17 October 2016
tags: android programming java opencv openshift

Recently (as recently as this backlogs go, I suppose), I was asked to make an app/webapp that automatically marks multiple choice exams. Because there is a dead line, I figured I will use tools that I am familiar with, and decided to go with:

An android app that runs openCV software, recognising exam paper template, performing warptransform and marks the exam using pixel depth. Then via http protocol, send to …

A webapp, that takes the array of answers and compare them with the actual answers.

Lots of lessons learnt along the way. Here are a few:

  1. classes such as getSharedPref should be instantiated after super.onCreate. Doing so before crashes the app.
  2. ScrollView can only contain a single view. Therefore, wrap the desired views in a single linearlayout if you want to include, say, multiple imageviews in a scrollview

Feeling chippy. Now, I can mostly diagnose why OpenCV crashes on me. Most of the time, it’s either the dimension ain’t right, or the depth ain’t right, or the number of channels ain’t right.