What type of images are required for voxel classification? In an algorithm, voxel classification approach is used to perform image segmentation. The aim was classifying voxels either as cartilage or background in MRI image. The project has to be completed in matlab.

MRI images has .dcm extension, it may have .avi and other types too, I am not sure.  Is it possible to perform voxel classification on .dcm images or it require another type of images?
In general it doesn't matter what the format is, because you will load it as array/matrix anyway.

That being said, I never saw preprocessing being done on DICOM images, usually they are transformed to nifty or something else before anything is being done to it. However, ignorance is not an argument.