Looking into why my nearest neighbor results are awful

Here I am comparing one of my test L's to half of my training L's. The test L is always on the right. Also the test L is a lot lighter than the training L's. In particular, the minimum value of the test L is 111 whereas the minimum value of the training L's is consistently 0. I am not sure if this will have an impact on my results or not.

Similarly, here are some 'o' comparisons, where the test 'o' is always on the right. No training 'o' matches the test 'o' exactly in size, which is a problem.

I'm not quite sure that the Viterbi algorithm is the right thing to be using for my case because it does not take into account the lexicon (roster) as much as it should.