MOTION DETERMINING APPARATUS, METHOD THEREOF, AND PICTURE INFORMATION CONVERTING APPARATUS

A motion determining apparatus for detecting a motion of a partial picture of an input picture signal is disclosed, that comprises a first detecting means for detecting a frame difference of the partial picture, a second detecting means for detecting a spatial activity of the partial picture, a threshold value generating means for generating a first threshold value, a second threshold value, and a third threshold value, a comparing means having at least a first comparing portion for comparing the frame difference detected by said first detecting means with the first threshold value and a second comparing portion for comparing the frame difference detected by said first detecting means with the second threshold value, a third comparing means for comparing the spatial activity detected by said second detecting means with the third threshold value, and a motion class determining means for receiving the compared results of said first comparing portion, said second comparing portion, and said third comparing means and determining the motion of the partial picture in at least three levels.