Image signal converter and method of converting image signal

An image signal converter for converting a progressive scan image signal having a given number of frames per given time into an interlaced scan image signal having a different number of frames per the given time from the progressive scan image signal, the image signal converter comprising:

• a field storage unit for storing therein fields separated from each frame of the progressive scan image signal;
• a picture switch detection unit for comparing each of the stored fields in the field storage unit and detecting whether a picture switch occurs between frames of the progressive scan image signal depending on whether there is a movement between each of the compared fields;
• and
• a field extraction unit for controlling the number of the fields extracted per frame from two sequential frames in which the picture switch occurs, whereby the stored fields corresponding to each of the two sequential frames form each of different frames of the interlaced scan image signal.

A computer readable medium storing program code for instructing a computer to execute the steps of:

• separating fields from each frame of the progressive scan image signal and storing the fields;
• comparing each of the stored fields and detecting whether a picture switch occurs between the frames of the progressive scan image signal based on whether there is movement between the compared fields;
• and
• controlling the number of fields extracted per frame from two sequential frames in which the picture switch occurs, whereby the fields separated from each of the two sequential frames form each of different frames of the interlaced scan image signal.