Camera-Based Instant Feedback Systems

Abstract

In this work we describe Instant Feedback Systems (IFS), that are designed to collect students’ responses to a series of multiple-choice questions. An IFS enables the educators to improve their teaching by generating real-time feedback from the students measuring their level of knowledge or the level of clarity of the lesson. A number of IFS are known using wired mini-keyboards, infrared clickers, SMS, Internet-based devices, etc. Our long-term goal is to create an IFS system based on the use of digital cameras. In the frame of camera-based IFS implementation, every student attending the class receives a specially designed card containing a predefined number of color markers and a 2D barcode. When later the students are asked a multiple-choice question, they answer by physically raising their cards. The 2D barcode on the card is used to encode the student’s ID, whereas the 2D orientation of the card encodes the number of the student’s answer. A number of images of the class are grabbed by one or more IFS cameras and processed by a computer, which generates a list of student grades. Reliability of several card designs, different camera placements and different Optical Character Recognition (OCR) algorithms is analysed. The feasibility and accuracy of the presented IFS approach is evaluated by means of MATLAB-based simulations as well as real life images. We conclude that the presented card recognition process demonstrates feasibility and efficiency of the camera-based IFS approach. KeywordsImage processing, 2D barcode, Color Recognition, OCR, Instant Feedback System