Automatic Assessment of Programming Assignments Using Image Recognition

Automatic assessment of programming tasks in MOOCs (Massive Open Online Courses) is essential due to the large number of submissions. However, this often limits the scope of the assignments since task requirements must be strict for the solutions to be automatically gradable, reducing the opportunity for solutions to be creative. In order to alleviate this problem, we introduce a system capable of assessing the graphical output of a solution program using image recognition. This idea is applied to introductory computer graphics programming tasks whose solutions are programs that produce images of a given object on the screen. The image produced by the solution program is analysed using image recognition, resulting in a probability of a given object appearing in the image. The solution is accepted or rejected based on this score. The system was tested in a MOOC on 2,272 solution submissions. The results contained 4.6% cases of false negative and 0.5% cases of false positive grades. The method introduced in this paper saved approximately one minute per submission of the instructors’ time compared to manual grading. A participant survey revealed that the system was perceived to be functioning well or very well by 82.1% of the respondents, with an average rating of 4.4 out of 5.