ASP: Arbitrary Segment Patterns Transferring complex data from seven-segment displays using smartphone camera technology

Abstract

7-segment displays are often used in industry for displaying limited information about the current state. In this thesis we investigate the possibility to transfer more content rich data using our proposed Arbitrary Segment Patterns scanned by a smartphone. It is a concept of allowing the displays to use the segments and dots of the display as bits representing the message. Further more this includes displaying the messages in sequences allowing for even more information. Five different algorithms for interpreting the patterns are evaluated where three are based on line detections and two on shape detection. They are analyzed from the aspects of both performance and correctness using 7-segment displays of the types LED with red diodes and reflective LCD. The result is that the most promising approach is to use shape detection allowing for sending patterns with a speed of more than two patterns each second. This frame rate allows for sending 70 bits of information during a period of 5 seconds on a machine with displays of two digits. This is a significant increase of information.