example by ignoring every other sample while up samping can be accomplished by repeating a given sample the output of switches 113 and 114 are applied to transpose memories 115 and 116 that transpose the pixel signals of the two dimensional image in the manner of transposing matrices transpose memories 115 and 116 are conventional memories where signals are stored in one way following rows but accessed in a different way following columns such memory arrangements are well known in the art for sake of completeness however the following simple implementation is suggested to obtain transposition one may use an address counter and a memory responsive thereto with a logic circuit interposed therebetween the logic circuit allows for interchange of a number of least significant bits of the counter with higher significance bits of the counter a normal sequence is thus obtained without the interchange of bits and the transposed sequence is obtined by interchanging the bits the output of memory 115 is applied to low pass filter 117 and to high pass filter 118 similarly the output signal of memory 116 is applied to filters 161 and 162 the outputs of filters 117 118 161 and 162 are applied respectively to subsamplers 163 164 165 and 166 which produce the ll lh hl and hh outputs of filter bank 110 the filters themselves can be implemented with short and simple finite impulse response fir filters a typical set of filter coefficients is 1 3 3 1 for the low pass filters 111 117 and.