Making little Physics Videos with a Document Camera
Here is my recipe for making little videos with a document camera. Please note that the recipe is specific to the make and model discussed (Lumens DC192) and set up particularly for videoing a human hand scribbling down a solution while speaking about it at the time. This is not flashy stuff, just material for a moodle page for a Physics course.
So the image on the video looks like this:
Well, it should be, but there can be a lot of trickinesses. Anyway, here is my recipe. I do not expect anybody to follow it closely (or at all), but the steps and the things I have to think about may be useful for some if they need to make little videos, often in relation to ‘flipping‘ a Physics course, which is very much the fashion these days.
How I made a very simple video using the Lumens DC192 Document camera
- Lumens DC192 document camera.
- USB memory stick.
- VGA cable.
- Pens, paper, your brain, your script, etc.
- Then computer and software for editing.
If using the camera on a desk rather than in lecture theatre, simplest is to use VGA cable from camera to monitor and that is all you need.
(1) Got a 4GB+ USB stick and deleted all files. Not necessary to empty the stick but this minimises chance of running out of space during a video capture.
(2) Picked a problem or two. Made sure I had good worked out solutions, and printed them out/wrote them up on paper – see image below (figure 2).
(3) Got some overhead markers. I find they give a dark line but are not too coarse. Staedtler ‘Lumocolor’ type pens with a fine tip were good.
(4) Printed out an A4 sheet with the problem occupying the top left of the page, landscape. Thought about whether more than the remaining white space was necessary, and had extra sheets ready. See figure 3. A few extra copies were useful too… made sure it was printed pretty dark and pretty big. (For scanned images I used ImageJ to Gaussian blur, then Brightness/Contrast to darken and turn the blur into thicker lines.)
(5) Got my sheet with the already-worked-out solution (figure 2) and marked a few key words on it for concepts I want to make sure I covered, things like ‘conservation of energy’ or ‘Newton’s laws’ or whatever.
(6) Also noted on it what colours I want to use where. I have a few pens — black, red, blue green and brown. No yellow (not dark enough on the white paper).
(7) Got remote control for DC192.
(8) Killed any sources of noise as I could – climate control, for example. Put ‘Do Not Disturb’ on my door. Shut all doors, turned on all lights. Used an extra lamp to avoid shadows on the page.
(9) Taped down an A3 sheet such that it filled the screen. Then put my A4 with printed problem on top of that, taped down with magic tape.
(10) Removed jangly things from my pockets — keys, for example. And coins. Do you write notes on the backs of your hands? Best wash them off. I didn’t…
(11) Inserted a USB stick into the DC. Screen said ‘copy to USB stick’ (it may not actually ask you this, depending on camera settings). Selected ‘no’ by pressing ‘Enter’ button on the DC. (Answer ‘yes’ if you want to copy the contents of the DC’s internal memory.)
(12) Adjusted the camera neck and zoom such that only my A4 page was visible. In fact, if the camera was positioned right it could only see the white A4 page. Made some small marks on the paper to indicate where the edges of the camera window were, so I would not write stuff off the edge.
May be good to use the remote to adjust the microphone level to about a quarter to reduce saturation and resulting lousy sound. This setting is remembered when the unit it on stand-by but should be checked if it has been turned off at the wall.
(13) Arranged my notes and pens ready for use while talking. Tested all pens, and placed so that they would not roll into camera shot.
(14) Reviewed my script. Thought about: How much intro? Dive straight in? Talk about problem solving skills in general or just do this particular problem? Talk about units, orders of magnitude, sanity checks?
(15) Pressed ‘record’ on the remote and got started. A picture of a camera appeared on the monitor to indicate recording was going on. (Note that the files will just have names like LUMN0001.AVI, so you either want to have a visual queue early in the video to identify the video or make a note as you go on a notepad or something — if you are making a bunch of them at a time, anyway.) I made sure I renamed the files to something meaningful when copying the files across to my desktop machine. Also, note that the files are AVI files, which are a non-compressed video format and therefore they’ll be much bigger than a final, produced mpg/mp4 type file — and may fill up the USB faster than you expect.
Some comments on recording:
- Don’t be afraid to pause while filming. They can be cut out in Camtasia. I made sure I just paused then continued, if necessary repeating myself a little, rather than continually stopping and retaking the video.
- I made some minor crossings out, and think that’s OK. Students don’t mind ‘warts and all’, but it should not interfere with clarity.
- I found that the microphone is pretty sensitive, so I can afford to talk normally or even more quietly. It is easy to cause distortion in the sound. As noted above, low microphone levels can be set using the menu accessed by the remote control or by the menu key on the unit, and you may well find it useful to set this low – about 1/4 seems good. Do this before starting to record might be good idea.
(16) Hit the record button to turn it off. Done! I kept the A4 sheet with the working out so I could scan and upload it along with the video.
(17) Turned off, clean up after myself, not forgetting the USB stick.
(18) Fired up Camtasia (or similar).
(19) This is NOT a Camtasia tutorial. I did this, though: Opened a new project, imported the video, normalised the audio and did noise reduction (I use default values), then edited out my pauses and idiotic remarks and produced to 480p video without SmartPlayer (‘MP4 only (up to 480p)’). Other useful things include speeding up sections (places with lots of algebra I just shut up and wrote, then later sped up by factor of four) and using callouts to highlight things. I tried to keep that to a minimum.
In more detail:
(a) Opened Camtasia
(b) File -> ‘Save project as’ … gave it a name.
(c) File -> Import Media -> selected the AVI file. I created a ‘Videos’ folder somewhere, created the camproj file in there and put the AVI files in some subfolder.
(d) Right clicked on the video thumbnail and ‘Add to timeline at playhead’
(e) Audio tab, then checked ‘Enable volume levelling’ and ‘Enable noise removal’
(f) Started cutting bits off the video, leaving the good/least worst bits.
(g) Produce it: File -> Produce and Share -> Whatever format (MP4 only (up to 480p)) -> and done! Files are not that big (15MB) in this format.
That’s the procedure, such as it is.