Letter codes
When the scanner receives an image for processing, it knows what the numbers mean, but it doesn't have information about the exercises. Therefore, additional information is required, like: "Exercise 1" is a Front Squat, "Exercise 2" is a Deadlift, and so on. Without that info, you will have to assign them manually.
There are two options to inform the scanner about a list of exercises in the workout. First, you can select a workout routine on the first step of scanning. This way is robust but inflexible. Second, you can assign unique letter codes to exercises you use during workouts. For instance, "FS" for the Front Squats, "DL" for the Deadlift, etc.
You can use such codes simply as a replacement for exercise names or together with their names. An algorithm is simple - when the scanner sees several uppercase letters in a row, it considers these letters as code and tries to find an exercise that the code matches. The same approach also works for cardio exercises. Also, exercises with codes are visually highlighted and displayed at the top of the exercise list.