scl_slope to 1 and scl_inter
to be 0 of slots of class nifti. This is so that when images are
rendered/written, the values correspond to those in the array (stored in the
.Data slot) and are not scaled.
resetSlopeIntercept(img)
zero_trans(img)nifti object (or character of filename). If an
anlz object is passed, the unaltered anlz object is returned.