The best way to recognize your fingerprint on iPhone screen

Question

I plan to let the user draw a number form (1 to 9) in the form of a 7-segment display. What is the best way to determine which number was drawn?

I know how to do all the touch tracking and the UIGestureRecogniser stuff - I'm looking for a good logic for this.

So far I have: When the touch moves from 1 half of the segment to the other, select that segment. Once the strokes are finished, check which segments have been highlighted, and decide which number is drawn.

The paths I was thinking about improving: Draw a finger path shape on the screen. If the line crosses the middle of the segment, select it.

Anyone have any tips or better ways to do this? I am open to any suggestion - even if it means giving up all my code and starting from scratch.

Answer 1

I used $ stroke resolver implementations to recognize a numeric number.

• $ 1 Unistroke Recognizer
• $ N Multiple Recognizer

Both algorithms refer to several implementations of Objective-C / iOS.

Attributes will compare input with predefined patterns based on different algorithms (a detailed explanation is available on the linked pages). To do this, you will have to create your own number patterns (basically just draw something and let the recognizer convert it into a data structure that you store for later use). Then at user input, compare with the patterns you wrote down earlier to find a match.

The $ 1 recognition tool was sufficient for my application, where I would let the user first practice drawing numbers. The $ N recognizer is able to distinguish between more complex sinks and can take more complex inverse numbers. This is something you will have to experiment with.

Answer 2

If you are interested in knowing the numbers 1-9, check out BGNumericalGlyphRecognizer . I spent several months working with the $ N-multistroke recognizer to create ScribbleMath (a mathematical application that allows children to draw answers on the screen) and discover the basic logic. It turns out that the $ N resolvers hardly differentiate between 6 and 9, and also very poorly recognize very simple letters like "1" and "-", and I created the logic for better control over them. This is not ideal, but you will get more from you than the $ N recognizer. Enjoy it!