1. A method of generating an interpolated image, comprising: inputting a video signal including a first reference image, a second reference image and a third reference image that continue in terms of time generating a first interpolation image put in a position of the second reference image, using the first reference image and the third reference image; computing a correlation value between the second reference image and the first interpolation image; generating a second interpolation image put in an interpolation position between the second reference image and the third reference image; and interposing the second interpolation image in the interpolation position when the correlation value is not less than a threshold.