Question

what is a technique that onwards data from text image mode into binary data

Answer 1

Whatever thing you wish to represent in a computer, you need to find a way of converting it into numbers. This conversion process is sometimes completely faithful, meaning you can recover the original object precisely from the numbers, or it can be an approximation. In the latter case, the digital representation of your original object is incomplete in some ways, and the trick is to make it close enough in the areas that matter, meaning close enough so that under ordinary circumstances, we can hardly tell the difference, or not at all.