Hi. Let's keep the greetings short, shall we....
The intro is going to be long, but it's relevant to the rest of the topic so you should read it, the will is yours. Also do excuse my poor grammar, I'm not native English speaker.
My mom is a lecturer on English, specifically for future librarians. Due to the poor English skill of the students, her employer, the Ho Chi Minh City University of Culture, Vietnam, decided to enforce a TOEIC course. It follows the TOEIC test's format of 200 questions, over two answer sheets and is a 4-choice A B C D test. Everything has been going nice and smooth (as far as I can tell) but recently, she complained about she and her colleague had to sat down and scored manually nearly 700 answer sheets, and took them the whole after noon to finish them. When I asked her about automated answer sheets scoring machine (I don't know how it's called in English), she said the university's budget couldn't afford it. As I know a few in automation, as well of have heard the Raspberry Pi via Null-Byte, I told her about my plan of building a low-cost grading machine using the Pi as the brain and using simple motors and conveyor belts for moving the answer sheets. And she agreed, as long as it's faster than human doing it, and costs less than auto-loading scanner (roughly 1000$ here, in Vietnam) plus a program to handle the grading/scoring (100$/year).
TL;DR: A machine that uses the Pi for cheap, quick and reliable auto-scoring on multiple choice
So, my plan is to use a camera (perhaps a GoPro) that can capture at at least 20MP for high-quality images, several white LEDs for lighting, servos and conveyor belts to handle answer sheet transporting, Lego blocks for the frame, and of course, the Pi for the brain. The operation would be like: Motors 1 and Conveyor belt 1 take one answer sheet from Holder 1 and put the sheet into the Center Block, then Camera snaps a pic, transfer it to the Pi, store it there, next Motors 2 and Conveyor 2 would move the already captured sheet into Holder 2. Upon recognizing a picture of pre-defined "emptiness" (a pic of the the center block, nothing else) for over a certain duration of time, the Pi would move to the grading part, which will use an inputted key answer sheet, and comparing the answer sheet to the key. The Pi will now store the results in a file, which will record the answer sheet's ID number along with its number of correct answers and percentage of right answers in an Excel file. The Excel can be use to input the score into the university's database, which can be done manually.
So, as a highschool student who is interested in automation and the Pi, as well as image recognition (sort of) but with zero knowledge on the Pi, I'm asking for your advices. Where should I start, what should I learn, what should I get, what should I do? I'm not rushing this project as I know there are a lot of thing to be done in preparation.
Thank you for your time reading this, and I would really appreciate your advices.