MATLAB Answer Sheet Recognition System with GUI Interface and Algorithm Documentation

MATLAB-based Answer Sheet Recognition System Using Moment Invariants (with GUI Interface)

Automated answer sheet recognition systems hold significant importance in educational assessment, substantially improving grading efficiency while reducing human errors. This MATLAB-based system integrates image processing techniques with a graphical user interface (GUI) to automate student ID recognition, subject identification, answer extraction, and score calculation.

Core Technical Process Image Preprocessing Implementation begins with grayscale conversion to simplify data dimensions, followed by binarization to separate foreground (marked areas) from background. Noise reduction is achieved through filtering algorithms, edge detection locates answer sheet boundaries, and image skew correction is performed using Hough transform methods.

Moment Invariants Feature Recognition The system utilizes moment invariants' invariance to translation, rotation, and scaling to accurately extract geometric features of marked regions. This approach ensures robust recognition of student IDs and answer areas under varying capture conditions through feature vector comparison algorithms.

Interactive GUI Design Users can import answer sheet images through the interface, with the system automatically annotating recognition results (student IDs, selected options). Backend functionality supports Excel standard answer import, real-time score calculation with pass/fail determination, and structured report export capabilities using MATLAB's table and file I/O functions.

Application Value This system is suitable for standardized testing scenarios, demonstrating significantly higher processing speed and accuracy compared to manual grading. The modular design allows for easy expansion to multiple question types (multiple-choice, true/false questions). The intuitive GUI lowers the technical barrier, making it accessible for non-technical users while maintaining professional-grade performance through optimized image processing pipelines.