Visualizing Large-Screen Electronic Chalkboard Content on Handheld Devices

While more and more educational institutions use high- resolution, large-scale electronic displays and interactive devices as a substitute for chalkboards, we observed that an increasing number of students wants to be able to play- back and view recorded lectures using their mobile devices. However, the presentation of large-scale, high-resolution content on a small-scale, low-resolution, handheld device is a challenge. Applying traditional image and video scaling methods make most of the content unreadable. This article presents a novel visualization algorithm tested with a con- crete electronic chalkboard presentation system, namely the E-Chalk system. It allows viewing of large-scale electronic chalkboard content on handheld devices. In addition, this paper presents different implementations of non-interactive and interactive viewer applications that can be run and in- stalled on different types of mobile devices.