a stage of periodically multiplexing black lines and the converted video input during the waiting period in the stage of conversion into a vertical format. Moreover, the method can include a stage of presenting the converted video input and a plurality of black lines which are periodically multiplexed with the converted video input on an imager.