this means that the present embodiment of the image processing apparatus is the same in construction as the first embodiment of the image processing apparatus except for the horizontal direction prefilter unit and the vertical direction prefilter unit fig4 is a block diagram showing a horizontal direction prefilter unit of the present embodiment the vertical direction prefilter unit is the same as the horizontal direction prefilter and will thus be omitted from description for avoiding tedious repetition as shown in fig4 the horizontal direction prefilter unit 40 comprises a horizontal edge strength calculating unit 41 for calculating an edge strength along a horizontal direction and a prefilter 42 for carrying out a filter processing in accordance with the edge strength along a horizontal direction the horizontal edge strength calculating unit 41 includes a vertical lpf 51 for carrying out an lpf along the vertical direction a delay element 52 and a delay element 53 each for delaying data a subtracting unit 54 and a subtracting unit 55 each for calculating a difference value between two signals an absolute value calculating processing unit 56 and an absolute value calculating processing unit 57 each calculating an absolute value of an inputted value and an adding unit 58 for adding two inputted values the vertical lpf 51 is adapted to carry out an lpf processing along the vertical direction by inputting three line signals and multiplying the line signals respectively by coefficients of for example u00bc u00bd and u00bc and adding.