If not, then which microcontroller will be suitable?
Not on nano and uno because of memory size. Really basic one with a low-resolution image and slower fps might be possible on mega. Still memory size might not be enough. Due is really marginal in acceptable processing speed with a low-resolution image but still have a memory problem. Just have a look at how much memory you need to store 2 or 3 images on your ram. That is the marginal ram requirement. You can use an external storage module which will take minutes to process a single frame.
Choose a board with more than 1.0GHz cpu, 128Mb ram with linux.
If it is a real-time SLAM for some real application I would say yes, it is impossible. You won't be able to process 30 fps on your arduino go for the latest Raspberry or Odroid or a similar SBC