How to distinguish results from empty image and image containing 1

[ghwn]

Hi,

I am using this classifier to recognize square images containing numbers.

In most cases this classifier performs very well but when there are no numbers in the image, it returns 1 (length: 1, digits: [1, 10, 10, 10, 10]).

It's confusing because it also returns same result when recognizing images containing only 1.

How can I distinguish them?