The scanner in my pocket

Quiz review has become a lot more useful now that

  • We review the questions immediately after writing the quiz
  • The students have their own completed papers in their hands
  • The papers have no grade or comments on them

I like that this allows students to assess their own work without having their judgement short-circuited by my evaluation.  Sometimes we do this just for practice, and that’s the end of it.  But if I’m going to update their skills list to say that they can do something independently, I need to have a record of their quiz from before the class review.  In the January semester, I got that by having all students complete two copies of their quizzes: one for them to assess right away, and one for me to evaluate later.  As you can imagine, this is tedious for the students.  When I wrote about this process in detail, I concluded that I needed a scanner that I could carry with me (I don’t have my own classroom).

I looked at lots of “ultraportable” scanners, and they were all too big to carry around, as well as ridiculously expensive.  Only one had on-board storage.  A few were autonomous, but most needed to be plugged into a computer, which would have to be booted, logged into, then wait for the drivers to download, etc.  I was imagining every student running their quiz through a scanner that would automatically email me the file, or store it somehow.  Then I stumbled across the most portable scanner there is: a smartphone.

There are a number of “document scanning” apps available, and they all do basically the same thing: take a picture of a document, try to figure out where the edges of the page are, then process it to correct parallax and improve contrast.  The result is probably a PDF, looking remarkably as though it had come from a scanner. Some of them will even do character recognition, so you end up with an editable Word document (for typed text only, of course).

In the May semester, I rolled it out.  I had grandiose ideas about electronic grading, so I bought a tablet computer (the Samsung Galaxy Tab 7″). At the end of the quiz, I walked around and took pictures of everyone’s paper, then tucked the tablet in my bag. We reviewed the quiz, the students wrote feedback to themselves.  Later, I reviewed the electronic files, marked them, and emailed them all to myself (or I could have uploaded them to Dropbox or Evernote or synced them to GoogelDocs).  The process worked fine.  Of course, the question isn’t, did it work.

The question is: Did it work better than paper?

It has its pros and cons.  Con: it is slower for me (I can collect 20 pieces of paper faster than I can take 20 pictures).  Pro: it is faster for the students.  They no longer have to copy out their entire paper a second time (wasting minutes that they could be using to check their work).

The context in which this makes sense is if you need a record of student work, you need to return the work to the student immediately (otherwise you could just walk to the photocopier), and you don’t want the students recopying their work.  In our case, problems are often so long that recopying them would mean cutting the assessed skills by half.  I’ve gotten around this by asking students to recopy only their final answers; obviously, this is not ideal.  I love the way this allows me to capture the whole story — what they’ve crossed out, doodles and mnemonics and scratch calculations, etc.

Final result: I’m sold.  I love having searchable electronic archives of each student’s work.  It allows me to cut down on paper without requiring a tablet computer for every student.  It’s a great record of progress.  I can email them back a file with my comments.  It works for flip charts and white boards too.  It saves trees.  Students can borrow it and do their own scanning (John Burk talks more about possible advantages here).

Once I was convinced I wanted to go this way, I had to choose hardware and software.  The document scanning apps I tried were Droid Scan, CamScanner, and Document Scanner.  I settled on CamScanner because it had the highest proportion of correct edge detections (it pretty much never failed to automatically recognize my page), and that is the slowest, fussiest part of the process if you have to do it by hand.  For hardware, I tried the Samsung Galaxy, the Acer Iconia, and the iPad 2.  The Galaxy and Iconia were pretty similar (I prefer the Galaxy for its small size and thorough integration of speech recognition).  The iPad was not suitable — its <1MPixel camera made documents illegible (see below).


The image quality has been degraded somewhat in these examples, possibly in the cutting and pasting and converting from PDF to an image format, but at least you can see the relative quality.  On screen, the Galaxy and the Iconia were quite legible — right down to the decimal point in 1.08A, although the Iconia was a bit washed out.

Overall, I’m happy with this and I’m looking forward to using it in September.  Next question: can a tablet computer be used as a document camera?  Stay tuned.


  1. I bought a sheet-feed desktop scanner for peanuts off eBay that the students can drop a class-set of A4 sheets into for this purpose (among others). I am impressed with the performance of the tablets though. I’m waiting on the arrival of one of these though .
    I had to order it from Taiwan, but I have high hopes. It’s essentially an independent, Linux driven, Wacom tablet which has a 2MP camera on the back. In theory it replaces a paper notepad and allows you to insert snapshots into handwritten notes and annotate them (or PDFs with a bit of freeware,)

    • The EEE Note looks like a great device. It is certainly annoying not to be able to use the Galaxy outdoors. Hope you’ll share the results once you’ve tried it!

  2. I love the idea. My father-in-law has a multipurpose printer copier scanner that scans to a UAB drive. These are relatively cheap and could be used and then only the drive comes with you.

    • This is a great idea if you have a permanent home for the multi-function device. Unfortunately, I teach in 4-6 different rooms over the course of a day, so portability is key. A sheet feed has definite advantages — drop a pile of paper in and walk away. The downside is that you are restricted to loose sheets of a certain size — no plotter paper, no magazine articles, etc.

  3. One advantage of the cell-phone camera approach over the sheet-fed scanner is that you can also record lab notebooks and whiteboard discussions, both of which will not fit in a sheet-feeder.

    Do any of the apps work off of jpg images from a camera? I could see using my digital camera to take pictures (better resolution and lighting adjustments than a cell-phone camera, and I don’t have a cell phone anyway).

    • Re: whiteboards: the results with a whiteboard were surprisingly good, especially considering how poor photos of whiteboards tend to be (due to glare).

      All of the apps I used were able to import photos (I didn’t check the format, but JPG seems likely), but they are only available for mobile operating systems. No question that a camera would give you more control and better results. In fact, if I could find desktop software that would do the image processing, I wouldn’t need the tablet/cellphone at all — just carry a camera and do the processing later. Unfortunately, I didn’t find a single piece of software, at any price, that could do it. I even installed the Android SDK to run a virtual machine on my desktop, in the hopes that I could install the app there and “pretend” to have a phone, but no dice. This seems to be possible in theory, but my underperforming desktop was not up to the task (every keypress resulted in minutes of wait time, or hung the SDK).

      So even if you use a camera to collect the images, it seems that a mobile device is necessary anyway.

  4. Hi Mylène,

    Are you doing still using a smartphone for scanning quizzes once they’re done?
    This year for one of my courses, I had students hand in their quizzes and then all the desks were cleared. I then returned their quizzes along with a green pen and they worked on the corrections and graded them. The students then handed in their quizzes and I recorded the grades. I use SBG with a 3 point scales, so it’s very easy for the students to assess their progress.
    However, I sort of like the idea of scanning the quizzes before returning them. How long do you think it would it take to scan a 2 page quiz for 30 students?

    Fantastic blog btw.


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