MR Image reconstruction

I have a code to reconstruct a image from sub sampling data but the sub sampling rate only 2. I need modify this code to reconstruct image for all case mean from full sampled , 2, 3 or 4 down sampled [login to view URL] sampling in y direction only x direction should be as it is. For example You're saying that if the original image is 256*256, then it over sampled to 256* 1024. a sub sampled image will be 128 *1024, and you need to reconstruct it back to 256x256 ( this is already done). You need to do next stage 96*1024 to 256*256, and then 64*256 to 256*256. thats it.