Clock recovery for a coded light receiver

• Main Authors: Baggen, Constant Paul Marie Jozef, Vos, Benjamin Johannes, Hoekstra, Peter
• Format: Patent
• Language: English
• Published: 29.10.2019
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

An apparatus, method and program for receiving a coded light signal comprising a periodically repeating message repeating with a message period. A portion of the message is received in each of a plurality of frames captured by a rolling-shutter camera, with different portions being received in different frames. Using each of a discrete group of trial values of the message period, the respective trial value is used to reconstruct a respective first version of the message from the portions received in a first subset of said frames, and to reconstruct a respective second version of the message from the portions received in a second subset of said frames. For each of the trial values, there is generate a respective value of a measure of similarity between the respective reconstructed first and second versions of the message. An estimate of the message period is determined based on this.