this procedure is repeated when the fields are in the order of a b c d and so on the respective fields have the information contents according to the combinations of ab bc cd de and so on in this manner the information changes in the order of fields so that the transition of images may be performed smoothly fig1 shows a screen where the normal interlaced scanning is performed with seven scanning lines scanning lines 1 3 5 and 7 indicated by solid lines correspond to a first field scanning lines 2 4 and 6 indicated by dotted lines correspond to a second field the latter half of the sccanning line 7 is scanned in the second field fig2 shows a first embodiment of the present invention and fig3 shows a second embodiment of the present invention in the embodiment shown in fig2 double scanning is performed by non interlaced scanning wherein the scanning lines of the first field and the scanning lines of the second field coincide with substantially the same contents in the embodiment shown in fig3 double scanning is performed by interlaced scanning wherein the scanning line of the second field has half each of the information of the immediately preceding and following scanning lines of the first field fig4 shows an example of the circuit configuration for performing double scanning shown in fig2 and 3 in the circuit shown in fig4 a video signal s supplied to an input terminal 1 is converted to a digital video signal at an a d converter 2 the digital video signal is converted by.